Sliding leg vise with X cross

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Man with many vises
Corporate Member
I am curious if there is a benefit in using the (3) plates as you have for the criss cross portion as opposed to using only (2) ?

My thinking is still evolving on inexpensive X-cross designs.

image.jpeg


In this case, notice that the single arm has two bearings and the double has one. This symmetrical configuration minimizes any twisting forces which would tend to reduce the linkage’s stiffness.
 
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Gripbd

BD
User
In various forums, people who have tried to build DIY x-crosses found that the vise would slightly release pressure after it was clamped down. It looks like you’ve solved the problem with the triple arm x-cross, and I’m going to copy it. My question is, did you engineer the shape of the arms, or is it just something that you liked? In other words, do you think that matching your dimensions is critical? I’m also thanking you for the idea of using a self aligning bearing in place of the garter.
 

NOTW

Notw
Senior User
I was all on board to mimic the 3 leg design with bearings but not being able to source the sex bolts to hold the bearing on at a reasonable price
1595602051673.png
so now i am leaning towards mimicing the crisscross 14 on the bencrafted site.
 

Cuprousworks

Mike
User
Do you think a small bock of delrin or hdpe would work? If they were allowed to pivot slightly wouldn't it provide a low friction, especially against the inset metal plate?
 

pop-pop

Man with many vises
Corporate Member
Do you think a small bock of delrin or hdpe would work? If they were allowed to pivot slightly wouldn't it provide a low friction, especially against the inset metal plate?

Both of those materials are “creepy” and will flow under load and your vise will lose its grip. HDPE is creepier than Delrin.
 

pop-pop

Man with many vises
Corporate Member
I was all on board to mimic the 3 leg design with bearings but not being able to source the sex bolts to hold the bearing on at a reasonable price View attachment 195281 so now i am leaning towards mimicing the crisscross 14 on the bencrafted site.
I don’t use sex bolts since they never seem to come in the right length. Instead, I use a short length of brass rod and use a tap to cut internal threads and a pair of flathead screws. Then you can make whatever length you need exactly. If you have a lathe with two chucks,it’s very easy to do accurately.
image.jpg

Note: use this setup BY HAND to get the tap started, then use a tap wrench.
 
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pop-pop

Man with many vises
Corporate Member
In various forums, people who have tried to build DIY x-crosses found that the vise would slightly release pressure after it was clamped down. It looks like you’ve solved the problem with the triple arm x-cross, and I’m going to copy it. My question is, did you engineer the shape of the arms, or is it just something that you liked? In other words, do you think that matching your dimensions is critical? I’m also thanking you for the idea of using a self aligning bearing in place of the garter.

A8F90DBB-3DF0-4AB3-8508-3372D24311E4.jpeg


The cutaway at 1 provides clearance when the vise is opened fully. The cutaway at 2 provides clearance for the other arm’s bearing.

The mortise depth is your pivot hole offset plus bearing radius plus the wear plate thickness. This dimension is fairly critical. Note that the drawing does not include the pivot hole offset.

The tool is a General flycutter with a shaped cutter and a brass rod instead of the drill bit. I drill a 15/64” hole and plunge until it bottoms. Then clear the center waste with a Forster bit. Here is a cutaway:
0DC9B079-0E3F-42A5-BA2D-0F84B6712B66.jpeg
 
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pop-pop

Man with many vises
Corporate Member
When buying a self-aligning bearing, be sure to get one from the SB series which have two set screws in the inner race extension.

The SA series use an eccentric locking collar which is a major PITA.
1BD5BA95-C917-4177-8DDB-752BD60F9EC9.jpeg
 

Gotcha6

Dennis
Staff member
Corporate Member
I was all on board to mimic the 3 leg design with bearings but not being able to source the sex bolts to hold the bearing on at a reasonable price View attachment 195281 so now i am leaning towards mimicing the crisscross 14 on the bencrafted site.
Most commercial door closers come with a set of 4 sex bolts to attach the closer to a 1 hour rated door as it is usually a gypsum core and wood screws won't hold for long. They are usually 3/8" O.D. with a 1/4-20 internal thread and 1-3/4" long. The shoulder end could be cut off to whatever length you needed and 1/4-20 countersunk screws used to hold it. I've saved a beaucoup of these over the years.
If you want to go smaller, find someone who installs toilet partitions.
 

Gripbd

BD
User
View attachment 195284

The cutaway at 1 provides clearance when the vise is opened fully. The cutaway at 2 provides clearance for the other arm’s bearing.

The mortise depth is your pivot hole offset plus bearing radius plus the wear plate thickness. This dimension is fairly critical. Note that the drawing does not include the pivot hole offset.

The tool is a General flycutter with a shaped cutter and a brass rod instead of the drill bit. I drill a 15/64” hole and plunge until it bottoms. Then clear the center waste with a Forster bit. Here is a cutaway:
View attachment 195285
View attachment 195284

The cutaway at 1 provides clearance when the vise is opened fully. The cutaway at 2 provides clearance for the other arm’s bearing.

The mortise depth is your pivot hole offset plus bearing radius plus the wear plate thickness. This dimension is fairly critical. Note that the drawing does not include the pivot hole offset.

The tool is a General flycutter with a shaped cutter and a brass rod instead of the drill bit. I drill a 15/64” hole and plunge until it bottoms. Then clear the center waste with a Forster bit. Here is a cutaway:
View attachment 195285
I see now what you did. Thanks.
 

pop-pop

Man with many vises
Corporate Member
I see now what you did. Thanks.

Here is a better cartoon showing how to figure your minimum mortise depth.

Start with your linkage closed fully. Half the distance between your pivot pin centers is the pin offset. Note that the each bearing center needs to be directly below the other arm’s pin center. The mortise depth is the sum of the pin offset, bearing radius, and bearing strip thickness.
3297D9E0-1D7C-45E9-BB8B-2A9C659A41B8.jpeg
 

pop-pop

Man with many vises
Corporate Member
Retrofitted a longer Acme screw into my sliding leg vise today and now have 9” of throat capacity. Almost immediately I needed that extra throat to finish re-sawing a board just a bit too wide for both my bandsaw and tablesaw.
FA17BB43-F01A-431F-BBB3-E508E59A0990.jpeg


Then, with the leg vise, holding the resawn boards for jointing. Maple is destined for a pizza peel that will be late for Xmas.
BAAA1D9B-3010-44C7-B275-CB54C4CC6203.jpeg
 

mdbuntyn

Matt
Staff member
Corporate Member
@pop-pop I've never seen anyone orient a board that way for resawing. It makes perfect sense. Did you make that jointer plane?
 

pop-pop

Man with many vises
Corporate Member
@pop-popDid you make that jointer plane?

Yes, about 15 years ago, when Bill Anderson was just starting teaching. Just another guy and I each made a jointer plane in Bill’s home shop on the edge of Chapel Hill. Pretty sure it was his very first jointer plane class. Making that plane today at the Woodwright’s School costs a bunch more.
 

pop-pop

Man with many vises
Corporate Member
@pop-pop I've never seen anyone orient a board that way for resawing. It makes perfect sense.

I didn’t even think about it. Only needed to remove a narrow web left from the two tablesaw rips so that was the natural thing to do. Sawed about half way down, inverted the board, and finished.
 

pop-pop

Man with many vises
Corporate Member
A design deficiency popped up today in my sliding leg vise installation. I had used the existing deadman groove in the bottom of the benchtop for the sliding leg vise leg tenon.

Today, I was holding a piece of 8/4 on the flat so it was in between the chop and the benchtop. The screw’s nut is in the leg thus the clamping force went through the 11/16” wide SYP edge of the deadman groove and it broke.

Previous items in the vise have been tall enough so that the clamping force went from the chop through the work through the leg to the nut. Thus there was much less strain on the groove edge.

Initial thought on a repair is first glue then maybe screws every few inches vertically to strengthen the groove edge.
18DE4E7F-D5D1-4BA7-9F2B-09A80928D4F7.jpeg
 

Lhloy

New User
Larry
I am curious if there is a benefit in using the (3) plates as you have for the criss cross portion as opposed to using only (2) ?
My .02 is yes. It should make the loading symmetrical and reduce twisting moments in the plates.
 

pop-pop

Man with many vises
Corporate Member
A design deficiency popped up today in my sliding leg vise installation. I had used the existing deadman groove in the bottom of the benchtop for the sliding leg vise leg tenon.

Today, I was holding a piece of 8/4 on the flat so it was in between the chop and the benchtop. The screw’s nut is in the leg thus the clamping force went through the 11/16” wide SYP edge of the deadman groove and it broke.

Previous items in the vise have been tall enough so that the clamping force went from the chop through the work through the leg to the nut. Thus there was much less strain on the groove edge.

Initial thought on a repair is first glue then maybe screws every few inches vertically to strengthen the groove edge.
View attachment 199342

My repair for this fracture was to first glue the break. Then, rip one leg of a 1” x 1” x 1/8” Al angle to fit in the groove, then screw that leg to the top of the groove.
C19B04BA-CE9A-409A-BF04-BF3A8B2A6D01.jpeg


The tongue atop the sliding leg vise and sliding deadman had to modified to fit. This view is confusing but it is looking up at the vise leg tongue in the groove and the crubber on the chop.


BFC6DFD3-0430-43A5-92A6-CA0D2E29C862.jpeg


Not pretty, but now the vise is functional once again. When I built the bench I did not foresee a sliding leg vise or I would have built in a reinforced groove.
 

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