Wednesday, January 25, 2012

Moxon vise screws

Since I have chosen not to have a vise on my bench, at least for now, having a good portable Moxon vise available is quite important.  I have been stymied for some time by the screws.  Wooden screws are the best but I don't have a lathe, a threadbox, or a tap and the cost of commercially available screws is prohibitive.  In a recent issue of ShopNotes (Vol. 20, Issue 120), the cover story was a project to build an etau, a historical vise from France.  The screw was an acme rod and nut obtained from McMaster-Carr with a shop-made wooden hub and handle.  It seemed like a great idea and I decided to try it in modified form.

I obtained two 12" long, 1", 5 tpi threaded acme rods and nuts from McMaster-Carr for $32.  There are many different sizes and tpi available.  I made hexagonal wooden handles 4" long and drilled a hole 2" deep in each to receive the rods.  I then epoxied the rods in place and drilled through the handle and rod for a machine screw for extra strength.  I read on a boat building forum that if you warm the wood and epoxy to 100 degrees, the epoxy will penetrate deeply into the wood, so that's what I did.  In this way, the epoxy strengthens the wood as well as forming a bond between the handle and the screw.  I also painted the end grain with epoxy.

The result is shown below.  I am extremely pleased with the result.  Definitely a good value if it holds up, which I expect.

By the way, if you have forgotten your high school geometry like I have, hexagons are easy to lay out.  Draw a circle equal to the outside diameter you want and then use the compass to step off segments of the circle (the radius and the length of the sides are the same). Draw straight lines between adjacent points and you will have a hexagon.  Hexagons are relatively easy to make with hand tools.  I used a saw and a plane.

The entire project took a couple of hours or so.  I'll post about the completed vise shortly.


4 comments:

  1. Is it required that you have a commercial/business account to order from McMaster-Carr? This sounds like a great way to get around the same screw issue I'm having.
    ralph

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    1. No, Ralph, it isn't. I just found what I was looking for on their online catalog and ordered with a credit card. It shipped the same day and cost less than $6.

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  2. Very cool, thanks!

    A few quick questions:

    Could you say a little more about the bolt you installed? Also, did you have any trouble drilling through the acme rod?

    I'm not very familiar with epoxy. How did you heat this thing to 100 degrees? (My oven doesn't go that low, for example.)

    Thanks!
    Matthew

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  3. I used basic #10-32 flat head machine screws that I had on hand. I countersunk the head and used a forstner bit to recess the nut, then cut off and filed the screw flush.

    I drilled the hole with a standard twist drill after the handle was in place, making sure it was held securely on the drill press table and supporting the screw. I was surprised that it drilled rather easily. I used the general purpose plain steel rods from this page: http://www.mcmaster.com/#about-acme-threads-for-threaded-rods/=fypasr

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