Machinist Jacks

firemaker76 said:
So the concentric grooves in the cap are really there for looks more than anything else.
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I think the grooves make the jacks look “groovy”… (sorry). I’m a firm believer that along with good quality, aesthetically pleasing is something to strive for.
 
firemaker76 said:
Phil,
I think you'll find that once you've gotten the calibration technique down, you'll have very little need to use abrasives for attaining good surface finish. Now on stock that is smaller diameter (5/8" and smaller), that is a different story. You may have to use some 3M scotch brite or something similar to get a nice surface finish. Most manual lathes won't spin small stock fast enough to get that beautiful surface finish on 4140. I would also recommend using the heat treated 4140...that helps a lot. There are many individuals on here with much more knowledge and experience than me, so these are just recommendations based on my own experiences.

-Mitch
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Hi Mitch,
Thanks again, I looked up the heat treated 4140 on OnlineMetals, but they are currently out of stock, I'll look around.
Phil
 
I use 4140 pretty routinely, but it takes some dialing in on each persons machine to get the proper finish. As others have mentioned, you need both DOC and higher feed rates to get a good finish, it also depends on your cutter/insert. You need a rigid lathe. Aluminum would be a poor metal to use for these types of jacks, I would recommend using some stress proof 1144, 01 or even 1045 steel which are readily available and easy to machine. I recently made a set and used 4140 for the body and 01 steel for the jack, a bit simpler design, with a threaded base for an additional screw on base or to fasten to the mill with a T-nut. Finish is mostly from the cutter with light sanding. If I recall the thread was a 1"-16, I made a male and female mandrel for sizing based on a tap that I had so everything is interchangable and stackable.
Adjustable Screw Jacks.jpg
 
StevSmar said:
I think the grooves make the jacks look “groovy”… (sorry). I’m a firm believer that along with good quality, aesthetically pleasing is something to strive for.
Click to expand...
Yea, I think I should have made them a little bit deeper now, but I may make some more later on with Multi-start threads. I think that would be a fun project.
 
Last edited:
mksj said:
I use 4140 pretty routinely, but it takes some dialing in on each persons machine to get the proper finish. As others have mentioned, you need both DOC and higher feed rates to get a good finish, it also depends on your cutter/insert. You need a rigid lathe. Aluminum would be a poor metal to use for these types of jacks, I would recommend using some stress proof 1144, 01 or even 1045 steel which are readily available and easy to machine. I recently made a set and used 4140 for the body and 01 steel for the jack, a bit simpler design, with a threaded base for an additional screw on base or to fasten to the mill with a T-nut. Finish is mostly from the cutter with light sanding. If I recall the thread was a 1"-16, I made a male and female mandrel for sizing based on a tap that I had so everything is interchangable and stackable.
View attachment 444708
Click to expand...
Those turned out beautiful Mark!
 
mksj said:
I use 4140 pretty routinely, but it takes some dialing in on each persons machine to get the proper finish. As others have mentioned, you need both DOC and higher feed rates to get a good finish, it also depends on your cutter/insert. You need a rigid lathe. Aluminum would be a poor metal to use for these types of jacks, I would recommend using some stress proof 1144, 01 or even 1045 steel which are readily available and easy to machine. I recently made a set and used 4140 for the body and 01 steel for the jack, a bit simpler design, with a threaded base for an additional screw on base or to fasten to the mill with a T-nut. Finish is mostly from the cutter with light sanding. If I recall the thread was a 1"-16, I made a male and female mandrel for sizing based on a tap that I had so everything is interchangable and stackable.
View attachment 444708
Click to expand...
Thanks Mark, I can try the 1144, 01, 1045 (getting use to all the terms) on the Sherline then and save the aluminum for another day. I see what you mean, in one case - the threaded T nut needs to screw into the bottom of the jack and aluminum will likely just strip out pretty quickly. Very nice work! I like the blueing too. What process did you use? It looks like a very even coat from the picture. What's the range of DOC you use on 4140?
Phil
 
I have a much heavier lathe (2400lbs) with carbide inserts for turning, so my DOC is anywhere from 0.02-0.1" with a feed rate in the 0.009-0.012"/R range for 4140. As Firemaker76 outlined, it is easy to hit your target by measuring the diameter change vs. the DRO/Dial reading change and compensating with each successive cut. When threading this diameter I make a female test mandrel in this case it was aluminum and the male was some scrap steel rod. This gives you an approximate DOC when threading and also as a fitment guide for multiple parts (i.e. a go/no go for threading) On a smaller lathe I would recommend sticking with 1144 which is easier to machine and is very durable. You can often find ends on eBay or scrap at very reasonably prices, shipping is less if 12" or under. Example below I would get two (1-5/8 or 1-7/8" Steel Rod 1144 High-Strength x 6" Long Stressproof), or a smaller diameter as I am not sure your lathe can handle heavy turning. The bluing solution is below, it kind off works, took a number of coats and I cleaned, then boiled the metal in distilled water and applied hot. This was my first time bluing, but it depends on the steel and it needs to be very clean. After a couple of coats, lightly go over it with fine steel wool and then apply a coat of oil.

Firemaker76, very nice work and attention to detail, wish I had more patience for the finer details you did. Much better to make your own machinist jacks to your own design, far better than what you can buy.

www.ebay.com

1-5/8" Steel Rod 1144 High-Strength x 6" Long Stressproof | eBay

A311 Class B Stressproof A311 Class B StressProof® is a steel produced using a proprietary process that draws the bar through a special die under heavy draft. StressProof® round bar,hex and standard cold finished or TG&P (Turned, Ground and Polished).
www.ebay.com
www.ebay.com

1-7/8" Steel Rod 1144 High-Strength x 6" Long Stressproof | eBay

A311 Class B Stressproof A311 Class B StressProof® is a steel produced using a proprietary process that draws the bar through a special die under heavy draft. StressProof® round bar,hex and standard cold finished or TG&P (Turned, Ground and Polished).
www.ebay.com
www.ebay.com

NU-BLU GUN METAL BLUING 8 oz | eBay

NU-BLU Gun Bluing is not your average Cold Bluing, it is designed as a reverse Hot Bluing, without the need for dipping tubs and the use of gallons of product. This eliminates blotchy, inconsistent results.
www.ebay.com
 
mksj said:
I have a much heavier lathe (2400lbs) with carbide inserts for turning, so my DOC is anywhere from 0.02-0.1" with a feed rate in the 0.009-0.012"/R range for 4140. As Firemaker76 outlined, it is easy to hit your target by measuring the diameter change vs. the DRO/Dial reading change and compensating with each successive cut. When threading this diameter I make a female test mandrel in this case it was aluminum and the male was some scrap steel rod. This gives you an approximate DOC when threading and also as a fitment guide for multiple parts (i.e. a go/no go for threading) On a smaller lathe I would recommend sticking with 1144 which is easier to machine and is very durable. You can often find ends on eBay or scrap at very reasonably prices, shipping is less if 12" or under. Example below I would get two (1-5/8 or 1-7/8" Steel Rod 1144 High-Strength x 6" Long Stressproof), or a smaller diameter as I am not sure your lathe can handle heavy turning. The bluing solution is below, it kind off works, took a number of coats and I cleaned, then boiled the metal in distilled water and applied hot. This was my first time bluing, but it depends on the steel and it needs to be very clean. After a couple of coats, lightly go over it with fine steel wool and then apply a coat of oil.

Firemaker76, very nice work and attention to detail, wish I had more patience for the finer details you did. Much better to make your own machinist jacks to your own design, far better than what you can buy.

www.ebay.com

1-5/8" Steel Rod 1144 High-Strength x 6" Long Stressproof | eBay

A311 Class B Stressproof A311 Class B StressProof® is a steel produced using a proprietary process that draws the bar through a special die under heavy draft. StressProof® round bar,hex and standard cold finished or TG&P (Turned, Ground and Polished).
www.ebay.com
www.ebay.com

1-7/8" Steel Rod 1144 High-Strength x 6" Long Stressproof | eBay

A311 Class B Stressproof A311 Class B StressProof® is a steel produced using a proprietary process that draws the bar through a special die under heavy draft. StressProof® round bar,hex and standard cold finished or TG&P (Turned, Ground and Polished).
www.ebay.com
www.ebay.com

NU-BLU GUN METAL BLUING 8 oz | eBay

NU-BLU Gun Bluing is not your average Cold Bluing, it is designed as a reverse Hot Bluing, without the need for dipping tubs and the use of gallons of product. This eliminates blotchy, inconsistent results.
www.ebay.com
Click to expand...
thanks again for the great tips Mark
With the supply chain nightmare, I'll look on eBay and go to the local metal supplier next week for shorter end pieces and scraps of 1144 and anything else they have that I can process to turn into chips
Phil
 
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