Leaf Brake

[Dave Lee]

Destaco clamps or their Chinese counterparts are cheap and available in a wide variety of sizes and configurations.


Dave

[milomilo]

Originally Posted by arizonian

Not real sure in actual lbs/in^2 or total lbs, but I'm thinking something along the lines of a Vise-Grip over-center clamp with adjustment built in to vary the sheet thickness. Not too excessive.

Maybe something like this. Pretty simple to make.

[Camaro Zach]

Originally Posted by arizonian

Not real sure in actual lbs/in^2 or total lbs, but I'm thinking something along the lines of a Vise-Grip over-center clamp with adjustment built in to vary the sheet thickness. Not too excessive.

My little brake uses toggle clamps.

[toprecycler]

Originally Posted by milomilo

Maybe something like this. Pretty simple to make.

Added screen shot pic.



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[arizonian]

Dragging this thread back to life...

Decided that the brake needed to be rebuilt/redone completely...

Remember, I am a welder first, machinist second, so a lot of torch cut plates...

First thing was to redo the torch cut edge. There were ugly notches from the flame cut bevel, so a 3/4"x1-1/2" copper bar was slid under the notches and filled with wire weld, then busted almost flat with a grinder. For the milling, I fabbed four (4) standoffs, machined them to the correct angle and height, then D&T.

Had to mill into the backing angle of the clamp and drill thru to set the clamp on the mill.

The mill has a 42" table but only 28" of travel, so the clamp had to be jumped during the milling process for the 31" length.

After the edge was cut, the clamp was flipped over and holes were drilled and counterbored for the camlocks.

More to come.

[arizonian]

OK, the clamp is complete, now on to the hinges.

The welds on the old hinges were ground off, new hinges were torch cut and machined. The leaf needed an extension on both ends, so they were added and the welds machined flush, then D&T for the hinge attachments.

The base of the brake was flipped over and drilled and countersunk to attach the stationary hinges. You can see the flathead screws poking out from under the base.

More to come...

[arizonian]

Cams were cut on the saw, then turned on the lathe. The cams were then moved to the mill and a flat was cut for the handles, then D&T. This allowed for a very precise way to locate the hole for the cam bolt. I'm shooting for almost over-center when the handle hits the stop.

After the cams, handles were turned and threaded on both ends.

A trip to Ace hardware for ball handles was a no-go at $7.99 a ball, so while at Industrial Metal Supply for other stuff, I picked up 1" hot rolled steel balls for a buck each. Once home, the balls were chucked into the lathe, center drilled then D&T.

The linkages pieces were saw cut, then D&T. The thread for the connection is a differential thread since I didn't want to mess with a left hand tap and die set. The lower linkage is 3/8-16 TPI, while the upper linkage is 3/8-24 TPI.

More to come...

[arizonian]

The final assembly went about as expected. I lost a bushing for the hinge and had to make another one. I did add a set of jack bolts at the rear to control the rearward motion of the clamp in order to set the radius of the bend.

I have bent 18ga galvanized (.0516) full length but it was a struggle to get the first 30°, so I'll limit it to 20ga (.0396) unless I really need thicker.

[toprecycler]

I really like the looks of that brake. The attention to detail, handles, things rounded off, and chamfered. Nice project.


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[Ironman]

Nice work Bill. and it handles fairly thick stuff.