Telescoping Jack Screw - FINAL PROJECT

mikey said:
Threads look good, Justin. It might be a good idea to chamfer the ends before threading for smoother engagement of the threading tool. You can also do it afterwards but do it so the thread start easily and it looks better.
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Did chamfer after these were taken, I originally forgot. Enjoy the threading video :)
 
Mikey yes the chamfer would be nice, but looking at the drawing, unless the instructor given them authorization to modify, Does not show any chamfer on that end, It just shows flat, Which I would say is an oversight by the person drawing it. OK my bad, I see he did chamfer them now.
 
So you guys who'd like to do this project will get to learn a few things today. At the expense of my mistakes lol.

I went in today at 9am. I turned down and knurled a section for the LG Jack Screw. Came back after a test at 1230pm and it dawned on me. I knurled before ever turning down my 1.375" sized stock to the 1.310 callout on the print. This was after I center drilled, faced, and cut sections out for the external thread. So, the key thing to learn here is that turn down your stock before knurling. Also note that knurling adds approx. 010" to your final dimension, depending on how much knurling you're doing.

Anyways, I started a new piece and got almost to tapping the inside. Was taking .125 thousandth passes here and a feed rate of about .006 and it worked out nicely. Lots of smoke, but I got to rip through the part and get a lot done!!

I drilled entirely through it so all I have to do is tap the inside, then do more external threads and done! Enjoy.

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jlsmithseven said:
and it dawned on me. I knurled before ever turning down my 1.375" sized stock to the 1.310 callout on the print. This was after I center drilled, faced, and cut sections out for the external thread............Anyways, I started a new piece and got almost to tapping the inside.
Click to expand...

Could you not just take a skim cut to remove the knurling?

-brino
 
brino said:
Could you not just take a skim cut to remove the knurling?

-brino
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Yeah I thought about it, but the piece was cut into like 3 different diameters so gripping it on the chuck wasn't going to be fun. I had another piece already cut so it didn't take me much longer to get back to where I was...
 
jlsmithseven said:
So whenever I get on the mill, can anyone help me with this hexagon collet block thing. Is it hard? How exactly does it work?

https://www.amazon.com/5C-CB-5C-Collet-Block-Set/dp/B0007Q1Q50
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Pretty simple. You find a 5C collet that fits your work piece diameter and slip it in the block, then put the work piece into the collet and tighten the black ring on the back of the collet to lock the work in solidly. Then you can turn the collet block in the vise to cut 3, 4 or 6 sided flats or features.
 
So basically the same size as I've been holding it on the lathe chuck right? Like in the middle? Then keep turning it for the 6 sides I need in the vise jaw? I think I'm talking about the left picture in the link on Amazon...
 
The diameter of your work piece has to be able to fit into a 5C collet but basically yes, you would put the collet in the hex-shaped block and lock it in place in the vise. Then you cut one flat, turn the block and cut another flat and so on until all six flats are cut.
 
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