+++ #621 Subject: Re: Cutting Tubing From: budd davisson On cutting tubing and making fittings: The two best tools you can buy (although they are invariably of questionable quality) when building a steel airplane are one of the $200 Taiwanese horizontal/vertical cut-off band saws (64 1/2" blade available everywhere) and one of the either 4 x 36 , or bettery yet, 6 x 48 stationary belt/disk sanders ($150-$190). Both available from Harbor Freight. Check their website. The bandsaw comes with about a six inch square table so you can use it like anormal metal band saw. You'll never use it as a horizontal cut-off saw because it is unnecessary. This is a rough machine but will let you cut tubing and flat stock like butter. On tubing, I just lay an overlength piece in position on top of the longerons, use a marking pen to mark the centerline angles of the longerons and cut those angles on the bandsaw. That gives the approximate centerline angles but about 1/2" too long. Then I grind the right curves in one end, so it fits, then work the other end down on the grinder till it fits. 15 minutes, tops. The belt sander lets you dress straight, clean edges on flat fittings and will sand radii in fittings ends in a heart beat. With those two tools, its like having a machine shop inhouse and you have less than $400 invested. Crude, but effective. +++ #863 Subject: Re: band saws From: csisters- has any body had any experience with a( central machinery)brand band saw. (harbor frieght). looks like a grizzly to me. +++ #864 Subject: Re: band saws From: Mike Meador I have one and it works great. The one I have is made in Taiwan. It will do for you everything that you need for building an airplane. Order the extra blades with it - they are usually twice the price locally (Sears, local hardware stores etc.,). Another tool that I have found indispensable is a bench shear. This little device is great for cutting up to .100 thick 4130. Hope this helps. +++ #866 Subject: Re: band saws From: Russ Erb > has any body had any experience with a( central machinery)brand band > saw. (harbor frieght). looks like a grizzly to me. Got one. Works fine for me. No complaints. +++ #868 Subject: Re: band saws From: Float-By Shooter > has any body had any experience with a( central machinery)brand band saw. > (harbor frieght). looks like a grizzly to me. We've got the Grizzly version of the same saw. It is one of the more useful tools you will ever own. +++ #873 Subject: Re: band saws From: Shelly > has any body had any experience with a( central machinery)brand band saw. > (harbor frieght). looks like a grizzly to me. Are you talking about a portable? One of the most useful tools I have is a portable bandsaw. It's handy, the blades don't slip off, the blades are cheap and easy to change, doesn't take up floor space and there are so many uses for it. I keep mine right beside the vice. Lots of companies make them - even imports. +++ #1438 Subject: metal cutting bandsaw From: J.T.Newbegin I received a Grizzley cat. and was about to order a metal cutting band saw (horz. and vert.) 179.99 + 42.00 shipping, reg. 199.99 Today I got a Harborfrieght cat. and the saw is 149.00 and free shipping. I can't see any difference from the photo or the description. Any one know if there is 72.00 worth of difference? +++ #1439 Subject: Re: metal cutting bandsaw From: budd davisson I used to sell those saws as part of a little side business and all of the castings were interchangeable as it appears they all came out of the same Taiwanese factory. I noticed the later saws have gone to 2 hp and have a better guide system. The originals had a hard time keeping the blade on. If it's the same horsepower,they are all the same saw and they are one of the handiest things in the shop. The 6 x 48 sander is the next handiest. With those two tools you've got a complete Okie machine shop. +++ #1441 Subject: Re: metal cutting bandsaw From: Archie Dunbar Maybe someone already mentioned this. I have one of those band saws and it is collecting a lot of dust. I use a sliding table on my tablesaw, with a metal cutoff wheel. It goes through 4130 plate like butter. I set a stop for repetitive cuts. I cut tube the same way or with a pneumatic die grinder type tool. The band saw will throw its blade in a heartbeat if you don't have a lot tension on it and mine needs blades that are slightly smaller than advertized because there is not enough tension adjustment. Mines a Delta but I think they are all the same. The blades will shed teeth if you don't get a lot of teeth per inch for cutting the thin stuff. The draw backs to the table saw are; the risk of getting hit with pieces of the cutoff wheel if it comes apart, so stay out of the arc ( I havn't had one come apart yet), also it is easy to start a fire, not a serious one but it is hard to get all of the sawdust out of the saw and inevitably some of what is left will start smoldering and the smoke adds to the final problem, smell. There is something about the wheels that creates a strong odor that my wife does not appreciate. just my 2 cents +++ #1443 Subject: Re: metal cutting bandsaw From: mskiba- Got a harbor Freight saw and paid 159.00 on sale, probably the same one you are talking about, works great, cut a 1x5" piece of steel in about 10 min. auto shut off, I did this several times and had no problems. Cut a allen wrench, and alot of 4130. Don't know how I lived without it before. I would check the horsepower rating ect to compare. but the one from Harbor freight is great for home use. I don't think it would last in a constant production shop. +++ #2421 From: Steve Eldredge Subject: Construction begun on 031! Well I cut my first metal on the bearhawk Saturday. I started with some .080 flap accutator arm blanks, since I havn't been able to assemble a steel order list yet. I had some 4130 left over from my Pietenpol, and started hacking. I learned that indeed regular HS steel doesn't last long cutting chromoly. I also discovered that my jig saw isn't the best tool for cutting either. I burned up the jig saw motor. After a trip to the store for some bi-metal blades and a new variable speed jig saw I made significantly more progress. I wish I could have found cobalt blades. The bi metal are better, but still dull quickly. Later in the afternoon Mike and I unboxed his new metal band saw. I think I'll be purchasing one.... 4 flap arm blanks complete +++ #2428 From: Shelly Subject: Re: [Bearhawk] Construction begun on 031! For many years, we have been using a hand held band saw...its the handiest tool I have in my shop. I keep it beside the bench and use it for tubing, flat, wood, aluninum etc, etc. Ours is a Rockwell, cost about $300 or $400, blades are very inexpensive, and last a long time. What you can't hold in the vise, you can clamp to the table. Cut anything, any angle, then finish with grinder and file. +++ #3209 Subject: RE: [Bearhawk] Bearhawk 023 Update From: William & Delinda Johnson > Is it true that you put a guide on the bottom of this tray to fit > into the miter gauge slot? I think I can almost see it in one of > the pictures. If so, how about a picture of the bottom side of > the tray? > > NOTE TO ANYONE USING THIS METHOD: What Bill says is absolutely > true! You need eye protection, and I would suggest a full face > shield. Those sharp aluminum shards travel at high speed and > hurt! I tried this once and gave it up because the way I was > doing it just seemed too hazardous. I still prefer the metal > cutting bandsaw method, although I will admit using a friend's > hydraulic shear to cut some of those pieces. Yes, the bottom of the tray has a guide that fits into the saw miter slot . . . The idea is that for large sheets, the tray enables a steady feed without the sheet twisting on the blade due to resistance. A twist with aluminum makes a really messy kickback . . . +++ #3219 Subject: Re: [Bearhawk] 023 Update From: Kent White Nicely done photos of the table saw work, et al. Note: 1) carbide snaggly circ.saw blades may be used (rather than the fine panel blade Bill used), IF the blade is reversed to "wipe" backwards through the cut. 2)Beeswax (dooreeze) may be wiped on the line prior to cutting to free the teeth, also. 3)A shotbag/sandbag placed on the sheet will absorb a LOT of the screech/howl of the surgery. 4)The use of the carrying tray is also a clever way to avoid "traffic", or scratches on the CLAD from sliding across the iron sawtable, a non-trivial corrosion-protection aspect of the aircraft fabrication process. Another method is to use contact paper (tough to remove) or PVC film (tough to find). Culver or ??? --nosebowl mfg tools: Large sandbag Post dolly and mount for it. Mallets to stretch and to shrink Slapper to smooth Hand dolly and spoon for detail planishing about $360. Heat source for annealing and welding. That is about it. Sure like the elegance of the Culver retracs. +++ #3220 Subject: Re: [Bearhawk] 023 Update From: Bruce A. Frank Where I work, we use 80 tooth cabinetry carbide blade in the table and miter saw(installed normally as used for wood) for cutting aluminum. We do use the wax, but we have never had any problem with this setup. I use the same in my home workshop. What are the problems with the carbide blade? +++ #3539 From: William & Delinda Johnson Subject: Answers to Questions Russ, the blade used to cut aluminum is a 150 tooth blade - non carbide. Metal chips do fly, however, even with that blade. Keep a tight grip on the part. Larry, the prop is a McCauley DES1A200, DFA9043 (90" with 43 pitch). I intend to make my test flight with those settings to get performance and have prop shortened/repitched as necessary. It is a true power prop - Bearhawk should just lift right off! It was used on a duster - not sure which one . . . >>> 2mar02 #7686-9153 +++ #7741 From: Jimmy Mathis Subject: Re: Cutting tube and Hydraulic presses Spend $175-200 and get a milwaukee or bosch or any high quality chop saw. Harbor Freight burns up quick. I still have the cheap one. Might make a good boat anchor. Jimmy 501 +++ #7747 From: Budd Davisson Subject: Re: Re: Cutting tube > I cut most of my tube to .049 and some heavier with a standard > copper tube cutter from a deptment store. I don't like adding > the concentrated heat that a cut off or chop saw applies... Since the end is going to be welded, i doubt if the cut off heat is a factor. A note about cheap metal cutting bandsaws (the kind that pivot). My original one finally died last week when the motor burned out. As near as I can figure it was at least twenty years old and probably closer to thirty. It was only 1/2 horse and one of the first brought into the country. I replaced it with a newer version of the same thing but it's 1 horse. I was amused to find they had managed to make a cheap tool even cheaper. Lots of plastic. A major note about these things: they can be really irritating because it takes nothign to jerk the blade off the wheel no matter how well you have it adjusted. They are particularly sensitive to the type of blade used. The better the blade and the finer the tooth count the less likely they are to jump blades. Use only the 32 tooth wavy blades for thin sheet and tubing or it'll drive you nuts and get high quality blades. A major point about using the bandsaw for cutting tubing versus a chop saw is that you can vary the angle, as needed, and it'll also do all the flat plate work with no sweat. I couldn't function around the shop without mine. If I had the money, I'd buy a better grade saw, like a Delta, but these work, as long as you can live with their inherent problems. bd +++ #7749 From: charles.k.scott@d... Subject: Re: Digest Number 561 > Why not invest $60 in a 14" cut-off saw from Harbor Freight I bought a Harbor Freight cheapo band saw to use for the tubing cutting and cutting of brackets. It was and is REALLY a cheap ass machine. It's got what has to be the flimsiest stand I've ever seen and it flops around and barely stands on it's own. But it does work. I've pushed a lot of material through it over the years and for the non professional shop, it's invaluable. Many's the time I wished it was more precise but rare was the part where increased precision actually made any real difference. Corky Scott +++ #7757 From: Ken Beanlands Subject: RE: Cutting tube and Hydraulic presses One tool that I used with a great deal of success is a hardware storetube cutter. You know, the ones that say for aluminum and copper tubing only? They are quite effective on tubes up to .049" wall thickness. Fortunately, that makes up 90 % of the Christavia's tubing. Of course, it is limited to making 90 degree cuts. Ken Beanlands B.Eng (Aerospace) >>> 20may03 #11298-18250 #11302 From: Budd Davisson Subject: Re: Water Jet Cutting Source Russ is dead on. Per usual. We had the first batch of fittings water jet cut but had to redo a bunch of them because the CAD disk that came from someone in the group was wrong. Then we realized that even in a production environment, a good man with a band saw and a stationary belt sander can knock out fittings easier than we can buy them or use them. At any given time we have a minimum of three fuselages on the floor and we still hand cut our pieces. We don' need no stinkin' water jet when we got Gustavo Cholula, our two-legged Bridgeport. bd PS - I'd also advise anyone who hasn't got one to get a Makita, or equivalent, 4" angle head grinder and a bunch of cutting disks. You'd be amazed how fast and accurately you can cut a blank or, in my case, I cut right to the line with the Makita and follow up with the belt sander. It looks crude as can be when you start, but you go from flat plate to a ready to sand fitting in about three minutes in .080 plate. It will take you twice as long to lay it out as it does to cut it. I'm not kidding, that stuff really moves fast. Just get some good blades for your little band saw. A Die Master costs about five times as much but lasts ten times longer. +++ #11314 From: "Kent White" Subject: RE: Water Jet Cutting Source This volley does my heart good, seeing plain old parts still being done in a "manly" fashion. After having my first dinner out with bd at Osh, I realized that he is actually practical, and would trust that his measure of things would add up to pretty skookum. And if the techie stuff is wasting time and effort, then clear away the machinery and let the fun begin! yeeehaw...common sense wins over setup times again! Kent +++ #11305 From: Del Rawlins Subject: Re: Water Jet Cutting Source > I'd also advise anyone who hasn't got one to get a Makita, or > equivalent, 4" angle head grinder... If you already have your air compressor, a good alternative to the electric angle grinder is an el-cheapo air cut-off tool, AKA muffler cutter. They take 3" cutoff disks, and are a fairly quick means of turning steel into sparks. It makes the same kind of cut as the electric grinder so the belt sander is still required. +++ #11308 From: Budd Davisson Subject: Re: re: angle grinder / cutoff tool > What if one already has the band saw, bench grinder (and compressor > and belt sander)? Does it do anything particularly better than any > combination of the others? the 4" grinder is a do-all metal shaper that is mostly useful on heavy plate and tight inside radii. A good blade on the hacksaw will do most of the work you talk about quickly including cutting tubing/plate close to the line. The little grinder is only fifty bucks and it'll pay for itself the first time you have to remove a tube from the fuselage or cut a couple of tacks. As far as moving tools. The handiest thing I've ever done in that area was to find an old kitchen base cabinet , one of the 1 foot units generally used as spacers in kitchens. Has drawer in top, cabinet door on bottom. Mounted 8" grinder on one end of top and 4" vice on the other. Wheels on the back that don't quite touch the ground, but do when tilted for moving it around. Great for doing fuselages but also great to move next to you when welding to give an elbow rest. bd +++ #11309 From: Del Rawlins Subject: re: angle grinder / cutoff tool > I'd also advise anyone who hasn't got one to get a Makita, or > equivalent, 4" angle head grinder and a bunch of cutting disks. I find that the cut-off tool is ideal for situations where you have already bent your fitting and are cutting/grinding the metal to its final shape. Such a part may be difficult to cut on a bandsaw, particularly if it has more than one bend. +++ #11311 From: Ken Beanlands Subject: Re: Water Jet Cutting Source Along with Budd's reccommendation, I would also suggest one of those 12"-14" abrasive cut-off wheels. I bought a cheap one (< $200 CAD) just before starting the struts on the Christavia and love it. It's great for cutting strap type fittings (ie main wing fittings) and it cuts a nice strait, square cut and has a guide for doing angle cuts. The angle grinder, 8" bench grinder and now the cut-off wheel are definitely the most used tools in my shop. BTW, if you are doing things like wing fittings that will not be welded afterwards, it's probably a good idea to normalize the fitting after cutting it. Ken Beanlands B.Eng (Aerospace) +++ #11312 From: "Montee, Dan L." Subject: 4" grinder(s) I can't imagine fabricating steel parts without my grinder(s). I have two 4" grinders hanging over my welding table ready to go. One has a wire wheel mounted and the other with the grinding wheel. I also have Makita die grinder with cut off wheel hanging along side the 4" grinders. All are plugged in and ready at moments notice to go into service. I keep all the steel fab stuff, grinders, sanders, welding, band saw, files, etc in one corner of the shop. Less space to chase all the steel dust around in. I keep the aluminum tools in the far opposite corner. Now, if there are any OSHA inspectors in the group, please delete this message at this point. None of my grinders have guards attached. The guards really limit the usefulness of the tool. Yes, I have the scarred knuckles to prove it. I gently mount my plastic case B & D 4" grinder in the pipe jaws of the 5" vise on the welding table to fish mouth tube or grind other parts. I find easier to hold the part I'm working than to hold the grinder. Holding the part in your hand also lets you know when you are putting a little to much heat into the steel. I prefer not to put the part in the vise when I'm grinding if I can avoid it. Dan Montee +++ #11314 From: Budd Davisson Subject: Re: Re: Water Jet Cutting Source > To each their own I guess. With over a hundred parts (168 I think > has been mentioned?) in the wing alone, I think it is worthwhile to > consider waterjetting the parts out. When you consider the large > number of parts, lightening holes, locating holes, and so on to be > added to parts, then waterjetting is a viable alternative. As for > the "Manly" part, don't forget you still have to bend and flange the > ribs and holes, and make lightening holes from the locating holes > when you are done bending them. That should keep you happy! :) One last comment on the below then I'm out of it: you're going to spend more time getting a viable CAD file, organizing the buy with enough purchasers to make it worthwihle for a cutter, and coordinating the distribution then it is worth. You could have made a bunch of parts by that time. You're trying to automate pounding a nail. Don't complicate your life so much. Make parts. I know it sounds like utopia to get a big box in the mail, open it, and have all the parts right there ready to use, but it's not that simple. Plus, count on it, some of the parts will be wrong. It's just going to happen. Believe me, if this approach was really worth it, we'd be doing it across the board, but we're not. bd +++ #11317 From: "Kent White" Subject: RE: 4130 fabrication Now that this mass of "true tool confessions" have started, I have to quietly smile and remember back a couple of years ago when my film crew and I flew all the way from CA back to NY to film "4130 Airframe Construction" with a guy who had done 27 fuselages, in a basement, with a picnic table, grinder, table saw/abrasive saw, wire wheel, and torch. ....and he was faster than any one else in his circle of aviation builders. I salute the older American Tradition of "get it done", over the newer "tool up and wait." Yeehaw! Kent +++ #11324 From: "zipppydoggg" Subject: Re: angle grinder / cutoff tool >>> 4" angle head grinder and a bunch of cutting disks. >> What if one already has the band saw, bench grinder (and compressor >> and belt sander)? >> >> Are you using it to cut and 'fishmouth' the fuse tubes as well? Just a note. I've heard that if a grinder wheel, sandpaper, or cut-off is used on the fuselage tube, the residue should be wiped off, and a file used to clean off the area where ground. This procedure is to remove any silicates and carbides that could comtaminate a weld. I did this on my last (and only) fuselage that I built. What do our welding experts think? By the way, I tried holding the grinder in one hand, and a tube (for my spar table) in the other, and have the wound to prove it. My Mikida 4 1/2 grinder (without guard) took out a nice divit from the small knuckle on my pinky. Rob "wont need fuselage steel for a while" Gaddy +++ #11327 From: "Bruce A. Frank" Subject: Re: Re: angle grinder / cutoff tool > Just a note. I've heard that if a grinder wheel, sandpaper, or > cut-off is used on the fuselage tube, the residue should be wiped > off, and a file used to clean off the area where ground. This > procedure is to remove any silicates and carbides that could > comtaminate a weld. I did this on my last (and only) fuselage that > I built. > > What do our welding experts think? I find using the 4 1/2" angle grinder free-hand very useful, but WITH THE GUARD ON. (Also wear leather gloves.) The way to do it is to use the square edge of the wheel guard as a rest. This is the way I grind tubes while standing in the middle of the fuselage tangle where it becomes difficult to crawl out to go to the bench grinder. As for contamination from the grinding process....maybe if I were welding in the bottom of a groove that was filled with grinding grit I'd worry, but the usual reason I wipe the tube is to remove the storage oil on its surface...which I guess in the process removes any grit contamination. I have almost never used a file on tube. Fit up is just not that critical nor does the file create any kind of surface that welds more easily than a ground edge. Sometimes I will go to the trouble to power wire brush, or sand, a piece of tube to remove the mill scale before I weld it. Removing oil with an acetone wet rag is something I do if the tube is heavily wet with oil. BUT, for the most part, I grind it until it fits or cut it with my Joint Jigger (and then still grind it until it fits) hold it in place then tack and weld it. I depend on the heat and filler wire additives to handle any contaminates. To me gaps are no problem, if I can bridge the opening with filler rod it is acceptable. Perfect fit up is just not necessary. To use an old cliche, it ain't rocket science, it's welding. A tight fit, a loose fit, a gap...if I can control the heat to make the fillet it is an acceptable weld. I am not above using my MIG machine, after tacking parts in place with it, to use the gun trigger like a spot welder to fill any large gaps. Oops, now I have mentioned MIG machines. My opinion on MIG and 4130 fuselage assembly?(yes it has been covered before) If you know how to use a MIG setup, have years of experience and understand the metallurgy (temps, crystal structure, temper, annealing, strain relief and normalizing) then have at it. If you are a novice welder then stick to oxy/acet or, if you have some spare change and want another cool tool, TIG. Bruce A. Frank +++ #11328 From: Reinhardt Quelle Subject: Angle grinders... I bought my first angle grinder just recently to clean up a lumber rack I welded up for my truck. 4" DeWalt - seems to fit my smallish hands better than the makita, which I've also used. As I was grinding away in the back yard, I started smelling things heating up a bit... then my 4-year old daughter ran up to ask what that "funny smell" was. I look up and flip up my face sheild, and the faint odor suddenly becomes a not-so-faint and unmistakable scent of burning grass. Well to make a short story long, my neighbor pokes his head out the door a moment later, sees me leaning over the fence hosing down the couple-square-yard burned area in his yard, and thanks me for putting out the fire. "Um.... er... well.... I set it, the least I could do is put it out!" Anyway, this talk of angle grinders and the earlier discussions of various incendary devices made me think you all would enjoy the story. So, the moral is that angle grinders are great, but do watch where you're sending your sparks! RQ +++ #11334 From: "Kent White" Subject: RE: 4130 fabrication > Kent, What do you think of the benchtop table saw with a cutoff > wheel like your NY craftsman used? Simply: awesome, efficient, convenient, schmaht. Kent +++ #11335 From: "Kent White" Subject: RE: Re: angle grinder / cutoff tool > Just a note. I've heard that if a grinder wheel, sandpaper, or > cut-off is used on the fuselage tube, the residue should be wiped > off, and a file used to clean off the area where ground. ....I second what Bruce wrote, and add: If cutting "off the hip" or knee, or thigh or whatever...Grip the tube tightly and the grinder loosely. This way the grinder will find its home in the tube and not in the biped. If I see grit, I wipe. If not, I weld. Gaps??? Heavens....I never get gaps in my work....over 3X metal thickness. What the heck is filler for, anyway? And thick filler rod is specially made for those looser gaps! Quit making micrometer adjustments and whack out tubes. Learn to weld gaps. It is a creative expression. Kent +++ #11337 From: "jrm_nh" Subject: Re: Water Jet Cutting Source Another great tool is the bandsaw from Jet or other sources. You can usually find one for under 200 bucks. http://www.hoosierparts.com/jet_2.htm A lot less sparks. +++ #11369 From: Budd Davisson Subject: Re: Die Grinders/Cutoff Wheels > A question about die grinders and cutoff wheels. Many years ago I > bought a pneumatic die grinder with the cutoff wheel at Harbor > Freight. However, it doesn't seem to have much torque. Putting > just a little pressure on the cutoff wheel quickly slows it down or > brings it to a stop. Is this unusual? Do I just have a bum die > grinder? I've had the same experience with die-grinders and I'm certain most of it is because I'm trying to run them with a too-small air compressor (3 hp). Torque needs lots of air and I don't think they were getting it. I've used some on bigger compressors (5hp and bigger) and they seemed to be better. The nice thing about the little 4" Makita/B & D is they have torque out the wazzoo and, with the right wheels will cut through anything. Down south, I needed to whack a bigger throat out of one of our small breaks (use it for .090 and bigger) to clear the second leg of one of the fittings. I needed a plate a half inch thick moved back about an inch for six inches. The Bob was standing there and thought it would take all afternoon to grind that much steel off. I just took a cut-off wheel and went right through the half inch plate an inch from the edge and was completely finished in 5 minutes. bd +++ #11370 From: Del Rawlins Subject: Re: Die Grinders/Cutoff Wheels > I've had the same experience with die-grinders and I'm certain most > of it is because I'm trying to run them with a too-small air > compressor (3 hp). Torque needs lots of air and I don't think they > were getting it. I've used some on bigger compressors (5hp and > bigger) and they seemed to be better. The air cut off tool is the only air tool (other than the tire changing machine) that I have ever used which required that I stop and wait periodically for the compressor to catch up. I'm not sure what its rating is, but that is the same large compressor we use to run the tire shop and which was able to more than keep up with my pressure sandblaster. If I had to use it with a small compressor I would try at the very least to add more tank capacity to the system. Since you don't typically have to run it for very long continuously, that might allow enough grinding time before you have to let the system recharge. +++ #11371 From: "bearhawk484" Subject: Re: Die Grinders/Cutoff Wheels -The use of air tool oil in the fitting before use on a daily basis will freeup the motor vanes ,allowing them to seal properly,greatly increasing the tools performance.Just a FEW DROPS.Works for me. Mike Mellor +++ #11372 From: "Kent White" Subject: RE: Die Grinders/Cutoff Wheels Speed and pressure make the wheel cut. Lack of speed wears wheel away (debris in arms) Drills are slow. Grinders are fast. Worn or wimpy grinders have no torque. Nice grinders spin 35,000rpm and have torque, too. Kent +++ #15809 From: Dan Shilling Subject: Re: Steel Tubing > The easiest method to cut it is with a $199 Taiwan power hacksaw. I have found the easiest way is to put a $5 abrasive blade in my 10" miter saw. Very fast and easy. Wear safety goggles!!! Dan Shilling +++ #15814 From: Ken Beanlands Subject: Re: Steel Tubing I've had great success with a 12" cuttoff wheel. Ken Beanlands B.Eng (Aerospace) +++ #15815 From: Budd Davisson Subject: Re: Steel Tubing This is going to test my powers of explaination! The goal in designing tubing structures is to have each piece of tubing act as a column in compression and a tension member when the forces to the other way. The ideal structure is designed so the primary loads result in compression most of the time. This would be counter intuitive until the welds themselve are taking into account. You never design to put the weld in tension. In fact, you try to design in such a way that the weld isn't really needed because the member is held in place by the compression. The rule in column design is to have a consistent cross section end to end unless you design the change to match the loads, probably fat in the middle with a gradual tapering towards the end, which may be optimal structurally but impractical to build. So, we just use round columns joint to joint. If you squeeze the ends flat and weld them to the other member the column would be stiff on one axis (the axis along the flattening) and weak in the other direction because the material has been moved from the outer circumference to the middle and offers no compressive resistance because it isn't stabilized side to side. It is also a rather abrupt change in cross section. This would cause the tube to want to fail in compression in the flattened area. It would also reduce the amount of weld length (pi x d) by approximately three times to the diameter only. Having said all of this, I'm not certain I've answered the question. Or have it? bd +++ #16860 From: "Kent White" Subject: RE: Steel Tubing Ways to cut the 4130 tube: Tubing cutter: does only 90 deg, but is fast, clean and dust free, and these cutters can be fairly stout devices, doing up to 2" tube. Table saw with abrasive blade: stabile, does miters really well, can do freehand work nicely. Any circular saw with abrasive blade: wish the cordless Dewalt 14.4v came with abrasive blade...neat and handy piece of gear Sawzall: hang on to the tube!!! Sabresaw: nice and delicate, hang on to the tube lightly. variable speeds and dojigger adjustments on the spendy ones make fiddling fun. Bandsaw: not fun for long pieces Shear: why? Torch: ick plasma: uhhh...well....ok I just had to add these. Been gone for a while, doing a Grumman Duck in Witchita and the H1 repairs in OR. Kent +++ #16861 From: Ken Beanlands Subject: RE: Steel Tubing I've found that the 14" "cut-off saw" works really well for tube, plate, etc. It's kinda like a large compound miter saw but with no compount or mitering ;-). I've even been cutting smaller fittings with it and it works great. Just got to watch the fingers near the big wheel. It's great fo making parts up to about 2' x 2'. Of all the tools I've had for cutting metal, this is definitely the best! (OK, well I don't have a plasma cutter ;-) Ken Beanlands B.Eng (Aerospace) +++ #16909 From: "Kent White" Subject: RE: Steel Tubing Same goes for a radial-arm saw or a small carpenters chop saw. Put the right abrasive blade in and they will also do brick, tile and stone. At least until the tender innards ingest enough abrasive material... Kent +++ #16911 From: "Bruce A. Frank" Subject: Re: Re: Steel Tubing > I would like to find the correct abrasive blade for cutting 4130 > steel with my mitre saw. I am not sure a miter saw will stand up to the abuse of using an abrasive blade (as Kent said). The bearings and pivots are not well protected from the grit. An inexpensive chop saw would save the expense of replacing the probably more expensive miter saw. As for the blades, you are looking for a metal cutting abrasive blade and it will be marked as such in stores such as Home Depot, Lowes, tool and hardware stores. Be sure to select a abrasive metal cutting blade no larger in diameter than the saw blade in your miter saw. You are going to get very heavy duty sparks that will ignite any saw dust piled up around your shop. Bruce A. Frank +++ #16913 From: "Kent White" Subject: RE: Re: Steel Tubing I have an Ace Hardware "Metal Abrasive Wheel" #ace 27516. These I have used in a B&D "sawbuck" miter saw for years. I spray the mechanical joints with "bugspray" (wd40) often. This washes the abrasive grit off and lessens the wear. I have a spark shield behind the saw, made of aluminum sheet. On decent days I let the saw spray outside, sometimes igniting the weeds. This spray of molten slag is more ferocious on solid steel, like bar and such, than on tubing. The slag will ruin glass on contact, so watch out for windows in buildings and cars, up to 15 feet away. I also have a 14" 220V sph slagsaw that will hurl slag 20 ft. Nice sight on a dark snowy night. (Another good looker is using plasma on titanium or if courageous, mag.) Use a respirator for dust, eyewear, headphones, and gloves. The blades wear down, so any sliding overhead saw needs the work repositioned to compensate for the abrasive diameter decreasing. Incidentally, Makita now makes a metal cutting chopsaw which is not abrasive but uses a toothed blade. Not cheap, about $275, it is not as slow as a true cold saw, but works nicely on bar and tube. Kent +++ #16914 From: "TheStones" Subject: Re: Re: Steel Tubing Harbor Freight has a 2 hp 14 inch cutoff saw #44829 in their catalog for $99.99. In their store's it's currently $49.99. This is would make a chore specific option. TimS. +++ #16915 From: Sam Butler Subject: Re: Re: Steel Tubing > Harbor Freight has a 2 hp 14 inch cutoff saw #44829 I bought one of those a few weeks ago, and it works fairly well, it doesn't cut real square, so I'm going to shim one side of it. But as soon as I fix that should work great, of course they're not the greatest quality but fine for a home shop. The blades are also real cheap at harborfreight, the 14" are just a few bucks. Sam Butler +++ #16921 From: Ken Beanlands Subject: RE: Steel Tubing > At least until the tender innards ingest enough abrasive material... That's the beauty of these metal cut-off saws, they're designed for cutting metal and masonary and don't even support a wood blade. With none of the delicate compound mitering mechanisms to get into, these guys are quite effective. Ken Beanlands B.Eng (Aerospace) +++ $Id: 3.1.3-Tools-Bandsaw,v 1.10 2003/05/22 04:02:23 bentonh Exp $