Small Machinist Jack

[Paul Jones]

Last week I was working on a project where I needed a very short machinist jack but instead had to improvise. I wanted to be better prepared the next time so I machined a 1.3” to 2” tall machinist jack from 7/8” dia. 1018 cold rolled steel (CRS) rod and used a ½-20 hex bolt for the jack screw. These machinist jacks are used for support and positioning parts for milling operations and also used as packing materials for cutting short stock on a horizontal bandsaw.

Using the lathe, I reduced the rod diameter to 0.864” to better fit a 21 pitch knurl and reduced the top of the jack base using a cutting tool with a 0.125” radius (see photo below). The internal thread of the base goes completely through and also provides a think 0.1” rim around the base bottom for better seating. An 8-32 x 1” stainless steel socket head cap screw provides a "handle" and another way to lock the jack screw. Using the jack base as a mandrel, I faced the steel hex bolt top flat, drilling 0.5” deep and then reaming a 0.251” hole in the top for any future attachments like a swiveling top, V-groove top, pointed rod, etc. (see http://www.homemadetools.net/machinist-jack-accessories ).

[Hotz]

Paul another tool with extremely high quality workmanship. Congrats
I loved your vise bench ...thanks for sharing.

[Paul Jones]

Hotz,
This was a fun and easy project. I also discovered that 5/16" or 3/8" dia. ball bearings fit perfectly in the top hole when supporting uneven surfaces. The vise is a 4" Wilton vise and I added the 1/2" thick copper jaws (see my project http://www.homemadetools.net/copper-soft-jaws).
Thank you,
Paul

[nevadablue]

Very neat tool. You gave me an idea... one of those coupling nuts and a bolt would make an instant jack!

[kbalch]

Thanks Paul! I've added your Machinist Jack to our Jacks and Lifts and Machining categories, as well as to your builder page: Paul Jones' Homemade Tools. Your receipt:

Machinist Jack by Paul Jones

tags: machining, jack, knurling

[kbalch]

This thread has been moved to the Must Read subforum. Congrats (and thanks) to Paul for making such a valuable contribution!

[Catfish]

Nice small jacks, need 3. I better get to making some. Randy

[Paul Jones]

Thanks Randy.
Next, I plan to make some special purpose attachments to fit in the top of the jack (using the 0.251" reamed hole). See the photos at http://www.homemadetools.net/machinist-jack-accessories .
Paul

[cgbaca]

Nice vise looks good

[Paul Jones]

Thank you cgbaca for your comment about the vise.

It is one of my favorite additions to the shop. Adding the copper jaws has made this vise very useful for doing small part press fit assemblies (and disassembling). I prefer using the vise instead of my small 1 ton arbor press when working with small parts because the pressing action can be controlled very precisely without overshooting the final assembly position. Also there is no problems with scratching or marring the surfaces of the parts when using copper jaws.

Regards,

Paul