Linear Bearing for leg vise

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Forum topic by Nicholas Hall posted 12-31-2013 10:59 PM 3751 views 2 times favorited 12 replies Add to Favorites Watch
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Nicholas Hall

350 posts in 1526 days

12-31-2013 10:59 PM

I saw an interesting post about the use of a linear bearing in lieu of the traditional pin board to prevent a leg vise from racking. It looked pretty effective, and it’s cheaper and easier to install than a benchcrafted Criss-Cross. That said, I’ve never seen anyone else post a successful implementation. Are there any lumberjocks out there who have tried it? BTW, I think Richard McGuire sells a ready-made linear bearing kit in the UK, but this isn’t in my budget. I’m talking about a linearing bearing implementation using off the shelf parts. Before any mentions it, I know it generally isn’t very much trouble to adjust the pin in the traditional pin-board; I just like the idea of having automated anti-racking built into my leg-vise.

Here is the link of the linear bearing mechanism:

Thanks in Advance and happy New Year!

-- Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. -Groucho Marx

12 replies so far

View richardwootton's profile


1698 posts in 1375 days

#1 posted 12-31-2013 11:11 PM

I remember seeing some one give it a try on the Work Bench Smack Down thread and if I remember right it didn’t go quite as well as planned, but still worked.

-- Richard, Hot Springs, Ar -- Galoot In Training

View jmartel's profile


6466 posts in 1570 days

#2 posted 01-01-2014 02:03 AM

That would be me, Richard.

Nicholas, I used the shaft and linear bearing idea on my workbench, and I cannot recommend it. While in theory it works, and it works in the above example, I couldn’t get mine to work properly and now have to use spacer blocks. So, all in all, it was a waste of about $75.

I’ve debated getting rid of it and going to the traditional pinned board. I’m sure I can find another use for the combo.

-- The quality of one's woodworking is directly related to the amount of flannel worn.

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Nicholas Hall

350 posts in 1526 days

#3 posted 01-01-2014 01:28 PM

That’s too bad. Have you figured out why it doesn’t work?

-- Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. -Groucho Marx

View shipwright's profile


7084 posts in 2218 days

#4 posted 01-01-2014 04:02 PM

Just thinking out loud but if this is supposed to work, as I assume it is, the way a holdfast works maybe it would do better with something that wasn’t designed to slide. In my mind a linear bearing that is a perfect fit to the shaft would have trouble jamming. The longer it was the worse the problem would be.
I’m not about to argue with Marc as I haven’t tried this but to me it seems that something shorter, looser and rougher than a linear bearing might work better …....... or not. :-)
The idea is certainly intriguing.

-- Paul M ..............If God wanted us to have fiberglass boats he would have given us fibreglass trees.

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Nicholas Hall

350 posts in 1526 days

#5 posted 01-01-2014 09:45 PM

I’ve been thinking about the use of friction in a leg vise, but I can’t find anyone else who has done something like this. There is probably a reason for that :)

I was thinking that it might be interesting to experiment with clutch lining material.

The idea would be that the vise would slide as long as it was wasn’t under torque, but that as soon as torque is applied when the vise is tightened, taking the parallel guide out of parallel, it would sieze up due to the clutch lining. The clutch lining is sold by the foot in a variety of widths. For about $10, I can buy a 1” x 48” x 3/16” precut clutch lining strip to play with.

I would glue some lining to the top & bottom of my parallel guide, and some to the top and bottom of the parallel guide mortise through my bench leg. In theory, the parallel guide would slide easily when not under torque, but would seize due to friction as soon as the guide went out of parallel. In practice, I’m guessing this would just make for a non-sliding, non-working vise that get’s hopelessly seized every time it clamps. I would still love to try it of course to figure out exactly why it doesn’t work :)

-- Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. -Groucho Marx

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Nicholas Hall

350 posts in 1526 days

#6 posted 01-02-2014 07:14 PM

So far I’ve heard one vote saying don’t do and nobody has responded saying it works. Surely there is some lumberjock who got this to work?


-- Outside of a dog, a book is a man's best friend. Inside of a dog, it's too dark to read. -Groucho Marx

View ekohlwey's profile


1 post in 671 days

#7 posted 01-02-2015 12:02 AM

I recently attempted this and experienced the same negative result. Finding no other discussions of this, I thought I would resurrect this thread to share my experiences in order to warn others that may be contemplating this idea. The TL;DR (for me) is to suck it up and go with some of the nice purpose-built, well designed and thought-through hardware that is commercially available for leg vises (via folks like Benchcrafted).

Technical issues aside, the costs of creating this system are quite high. I think I invested a total of around $500, between parts and labor at my local machine shop. I see no evidence that the performance can be any greater than the St. Peter’s Cross systems created by Benchcrafted (for example) but the risks posed by the design challenges are much more significant.

I think that there must be some significant details missing from the build shown on TWW’s site. It seems unlikely even theoretically that such a design could work, due to the very tight tolerances required of the bearing, and the extreme load that would be produced in the linear bearing.

I used a ceramic bearing that allows for approx. 2 degrees of shaft play, and tolerates very high loads compared to ball bearings (I think up to 20,000 lbs), thinking this would be a more robust configuration. The shaft racks severely in the bearing (visibly more than 2 degrees) and as a result is probably also destroying the bearing. It gets stuck against the floor and is a bugger to unbind.

Seeing this result, I am skeptical that a ball bearing with lower tolerances and load rating could possibly work.

As jmartel notes, it clearly has worked for someone, but the details of their build and reproducibility make this a bad bet for most folks.

View Rick M.'s profile (online now)

Rick M.

7698 posts in 1800 days

#8 posted 01-02-2015 08:49 AM

Better alternative

Click for details


View Jsavalla11's profile


1 post in 15 days

#9 posted 10-08-2016 06:02 PM

I think to solve racking problem, you’d have to increase the length of the linear bearing shaft. If a tolerance of play at 1” long bearing is say 1/32’ that’d suck. Increase the same bearing to 4” and the length of the vice shaft inside the linear bearing would probably be 1/128”. The loads are probably not even close to what they can handle. Get the double wide flange mounts. I’m going to try it if I ever start on my roubo.

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Rick M.

7698 posts in 1800 days

#10 posted 10-08-2016 11:35 PM

Yeah I don’t see any reason it wouldn’t work if the bearing service is long enough and attachment to the vise face is rigid.


View unbob's profile


692 posts in 1323 days

#11 posted 10-09-2016 06:29 PM

I will look for a photo of my traditional leg vise I rebuilt from a 100yr old one. I find the racking action important to grab the hard to hold pieces. In this way, adjusting the pin location to effect the jaws to contact more at the top or pinch the work. If the jaws contact even a little at the bottom, the part will slip out. The linear bearing would make for no further adjustments for jaw angle.

Here it is holding a #7 handplane for hand scraping flat, a very slippery item needing just the right amount of top pinch to hold solid, using the lower pin location to achieve the jaw angle.
Some woods that I am working are as slippery as the cast iron plane, and need that angle adjustment.


View crank49's profile


3979 posts in 2391 days

#12 posted 10-09-2016 07:49 PM

Just thinking out loud here, but I built a press a few years ago for a manufacturer of auto components and it used four heavy duty drawer slides to acheive perfect liner motion without racking.

-- Michael: Hillary has a long list of accomplishments, though most DAs would refer to them as felonies.

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