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Lathe parting

Surface speed is a compromise on parting.

That's what I was thinking. I'll try 5 mil/rev. I like to take it easy to preserve tooling. Stainless needs a bit deeper cut to avoid work hardening issues.

I have oil in my coolant system and it works great except I really have to keep the RPM down to avoid throwing it all over. For high RPMs I brush it on.

Indeed, I use high speed on small tool bits...parting, not so much.

-Jerry
 
20180127_165009.jpg 20180127_165739.jpg
A tool I used for this CM barrel it was dull and chiped cutting this one so i need inserts but it worked great I have it hanging out a ways too and I know I'm running slow but it works for me and that tool has done a lot.
I had it hanging out for making some Parker Hale stile jags.
 

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Don't tell people you part your barrels!:eek: (I part mine too). I've started parting before final alignment. I put it in the spiders, rough align with indicator on outside of barrel. Part. face. rough cut the thread diameter and shoulder at high speed with heavy cut (indigo chips). Stop and do final alignment with precision indicators inside barrel. Finish shoulder and thread prep with small cuts. Same process on both ends. Before I did this I always felt compelled to get the indicators back out to make sure it didn't move during parting and material removal. Never caught it moving but this way doesn't add any work, just reorders steps, and provides peace of mind. You're welcome.

--Jerry
 
Don't tell people you part your barrels!:eek: (I part mine too). I've started parting before final alignment. I put it in the spiders, rough align with indicator on outside of barrel. Part. face. rough cut the thread diameter and shoulder at high speed with heavy cut (indigo chips). Stop and do final alignment with precision indicators inside barrel. Finish shoulder and thread prep with small cuts. Same process on both ends. Before I did this I always felt compelled to get the indicators back out to make sure it didn't move during parting and material removal. Never caught it moving but this way doesn't add any work, just reorders steps, and provides peace of mind. You're welcome.

--Jerry
oops :confused:
I take about .200 off after but yes I part my barrels and they don't move with that spider I made they are secure (it's the balltip screws and the pads with the same radius).
 
3/8-24
Just got some 1.5-2.0
Screws and turned a .1875 radius on the end then a ball tip .375 endmill for the pads easy n quick
 

Then maybe I'm worrying too much about mine moving. My screws are 1/2 20 and I tighten them plenty tight. I once had a barrel shift tightening an action too tight on the barrel after the chamber was cut. No big deal since I was done.

--Jery
 
I think things move when there is some flex induced in the barrel when it is dialed in.
I check my work all the time and when I started using this holding system that moving from tool presure whent away.
 
I bought these off eBay

4pc 3/32 x 5/8 x 5" HSS CUT- OFF BLADES, BEVELED

I part at 300ish rpm with lots of oil. I’m new, so I’m sure there are better ways, but this works for me
Your 300ish RPM equates to about 100sfm on a 1 1/4" diameter. That's plenty fast for a HS tool. Republic Steel recommends .0016" per rev for 4140 annealed. I never work barrel steel much faster than 80-85sfm. I was taught years ago to machine on barrels 'gently'. Running full sfm and max feeds can induce stress into the part being worked. When cutting-off, 200rpm with a feed of .001"- .0015" per rev under power feed, with a constant flow of coolant, has worked for years on lighter weight equipment. Just need to make sure your tool has proper clearance (top rake is built into the holder) and the edge is sharp with the blade stuck out no further than necessary. The tool needs to be exactly 90* to the work, also. I use "T" style blades of the proper size (P3 or P3N) in a quick change holder on a BX tool post. I found a bunch of those P3s and P3Ns made by Cleveland Twist on ebay. Got a 'life time' supply as they can be re-sharpend many, many times. I keep two c/o holders, 1 with a 1/8" wide P3 and the other with a 3/32" P3N.
 
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Thanks to all for the suggestions. I really appreciate all the info.

Thanks,
Acsr
 
This picture is of the parting tool I have been using. I need suggestions on what parting tool would be better because all I get is chatter!!!! I have adjust the speed of the lathe with no correction. Any and all suggestions are greatly appreciated. Thanks, acsr
Make sure your tool is on center. i got a scare on my face when i was a apprenrice, and yes it did;nt help i'm still ugly.
 

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