- Joined
- Jun 7, 2013
- Messages
- 10,142
Negative, yes, but polite and respectful.
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Dogmeat cantilever clamp kit
- Thread starter ericc
- Start date
- Joined
- Oct 16, 2014
- Messages
- 316
This^^^
Even Kant-Twist has it's limits. I've kinked more than one in my day.
Personally, I would LOVE a set like this. Put the machining where it belongs: on the pivots and clamping faces. Everything else looks like it came from a coal mine? Cool.
You might be the next trendsetter in machineshop fashion!
Hi wrat. Not really a trendsetter. That was how machining was done over a hundred years ago. Items were forged close to form and a minimum amount of material was removed with slow cutting carbon steel tools.
The part that disappointed me the most was not that the legs of the clamp were different. It was that the boss lacked mass at the inside of the bend. That's why the second piece is fatter, since I tried to overcompensate by using more stock. Unfortunately, failing to take it down resulted in too much filing to fit. The boss should be the main feature, then the legs should be drawn out to meet dimension, since as soon as the boss becomes undersized, it is not possible to upset material back into it without creating cold shuts. Another problem was that I didn't have a template to work from. I was working from memory at a coal forge after the tong making session, and before take down. Anyway, from my understanding of cantilever beams, my plates should be strong enough. As baronj pointed out, there is only one critical dimension in the whole clamp; the relation between the three pivoting holes in the short and long legs. As long as you get those correct, and the plates are parallel, the clamp should work.
- Joined
- Oct 16, 2014
- Messages
- 316
Okay, so let me go back with something more blunt.
NO clamp is "strong enough". Never has a clamp been made that someone hasn't overtorqued or overloaded to the point of irreparable distortion.
You're obviously going for the aesthetics or you'd be using a different material. Building tooling from scrap is time honored. Building tooling from junk scrap is not.
I'm totally loving the aesthetic. I may pursue a similar pair. So you're that much of a trendsetter. You sold me.
Now sure, i might not use them to hold die shoes tight, but hey, the proper tool for the proper job, eh? These were certainly never intended to replace a (single) $50 Kant Twist in performance - at least I hope not. I just think once you get them drilled and the swivel faces made, they'll be an excellent addition to your tool rack and you, being a craftsman, instinctively understand their limits.
And (again were they mine) being hammered out, you could concoct ancient tales of derring-do surrounding these clamps that old Zeke the pioneer carried across the prairie - or somesuch shop talk for its entertainment value.
If it ain't fun, it ain't worth it.
Strong enough means that it is difficult to spring the frame with the specified 2.75" handle of 1/4" round. I plan to actuate the clamp only with the handle, not with wrench flats or a breaker bar. I don't think that I can apply the full 1500 lbs with that short handle. Heck, maybe I'll throw caution to the winds and use a 3" handle. The clamp is short of material on the inside of the critical 90" bend, which is where the maximum stress in a cantilever beam should be, but the material is thicker than the spec'ed .125" there as well. I'll do a trial fit-up, clamp something, and see.
The trial fit-up went well. I left out three of the pins that keep the frame from bowing and replaced one with a temporary 1/4-20 bolt. I was able to tighten to spec without any cracks or excessive deformation. This thing grips tightly! It should be pretty solid with the requisite three pins in place.
Attachments
It is just the difference between the raw kit and the semi-finished fit-up test. The round pivots turned out to have a nice finish after turning in the lathe. They were made from medium carbon, as forged. The plates could have been finished in the horizontal mill, but it would not add to their functionality. Also, it eats cutters.