Front vise racks from top to bottom

[Matt Gaither]

Hello all, I had a question about my Lee Valley front vise's misbehavior. I have the large model (http://www.leevalley.com/US/wood/page.aspx?p=31137&cat=1,41659,41661), and had it previously installed on my doug fir and tamarack bench using 2" thick, 17" long doug fir jaws. I noticed that when clamping the top edge of the front jaw would pull away from the workpiece, leaving it unsupported and prone to rattling when sawing. I attributed the movement to using a relatively soft wood for the jaws so in my recent bench tune up I bought a chunk of hard maple to replace them with.

Long story boring, the same thing is happening with the maple jaws. If you've installed one of these things you can maybe understand the disappointment/rage that followed after completing the almost 30 step process. When viewed from the side, you can see the bottom of the front jaw get sucked out of plumb into the bench when clamping. Any ideas?

Thanks much!

[John Lanciani]

Step #16 from the instruction sheet;

Remove the vise front assembly, then the front jaw from the vise front assembly. Do not remove the carriage or rear jaw from the bench. If required, trim the jaws to length and drill any desired 3/4" dia. bench dog holes. Plane a 2° taper on the clamping face of the front jaw, so that it is thinner at the bottom than at the top, as shown in Figure 10. This will ensure that pieces clamped in the vise will always be gripped at the top of the jaws. This can be achieved by using a hand plane or a belt sander. Or, by temporarily adding a scrap of wood to the opposite side (using glue or double-sided tape), the jaw can be passed through a thickness planer.

[Prashun Patel]

Matt-
I have the exact same vise, and the exact same issue. I also have the LV tail vise screw that I use in a leg vise, and it hold superbly. I conclude that my issues with the front vise are not due to the hardware, but perhaps the way I'm using it. I also notice that I did not have the same issue with the smaller, Rockler vise hardware.

I solve the problem by using spacers (read, cut offs from the piece I'm working. I just lay them on top of the screw, and then clamp my work piece above it. It's a hassle, but it reduces the racking.

I've been meaning to change this out for a leg vise.

[Matt Gaither]

Thanks guys. John, I should have mentioned that I did plane away the bottom half of the front jaw per the instructions. It seems that no matter how much material you remove the racking action overcomes the positive angle you create.

Prashun, good to know. I'll try the spacer resting on the screw, I could see that working.

[Jim Matthews]

It sounds like a trade-off between an easily adjusted coarse thread and the amount of lash in the mechanism.

If you're regularly clamping pieces less than the thickness of your bench, I would suggest fabricating something that
slips into the vise - are you working with lots of stock that isn't held by at least half the vise face (down to the screw)?

[Prashun Patel]

Actually, it's better when the spacer extends BELOW the screw. I try to stick my piece through the screw so it doesn't fall thru while tightening, but still extends below. I wish there were a way to hold them better...

[Matt Gaither]

Jim, I'm normally clamping stock between 3/4" and 2", usually with the bottom of the stock resting on the guide bars. In my jaw setup that's a little more than half of the jaw height and the racking problem is still present.

Prashun, that makes sense. Maybe something that is T-shaped to hang on the guide bars but extend below them as well would work? I think I've just been surprised overall that such beefy hardware and jaws still have so much slop and require shop made jigs and spacers to work properly. It sounds like the smaller Rockler setup was more solid?