Sheet Metal Bender

This metal bender project arose out of the need to often make small enclosures for various radio related projects.  Some time back, I purchased one from Ebay but it was not very good and would flex while bending even thin aluminium.

The angle iron was purchased from Bunnings hardware, it was about $20 for a 2 metre length of 40mm x 40mm x 5mm thick.  The pins for the hinge were also from a length of 10mm black iron rod sourced from Bunnings.  Unfortunately I had to buy a 2 metre length when I only required 60mm or so.

The design is quite simple and like many others that can be found on the internet.  The work clamp, base and folding part are all made from the same 40mm angle iron.  I wanted to make sure it was very rigid, so I decided on a fully welded construction.  This is a bit risky as things tend to move as they cool when welded.  The parts were clamped very tightly as they were welded and fortunately, it came out pretty well.  The same can’t be said for the quality of some of the welds though.  I probably should have practiced a bit more on some scrap to get the welding current correct before starting on the actual project.

The fixed part of the bender (rear angle iron) and pivoted part (front angle iron)

The pivoted section of the bender is at the front of the photo.  This angle iron section is about 5mm shorter in length than the fixed part at the rear.  Two short 30mm lengths of 10mm diameter rod are welded in a notched out section of the pivoted section.  The rods are centered into the bending axis.

The fixed section of angle is 350mm long and the pivoted section 345mm.

The fixed section is also notched out at each end to allow for the hinge rod.

Side supports

Each side support (upside down in the photo) are made from the same angle with a bit of angle added on to obtain a clearance height from the mounting surface.  Rather than buy a different size of angle, I just cut a flat piece out from a bit of angle and welded it on.

Note that the photo is upside down!  The side supports will need to have hole precisely drilled out for the pivot.  To precisely locate the hole, it was drilled as accurately as possible and then the whole side support moved so that it was on the bending axis.  Once located, the side support was tack welded and then finally welded.

The side support welded to the rear fixed angle of the bender

This is shown in the photo to the left.  It wasn’t too hard to keep it all clamped while the side support was welded, and thankfully nothing moved.

The next step was to mount the clamp for the material to be bent.  This is much less critical as the fixing holes are oversized so that the clamp can be adjusted before the clamp is tightened down.  10mm bolts are used to hold down the clamp angle section.

The nuts of the bolts are tack welded to the base so that they wont move when the clamp is tightened.

Handles on the pivoted bending section are simply 200mm 3/8th bolts from Bunnings.  Two nuts for each bolt are welded to the underside of the pivoted bending section.

Completed bender. It needs a rustproof and a paint!

It works pretty well.  I have tried 1.6mm aluminium and there is not noticeable flexing anywhere while it is bending.

One improvement is that the clamp section of angle has a slightly rounded edge.  For a nice tight bend, this should probably ground for a slight chisel edge, although I am not sure how to do this accurately at the moment.

First go at bending, looks fine

Another improvement is to cut some slots into the clamp section so that box sections can be made, the previous bends can be recessed into the slots in the clamp.

All of the angle iron cuts were made with a hacksaw (2 blades in total).  Originally, I set up an angle grinder in a cut off saw table and just as I started the first cut, the angle grinder burned out 😦

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