# Machinist Jacks



## firemaker76

So another tool crossed off the 'To Do' list.  Made a pair of machinist jacks, and wanted to post a few pics.  
I started by turning down some 1.250" diameter Heat Treated 4140 and made the screw/head pieces first.  That way I could measure my thread pitch and make sure it was within proper 2A specs.  Then I drilled the top of the heads to accept some .375" diameter bushings with a .0005" press fit.  
After that, I turned the jack bodies down to 1.200".  With the screw threads already done and within specs, I was able to bore and thread the bodies 3/4-20 and get a very smooth and precise fit with zero slop.  Then I turned some grooves along the outside of the bodies for aesthetics and better grip. These were parted off and faced to an OAL of 1.750".  
The extensions are made 1.000" long with an upper shoulder for the body to sit on and a lower inner shoulder in case another extension needs to be added.  The shoulders mated up very well.  
Finally I made some caps and drilled and reamed the bottoms to .375". This allowed them to engage the head bushings and spin freely.  I also put several varying-sized diameter grooves around the top and milled a .075" deep V-groove through the center of the cap.  This allows smaller diameter stock to engage the groove and sit dead center when supported by the jack.  I did not realize how handy and necessary these little jacks were, but I use them all the time now.  
One more quick note...I also attached a magnified pic of some chips from the 4140.  I spent more time trying to remove these little monsters from my shop broom than I did actually building the jacks.  Now I know why LOL.  Take a look at the teeth on those chips! 

Thanks for reading guys and Happy Machining!!  Be safe.


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## mattthemuppet2

that is beautiful work!

I have a set of jacks on my to do list, they've just never made it to the top


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## benmychree

I have several Starrett jacks, and used them today, seems like I use them about once in a decade, but they show a lot of class in my Gerstner tool box drawer, sharing space with a pair of 1-2-3 blocks and a few other goodies from, oh so many years ago, like maybe 50 or so.


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## firemaker76

Thanks very much!  The hardened 4140 has a beautiful finish.  I really enjoy working with it.


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## firemaker76

benmychree said:


> I have several Starrett jacks, and used them today, seems like I use them about once in a decade, but they show a lot of class in my Gerstner tool box drawer, sharing space with a pair of 1-2-3 blocks and a few other goodies from, oh so many years ago, like maybe 50 or so.


50 years? Wow! I am truly grateful for you experienced guys sharing your experience so us Noobies don't have to learn so many hard lessons   Thanks very much for reading and commenting!

-Mitch


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## hman

@firemaker76, those are truly fantastic looking jacks - well beyond the run-of-the-mill, store bought ones I have!  Very sturdy as well.  And unlike @benmychree, I use my  machinist jacks every couple months or so.  Different strokes for different oarsmen, eh wot?


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## Just for fun

Holy cow, those are beautiful.   Great job! 

Thanks for sharing. 

Tim


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## firemaker76

hman said:


> @firemaker76, those are truly fantastic looking jacks - well beyond the run-of-the-mill, store bought ones I have!  Very sturdy as well.  And unlike @benmychree, I use my  machinist jacks every couple months or so.  Different strokes for different oarsmen, eh wot?


Thanks Hman! I built these after trying to shortcut and dimple an AR barrel for a gas-block.  Instead of following my instincts and doing the "machinist jacks" project first, I figured I'd jump ahead on my To-Do list and knock out a "quick'n easy" project first.  Well I ended up with egg on my face after I dulled a brand new hss drill bit trying to push it through the thin layer of melonite.  Yep, humbling moment, but needless to say, the very next day I started on turning some Machinist Jacks :-D
And yes different strokes my friend ;-)

Thanks for reading and commenting!


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## firemaker76

Just for fun said:


> Holy cow, those are beautiful.   Great job!
> 
> Thanks for sharing.
> 
> Tim


Wow thanks for your kind words Tim, I really appreciate your support! 

-Mitch H.


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## davidpbest

Nice work - 4140 is the ideal choice here.  You are really churning out some great items (spider, etc.).  Now you need a wooden box for your machinist jacks.  Like mine.


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## firemaker76

Oh Snap! That is a cool little box.  Very nice touch!  Thanks very much David.

-Mitch H.


davidpbest said:


> Nice work - 4140 is the ideal choice here.  You are really churning out some great items (spider, etc.).  Now you need a wooden box for your machinist jacks.  Like mine.
> 
> View attachment 380467


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## davidpbest

firemaker76 said:


> Oh Snap! That is a cool little box.  Very nice touch!  Thanks very much David.
> 
> -Mitch H.


Have you gotten around to this yet?  LOL









						Custom Case for Precision Stones
					

Precision Ground Toolroom Stones from Lance Baltzley of 26 Acre Maker. Click image for descriptions.




					www.flickr.com


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## firemaker76

davidpbest said:


> Have you gotten around to this yet?  LOL
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Custom Case for Precision Stones
> 
> 
> Precision Ground Toolroom Stones from Lance Baltzley of 26 Acre Maker. Click image for descriptions.
> 
> 
> 
> 
> www.flickr.com


No sir I have not, but that is outstanding! Very impressive David!  This is exactly why I joined here.  So many good people with great ideas, willing to share their knowledge with others.  Love this forum.

-Mitch

-


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## firemaker76

Dav


davidpbest said:


> Have you gotten around to this yet?  LOL
> 
> 
> 
> 
> 
> 
> 
> 
> 
> Custom Case for Precision Stones
> 
> 
> Precision Ground Toolroom Stones from Lance Baltzley of 26 Acre Maker. Click image for descriptions.
> 
> 
> 
> 
> www.flickr.com


David,
Is that UHMW?

-Mitch H.


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## silverhawk

Even the chips are beautiful! Nice work!

Sent from my SM-T500 using Tapatalk


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## firemaker76

silverhawk said:


> Even the chips are beautiful! Nice work!
> 
> Sent from my SM-T500 using Tapatalk


Thanks Silverhawk!


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## woodchucker

davidpbest said:


> Nice work - 4140 is the ideal choice here.  You are really churning out some great items (spider, etc.).  Now you need a wooden box for your machinist jacks.  Like mine.


I'll agree with Dave's first 2 sentences.. but Boxes just eat up space. So I think avoid the boxes, but holders to prevent them from rolling around +1... so the insert in that box would be good. The box -1


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## davidpbest

firemaker76 said:


> David,
> Is that UHMW?


Similar - it's a marine version of HDPE called King Starboard which is impervious to solvents and UV light.  _*McMaster has it*_, as does *Tap Plastics.*  I use it for a lot of things in the shop - my *chuck saddles* are another good example:


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## davidpbest

woodchucker said:


> I'll agree with Dave's first 2 sentences.. but Boxes just eat up space. So I think avoid the boxes, but holders to prevent them from rolling around +1... so the insert in that box would be good. The box -1


Just to be clear, I prefer insert caddys for a lot of tools like this, but when the grand estate sale comes around, my kids will get more revenue selling tools that come in a nice fitted wooden box.   LOL


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## woodchucker

@davidpbest  nice boxes for the stones Dave. That's where I think boxes make sense. Stones are easy to fracture and oily.. So boxes are good protection.

edit: and remember these are only my opinions, I'm not telling anyone that it's good or bad, just how I feel. And if that helps make a decision ok, if you disagree ok.

we all like different things.. except it appears we all like to work metal/plastic/wood/ and make things.


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## firemaker76

davidpbest said:


> Similar - it's a marine version of HDPE called King Starboard which is impervious to solvents and UV light.  _*McMaster has it*_, as does *Tap Plastics.*  I use it for a lot of things in the shop - my *chuck saddles* are another good example:
> 
> View attachment 380699


Got it, I was just looking at some on McMaster Carr.  I have several projects in mind that I could use some of that for.....and now after seeing those chuck saddles, I'll have to add that to my list LOL.  Thanks very much David.  Your projects absolutely inspire.

-Mitch H.


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## McDingus

These have been on my todo list for a while now. Nice design and great work. Thanks for sharing.


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## firemaker76

McDingus said:


> These have been on my todo list for a while now. Nice design and great work. Thanks for sharing.


Thank you


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## Christianstark

I am ashamed of my jacks now.


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## firemaker76

Christianstark said:


> I am ashamed of my jacks now.


LOL thanks man, but I can't lie.....I had one almost complete and was making the final cleanup pass on the internal threads when I accidentally bumped the compound rest and had to start over.  (Large palm to forehead and swift kick to a**)

Lesson learned, and now I lock the compound rest.


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## Leonard

Truly beautiful work!


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## firemaker76

Leonard said:


> Truly beautiful work!


Thanks very much Leonard


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## Reppel

Awesome set of jacks.  Very nice work


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## firemaker76

Reppel said:


> Awesome set of jacks.  Very nice work


Thank you


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## snoopdog

firemaker76 said:


> So another tool crossed off the 'To Do' list.  Made a pair of machinist jacks, and wanted to post a few pics.
> I started by turning down some 1.250" diameter Heat Treated 4140 and made the screw/head pieces first.  That way I could measure my thread pitch and make sure it was within proper 2A specs.  Then I drilled the top of the heads to accept some .375" diameter bushings with a .0005" press fit.
> After that, I turned the jack bodies down to 1.200".  With the screw threads already done and within specs, I was able to bore and thread the bodies 3/4-20 and get a very smooth and precise fit with zero slop.  Then I turned some grooves along the outside of the bodies for aesthetics and better grip. These were parted off and faced to an OAL of 1.750".
> The extensions are made 1.000" long with an upper shoulder for the body to sit on and a lower inner shoulder in case another extension needs to be added.  The shoulders mated up very well.
> Finally I made some caps and drilled and reamed the bottoms to .375". This allowed them to engage the head bushings and spin freely.  I also put several varying-sized diameter grooves around the top and milled a .075" deep V-groove through the center of the cap.  This allows smaller diameter stock to engage the groove and sit dead center when supported by the jack.  I did not realize how handy and necessary these little jacks were, but I use them all the time now.
> One more quick note...I also attached a magnified pic of some chips from the 4140.  I spent more time trying to remove these little monsters from my shop broom than I did actually building the jacks.  Now I know why LOL.  Take a look at the teeth on those chips!
> 
> Thanks for reading guys and Happy Machining!!  Be safe.


Beautiful


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## firemaker76

snoopdog said:


> Beautiful


Thank you for your support.


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## Red96

Apologize for posting to an older thread, but could you enlighten a newbie as to the purpose/thinking behind the coencentric grooves in the cap?  The V-Groove I get, but are the circles there for a pragmatic purpose, or because they look great. (And they *do*!)

Thanks,
Newbie in Snohomish, WA


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## firemaker76

Red96 said:


> Apologize for posting to an older thread, but could you enlighten a newbie as to the purpose/thinking behind the coencentric grooves in the cap?  The V-Groove I get, but are the circles there for a pragmatic purpose, or because they look great. (And they *do*!)
> 
> Thanks,
> Newbie in Snohomish, WA


No problem, thank you for taking time to look at the post.  So the concentric grooves in the cap are really there for looks more than anything else.  I did turn the grooves at .600", .800" and 1.000" diameters, but they serve no real pragmatic purpose.  Thanks again for looking and commenting!


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## dkemppai

firemaker76 said:


> Thanks very much!  The hardened 4140 has a beautiful finish.  I really enjoy working with it.


Kinda late to the game. 

So, I was wondering how the surface finish turned out so nice. So it's HT 4140 then? Do you need any special tooling geometry for this?


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## firemaker76

dkemppai said:


> Kinda late to the game.
> 
> So, I was wondering how the surface finish turned out so nice. So it's HT 4140 then? Do you need any special tooling geometry for this?


Yes sir, this is heat-treated 4140.  I didn't use anything special, just standard CCMT carbide inserts.  I did however keep a healthy feed and DOC.  I found out very quickly that trying to take very light passes or sneak up on the OD did NOT work and resulted in terrible surface finish.  Instead, I opted to calibrate my DRO as I was cutting.  Basically, I took a .030 pass, stopped the lathe (without moving the cross-slide), checked the OD with a micrometer and punched that value in to the DRO.  I repeated this a couple times until my micrometer and DRO matched up.  This method proved to be very accurate and got me within .0005" almost every time.  The trick is to make sure you keep (at least) the last two passes at the same DOC after your DRO is calibrated.  I'm sure some of the veteran machinists on the forum here can explain this better than me, but hopefully this helps out.  Thanks for looking and commenting!  Happy New Year!


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## benmychree

I prefer TPG inserts for nearly all work, including stainless and 4140HT; with its sharp edges, very light cuts can be taken without work hardening, sure, they have less edges than other types of inserts, but they can be sharpened by hand on to radius with a diamond wheel.


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