Well I have slowly been making progress with the metal brake. It was time to start focusing on the fingers of the brake, the portion that would clamp the metal and provide a clean edge for the bend. I had chosen to use 2 x 2 x 3/8” angle iron. The idea is this. I wanted to make a box pan style brake therefore I need to allow for different lengths of fingers. I chose to divide the 48” bending envelope into 6” sections. This would allow me to make box pan bends in 6” increments up to a total length of 48”. By building a sequence of figures for the brake I would be able to configure the setup to allow for the 6” increments. By dividing my 48” finger section into two 6” sections, one 12” section, and one 24” section I would be able to mix and match fingers to accommodate a 6, 12, 18, 24, 30, 36, 42, and 48” bend. Got that? Yeah, I know, for the mechanical minded it’s hard to read it and not see it. At this point in time none of this is relevant, let’s move onto the actual fabrication.

 I started with a 4 foot length of angle 2 x 2 angle iron. The factory edge on the iron is too rounded to allow for a clean edge. I decided to continue my milling practice by giving the angle a nice sharp edge. Since I still lack proper tooling I was left with having to engineer something. Since the machining of the angle iron is not very precise I was able to weld a jig together. I needed to be able to stand the angle iron up on end in order to machine the edge of 1 side at a 45 degree angle. I opted to us a scrap piece of angle iron welded to 3 riser blocks made from 2 x 2 x .100” square tubing. I then added a clamping mechanism to each riser block to allow me to hold the angle iron solid while milling. It’s probably easier to just look at the jig picture rather then decipher what I am trying to explain. I added a few C-clamps as added rigidity. Using a ½” 4 flute end mill I was able to shave the edge of the angle iron down to a nice sharp point. I ended up cutting my 48” length in half in order to allow me to complete the machining; I was restricted by my working envelope of the mill. I decided not to cut my figures down to their engineered spec. at this point in time. All they need is a slice on the band saw therefore I will leave the fingers in two 24” sections until I have a need for the shorter configuration.

 Once the fingers were machined I needed to trim off the opposite side of the angle iron in order for it to sit flush with the 3” channel it would eventually get bolted to. A straight edge placed along the channel and a slice with the plasma is all it took to get the angle iron dimensions to specifications. The edge needed to be flush in order to allow clearance for the circular saw; this will become clearer as time goes on.

 It was time to secure the fingers to the 3” channel. This was going to involve bolts. I created a template so that I could drill bolt spacing in such a configuration that it was separated into 6” sections. This way it would allow me to bolt 6” sections, in sequence, along the length of 3” channel. I welded and drilled a jig to ensure that my spacing would be drilled consistently. I clamped the fingers to the channel and drilled them all as one unit. I drilled all the holes to ½” in order to accommodate 1/2” threaded rod.

 Once the holes were all drilled I cut 16 sections of ½” threaded rod and cleaned them up on the lathe. Each section then got TIG welded to the 3” channel. Ok…time to confess to screw ups. TIGing the ½” threaded rod sections in warped out my 3” channel. This is both good news and bad. The bad news is that my 3” channel is no longer straight. I had mentally engineered a spring loaded riser mechanism to allow me to raise the 3” channel up while positioning the metal to be bent. I will spare you the details, it will no longer work. The good news is that the 3” channel warped in such a way that it will clamp the metal to be bent in a more secure manner. The 3” channel warped in a concave manner as apposed to a convex manner, get it?

 It was time to perform a bit more R&D to ensure that my amateur engineering was still on track. I made a few test bends using a scrap piece of 19 gauge galvanized metal I had laying around. The metal clamps down good in the brake. I only used a pair of Vise grips as my leverage; I didn’t have handles fabricated to the bender yet. The 19 gauge bent smooth and even however the bend radius was not great. It worked however it was sub-par in my opinion. There is a bit of flex in the 56” length of angle iron that is doing the actual bending. I am not too concerned about this; I think that a simple truss addition to the angle iron will help diminish the flex. As far as the inadequate bend radius goes I am going to blame it on the brake and finger design however I do not consider this an issue. In fact I consider this a welcome problem. I designed this brake to bend 10 gauge “scribed” metal and not bend the lighter stuff. If I ever have a need to bend lighter gauge steel I have a much better idea of how to build a better brake for that specific purpose, I will spare you the details for now.

 The only other progress I made on the brake was adding some 1” angle iron guides for the 3” channel to slide in. The guides were welded in position to allow for the proper offset between the finger clamps and the angle iron performing the bending.

 The next stage will involve fabricating the attachment for the circular saw. The attachment will act as a guide that will slide on top of the 3” channel to help guide the metal saw blade and ensure an accurate “scribe” cut.

 

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Comments
  1. Chris Muncy says:

    Nice Gord.

    Keep ’em coming! I do want to see the sheet metal brake. Maybe even a press brake in the future????

    • gordsgarage says:

      Hey Chris, building the 10 gauge bender has given me lots to think about if, and when, I build a sheet metal brake. I think I would plan on dedicating some major machining time towards the fingers and clamping system. As far as a press brake goes? Hmmm…..

      Gord

  2. Chris Muncy says:

    In for updates (d’oh!)

  3. Chris Muncy says:

    I’ll get pics of the 30 ton press I built last summer. Needs a coat of paint and that’s probably it. Getting a brake to work with that to bend the thick stuff for brackets would be great.

    • gordsgarage says:

      I’d be interested in seeing your press fabrication. I had an oppurtunity to get my hands on a 17 1/2 ton for next to nothing, the pump would have required a rebuild. I didn’t pursue it because I wasn’t sure I wanted to commit shop floor space to it. I’m still up in the air on it. Your 30 ton should be able to handle some decent bends.

  4. syafi says:

    one thing, how you compensate the thickness of each different sheet since the top angle need to be moved a bit further back for a thicker material and a bit front for thinner sheet,

    • gordsgarage says:

      Hi syafi, I will try and answer the question, I am not sure I understand it 100%. If you are asking how I account for different thicknesses of metal when it comes time to bend them and how they are positioned under the bending fingers dependng on thinkness then…the answer is; the distance between the clamping fingers and the angle iron that performs the bendng is fixed. The clearance was predetermined by using a sheet of 10 gauge as my reference. I had contemplated making the bending fingers adjust, forward and backward, for different thicknesses, it would be easy to do, however the brake is not nearly precise enough to be concerned with the small tolerances. I find that the biggest determining factor for the bend is the saw kerf cut. The 10 gauge will not want to bend anywhere else other then where it was scribed. I haven’t tried really thin stuff on the brake yet but I suspect it won’t be an issue. Hope that answers the question.

      Gord

  5. Dave says:

    nice bending brake, if I would build one 60″ wide, do you think it would bend a piece of 14 gauge at 60″ without having to scribe the bend?

    • gordsgarage says:

      Hi Dave, I do not think the unit will work for a 60″ bend of 14 guage, in fact, I know it won’t work. You would be asking too much from it. Metal brakes that are available to the home hobbyists max out at 16 guage bends, anything heavier then that and the equippment costs go way up.

      Thanks!
      Gord

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