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Fred's superjaws / jawhorse clone design thread 
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So I'm in the process of doing a restoration on a very old Record Number 52 1/2 woodworking vice, and I don't have a bench to mount it to once it's mint again. Context:

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Last time I saw the title products I thought "I could do with one of those, often working outside, that'd be good to have" but they're a bit pricey and a bit chincy.

Click: Build a better saw horse and design it around the Record wood working vice!

Features:

Jaw is 230mm wide, so the obvious size to make both the cheeks and the work surface is 250mm, or 10 inches. Having used dad's 8"/200mm saw horses many times, I prefer these bigger wider more stable platforms, anyway.

Compact. Aside from the top surface, and vice, the legs should be stiffly supported by a perhaps steel structure under the top surface, and be foldable or disassemble-able. Keeping them small means steel, not timber, for the legs. But 3 or 4? Decide later.

Given steel legs (maybe 1"/25mm 2mm wall box?) some carefully angled press-fit feet with a larger footprint would be ideal for soft surfaces, such as dirt or even sand.

Cheeks for the vice need to be 90mm from lip to lip, plus optional 10mm from bars to lower lip, plus 10mm of overhang to protect saws from iron and iron from saws. Or 110mm total height.

Bottom of mounting surface needs to be 90mm below the iron lip, and with 10mm above, 100mm thick in total, at least where it's fastened by four bolts. There are two webs that would need relief anyway, so a square or semi circular cut out could replace them to save a bit of weight. Or even just two rectangles of extra thickness and a fully exposed rear underneath.

Length should probably be 750, 1000, or 1250mm, from inner face of vice, to far end. If it's a bit shy of 1200 then a stopper could be used at the non-vice end and a jaw extension at the vice end to firmly hold full sheets of plywood/MDF/etc. Given the 52 1/2 can open 330mm with no cheeks, if the main deck is 1000mm, then I can make the cheeks up to 40mm thick, each before I can no longer fit a 1200 sheet. With 1220 that would be 30mm thick, each. But realistically it'll be around 15-25mm thick in there to maximise opening capacity.

Height, cheap kit saws tools [1] are 590mm high, too low to comfortably work on anything that's not about 150-300mm thick, unless leaning is an advantage, which is rarely true. Online they say 34 inches [2], which is 863.6mm and a comfortable height for me to work at. And in other places, more detail and higher through to 39"/1m [3]. I'd need a companion support the same height, and another 110-112mm less to match the rails of the vice for low-slung clamped work. Referring to my precision table thread [4], 920-970mm or 36 to 38 inches for standing work surfaces. From link 3, the following applies:

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[1] https://www.bunnings.co.nz/hume-pine-14 ... _p08910480
[2] https://www.woodmagazine.com/workbench/ ... nch-height
[3] https://www.theenglishwoodworker.com/workbench-height/
[4] viewtopic.php?f=15&t=2541

Perhaps more thoughts later. But for now, a few pics of the inspiration:

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Tue Feb 26, 2019 12:20 pm
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So.. You are planning to replicate the 'Jawhorse' by means of that old vise? Is that what this is about? What is the endgame of this endeavor?
Also- that Rockwell looks tippy as hell. 3 legs? cheap... I'm trying to imagine what this tool was designed to accomplish. Perhaps building trusses? Kinda gives me ideas (distractions, really :P )
I built a workbench that I use, of 2x6's. It has one surface made of 2 rows of removable 12' 2x4's that rest on a rail beneath them. The purpose was to have modules and jigs that would interchange into the bench. That vice, if it was mine, would fit on a 12x12x1.5" slab that would fit into the bench, anywhere along it's length that I chose. ... if it were me.


Sat Mar 09, 2019 5:19 am
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Yeah, currently the plan is to use a chunk of 240mm by 45mm LVL structural laminated pine for it as it's stiff and straight as a die. 240mm gives 5mm of saw protection each side of the cast iron :-)

You can get those vices regularly for 50-200nzd in used UK built condition. I'm certain I'll end up with 3 or 4 of them at some point. Just so beautifully made.

Stability, yeah, true when full width, but not really true for small heavy items as the weight would be over the two leg end, and the third leg would provide side to side stability. But I agree, easy enough to go 4 legged.

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Mon Mar 11, 2019 8:57 am
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