Machinist Jack/Adjustable Parallel

I was watching a John Mills (Doubleboost) video on youtube and I saw him using a little machinist type jack on his mill. I am not sure you can call it a jack or maybe an adjustable parallel. I liked the idea so I made one this weekend and it seems to work ok. I had no dimensions so I looked what I had in my little home shop and used what I could find. It is very small as I made it from a 25mm x 25mm piece of square stock. It is 58mm long and it extends 10mm. Once the lock down is over and the shops are open I will be able to buy some bigger stock and make one from 40mm square stock.

Attachment 34218 Attachment 34219 Attachment 34220 Attachment 34221

That's a nice jack which looks much more robust than the adjustable parallels I sometimes use.

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Thanks Dbj58! We've added your Machinist's Jack to our Machining category,
as well as to your builder page: Dbj58's Homemade Tools. Your receipt:

<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/homemade-machinist-s-jack-3"> <img src="/uploads/231484/homemade-machinists-jack-3.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/homemade-machinist-s-jack-3">Machinist's Jack</a> <span> by <a href="https://www.homemadetools.net/builder/Dbj58">Dbj58</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/machining'>machining</a>, <a href='https://www.homemadetools.net/tag/jack'>jack</a> </div> </div> </div> </div>
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I see you can make it taller with the threaded handle, but no controlled way to make it shorter. Is that correct? Will you change that on the larger version?

How do you know how tall to set it? Is that something you measure on your bench before hand, or do you just snug it up until it feels right. It seems it would be easy to wind up pushing your piece out of position with the mechanical advantage of the screw. (I wonder the same thing about traditional machinist's jacks.)

Thanks for the share!

Hi Karl_H,
You are correct it comes back on its own as one screws the handle out. It slides in and out smoothly. I just snug it up, one can put a shim on top of it to prevent it pushing things forward as you tighten it. As a parallel it's out by 0.01 front to back so not suitable for really accurate work.
One thing I like about it is the ease of adjustment.

Congratulations Dbj58 - your Machinist's Jack/Adjustable Parallel is the Homemade Tool of the Week!

This was an enormous week around here, even bigger than last, which makes winning this prize even more difficult. Many of the homemade tools posted this week would've easily won here on more normal weeks. It's excellent to see so many people making such good use of being locked down in their homes, and this build, made with limited stock, is a particularly good example of that.

Some more good builds from this week:

Handgun Suppressor by Jughead
Tool and Cutter Grinder by celsoari
Panavise Hook by mklotz
Rotary Broaching Tool by thehomeengineer
Dummy Rivet Dies by thehomeengineer
Rear Window Protector by Frank S
Wire Twister by Kwandotechnic
Lathe Indexing Wheel by baskarz
Hand Sanitizer by HandmadeCreativeChannel
Horn Stand by rendoman
Tie Down Strap Repair by rgsparber
Adjustable Router Sled by diyfixman
Chainsaw Mill by liberal
Chuck Jaw Grinding Method by bouboulas
Bandsaw Jaw Modification by jdurand
Articulated Clamp by Kwandotechnic
File Storage by olderdan
Anti Contamination Faucet Handle by rgsparber
Saw by bridger
Curved Bottom Hollowing Plane by Art of Boat Building
Fuel Filler Modification by Frank S
Flat Sanding Cawl by Christophe Mineau
Shop Stool by Christophe Mineau
Coat Hanger by Catfish
Dress Form by Christophe Mineau
Model Wheel Spraying Stand by thehomeengineer
Lathe Chuck Key by craig9
PVC Kayak Skeg by rgsparber


Dbj58 - you'll be receiving a $25 online gift card, in your choice of Amazon, PayPal, or bitcoin. Please PM me your current email address and gift card choice and I'll get it sent over right away.

This is your 2nd Homemade Tool of the Week. Here are both of your Homemade Tool of the Week winning tools. Congrats again :thumbsup:


<div id="blocks"> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/float-lock-vise-74503#post139298"> <img src="/uploads/225530/homemade-float-lock-vise.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/float-lock-vise-74503#post139298">Float Lock Vise</a> <span> by <a href="http://www.homemadetools.net/builder/Dbj58">Dbj58</a></span> </div> <div class="tags">tags: <a href='http://www.homemadetools.net/tag/vise'>vise</a> </div> </div> </div> <div class="block b1 pngfix"> <div class="bimg"> <div> <a href="https://www.homemadetools.net/forum/machinist-jack-adjustable-parallel-78652#post155593"> <img src="/uploads/231484/homemade-machinists-jack-3.jpeg"/> </a> </div> </div> <div class="head pngfix"></div> <div class="left pngfix"></div> <div class="right pngfix"></div> <div class="blockover b1 pngfix"> <div class="title"> <a href="https://www.homemadetools.net/forum/machinist-jack-adjustable-parallel-78652#post155593">Machinist's Jack</a> <span> by <a href="https://www.homemadetools.net/builder/Dbj58">Dbj58</a></span> </div> <div class="tags">tags: <a href='https://www.homemadetools.net/tag/machining'>machining</a>, <a href='https://www.homemadetools.net/tag/jack'>jack</a> </div> </div> </div> </div>

Dear Jon,
Thank you for the award, my Paypal is davebjames@yahoo.com
Thanks again and keep up the great work with a fantastic site.

Great, just sent it. Congrats again :hattip:

It's nice to see a precision tool win once in a while.

I need one of these, probably I'll build myself