Do I Need Acme Screws for a Wood Vise?

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SteveHGraham
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Do I Need Acme Screws for a Wood Vise?

Post by SteveHGraham »

I have been getting back into woodworking. I got my machines running and tuned, and I did a bunch of other stuff I should have done a long time ago. Now I'm working on putting a vise on my workbench. I don't have a real woodworking bench, but this one will do until I spring for one. It's a really heavy job built mostly from two-by-sixes.

Woodworking vises generally sit flush with the top of benches. I considered getting a 10" Eclipse vise or something similar, but they have a bunch of hardware that has to go under the top, and they're made for thick benches, like 3" or more. To put one on my bench would involve a lot of hacking. I decided to try something called a Moxon vise, which is a fancy name for two slabs of wood with two fat screws running through them horizontally. You tighten dials on the outside of the outer piece of wood, and it pulls it against the inner piece of wood, and you put your work between them.

To do this, I needed a fixed wooden jaw on the side of the bench, so I hacked up a couple of two-by-sixes that were cluttering the backyard. They were horrible, with lots of knots, but I picked the best parts and glued them together. Now I need to run two big screws through them.

This is where the question comes in.

If you buy a real vise made in a factory, it will have acme screws. I can't get those around here, and anyway, they're expensive. They would have to be ordered online. I was standing in the hardware store where I bought the maple for the outer jaw, and I saw 3/4" threaded rod. Here's what I'm wondering: do I really need acme screws? Far as I know, plain old screws work pretty well. It's not like a milling vise that has to exert humongous pressure, and it won't be going in and out all day for eight-hour shifts.

I picked up 36" of threaded rod, but I can always get acme screws later if this turns out to be a bad idea. They will fit the same holes.

Attached is a photo of the progress so far.
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07 12 15 moxon vise fixed jaw attached to workbench.jpg
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ken572
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Re: Do I Need Acme Screws for a Wood Vise?

Post by ken572 »

Steve, :D

Go ahead and try your idea,
Then test it to see if it meets
your needs. Do a follow up
with pictures and your comments 8)

Have fun. :wink:

Ken. :)
One must remember.
The best learning experiences come
from working with the older Masters.
Ken.
SteveM
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Re: Do I Need Acme Screws for a Wood Vise?

Post by SteveM »

The acme screw thread can transmit a lot more clamping force than a regular screw.

On a milling, machinist or mechanic's vise, I would say it would be mandatory.

For woodworking, you are not dealing with the same clamping forces, so it may work.

As an alternative, if you have a used machinery dealer near you, see if they have a spare leadscrew sitting around.

Steve
Last edited by SteveM on Mon Jul 13, 2015 7:58 am, edited 1 time in total.
f350ca
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Re: Do I Need Acme Screws for a Wood Vise?

Post by f350ca »

The first time you want to open the vice to hold a 4x4 and have to turn the handle 40 times you'll think AH I should have made an Acme thread.
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SteveHGraham
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Re: Do I Need Acme Screws for a Wood Vise?

Post by SteveHGraham »

Okay, I thought of that. I have an idea for a quick-release thing.
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hammermill
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Re: Do I Need Acme Screws for a Wood Vise?

Post by hammermill »

steve make your own threaded rod and nut on the garage full of machinery you have. the coarse thread offers less cloging under saw dust, less wear buy a long shot and you will be able to have a faster pitch and better grade of steel than a hardware hunk of ready rod
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Harold_V
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Re: Do I Need Acme Screws for a Wood Vise?

Post by Harold_V »

SteveM wrote:The acme screw thread can transmit a lot more clamping force than a regular screw.
Don't think so. All conditions being equal, the amount of energy is determined by the pitch, not the thread form, thus the higher the pitch count, the higher the clamping effort. That's assuming a single entry thread. However, it comes at the expense of time. Acme screws tend to have rapid lead (coarse pitch), while a 60° thread form typically would not, assuming you're comparing identical diameters. I'm inclined to agree with f350ca.

Harold
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reggie_obe
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Re: Do I Need Acme Screws for a Wood Vise?

Post by reggie_obe »

You can buy acme threaded rod and nuts. 2x6 dimensional lumber is soft wood, Hemlock, Pine, Fir, etc., unsuitable for vice jaws. Hardware only woodworkers vice kits are also available,
SteveM
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Re: Do I Need Acme Screws for a Wood Vise?

Post by SteveM »

Harold_V wrote:Don't think so. All conditions being equal, the amount of energy is determined by the pitch, not the thread form, thus the higher the pitch count, the higher the clamping effort.
I was assuming the same pitch, but yes, acme is usually a coarser thread pitch.

Steve
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SteveHGraham
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Re: Do I Need Acme Screws for a Wood Vise?

Post by SteveHGraham »

I found acme screws at Surplus Center pretty cheap. Still thinking this over.
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SteveHGraham
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Re: Do I Need Acme Screws for a Wood Vise?

Post by SteveHGraham »

I am thinking threaded rod might work better with quick-release half-nuts. Easier to engage.
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warmstrong1955
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Re: Do I Need Acme Screws for a Wood Vise?

Post by warmstrong1955 »

Just a thought....with 60 degree threads, what's to keep the half nut engaged when you load it up? Seems to me, because of the angle of the threads, that the more torque, the more they would push each other apart.

Acme threads would not tend to do that as much, as they are 29 degrees. You may need some mechanism to hold the half nut down.

Would be worth a bit of 'sperimentin' I think....

Bill
Today's solutions are tomorrow's problems.
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