Machining 4140
#2
Use good sharp carbide tools.  Rough it in about .050" oversize then let it cool off to room temp.  For roughing use a .062" radius on the tip and finishing .032" or less. Start with .010" feed and increase it until your getting nice 6's and 9's.

You didn't indicate if you have carbide insert tooling or if you need to use cemented carbide.  Another factor is the size and condition of your lathe so I cannot recommend depth of cut.  If you have a nice tight American Pacemaker you can take .250" deep cuts with the right tooling.  A 13" South Bend is going to balk at .050".  BTW, I've taken .500" deep cuts in aluminum bronze with a MoMax HSS 1" square tool ground with a chip breaker that would throw the chips off to my right in a Pacemaker.  Machine tool and tooling make a big difference as the ensign who was getting under my feet found out.   Rotfl BTW, I was a Second class Machinery Repairman (E-5) with less than 90 days remaining in my enlistment. Big Grin and I didn't give a da#n.
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Messages In This Thread
Machining 4140 - by Cross Slide - 07-03-2020, 03:44 PM
RE: Machining 4140 - by Dr Stan - 07-03-2020, 07:37 PM
RE: Machining 4140 - by Cross Slide - 07-04-2020, 09:28 AM
RE: Machining 4140 - by EdK - 07-04-2020, 10:40 AM
RE: Machining 4140 - by Cross Slide - 07-04-2020, 10:58 AM
RE: Machining 4140 - by f350ca - 07-04-2020, 06:24 PM
RE: Machining 4140 - by Dr Stan - 07-04-2020, 08:42 PM
RE: Machining 4140 - by Cross Slide - 07-04-2020, 10:49 PM
RE: Machining 4140 - by Cross Slide - 07-04-2020, 10:54 PM
RE: Machining 4140 - by EdK - 07-04-2020, 11:01 PM
RE: Machining 4140 - by Cross Slide - 07-04-2020, 11:07 PM
RE: Machining 4140 - by Pete O - 07-05-2020, 05:53 AM
RE: Machining 4140 - by Cross Slide - 07-05-2020, 11:09 AM



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