siggy Posted October 16, 2005 Share Posted October 16, 2005 Not my idea but a good Idea FROM HERE SHEET METAL BENDER - By Neville Sweeney Making a simple sheet metal bender While reading and old book on sheet metal work, (How to Work Sheet Metal by H.J. Dyer, first published over 50 years ago), I came across a bench modification for folding sheet metal. The idea is simple, based on a piece of angle iron, let into a bench and a length of flat steel strip bolted to it. I made mine on a much smaller scale that the one recommended, but I only used materials that I had on hand, and it works well for me. Construction details sheet metal bender The first thing to do is work out the size that you want. It may be anything up to the full length of the bench. Mine is only 2/3 as long as the bench or 850mm (33in). Once your angle iron and steel strap are cut to length the angle iron needs to be let or recessed into the bench. I used 25mm x 25mm (1 x 1 in) angle iron about 6mm (1/4 in) thick, so I did not need to remove a lot of wood. A power router would be the quickest, neatest way to remove wood from the bench. I don't have one so I used a mallet and a 25mm (1 in) firmer chisel. I may be basically destructive but I found it good therapy pounding away with the hammer and chisel. Also, my bench is pine and not too heavy going. Once the angle iron site flush with the top and front of the bench it can be secured with wood screws. I drilled 3 holes for each screw; the first was a pilot hole through the angle iron and wood large enough to allow the screw to bite. The second hole I drilled (on the same axis) just passed through the iron is the width of the screw. I then topped it off with a large drill to give enough countersink so the screw heads would sit flush. This is especially important on the front of the bench. I used 25mm x 8 gauge wood screws on the top (5 off) and 50mm x 8 gauge wood screws (6 off) on the front face. The angle iron is now secured and sitting flush with the bench and it is time to drill clearance holes in the steel strap and tapping holes in the angle iron. (For the front piece I used 37mm x 6mm steel strap). The next decision is what size bolts to use. You need to have a few (I used 10) the same size, and a tap the right size to thread the holes with. I used 5/16" Whitworth bolts (18 threads per inch) because I have a stock of them and as luck would have it, also a tap that size. After marking out the steel strap and putting a centre punch mark where the holes were to be drilled, I clamped the strap onto the angle iron in the position it was to occupy when it was finished. I then drilled pilot holes through the strap and the angle iron (3mm diameter) so any subsequent enlargements would line up. Removing the steel strap I drilled the clearance holes in it to allow the bolts to pass through without binding. This happened to 8 mm diameter. A drill press helps here to ensure that the holes are at 90° to the face of the iron, although it is not essential. I then ran into technical difficulties when I cam to drill the angle iron for tapping. According to the chart that I have for such things, the correct drill size for a 5/16" Whitworth tap is size "F" (what the hell?). Not having one (or even being sure where I could GET one!) I had to use the closest I had which was 17/64" diameter (slightly oversize). The finished hole when threaded is a bit loose but OK. So could then finish tapping out all the holes. I do not come from an engineering background and tapping threads into holes in metal is somehow satisfying to accomplish, maybe it's just me! It is quite simple to do but a bit difficult to describe, and competent fitter/machinist/ boilermaker can show you how. All that is required then is to bolt it together and see if it fits. The left hand end bolt was binding a bit, but drilling out the hole in the strap to the next size up fixed the problem. You use the folder by removing enough bolts to allow the metal you wish to bend down to fit between the angle iron and the strap. The remaining bolts are then tightened up and the metal bent over using your hands, a lump of timber used as a former, or judicious application of a "gentle persuader" (hammer). It took me five hours to put together. The only specialized part of this process, being the tapping of the holes, which is easily done when you have the right equipment. I have folded sheet steel up to 1mm thick in this machine with little problem. It is one of those tools that enables you to do work that otherwise would be very difficult or impossible without access to a metalworking shop. Happy folding! Materials and sizes Angle Iron I used: 25mm x 25mm Recommended by the book: 2 ½" x 2 ½" Steel strap I used: 37mm x 6mm Recommended by the book: 2 ½" x ½" Wood Screws I used: 25mm x or 50mm x 8 gauge Recommended by the book: 2 ½" x ¼" Bolts I used: 5/16" Whitworth Recommended by the book: ½' Whitworth. I thought of welding two bolts on to the bench side of the bender and instead of using a flat metal strap use angle iron and nuts to tighten the two pieces together Quote Link to comment Share on other sites More sharing options...
siggy Posted October 16, 2005 Author Share Posted October 16, 2005 Quote Link to comment Share on other sites More sharing options...
simonr Posted October 16, 2005 Share Posted October 16, 2005 Simple but effective! Maybe we should have a series of grown-up tools you can make yourself in the technical archive? Si Quote Link to comment Share on other sites More sharing options...
whistler110 Posted October 17, 2005 Share Posted October 17, 2005 I vote for that. Quote Link to comment Share on other sites More sharing options...
Fatboy Posted October 17, 2005 Share Posted October 17, 2005 Siggy, I made something similar out of box section. A couple of thoughts... Its difficult to stop it buckling if you are bending thick or long pieces of metal so put bolts through every six inches or so.. Then get as many bolts in as you can. Its worth making the angle at the back a bit deeper and brace it back to the rear of the bench (underside) to counter the reaction forces as you bend the metal forwards. I made mine so it could be fixed between a pair of vices - The advantage being I can move it about to provide an open end if I need to bend on an axis when there is already something else in a different direction. If you were doing a fair bit of bending - I'd bolt a couple of strong gate style hinges to the back part of the bench to give you a lever to tease the bending. Then keep it even with a rubber hammer. Quote Link to comment Share on other sites More sharing options...
Mark Posted October 17, 2005 Share Posted October 17, 2005 I thought of welding two bolts on to the bench side of the benderand instead of using a flat metal strap use angle iron and nuts to tighten the two pieces together As I think has already been said, you want the bolts as close to the end of the workpiece as possible, ie if you are bending a 6" bit then the bolts only need to be 6" apart, and if you are bedning a 18" bit, then 18" apart, etc. nicked the picture from the website: As per siggy's diagram though, I would think that using angle rather than strip for the non-bench half would be better, as less likley to bend as you make the bend... a thread for simply made fabrication tools in the tech archive would be a great idea! Cheers Mark Quote Link to comment Share on other sites More sharing options...
PaulMc Posted October 17, 2005 Share Posted October 17, 2005 Here's a couple of links for making your own workshop tools - A Simple Hydraulic Press Clubman Builders Resource - Tools Paul. Quote Link to comment Share on other sites More sharing options...
john cranfield Posted October 17, 2005 Share Posted October 17, 2005 I quite often bend sheet metal by inserting a couple of lengths of 1/4inch angle in the vice. If the length is too far beyond the vice jaws a couple of Clamps are used to hold the angle pieces at the ends. John Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 17, 2005 Share Posted October 17, 2005 I was in MachineMart this morning buying one of those sexy lie-on thingys with wheels that you can scoot under a motor on. They have a couple of sheet metal benders for sale - one is held in a vice/fixed to a work bench, and the other is free-standing. They had the free-standing one on display and I noticed that the gap in the 'jaws' was easily a three mm in the centre, but only about one at either end. Strikingly poor quality for an item that costs £152 squids The bench one looked to me a lot better quality and value. Still just a lot of angle iron for too much money though, and it didn't look at all adjustable to me. Les. Quote Link to comment Share on other sites More sharing options...
Turbocharger Posted October 17, 2005 Share Posted October 17, 2005 They had the free-standing one on display and I noticed that the gap in the 'jaws' was easily a three mm in the centre, but only about one at either end. Strikingly poor quality for an item that costs £152 squids You obviously misunderstood, Les. The gap is to allow for deformation of the tool, which has been carefully designed using the latest finite-elephant techniques and has endured hundreds of hours of fatigue testing and field experience. You ran your finger along one man's life's work and sniffed. Quote Link to comment Share on other sites More sharing options...
Les Henson Posted October 17, 2005 Share Posted October 17, 2005 [cough]bull[cough]sh[cough]it[cough] sniffed. Other end! Les. Quote Link to comment Share on other sites More sharing options...
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