+++ #88 Subject: Re: Another hole method for tubes From: Kevin Deutscher (bearhwk27-) Another method for drilling holes in tubing. Purchase a #1 or a #2 center drill from a machine tool supplier, high speed steel will work just fine. Spin that little guy up as fast as you can, use a little oil, just peck on the surface to stabilize the bit. Stop drilling when about half way up the fluted 60 deg angle. This method will even drill holes offcenter on tubing! Finish out with correct final drill at proper speed. If you need to start a drill on a very crowned or angled surface begin with a 4 flute center cutting end mill to spot the surface and then follow the above. A 3/32" end mill should work fine. +++ #89 Subject: Drilling Accurately Through Tubes From: Russ Erb Most, if not all, of us bought a drill press or plan to for several reasons. Primary among these is the ability to drill holes accurately in position and direction. This generally works very well on flat surfaces drilling holes perpindicular to the surface. However, if any side loads are placed on the drill bit, it can be moved over a small amount, enough to screw up the alignment of holes. Even if the bearings around the drill shaft had zero slop, the bit could still bend. Zero slop would also make it extremely difficult to feed the drill bit. One of the places that these side loads will become apparent is when drilling a hole through the center of a tube. This places the bit on the top of a convex surface, which makes it unstable to either side, and even a perfectly lined up bit prior to drilling will move slightly to one side once you start drilling. So what to do? If we could somehow support the end of the bit so it wouldn't move to the side, we wouldn't have this problem. In this case, a center punch mark is insufficient. What we need is a small pilot hole for the bit to feed into. Generally a #40 hole will do just fine. How do I accurately drill the pilot hole? In a strange twist of events, I can more accurately drill the pilot hole using my HANDHELD drill motor. You know, that thing you bought the drill press to replace so you could drill more accurate holes? You only need to do it on the top side. Drilling all of the way through the tube, the far side is concave and thus stable to the drill bit. Give it a try! It works! Drill Press Bufoonery Department: I was drilling through a tube tonight. The drill bit went through the top side with no problems. As for the bottom side, it started acting like the drill bit had suddenly gone dull (I recently had a high-speed steel drill bit go dull--spend the money for some good cobalt drills). After trying several things to fix the problem, I found the real problem. The depth stop was still set from a couple of nights ago and I had hit the depth stop. Ooops! Don't think it can't happen to you! Keep this in mind the next time a drill suddenly doesn't seem to work right anymore. +++ #90 Subject: Re: Another hole method for tubes From: Fox, Dan A method that I have found to work well is to take a 3-corner file and cut a small "X" or cross right where you want the hole, with the 2 arms of the cross being at equal 45 degree angles to the axis of the tube. This will give the flutes of the drill sufficient symmetrical bearing surfaces long enough to cut its own "spot" to follow. This is limited by your ability to cut a nice even cross right where you want it, but it'll get you down the road when you need it. It is (relatively) insensitive to cross arms filed to non-equal depths, but the hole _will_ go where you put the cross, not where you _intended_ to put it, so be careful. Yours is the "right" way and mine is the "quick and dirty" way for sure, but mine has the advantage of not requiring you to purchase any more tools. (Some may not see this as an advantage :-)) ps - obviously, you need to have the piece of tubing immobilized and the hole location exactly on top when you drill. Goes without saying. :-) +++ #91 Subject: Re: Another hole method for tubes From: Tim I've drilled a few blondes....err...I mean holes in aluminium tubing, over the years (4 ultralights). I bought a jig from Leaf (Leading Edge AirFoils) a couple of years ago and it has worked out just fine...It is called 'Centre it' and now can be found in the Aircraft Spruce (ACS) 98/99 catalog on page #454 top right of the page, it's used with a Drill Press. The very bottom of the jig is angled like the drill bit, you lower the chuck to centre the drill, then 'fiddle' rest your piece of tube in the craddle and HAVE AT HER...Boy! +++ #92 Subject: Re: Another hole method for tubes From: Russ Erb Tim--I know of what you speak. I have one of those jigs. It is very nice, but all it does it line up the tube with the drill bit. It doesn't stop the drill bit from walking off of the top of the tube. That's why I didn't mention it--it solves a different problem than what I was addressing. Thanx for mentioning it, for those who may not be familiar with it. +++ #97 Subject: Re: Another hole method for tubes From: CT (bearhawke-) Center drills are essential for accurate holes as Kevin points out. All you really need to start a good hole if using a mill. When drilling with a hand drill or even a drill press it helps to tap the X on your layout with a center punch, the simple ones with a sharp point are easiest to make an accurate mark with. I like a 90 degree point and I sharpen often when working in steel. The spring loaded center punches are lots of fun to use but harder to get exactly where you want them to be and are more erratic when it comes to punch depth. If you miss your mark with the center punch you can always slide the divit over a little by punching a little deeper at an angle in the direction you need the effective center to be. Another center punch trick is to actually slide a drilled hole over after you've started it when you realize its off (need to do this just after you've made a little divit with the tip. Just take the center punch and pound in some points in the bottom of the started hole in the direction you need it to move. The drill point will then find this new "center" when you come in again. You can repeat this a couple of times if you are careful and don't go to deep before the drill diameter starts cutting. If you are trying to drill accurately placed holes without a center punch then you are doing woodworking;^) BTW, one the subject of good holes, one might consider that a reamed hole will have a much higher fatigue life than a drilled hole. Something to consider on higher stress and flight safety related fittings like wing attach brackets and lift strut brackets. +++ #98 Subject: Re: Another hole method for tubes From: Float-by Shooter > BTW, one the subject of good holes, one might consider that a reamed > hole will have a much higher fatigue life than a drilled hole. > Something to consider on higher stress and flight safety related > fittings like wing attach brackets and lift strut brackets. I'll second the recommendation for reamed holes. I bought several chucking reamers from Avery and whenever I drill a hole at a location that isn't welded I drill 1/32 undersize and finish with the reamer in the press liberally doused with marvel mystery oil. I know it should be possible to make quality holes with just a good drill bit, but I haven't had a lot of luck doing it, usually they end up a little ragged. Using a reamer seems to be an easy way to compensate for less than perfect drilling technique. The only drill bits I've used which produce as good a hole as the reamers are my Unibits, and they are limited in the depth they can do because of the step design, so whenever anything has to be match drilled out come the reamers. +++ #101 Subject: Re: Another hole method for tubes From: Bruce A. Frank Any hole in sheet or thin plate that is carrying load or subjected to shock should be reamed to final size (ie; gear mounts, wing and lift-strut attach points and engine mounts). The reamer should be selected to size the hole to allow for a heavy push fit or tap in fit with a soft face hammer (not a press fit). These bolt together parts can be preprimed before assembly because the process of inserting the proper fitting bolt will clean the contact surfaces as it slides home (a regular paint primer, not epoxy-- epoxy can be tough enough that the bolt cannot be driven home). +++ #109 Subject: Cutting Oil and Tapping From: Russ Erb To the trained machinists in the group: Get it out of your system now and say "Well, DUH!" Then read on and respond to correct any of my errors and add your own insights. This is a topic that doesn't get much ink in the popular books, possibly because "they" assume we already know it. The following is a combination of what I've managed to pick up here and there. For the rest of us: Recently I was drilling some fairly deep holes in steel and dulled the high speed steel bit I was using. Therefore, I put an order in to Avery Tools for some cobalt drill bits (highly recommended for aluminum and especially steel). While I was at it, I decided to spend an extra $3.50 and get the 4 oz can of "Rapid Tap" cutting fluid (Avery #7016), since I was tapping these holes and I thought I'd find out if this stuff made a difference. Back in shop class, we had talked about using cutting oil, and I never really understood what difference it made. Occasionally when drilling steel I would use some oil, usually some motor oil that was handy. I never could tell what difference it made other than to make a mess and smoke. Otherwise I'd just drill it dry. I finally got the fancy cutting fluid and the new drill bits. I drilled the holes (15/64" hole 7/8" down in steel) using the new cobalt drill bit and some of the new cutting fluid just for grins. I almost felt like I was drilling wood (except for the smoke) it worked so well! Next I went to tap the holes, and was greatly surprised at how much the cutting fluid cut the friction from turning the tap. Nothing else had ever made such a difference. I'm sold, but I don't really understand why. If anyone has a good explanation for how cutting oil works (preferably other than "it lubricates the cutting surface" (how would that make a difference?) or "it cools the cutting surface") I'd love to hear it. Anyway, here's a summary of how to tap holes, as best I know how. 1. Drill the appropriate size pilot hole (see below) 2. Line the tap up with the hole. 3. Squirt some good cutting oil on the tap. 4. Start screwing the tap into the hole. Be sure to keep it straight for the first few turns. After that it will take care of itself. 5. As the tap gets harder to turn, back it up about a half turn. This breaks the cut shavings off of the wall of the hole. As you get deeper, you may only be able to turn the tap about half a turn before having to back it up. You may want to periodically back the tap all of the way out and clean off the shavings before continuing. 6. If tapping a blind hole, be sensitive to where the bottom is. If the tap suddenly gets very hard to turn, you're probably at the bottom. Continuing to turn will either strip the threads or break the tap (both very bad). The Right Size Hole: Some taps will be stamped with the recommended pilot drill. Tables are also available (see Avery catalog). For lack of any better data, this is a good place to start. Realize that the recommended size may be okay for aluminum, but will probably be too small for steel. In general, you're looking for a drill the size of the minor diameter of the threads. However, cutting full depth threads may be more than your tap can handle, especially in steel. Try the recommended drill size first. As you tap the hole, if it starts to become very difficult to turn the tap by hand, to the point you feel like you're going to twist the tap or break it, STOP! Back the tap out and increase the diameter of the hole slightly, such as an additional 1/64" diameter. This should allow the tap to cut the threads easier. Note: Taps cut threads because the tap is harder than the metal you're threading. Hard metal means it is brittle. If you twist it too hard, the tap will snap off. This is very bad. You won't be able to drill it out because the tap is as hard as the drill bit. I have seen expensive equipment that will essentially use electric arcs to burn the broken tap out. You'll probably be better off just re-making the part. For through holes, you will probably use a normal tap (the Aircraft Spruce catalog calls them "plug" taps). These have a 3 to 5 thread chamfer (relief) at the point. That's how many turns it takes to cut a complete thread. "Taper" taps have a 8 to 10 thread chamfer and are used for easy starting and tough threading jobs. Bottoming taps have a short chamfer (1 to 1-1/2 threads) and are used when threads go to the bottom of a blind hole. To tap a blind hole, first tap as much as possible with a plug tap. Then use a bottoming tap to finish the threads at the bottom of the hole. That's about all I know about taps. I'd like to hear on the list here from anyone who knows any more. +++ #113 Subject: Re: Cutting Oil and Tapping From: Bruce A. Frank >From where does the friction come when drilling or tapping? One would think that there is no way that cutting oil could lubricate all the way to the cutting edge of the bit or tap, but it does. The resistance is the friction between the steel surfaces, the drill and the steel being drilled. At just about the molecular level the layer of oil dramatically reduces the friction even on the cutting edge itself. The proper weight oil penetrates and and clings all the way to the leading edge of the cutting process. I have used motor oil in a pinch also, but it is not the correct viscosity to go where it needs to go and cutting oil has a higher affinity to the steel than motor oil does. Motor oil is designed to move between surfaces down to about .0001". Cutting oil will maintain a film at about one tenth of that. As for the drill bits, cobalt bits are actually on the bottom end of the better quality bits. Titanium Nitride, abreviated TiN in most catalogs, will last much much longer and costs very little more. BUT, if you are using Tap Magic or similar cutting oil even the economy bits will work very well. A problem with 4130 is that it has a tendancy to work harden if the bit is dull. After the spot you are drilling work hardens it is even difficult to drill it with a new sharp bit. Cutting oil will allow a less than optimumly sharp bit to continue to work in 4130. Once the hole is started in 4130 maintain the pressure so the bit cuts all the way through. If you ease off so the bit just spins against the steel for a few revolutions it will work harden just that quickly. Most taps you get in the hardware store and the discount catalogs are two flute, like a drill bit. The stronger tap is a three flute. It is much stronger and has less tendancy to break when hand tapping. A good way to get the tap straight is to use the drill press. After drilling the hole, chuck the tap in the press and start it into the hole by turning the chuck by hand as you apply firm pressure with the drill press handle. Once the tap is started, unclamp the tap from the chuch and attach the tap handle to finish the tapping job. Another way is to chuck tap in the drill press, turn the switch on then off; as the tap coasts to a stop use the drill press handle to press it into the hole. The press stops in a couple of revolutions which cleanly starts the tap in to the hole. If you try this method, use cutting fluid, a three flute tap and be very careful when using a tap smaller than 3/16"--Oh, also make sure the part being tapped is clamped tightly to the drill table. One last point, the most common tap is called a "gun" tap. This doesn't mean it has anything to do with guns, it means that the chips are shot forward of the tap as it goes through the hole-- the chips do not sprial back out of the hole like when using a drill bit. The chips and cuttings build up fast in a blind hole and will jam the tap before full threads are achieved. Therefore the tap must be removed every few turns to clean the hole. Always finish with a "bottoming" tap which cuts the threads all the way to the bottom of the hole. Also cutting oil prevents gauling, sticking together of two metal surfaces in moving friction contact with each other(like when the bit gets dull), of the bit and the steel. Many of the cutting oils or fluids available work fairly well on aluminum but it is best to check the lable. There are cutting fluids made specifically for aluminum. In a pinch either WD-40 or kerosene work OK for aluminum. +++ #1039 Subject: self centering drill bit From: Float-by Shooter I'm looking through my 2000 Grizzly catalog and just noticed a set of drill bits that might be useful. They are for drilling pilot holes for mounting hardware that has already had its mounting holes drilled out to full size, like if you forgot to match drill 2 pieces. Part number G3275, page 162. The bits are only high speed steel but it says they are replaceable. +++ #2829 From: Mike Eldredge Subject: Reaming Hi all, here's a basic builder question: I understand the concept of drilling a hole undersize then reaming it out with a special tool (the reamer) to its exact final size. What I'm wondering is how to make sure the reamed hole is exactly in the right place, especially if the drilled pilot hole is a little off center. How do you know which holes need to be reamed and which are OK just being drilled? I'm also assuming that reaming with a drill bit rather than the special reamer is an exercise in futility. Correct me if I'm wrong, and thanks for helping me learn how to do this stuff right! +++ #2830 From: Float-By Shooter Subject: Re: [Bearhawk] Reaming > I understand the concept of drilling a hole undersize then reaming it > out with a special tool (the reamer) to its exact final size. What I'm > wondering is how to make sure the reamed hole is exactly in the right > place, especially if the drilled pilot hole is a little off center. The quick, useless answer is not to let any of the holes get off center. On parts which have to line up correctly in order to fit, I try to stack them up, and match drill them at once, followed with a reamer of the final size. For example, with the outboard flap arms, I first drilled the large hole at the bottom to final size with my unibit step drill (does as nice a job as a reamer), and then found a socket which fit the hole exactly. I stacked all 4 pieces together, using the socket to make sure they were all lined up with each other perfectly, lined them up in the drill press and then clamped them down. Drilled the holes in the tip end 1/32 undersize simultaneously, and finished them with the correct size reamer. > How do you know which holes need to be reamed and which are OK just > being drilled? I've been reaming everything that is going to take a bolt. > I'm also assuming that reaming with a drill bit rather than the > special reamer is an exercise in futility. Correct me if I'm wrong, > and thanks for helping me learn how to do this stuff right! I bought some chucking reamers from avery tools (1-800-OK-AVERY...Russ has posted it so many times that I eventually memorized it). +++ #2832 From: Donald Schindler Subject: Re: [Bearhawk] Reaming Mike-I dont know if this will help but we generally ream any hole that a bolt goes through that supports a moving part. The point here is that a tight fit for the bolt will keep it stationary in the airframe and the moving part will wear the bolt instead of turning the bolt and wearing the airframe. Its kinda confusing to put into words but just remember that bolts should stay put when something turns around them. +++ #2835 From: mailstuff Subject: Re: [Bearhawk] Reaming I thought I would throw in my 2 cents worth. Lets use the holes in the spar end plates and the holes in the wing mounting brackets on the fuselage for an example. If both holes are extremely undersized (referred to as piloted in the industry), you want to start by aligning the major components and not the holes. Get the wings and fuselage into proper symmetry via saw horses, the wife's car, the kid's bunk beds, whatever you have available. Once the parts are in correct alignment, look through the holes and see how far off of center they are. If they are very close, clamp them together so they wont move, and chase the holes with the smallest size drill that will clean up all the holes to one straight clean hole. If they are off by a lot where the two holes make a figure 8 pattern) determine if the final hole size will remove the figure eight and leave a clean hole. If so, determine which hole you should use as the one closest to the desired center point. Take a drill bushing that has an internal diameter equal to the current hole size, cut the pilot off so it can be clamped directly on the hole, and then very carefully drill through the bushing, hole, and into the bad hole. Now these two holes will have a common center. Use a piloted reamer that has a pilot equal to your hole size and a final size equal to your desired final hole size, and carefully ream the hole. A reamer does not cut in a twisting fashion like a drill bit, so it will tend to follow the pilot very well and not wander. Finally, if the figure 8 was larger than the final diameter needed, or enlarging to remover the figure 8 causes you to loose your edge distance, remake the offending part. Hope this helps! +++ #2842 rom: Benton Holzwarth Subject: Re: [Bearhawk] Reaming > >How do you know which holes need to be reamed and which are OK just > >being drilled? > > Mike-I dont know if this will help but we generally ream any hole that a > bolt goes through that supports a moving part. I always thought reaming implied a certain amount of 'work hardening' of the material around the hole as well, that the metal is both cut and pushed away. I haven't done any reaming (nor bought the tools) but took a term of clock repair -- funny the things one finds in the community college catalog (!) -- and bought a set of 'broaches' for working the holes larger in the little insert-bushings used to repair the bearings on windup clocks. I've always presumed these 'broaches' are just small reamers, no? +++ #2873 From: Bob Romanko Subject: Pneumatic Drill Recommendations? I'm looking for a good quality pneumatic drill for the Bearhawk. I've been using a DeWalt 18V XR2 portable, and between the heft of the tool, squeezing snips for the ribs, and hoeing the 2024 fields, I'm starting to look like I've been exercising (heaven forbid). That will NOT do! Any drill suggestions? As my father always said, "Money's no object when you don't have any." Thanks, folks! +++ #2877 From: Subject: Re: [Bearhawk] Pneumatic Drill Recommendations? Bob, Avery Tools sells a couple of good air drills. The Souix is the best - and the most expensive. I used their Nesco drill and was very happy with it. www.averytools.com They sell good tools at fair prices. Good luck. Mark Goldberg Austin TX +++ #2878 From: Bob Romanko Subject: RE: [Bearhawk]brakes and stuff Try this link: http://www.surplusrecord.com/ It is the MOTHER of all web sites for what's going on in the heavy surplus world. Many, many links are here. The search engine on the site is also very good. I have an 8' D&K 818 that Shelley turned me on to, right from the good 'ol Bearhawk eGroup. Turns out the brake was located only about ten miles from my brother's house in western PA. I hauled it down to the shop about two weeks ago on my trailer. The best $400 I ever spent. Thanks Shelly! It only took about three hours to level and adjust, and now I'm a breakin' fool. Now if only I could find a similar deal on a 2-stage compressor! +++ #2885 From: Russ Erb Subject: [Bearhawk] Pneumatic Drill Recommendations? I have one from Sears that has an acceptable trigger on it. Not as good as the Souix, but it has worked well for me. I also have a cheap one from Harbor Freight that has about three speeds--off, slow (tough to get), and full speed. +++ #2886 From: Subject: Re: [Bearhawk] Pneumatic Drill Recommendations AND Compressors I have the Sioux drill and am very satisfied with it. Remember.... The wife likes you to buy good quality tools to help around the house. Air compressor Got mine from Graingers, 6 HP 15 SCFM @ 125 PSI 60 gal vert tank 2 stage......... for a $400 bill. Cast Iron compressor with piston rings. +++ #2887 From: Bob Romanko Subject: RE: [Bearhawk] Pneumatic Drill Recommendations? Looks as though I'm going with a Sioux. Thanks for all the tips! I have one more question. At PIA we had old, beat up, nasty drills. I can't recall the RPM of any of them. Most of the drills I've found are 2500-2800. I found a website that carries a Sioux Model 1456HP, a 1/4" 6000rpm drill with a teaser trigger, new, for $168. This seems like a pretty good deal to me, but I'm curious as to whether I should go with a less expensive Sioux 3/8" that turns at 2800 rpm. Thoughts? The way I see it, the faster I spin the rounder my holes. Same thing for my drill (grin). +++ #2890 From: Bob Romanko Subject: RE: [Bearhawk] Re: Pneumatic Drill Recommendations? >> of the drills I've found are 2500-2800. I found a website that >> carries a Sioux Model 1456HP, a 1/4" 6000rpm drill with a teaser >> trigger, new, for $168. This seems like a pretty good deal to > >Sounds like a great price! Can you give us the web address? The website is: http://www.robertstool.com/WEB-TRANSFERS/itm1456hp.htm Based on my surfing, they have a great Sioux tool selection at reasonable prices. The guy I talked to there, Chuck, was pretty friendly. I think I'll give them a try. There's the exact same model right now on eBay, but I'm sure by the time the bidding war is over it will be over $100. For the extra money I'd rather go new. +++ #2904 From: Russ Erb Subject: RE: [Bearhawk] Pneumatic Drill Recommendations? > Looks as though I'm going with a Sioux. Thanks for all the > tips! I have one more question. At PIA we had old, beat up, > nasty drills. I can't recall the RPM of any of them. Most > of the drills I've found are 2500-2800. I found a website that > carries a Sioux Model 1456HP, a 1/4" 6000rpm drill with a teaser > trigger, new, for $168. This seems like a pretty good deal to > me, but I'm curious as to whether I should go with a less > expensive Sioux 3/8" that turns at 2800 rpm. Thoughts? The way > I see it, the faster I spin the rounder my holes. Same thing > for my drill (grin). I'm not sure you really want a 6000 rpm drill. It would only be suitable for very small diameter holes. Might not work very well for #21 or #12 holes. Would be way too fast for drilling steel. I think you should all realize why we build airplanes. As stated by a good friend of mine (a Glasair II builder with all of the kits): The reason we build airplanes is so we have reason to buy all of these cool tools! +++ #2909 From: mailstuff Subject: Re: [Bearhawk] Pneumatic Drill Recommendations? DON'T BUY THE 6,000 RPM DRILL!!! Buy something that is around 2800-3000 and has a 1/4 inch chuck capacity. You will be tempted to buy the 3/8 chuck for the difference in price. Any drill bit bigger than 1/4 in should be turning less than 1,000 rpm. It is so rare to bore this big of a hole, so you can use your 3/8 or 1/2 inch electric variable speed drill. I know of 300+ Souix drills currently in service that get used daily and last a long long time. The 6k drill can catch and mess something up, and the trigger wont tease as easily. +++ #2914 From: Bob Romanko Subject: RE: [Bearhawk] Pneumatic Drill Recommendations? Thanks for the good advice, Forrest. Just the answer I was looking for! Having said that, why would someone want a 6000 rpm drill, unless they were drilling teeny holes? My 'ol school teachin' said the faster the drill the rounder the hole, so it made sense to go for one. +++ #2981 From: Tony Chisum Subject: Puneumatic Drill I am new to the bearhawk group. I saw the emails on drill motor recommendations. I work for Boeing Building leading edge slats for the 777. So I drill around 700 holes a day ranging size from #40 to 1/4. I have several different that I use including a 3000rpm Souix. I also have a rockwell 6000rpm drill that I use for all my drilling because of the higher rpm. It makes a better hole in aluminum. So I recommend the 6000rpm drill. I also use piloted drill bits in all sizes over #30. +++ #3055 Subject: Drill Bits From: Tony Chisum A piloted drill bit is just another name for a stepped drill. Black & Decker calls them pilot point. +++ #3167 Subject: Re: [Bearhawk] Lightening Holes From: Donald Schindler >What's a Greenlee punch and where do you get them? Greenlee punch's are what Electricians have used for years to punch out various size holes in electrical box's so they can run conduit etc. They come in various sizes and resemble two hockey pucks that have a machined male and female face. The pucks oppose each other on either side of the metal and there is a hole drilled through each puck that a bolt goes through. When the nut is tightened on the other side it draws the pucks together and a circular hole is cut. The big electrical shops sell them individually or in sets. They work real well but do cost some bucks.....PS I am going to get your novel. I gave up on novels years ago cause Im to impatient and bored to get through them. I think that I might enjoy yours, if I dont then I know there is no hope for me and I am sentenced to a life of just magazines. Soldier on........ +++ #3169 Subject: RE: [Bearhawk] Lightening Holes From: Bob Romanko > OK, now what can you tell me about a Malco hole cutter. I can't > seem to find one in my catalog sources. Plenty of places on the Net that sell them. Aircraft Tool and Supply has them for $49.95, and is reputable. Go to http://www.aircraft-tool.com and look up part number HC1. I've seen them in other spots for about $5 less, but ATC has a good track record. Their website has a pic of one. The cutter is designed for HVAC folks. It has a 3/16 pilot in the center, and an adjustable slide houses a rotary cutter that is powered by your drill. That's about it. Replacement cutters are 8$. Personally, I'm happy just using an 1/8" bit and cleaning up the perforations with my rotary tool and a cutter bit. +++ #3170 Subject: Re: [Bearhawk] Lightening Holes From: Paul Foster Avery Tools has a Malco for about $60. I do not have the catalog at work so unable to pass on the phone number, maybe someone else can help in that regard. +++ #3171 Subject: Re: [Bearhawk] Lightening Holes From: Russ Erb > What's a Greenlee punch and where do you get them? Greenlee punches are listed in the Aircraft Spruce catalog. The largest shown are 2-1/4" (89.50) and 3-1/8" (250.95) (standard instrument sizes). Avery sells a combination punch that does both sizes with the same tool for 110.00. While I'm sure they would work fine if you had access to them, I think they'd be way overpriced for just punching lightening holes. +++ #3173 Subject: Re: [Bearhawk] Lightening Holes From: Float-By Shooter > OK, now what can you tell me about a Malco hole cutter. I can't > seem to find one in my catalog sources. Shelly, take a look at the following picture from my website. It shows the malco hole cutter and a just-cut lightening hole in one of my center ribs: http://www.netpackrat.com/planes/images/holecut.jpg +++ #3176 Subject: Cutting the goofy (lightening) holes From: Benton Holzwarth > For the goofy holes, cut one hole with your fly cutter, the other > one(s) out with a 1/8" bit spaced close together, punch out the > piece along the perforation, and dress with a cutter in a > high-speed rotary tool. Or you can cough up the bucks for a Malco > hole saw to cut twelve holes (grin). Anyone used a 'nibbler' for the odd shaped cutouts? It's a 'V' shaped hand tool, with a pivot at the bottom to operate a small chipper at the end of one of the legs. Inserted from the backside (underside) through about a 3/8" hole, it takes out a chip of metal about 1/4" wide by about 3/32" deep per stroke (hand-pump of the 'V' action.) pro's: - quiet - good control - reasonably cheap ( < $20 ?) - less dressing req'd, compared to 1/8" 'perforations' - low set up time, reasonably fast - chips are easy to clean up - zero distortion of the metal as it works con's: - gives you one of those impressive handshake grips - takes a 1/4" kerf +++ #3177 Subject: RE: [Bearhawk] Cutting the goofy (lightening) holes From: Bob Romanko I would use a nibbler, but I don't have one. I'll be buying one of those, a bunch of rivets, and some zinc chromate this next order coming up. The 1/8" perfs go VERY fast, as does cleaning them out with my rotary tool. The nibbler DOES have those benefits you mentioned, and that's why I'm buying one. You need one in many other places on the project anyhow. I've seen air nibblers VERY cheap on eBay, if anyone's interested. +++ #3230 Subject: Re: [Bearhawk] Lightening Holes From: Steve Harmon I got mine at the local Northern tool & Equipment Co. Try northerntool .com, you do not need the big one, unless you can use it for something else. +++ #3245 Subject: Cutting/Drilling Small Holes in Ribs From: Bob Romanko Here's a tip on cutting small (less than 1 1/2") holes in your ribs: Yes, a wood bit with the edges pointed DOES work great! I cut the 1" holes in the .032" center ribs this morning. At first, I had some problems with the hole shape because my bit was too long. I just clamped it in a vice, fired up the rotary tool with a cut off blade, and whacked it down to about a 2 1/2" shank. I put it back in the press, and made the nicest holes you'd ever seen. Simple, cheap, fast. Wood bits work. I drilled quite a few holes and the bit didn't dull the least. I used the same technique for the 5/8" hole for the "odd rear hole" of the .032 ribs. Just remember to turn these at slow speeds, as you would a fly cutter, and you'll be happy with the results. There's no need to purchase more expensive tools for drilling or cutting holes less than the minimum capacity of your fly cutter when this technique works so well. For what it's worth... +++ #3836 From: Dan Montee Subject: Bolt hole clearance I'm working on wing steel parts. I reamed the 3/16 holes and I find the 3/16 AN bolts are an interference fit. I'm ordering a #12 drill size reamer that should give me a couple of thousandths clearance. Here's my question: are all sizes of AN bolts this exact and will I need to ream all of them oversize? +++ #3837 From: Steve Eldredge Subject: RE: [Bearhawk] Bolt hole clearance If you have close tolerance bolts you will. they have a dimpled head, and usually only a 1/4" or so of threads instead of 3/16" +++ #3851 From: Russ Erb Subject: [Bearhawk] Bolt hole clearance There is a small variation allowed in AN bolt diameters. In general, it's not a problem. I've had a few cases where I drilled a hole with a 3/16" bit, tried to stick an AN3 bolt in the hole without success, ran the same bit through the hole again, and the bolt fit fine. Sometimes it helps to run a 3/16" reamer through it. I wouldn't use a #12 reamer--that might be more clearance than you want. +++ #3861 From: Lee H. Erb Subject: AN Bolt Installation (more than you want to know) An AN3 bolt is larger than a 3/16 bolt. AN3 is a #10 bolt. An AN3 cad plated bolt diameter has a 0.001 tolerance (0.1885 to 0.1895 inch diameter). The recommended hole diameter for most aircraft #10 bolt applications (Class 3 fit) is 0.191 plus 0.006 and minus 0.000. Standard drilled hole sizes (Leading Edge, Dec 1998) for a 3/16 (0.1875) inch twist drill is 0.1865 to 0.1925 inches. Therefore a 3/16 drill can make a hole that the AN3 bolt can not enter. Hence Russ's pass the drill through again is a solution to get the hole up to 0.192. +++ #3863 From: Dan Montee Subject: Re: [Bearhawk] AN Bolt Installation (more than you want to know) Thank you very much. That is exactly what I needed to know. I have a bunch of precision .187 holes I reamed into my wing hardware and I just dreaded hogin' em out without understanding what the problem was. I think the #12 drill size reamer is .189 and a #11 is .191. I try both and sneak up the clearance. +++ #4938 From: Bob Romanko Subject: Building Airplanes: Triangular Holes in Aluminum Okay, FINE, here's a valid "building airplanes" discussion: I have two drills, one is an Ingersoll-Rand air drill with a 1/4" jacobs chuck, and the other is a DeWalt 18V cordless with a 1/2" jacobs chuck. I'm turning both drills turn at a nearly identical rpm (1800). The IR air drill leaves a WICKED triangular-shaped hole, but if I put the same bit (let's say 1/8" for discussion) in the DeWalt cordless, I have an almost perfectly round hole. There's no slop in either drill, I'm not doing anything different between the two when I drill the hole, but this is a consistent thing. I'd like to use my air drill, as it's a lot lighter than the DeWalt. Could this really be me moving the drill and not noticing? I don't think so, as my hand's pretty steady when I drill. The only difference I can think of is that with the DeWalt I'm able to start the hole at a slightly slower speed (variable) than the IR air drill. Both are variable, but the DeWalt starts a touch slower. Any thoughts on what's going on here? My gut feel says to simply use the DeWalt and set the IR to the side, but once this thing starts going together, I can see MANY places where the HUGE 1/2" 18V cordless won't go. The battery alone is probably heavier than an aileron (grin)! +++ #4942 From: Russ Erb Subject: [Bearhawk] Building Airplanes: Triangular Holes in Aluminum > The IR air drill leaves a WICKED triangular-shaped hole, but > if I put the same bit (let's say 1/8" for discussion) in the > DeWalt cordless, I have an almost perfectly round hole. I don't have a real answer, but the triangular thing mostly happens in thin sheets. That's why I use a Unibit for any hole bigger than about 3/16" in thin sheet (aluminum, steel doesn't seem to have as big of a problem). Reamers work well too. +++ #4947 From: supermexgarza@a... Subject: Re: Building Airplanes: Triangular Holes in Aluminum in my dads shop we neeeded some pretty exact holes , and i learned that drill bits with 4 cuting edges cut some extrimely nice holes, we checked then with a micrometer, i have never look for small drill bits (under 1/2) with 4 cuting edges, we were drilling holes on 1 plate in 3/4dia, it maybe worth loking for drill bits with 4 cuting tips "specialy for rivets" +++ #4951 From: Budd Davisson Subject: Re: rivet holes Re: triangular rivet holes Ahah! We finally hit a subject I'm qualified to talk about, having been a fastener specialist in the aerospace industry (Grumman, deHavlland, etc) in the late 60's. The problem of triangular rivet holes has been around forever and one way to totally eliminate them is to use a brad-point sheet metal bit. Also, a slower feed rate (not rpm) at the instant of contact, helps. However, when working with driven, not pulled, rivets, the triangular nature of the holes isn't a serious problem because the rivet "flows" into the corners and shapes itself to the holes. Pulled rivets, however, are limited in their final configuration by the mandrel shape. Rivets like the Cherry Max and Bulb-Loc and Huck MLS mash the end hard enough to do a better job of hole-filling. Of course, at something like a buck a shot, they'd better do a good job. Incidentally, a driven rivet will normally be an interferance fit, meaning, if you cross section the rivet and the hole, pop the rivet out then measure it, most of the time, you'll find the rivet is slightly bigger than the hole it came out of. 3% is the usual rule of thumb difference in the measurements. Let's hear it for driven rivets!!! +++ #4953 From: "Kent White" Subject: Re: [Bearhawk] Building Airplanes: Triangular Holes in Aluminum Apparently there is a stability aspect with heavy slow drilling units, as "chatter" always seems to introduce triangular holes. Light drill motors can chatter, and so also do drill presses, (for instance when shoving a 5/8 twist through heavy plate), tend to "triangle" if any chatter or vibration occurs in either the workpiece or in the headstock. Damping the workpiece to absorb vibration (shotbag), using a heavy drill motor (if possible) and turning at the correct speed all seem to aid in producing "round" holes. ----So also do fancy cutters and drills. +++ #4956 From: "Tim Anderson" Subject: Re: Building Airplanes: Triangular Holes in Aluminum Strange - one would think a drill press would work well. maybe sand bag the drill press. +++ #5018 From: Joel Mayhall Subject: Re: Building Airplanes: Triangular Holes in Aluminum The problem may be an imbalance in the air drill. The drill bit is rotating around the center of mass of the drill rather than the centerline of the drill. The larger weight of the DeWalt would also have a greater dampening effect. +++ #5022 From: Budd Davisson Subject: Re: [Bearhawk] Building Airplanes: Triangular Holes in Aluminum The only guarantee against triangular holes in thin metal with hand held machines that I'm aware of is to use brad point metal bits. However, as I've said before, if the holes are for rivets, not bolts, I wouldn't worry about it as the rivet will fill the hole and do exactly what it was designed to do. +++ #5697 From: "Dan Montee" Subject: Which Sioux? I've reached a point in construction where I need to make a decision on a new air drill. I intend to buy the Sioux. It is available in two RPM's, 2600 and 3600. Any recommendations? Thanks, Dan Montee # 415 +++ #5699 From: Russ and Penny Erb Subject: RE: [Bearhawk] Which Sioux? We had a discussion before on RPM on the Bearhawk CD V2. Look on "Technical Guidance" for "Pneumatic Drill Recommendations". The primary issue there was a 6000 RPM model Russ Erb +++ #5700 From: Bob Romanko Subject: RE: [Bearhawk] Which Sioux? I think I was the originator of that earlier RPM thread. The general agreement is that the 2600 rpm drill was the one to go with. I was looking at a 4000 rpm drill, and most agreed that was too fast and could lead to a higher chance of the dreaded triangular holes. Since almost all my holes are triangular, whether I drill them at 600 rpm or 30,000 rpm, I'm wondering just how much it all matters now. By the way, if you're drilling any quartz or granite quarried in Virginia, I found a 3/8" masonry bit in a 1/2" drill motor at 450 rpm works great. No triangular holes thus far, but a lot of dust. Planter Bob +++ #5707 From: "William & Delinda Johnson" Subject: RE: [Bearhawk] Which Sioux? Dan, I purchased a Sioux at Sun & Fun ($200). Go for the 3600 rpm, higher speeds work best for small holes (rivet holes). If your intention is larger holes, then perhaps the 2600. Bill >>> 20may03 #11298-18250 +++ #11946 From: Del Rawlins Subject: Re: Spar Riveter > A comment on spar riveting: we use guns because it takes such a big > set-up table to ensure perfect alignment of the spar with a fixed > riveter that you stood a bigger chance of messing up than when using > a flexible one. The spar rivets are big enough that it's pretty easy > to align the gun and bar. How do you drill the holes for the capstrips? Do you use a drill press with a big table and move the spar, or do you jig the spar stationary like you do when riveting and use some sort of jig to hold a hand drill square? Or some other method? +++ #11947 From: Budd Davisson Subject: Re: Spar Riveter We have a long (it's actually about 30 feet) table with guides and a drill press mounted in the appropriate place. bd +++ #11948 From: Bob Romanko Subject: RE: Spar Riveter I could be wrong, but I think Bob Barrows drilled all his with a hand drill. Mike or Budd, care to comment? Planter Bob +++ #11951 From: Budd Davisson Subject: Re: Spar Riveter I don't know that he drills them by hand for a fact, but I don't see any reason why not. Incidentally, where I need a seriously square hole in something and can't use a drill press I make up crude little drill blocks. I'll do a rough e-sketch and attach it. This kind of thing has worked miracles a million times and doesn't have to be too sophisticated. In fact, I've made them out of wood, drilled the hole big enough to pound a piece of 4130 tubing through it and glued it in place and used the tubing like a drill bushing. If I was hand drilling spars, this is how i'd do it. I'd also probably put an index pin in the bottom that indexes in the first rivet hole and spaces each hole accordingly. I must have a dozen blocks like this laying around. bd +++ #11953 From: Del Rawlins Subject: Re: Spar Riveter > If I was hand drilling spars, this is how i'd do it. I'd also > probably put an index pin in the bottom that indexes in the first > rivet hole and spaces each hole accordingly. If you wanted to get extra fancy, you could glue a strip of wood to the block that would index the block down from the edge of the capstrips. That and the index pin would ensure holes in the right spot every time. -- Del Rawlins +++ #11954 From: Budd Davisson Subject: Re: Spar Riveter You can apply this concept in a lot of different ways. Like I said, I've got them laying all over the place in all sorts of different shapes, many used to drill just one hole that I wanted square or at a given angle. When I haven't had a block thick enough to drill, I've even welded a couple pieces of steel together and drilled through the seam. I've used square tubing, blocks of maple. Just about anything that would align the bit square to the surface and keep it there long enough to drill the hole. bd +++ #11960 From: "Dan Montee" Subject: Re: Spar Riveter Here is couple of drill blocks similar to what Budd suggested that I used to drill my capstrips and verticals. The third jig that is made from two pieces of 1/8" X 1/2" Alum is what I used to pilot the vertical holes in the web once the cap strips were located. The jig for making the verticals is 1/4" deep. That allows one 1/4" vertical or two 1/8" verticals at a time. I used the drill press for these since it is only about 5" long. The cap strips were had drilled and indexed using the shank end of a drill bit to locate the last hole. As you can tell I consider the bench top expendable and drill into the top. This helped keep everything located as I went. I even cleco the parts to the bench. After one strip was drilled I match drilled the partner and the 6' strips. Just another way to skin the cat. Giving credit were do I think Kevin suggested this to me a couple of years back. Dan Montee #415 +++ #13605 From: bcgh@a... Subject: RE: Suggested tools > You don't need a router for the rib blanks. Use snips. It's just as > fast, cleaner, quieter, and MUCH more relaxing! For the price of a > router you can buy a left/right/straight pair of good snips, a good > fly cutter for your holes AND a dead blow hammer. I agree with him on snipping out the rib blanks. It's everything he said, and a darn sight less messy. I'm still getting the AL chaff out of places I didn't know I had places. Here's my thoughts -- Yes, snips and a fly-cutter to make rib blanks. You will need a drill press if you ever expect to have any of your holes drilled *straight* through the material. (Like getting jig pins in the same place on both sides of the formblock.) I have one of the $100 Taiwan Delta benchtop drill presses. I can't recommend it. Both for quality and size. It has plenty of oomph, but just *barely* enough throat to reach the center of the lightening holes in the largest rib. The minute I have a need that this unit can't handle, I'm out the door to go buy another. Start with a larger one if you're shopping. It doesn't have to be a genuine (domestic) Delta, I've heard Jet is a decent brand. Having said yes, snip out the ribs, I'll go back and say, the router *is* just the "bee's knees" for doing long straight cuts. I wanted to avoid all the sharp slivers (hacked edges) and bending required to get the metal out of the way, so tried the router to cut my flap and aileron spar pieces. These points seemed key: I tried a 1/4" laminate bit, thinking I'd save a little metal in a narrower kerf. Wound up going back for a 3/8", it really does make a difference. (Higher cutter velocity?) Budd and others said to wax or oil along the cut line. It seemed to be working well enough without so I just did it that way. On the last cut I did, I happened to notice a candle on a shelf (the pumpkin had finally decayed enough to reveal it 8*) ), so thought what the heck, and smudged a bit along my line. Result -- there *is* a difference between 'well enough' and 'better'. I'll use wax on all future cuts. Not essential, but it reduced the clean up from a quick swipe with a file and then scotch-brite pad, to just the swipe with the scotch-brite pad. Very tidy cuts. Notice that, because of the rotation of the router cutter, as you work from side to side, it'll try to climb towards or away from you. Since I'm working with the straight edge behind the cutter, I cut from left to right. Helps hold the cutter against the straight edge. For my cutter straight edge, I made another field mod (337 papers not yet completed) to my Chapter 1000 work benches. First I made the benches 8' long (sorry Russ), less waste, and makes a good 8' long surface for rolling out Al upon. (And with two end to end, I don't even need to clear the entire length to lay out a full sheet of Al.) Then, I shopped up an 8' length of extruded Al angle, about 1-1/4" by 1/8". Routed out a nice straight line in the table edge (using the new extrusion, well supported along it's length) to inset the Al, and screwed it down to the bench top/edge. Now to cut, say an 8' long flap spar piece, I just measure in the needed distance, add the 3/8" for cutter kerf, and clamp the metal down to the bench, and rip it out with the router. I will say that it's worth while to plan to make as many cuts at once with the router as you can, since the cleanup is such a nuisance. Benton 9jan03 +++ #13606 From: Del Rawlins Subject: RE: Suggested tools? Before buying my current JET drill press, I actually looked around for an american made unit and didn't find anything. The new Delta tools are mostly made in taiwan or china, probably in the same factory with jet/grizzly/powermatic, et al. Maybe I looked in the wrong places, but if there still is a US made drill press I probably can't afford it anyway (i.e., if you have to ask, it's too much). The usual suggestion is to find a used american made Delta, but at some point you get tired of trying to scrounge up something and just buy a new tool. Almost as bad was trying to find a decent sized press that was not manufactured in red china. I've decided to support those bastards as little as possible, and also based on my poor experience with my old Grizzly chinese press I didn't want to go there again. After a bunch of calling around (the country of origin of most of these machines was not listed on the web anywhere) I finally determined that the JET press I was interested in was at least made in Taiwan. By my fuzzy logic, I figure that they are an ally and supporting them works against the red chinese in some small way. I've set my new press up and run it some, although I haven't actually used it on anything yet (soon!). It is a higher quality unit than the Grizzly (which is to be expected since it cost twice as much) and quieter in operation. The castings are finished to a higher level as well. One bonus that I wasn't aware of until I assembled it, is that it has a built in work light. -- Del Rawlins +++ #13607 From: Budd Davisson Subject: Re: Suggested tools? Regardless of who made the press, grab the chuck and try to move it side ways to see how much play there is in the quill shaft. There should be next to none. I've find slop in high quality presses and tight quills on cheapies. They seem to vary quite a bit. bd +++ #13608 From: "Matt Prather" Subject: Re: Suggested tools? This makes me wonder whether the tension in the thrust bearing might be adjustable to dial in the slop... MAP +++ $Id: 3.1.1-Tools-Drilling,v 1.9 2003/05/22 04:00:35 bentonh Exp $