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bflint
Rich,
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I'm getting good results on mild steel like 1018 using HSS tools with no coolant. What type of inserts are you using? I haven't gotten as good results with coated carbide inserts no matter what I seem to try. Carbide generally likes higher speeds and deeper cuts. The HSS inserts from LMS in indexable tool holders have worked well for me, as have ground HSS bits. I'm getting a good finish with relatively light cuts anywhere from .001" up to about.020". For 1/2" diameter, I'd have the dial on my machine about halfway on the low range. Assuming that's about 600 rpm, I think we're talking about 75 feet per minute surface speed, which is well under the recommended max for turning mild steel. I'm also getting better results with steel now that I have completed the JWE compound mods and have a good size QCTP (series 100). It's more massive and more rigid than the stock mini lathe toolposts. You also have to make sure you have the gibs on the cross slide and compound snug. Also, if you're turning a workpiece longer than about 2 or 3x the diameter, you probably need to have the tailstock end supported by a center. Otherwise it will deflect and give you a bad finish. I'm sure other people may use different setups, but that's what has worked best for me. B Flint ----- Original Message -----
From: "Richard Kleinhenz" <woodnpen@...> To: <7x12minilathe@...> Sent: Sunday, March 30, 2003 5:37 PM Subject: [7x12minilathe] cutting speeds I understand that cutting speeds published in the books are generally usedfor large machines, and that they are totally inappropriate for our 'toys'. (I have a 7x12). We should go by what feels right. steel. Where should I be approximately? I have an inexpensive indexable toolset from LMS. The surfaces I get are nothing to write home about... Can anyone with some experience steer me in the right direction? Should I always apply cutting oil? How much to remove in a pass? What speed? I am on the low range. What dial setting appr.? It seems easier to take a heftier cut than a small cut... something seems wrong ;-) Is there something like a lower limit for a lathe cut? make, but I sure would like to do it better eventually.
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