Here is the 3d model of a little swing brake I built. I will post some pictures of the actual unit tomorrow.
It is meant to be bolted to a table, and weighs 20-30 pounds, made from 1 1/2" angle iron, 1/4" plate, and some scraps of tubing. Each finger is 1" wide (made by cutting up a 1/2" x 1" bar and grinding to length by hand) and is held in by a 5/16" bolt. I will weld some of these in groups, just for convenience of alignment. This brake is capable of bending 2' of 16 gauge with a respectable radius. Also, no parts interfere with the metal, so you can push it all of the way through.
This picture shows construction and operation a bit better. The red section is a pipe welded offset to a rod to form a cam (in the actual build I ended up welding a nut in square tubing as the cam). When the cam rotates, it pushes the yellow assembly, which pushes the green tooling holder, forcing the blue fingers against the metal. A lever allows the operator to swing up the purple section to bend the metal.
If you want to change the fingers, release the red cam, and flip up the yellow assembly. This will allow you to flip up the green assembly, and access the teeth with ease.
In the actual build, I ended up welding nuts to all parts, so that I can just bolt them into the frame, so all moving parts can be removed. It took two days in the school shop, at about three hours a day. It can be made with only a welder, an angle grinder, and a drill (I had access to a CNC plasma cutter, which is why the ends are that shape, but rectangular should be just fine. I drilled the holes in a drill press because plasma cutters don't make nice holes and I didn't want a sloppy machine)
Last edited by Strostkovy; 07-04-2016 at 12:09 AM. Reason: I adverbed when I should've adjectived.
I really like this, Strostkovy, - Nice simple well thought out design. Here in the U.K. we would call this a 'Box & Pan' folder, which allows various clamping segments to be removed to permit folding of pans, etc., with side flanges. Can I ask what height side flanges can be accommodated with your design as it stands at the moment?
The first part of the brake is to make two of something like this, out of 3/16" or 1/4" plate:
The curves on top don't matter at all, only the hole positions and the little kick in the front. I recommend drilling the holes, even if you have access to a CNC cutter as I did.
I would like to upload a dxf file with these so people can cut/trace the contour, but I don't know how; any help would be appreciated. I could probably rename it to a .png and tell people to save it as a .dxf, but somehow I don't think that would be appreciated by forum staff.
Anyhow, once those are made, cut 3 pieces of 1 1/2" x 1 1/2" x 3/16" angle iron to 26". (This project takes about 15' total, so I'd recommend buying a full 20' stick)
Weld them like so:
Be sure to make the frame very square. Time spent here will save time in later steps.
Later I will post a picture with what you should have in front of you so far, along with the next steps.
EDIT: Here is a render of what you should end up with, I'll still have an actual picture later.
Last edited by Strostkovy; 07-10-2016 at 05:17 PM.
Thanks for that, looking forward to seeing more more steps and drawings. What diameter are the holes to drill?
As for uploading, I think you will need to use a 3rd party hosting service, maybe something such as https://www.dropbox.com/ ?
Maybe a forum moderator has a better idea.
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