# Homebuilt metal forming tools

Discussion in 'Workshop Tips and Secrets / Tools' started by Othman, May 26, 2006.

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1. May 26, 2006

### Othman

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Hello everyone,

I was wondering if anyone has any good "home brew" solutions for bending sheet metal without buying an expensive brake... especially for dealing with long pieces for wings and fuselages.

I would like to come up with some inexpensive design that can be built with simple materials, and later dismantled when no longer needed. I thought I would ask the experts first since many of you have done this before.

Also what about cutting? What do you find to be the best way to make long STRAIGHT cuts (straight being the key word there)?

Thanks!

2. May 26, 2006

### Craig

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Metal forming

Ah, Ashraf, you have opened an interesting topic!

I am lucky enough to have a friend with a 4' shear AND a 4' very heavy (1,000#) brake. For smaller pieces, I generally cut them with a cutoff wheel in a die grinder, or snips if the gauge is light enough.

For bending small pieces, I use a block of wood, to which I have bolted a piece of 1/4" aluminum, radiused to about 1/8". Works pretty good most of the time. Slide the piece to be bent between the two, and force it over with another piece of wood whilst holding it all in my vise. Not the best method.

Been thinking of one of the lightweight brakes from Harbor Freight.

But - I am starting an AcroSport, which has some nice long steel pieces that have to be bent, like 6-7'.

I have been thinking about our local aluminum shop, which does have the big shears and brakes. So I will be very interested in the responses we receive.

3. May 29, 2006

### Othman

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Thanks Craig,

I was thinking about a brake similar to what you mentioned, more along the lines of a leaf brake made from wood with metal face plates to ensure strong edges. Different bend radii could be built-up by bending several light gauge sheets (standard practice). I'm just curious as to how this system would perform for long bends. i guess that all depends on how good of a clamp you can get out of it, and how stiff the brake and leaf are. Would be nice if it could handle up to 0.063 aluminum.

You mentioned cutting with a die grinder... how much work is required to finish the edge when you're done?

4. May 29, 2006

### wally

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for cutting sheet metal, I have pretty good luck with offset blade hand shears. They are harder to find than the regular aircraft shears but worth looking for. Aircraft Spruce P/N 12-00366 or 12-00367 to see what I am talking about.

If the sheet metal (aluminum) is .032 or less, and you have a nice narrow straight line drawn with a Sharpie marker, it is possible to cut very straight and with care keep both pieces flat too. What works for me is watching the pointy end of the shears and not back where it is cutting to help stay on the line. A large flat file is all you need to clean up the cut edge. I prefer cutting large pieces on the living room carpet since it doesn't scratch the metal, is easy on my knees and always cooler/warmer than the garage. My wife, on the other hand, isn't too keen on the idea.

For a bending brake, you might have to ask at your local air cond. and furnace instl. shop if they would loan or let you use theirs.
Wally

5. May 30, 2006

### Craig

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Cleaning edges

Ashraf, cleaning up the edges is really quick - I use a coarse file (files are my favorite tools!), and a few quick swipes are usually all it takes. Be sure to smooth over the edges of ANY cut metal, no matter how it is cut - it will slice your fingers to ribbons.

If I have straight cuts to make in aluminum, I use the table saw - works a charm! Almost any wood tool can be used on aluminum. The "planer" blade, or a plywood blade, makes a smooth cut. When I had one, the bandsaw also worked well. Wish I still had it.

Do wear your safety glasses when cutting metal!

6. May 31, 2006

### Othman

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Thanks for the tips guys.

Wally, I was just thinking that your wife wouldn't be too pleased with you...

Craig, I would be a little bit scared to cut thin sheets with my table saw because they're so flimsy it would be hard to keep it flat over the blade (my table is only about 3ft X 1.5ft). I would have to put a whole lot of supports around, could get tricky. Maybe it's not as bad as I'm imagining it to be.

I visited a local EAA chapter here, and found that they have a shop with lots of equipment to use. That will come in handy when the time comes, but it would be nice to not have to rely on that being available. For the aircraft I'm designing, I would like homebuilt to mean that the airframe can be built at home... my home

Thanks again guys

7. May 31, 2006

### Craig

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Thin stock

Ashraf, for cutting thin aluminum stock, like less than .040, I use a pneumatic nibbler. Works absolutely great. I forgot that I had it in my tool box, and had used it so many times when cutting the forward skins for the Duce.
Glad that I remembered I had it - gonna try it on some .025 4130, and see how it goes.
When I cut the bigger sheets on the table saw, first I clamp a long piece to the fence - keeps the metal from creeping under the edge of the fence. Sometimes I use a scrap of lexan for this, sometimes a piece of aluminum.
Next, I move the table saw a bit - I made a 24' x 84" workbench exactly the same height as the top of the saw table. I only have the blade about 1/2" above the surface of the material being cut.
If the piece is a bit unweildy, I use a friend - put them on the "pull" side - they won't stay a friend long if you subject them to the cloud of aluminum chips! Always use a push stick. Use safety glasses or a full-face shield.

For a lot of the small, intricate parts, sharp curves, etc., I use a jeweler's saw in a 5" frame. It cuts right to the line - with some of the thinner blades, you can actually split the line a fine-tip Sharpie makes! And it will turn in it's own kerf. On the tougher metals (SS), a bit of beeswax will help a lot, as will using a fresh blade. Cuts through 6061 rather quickly.

If you are cutting parts for your airplane that will get bent, remember the bend allowances!

8. May 31, 2006

### Othman

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very good, very good!

I did some more research on the homebuilt long brake... and it seems like it's not very feasible, at least from a quality point of view. It may be ok to make something small for bending brackets and shorter members, and long stuff may actually have to go out to a metal shop.

9. Jun 8, 2006

### Midniteoyl

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Angle-iron.

Though your not likely to find it longer than 6' at the local yard.

10. Jul 20, 2006

### tscheevel

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11. Jul 20, 2006

### N2T18S

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I have a four foot brake made of oak that was in one of the Thorp T18 newsletters. I can take a pic if there is any interest. Basically a 2x6 with bolts to clamp the material. Top board has an angle for spring back so you can bend past the 90 degrees. piano hing mounts the bending board.

Bob

12. Jul 20, 2006

### Craig

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Been slaving away on the wings of the Acro Sport.

The pneumatic nibbler does well with .032 4130, but .050 is too much for it. Bought a well-used 3' squaring shear that can handle slightly more than .063 steel, .090 aluminum. Also got a 3' brake (Harbor Freight) which is quite adjustable.

Only problems I have bending now are the little pieces with two 90 deg. bends 1/2" apart! They are a pain.

The blades from Roto-Zip seem to be the best for the die grinder. They whiz right thru even .750 od x .250 id steel tube. Seem to last a good long time, especially cutting the thin stuff. Pay attention to the cut angle - they seem to cut best when the steel is at the 3:30 position, looking from the handle end of the die cutter.

And I've run out of blades for the jeweler's saw - got to get more!

Holes - start small and fast, move up to big and slow. I usually make a pilit with a 1/8", about as fast as the drill press will run. But as I move up, I slow the press down so that when cutting 1/2" holes in steel, it is running as slow as it can go. Use moderate pressure, and a good cutting oil. Use good bits. I use standard or piloted a/c bits for metal, brad point bits for wood.

And keep posting all your good ideas here. I am looking forward to seeing Thorp T18 Bob's oaken brake!

13. Jul 21, 2006

### PTAirco

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Bending Leading edge skin

As an alternative to using some kind of brake/rollers/2"x8"'s /whatever, to produce the initial bend in the leading edge wing skins,
has anyone tried this method?

http://www.mybearhawk.com/wings/skin1.html

Looks very neat and effective.

14. Jul 21, 2006

### Craig

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That sucks . .

And seems to work wonderfully! Amazing what a little pressure will do.

I was planning to mount two 2 x 6's vertically, two inches apart, and force the aluminum sheet down with a piece of 2" pipe. I do know that I can get the correct LE radius that way - the bend usually comes out about 120-130 deg.

15. Aug 28, 2006

### CNCRouterman

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Wood tools in aluminum.

Regarding the comment that most any wood tool will work in aluminum.

This is kinda-sorta true. Basically the key is to use a sharp tools, good work holding techniques, and careful feeds. I machine aluminum with my router often, however, my router weighs in at about 16000 pounds. Just last Friday we cut two 0.190 5052 h34 compass rose like logos about 5 foot in diameter for an exhibition company. We used tooling designed for routing aluminum, cutting with (for aluminum) a moderately high feed rate, heavy chipload and yeilded a very nice edge finish. As both 60" diameter parts had to matchup back to back (mirror images) we ran rough and finish pass to maximize accuracy. Having machined my share of aluminum I want to caution folks out there about some of the issues on this subject.

1) Wood working tools, ie router bits, saw blades etc, are designed with similar cutting geometries as those used for cutting some aluminum alloys. Note the qualifier "similar". For routing or sawing purposes, you will be safer buying tools designed for aluminum. Using the right tools will generate fewer aluminum Popsicle sticks as well. (an aluminum Popsicle stick is when the tool gullets load up with chips and the tool begins melting its way through rather than cutting, it either breaks the tool or you get a big blob of aluminum welded on the tool, yes I learned this the hard way...). I have found that chopsaw blades with a negative rake work fairly well in aluminum, however wood geometry router bits are a bit of a crap shoot. Some wood geo tools work fairly well in profiling or chamfering operations, but for parting cuts, I only use very specific tools designed for routing aluminum. When I first started routing aluminum, I figure that lube and a little trial an error would give me the right combination of rpms and federates with standard carbide spiral tooling. WRONGO BUDDY, several hundreds of dollars (and a lot of aluminum Popcicle or broken tools) later and a lot of research, I found that using the right tool is simply the only economical way.
2) For routing and sawing anything, be aware that the heat generated in the cut is carried away (you hope) with the chip, big chips are generally better than little chips. The faster a tool moves through (ie: spins-rpms) the work, the hotter it gets. The sharper the tool, the cooler it runs. Proper cutting fluids, or mico lubes are your friend for machining many materials, including aluminum. Point summary, big chips, sharp tools, rigid work holding and a micro lube are optimal. SFM will be dictated by tool selection and material.
3) For sawing aluminum, zero rake or 5 deg negative rake triple chip grind or 10 degree alternate top work pretty well. The number of teeth is dependent on how thick the material you want to cut. The object is to engage some number “z” teeth in the work at any given moment. The value of “z” is recommended by the saw blade manufacturer for a given application, in a given type of machine, so table saws may be different than chop saws for this purpose. Check with the blade manufacturer. I believe that both Amana and Freud both offer saw blade for these purposes. The zero or negative rake saw geometry reduces the tendency climb or self-feed when used on chopsaws or radial arm saws. Table saws using these blades will have a tendency to float the material up and over the saw blade, so be sure to use holddowns/ featherboards.
**********
Be very cautious about the kickback risk, as a kickback with wood is dangerous enough, but now you are talking about sheet metal, read that as a potential horizontal guillotine.
**********
4) Routing aluminum. For chamfering or profiling, brazed carbide wood geometry tools do work pretty well, just keep the feed force light, and where possible, use lube suited for aluminum. For full parting cuts, wood geo tools are not a good choice, they will load up and become popcicle sticks at the most inconvienent times, usually about 12 to 16 inches into the cut. Votex, Onsrud, and Southeast Tool all make tools suitable for machining aluminum. I resell tools for Southeast Tool, but frankly, the best tools I have found for machining aluminum are from Onsrud.
5) Aluminum shavings are sharp, invasive, annoying, and sometimes devious. You will
find out what I mean about devious when you put your shoes on again tomorrow…

In my experience, harder alloys of aluminum are easier to get good results in than softer alloys. Soft alloys like 3000 series tend to stick to the tools and raise burrs more easily than harder alloys such as 5052 or 6061. If you can find a router job shop with a robust machine, you may find that having your parts CNC routed is actually not so bad cost wise, and certainly nice from the standpoint of throughput, accuracy, and repeatability. Ok, so I am plugging for my industry. Any way you choose to get the job done, I wish you well, and be safe!

I apologize for the poor structure of this reply, but I am actually supposed to be programming a job, so I rushed a bit.

16. Aug 29, 2006

### Craig

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Appreciate it

Eric -

Thanks for all the information. Right now the metal cutting I am doing is minimal with power tools - a piece here, a piece there.

The only time I made "popsicle sticks" was when I tried to make a tree stand for a fellow with road signs - the stuff was just so soft it clogged the tools. Generally have no trouble with the 6061 and 2024 that I cut on the saw.

And you are absolutely right about the chips in your shoes.

The die grinder still cuts pretty danged good, as does the pneumatic nibbler.

The Harbor Freight 3' brake works pretty good. Radius of the bend is generally done by set-back of the nose piece - it is very adjustable. It will go back far enough that I may be able to slip in a piece of .250 stock to use for those very narrow U-bends.

Almost done with my wings - a bit over one to go.

17. Aug 29, 2006

### CNCRouterman

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Once you go industrial, you'll never go back

Something I have found when shopping for tools/equipment is that the offerings one finds through sources like Home Depot, Menards, Lowes, Sears, etc range in quality and suitability from "you have got to be kidding" to just serviceable for consumer use (ie; NOT industrial use, no matter what the advertisement says).

Now, I admit I am spoiled, my idea of a light duty table saw is my cabinet makers Delta UniSaw with extended table, table router adapter and multi speed powerfeed, and if I need to move anything heavier than about 100#, I get on my forklift. All that being said, I highly recommend any serious builder of anything to consider used industrial tools, presses, brakes, lathes, mills, welders, material handling equipment etc.

The pro side of the balance sheet for going used industrial includes:
Cost: A used industrial radial arm saw may run from $400 to$1500, which is not that different than a semi-decent new one from Sears. Wood lathes are similarly priced, metal lathes have a wider price range, but are also much more varied in capacity and capabilities. Used mills for about $1200 and up, and boy, once you get used to drilling with a mill, you will just snort and laugh yourself silly if someone suggests drilling anything with their trusty$129, 20 pound, 1/2" drill chuck Menard's special.

Rigidity. Industrial equipment is typically designed to perform its designed task for a minimum of 40 hours a week for many years, and often designed for 24/7 operation with minimal time-outs for periodic maintenance. For example, I used to run a radial arm saw for my employer, originally we had a “top of the line” Sears Craftsman, about a 1988 or ’89 model (this was in 1990-91). That saw was prone to climbing the cut if the operator was not careful, it was loose, not very accurate, and frequently in need of repair or “tweaking”. Around ’92 we acquired an old Wilson 7.5hp three phase saw with 14” blade. It was a saw to make Tim Taylor grunt prodigiously in admiration. Neither Oak nor Maple at 4” thick would keep that saw from it’s appointed rounds, and it was older than me at the time. In all the time I worked with it, never did it miss-behave and eat anything it was not supposed to eat, never prone to self feed (a chronic problem with light consumer or contractor styles radial arm saws), and never lacked for power, even with 1.5” wide dado blades in hard maple. It may have looked intimidating, and it lacked some of he “proper” safety devices now mandated, yet it was, and is still far safer than anything Sears, or anybody else I know of, sells to the general public. It is not safer because of guarding; it is safer because it is predictable, stable, and rigidly built. Now, keep in mind that it is quite capable of cutting flesh and bone as easy as pine, therefore, like so many other aspects of life, DON’T BE STUPID, and DO USE CAUTION and COMMON SENSE in operating ANY power tool or equipment. Industrial equipment will get the job done better, faster, safer and more accurately, provided that the operator uses the absolutely most important general safety tool available… the BRAIN.

Old industrial tools, such as mills, drills, and lathes are not so hard to find, and even when they are old enough to vote are so superior to the low grade consumer stuff being marketed these days as to defy sensible comparison.

Reselling your industrial equipment when you no longer need it. Say you buy a 20-year-old J-head Mill for $2400, use it to drill, mill, flycut, whatever you need for you project. Note: I highly recommend a decent 6” or 8” milling vise, and if you can afford it, at least a 2 axis DRO, preferably 3 axis, an X-axis power feed. A power drawbar is like an automatic transmission on a car, you don’t need it but is sure is nice in town. At the end of your construction, presuming you haven’t truly “bonded” with your … equipment… you can bring it back to the used equipment consignment shop and resell it, taking maybe a 15 percent hit for consignment commissions. While you had it, you could do everything that you could do with a$700 Craftsman 20” drill press and get it done faster, more accurately, and assuming you use standard safe milling practices, safer to boot. You could also mill, which I do not recommend with a drill press, except maybe in plastic, but you would have to get an XY table, plus a better tool chuck that the standard drill chuck. So, $700 drill press, which you get to keep, or sell for 1/2 price, or, the use of a much more capable tool and take a hit on the nose for about$500 if you resell it through a consignment shop, perhaps break even if you sell direct. Tools are expendable for the most part, although accessories for the mill will likely retain their value better than accessories for the drill press. Personally I would tend to keep the mill as a important tool for maintenance purposes, or maybe for that next project?

The Cons to such equipment include:
Many were built back in the days when common sense was actually common, so there may not be a guard or warning sticker telling you not to stick your fingers in the whirling razor sharp cutters, you are expected to know that already. This becomes a bigger factor if you have very young and or overly enthusiastic helpers around. If you go this way, make sure to let any visitor or helper know beyond a shadow of a doubt not to use that equipment until you are sure they know how to do so in a safe and proper manor, actually, this bit applies to any power equipment of any age.
Electrical hookup. Many, perhaps most, industrial equipment is equipped with 3 phase motors. This will require some accommodations on your part, either a 3 phase equipped shop, or a phase converter suitable for the load or replacing/rewinding the motor(s).
Owner’s manuals may or may not come with the equipment so consider the complexity of the equipment, your own ability and mechanical prowess when making a purchase decision.
Transporting your new toy, ehem, I mean serious industrial whatever. The afore mentioned radial arm saw weighed enough that it took 4 husky guys to move (slide/scrap paint) it to the back of the pickup truck so I could offload with the forklift. Do you have enough muscle to position your new (to you) equipment in your shop? (Anybody get the idea I like my forklift almost as much as my router?)
Tooling. Ok, this could go in either column. Industrial equipment often requires industrial tooling. Big saws need big blades, which you will pay a lot more for initially. Mills and lathes use special tools too, although a drill chuck for a mill will make it easily as versatile as any consumer level drill press with the bonus of a serious work table, X & Y travel table, and maybe a tilting spindle for J-head models, lots of rigidity, etc... Of course, with suitable tools and tool holders, you can mill parts too. Yep, a decent J-head vertical mill is way up there on my wish list, with a DRO, and a power feed, power drawbar and…drool getting on keyboard now, must change train of thought.

The upside to “industrial tooling”, as in REAL industrial tooling, not the stuff they SAY is industrial tooling at the hardware store, will generally last many times longer than the consumer targeted tooling. I have a beam saw (well used, but great cut quality) coming some time this week, for which I have already picked up the extra saw blades. Each 16” blade sells for about $150 to$200 dollars, and there are about 6 of them, they are not new, they are probably 5 to 10 years old. The beam saw was used in a cabinet shop for one and two shifts a day until the day the brand new bigger badder faster taller feeds-itself unit was installed. These blades have each cut more particleboard and other cabinet materials in a week than most DYI’ers will cut in a lifetime, seriously, and there are many truckloads of material cutting life left in them.

Floor space. Industrial equipment, besides usually being heavy, usually is larger than a corresponding consumer oriented version. The Wilson Radial arm saw mentioned earlier was close to 6 feet high, 4 feet wide and roughly 4 or 5 feet deep. A real mill, even a smaller 8” x 40” table version is going to use up easily 5 feet in width and as much in depth, height will likely exceed 6 feet 6 inches, I would expect 8 feet plus for planning purposes for a 10” x 50” variable speed J-head mill to permit full access to the motor and allow for forward head tilt. An industrial drill press will be a bit bigger, a lot heavier, and a little taller than a consumer version, although, if a drill press is what you select, a used industrial version will be worth it hands down in my opinion.

In summary, I find that used industrial equipment and tooling is truly worth investigating, and usually a valid economic choice for any serious project. Often times I can find a used industrial tool that is price competitive with a new consumer version, and the industrial option will be far superior in all the important-to-me areas, rigidity, capacity, capability, ruggedness, and if I only need it for a short time, or a specifice project that is not likely to repeat, then the used tool has already been depreciated and re-selling it recoups most or sometimes all the initial purchase price. Returning a saw or drill press to Sears or Home Depot after a serious project, besides being bad form, is possible, but only if done in short order.

This whole diatribe is ignoring the possibility of renting industrial quality tools for the task.

Not being a part of the sheet metal bangers club, either professionally nor in hobby, I have not paid much attention to used sheet metal forming equipment, though I would expect you to find much the same trends as I have found with milling, drilling, and cutting equipment.

18. Aug 29, 2006

### Midniteoyl

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Have to totally agree with all routerman has said....

If you have never worked with 3-phase equipment you really are missing out. There is no comparison between power, rigidity, smoothness of cuts, and longevity. For any motor higher than 1hp, 3-phase is usually cheaper also.

And on that note, I have found the best Phase Converters come from http://kayind.com/. I have worked there myself (a plug, but I no longer work there due to health reasons) designing and building converters for the radio and cell phone industries (they are the largest supplier for both, as well as professional woodworking shops), and can personally attest to the quality and customer service. Many, many units are still going after 25+ years. The price is very competitive with a higher than standard re-sell value, and MUCH lower than going with Utility 3-phase from the power company.

Last edited: Aug 29, 2006
19. Aug 30, 2006

### Jman

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Eric,

Thanks for the insightful comments. Where is a good place to start looking for good quality used tools besides the local classifieds? I went looking at new jointers yesterday at Lowes and came away very disappointed.

20. Aug 30, 2006

### CNCRouterman

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Used tools.

Jake,
There are a number of used tool re-sellers and consignment houses around. Here in the Minneapolis area there are at least 4 that are worth spending the day at. The one I go to the most is called Tried and True Tools in Blaine MN. As for looking, you could start with a google search "used industrial tools" which returned 86,500,000 hits. Obviously refining your search to your locale would be wise. Also, try variations on the theme, try used equipment, commercial, refurbished, etc.

I would hazard the guess that you will find more opportunities in NY than you will have time in this life to fully investigate!

One Internet resource that comes to mind is a place called X-Factory. It seems to me they had a lot more than just CNC Routers for sale, some in house, many still at the seller’s facilities.

Try this out and let us know how well it works for you.
I am about ready to hit the sack, I will check back on this thread later (like… tomorrow) to see if you were successful.

Night all….