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View Full Version : Optomizing Surface finish.



Boucher
07-20-2009, 04:18 PM
The surface finish that Evan demonstrated on pipe in another thread really got my attention and admiration. I know that on HSS bits nose radius is important. What are those tipe of fundamentals that go into producing a fine turned finish. I have a Nardini 1230 lathe. It is not Big Iron but it is substantial with flood coolant and high speed avaliable. Most things that I turn are less than 2.5 inch diameter. 416 stainless and 7075 T6 have been fairly easy but things like that pipe I haven't had much luck with. It is time to put luck aside and learn how to do it correctly. Lets start with 1 1/4 - 2" pipe and 2" stressproof which I have in good supply. Your help is sincerely appreciated. Give me some inputs and I will start with Evans 800 rpm and .020 cut. What feed rate would you try first?

GadgetBuilder
07-20-2009, 05:30 PM
I use a peculiar bit for finishing, might not work for all materials but it is easy to grind and worth a try:
http://www.gadgetbuilder.com/VerticalShearBit.html

John

tattoomike68
07-20-2009, 07:59 PM
I will start with Evans 800 rpm and .020 cut. What feed rate would you try first?

I would run carbide with a honed nose radius and use .008" to .012" feed and run 1,300 RPM for a light finnish pass like .020" DOC.

After that use a bit of emory cloth just be carefull. if you then have some worn out emory cloth cloth you can get a real nice finnish, you can hold your finger up to the shaft and see your finger prints in the refection. then its good to go.

For milling I like to finnish pass .002" with a 2.5" face mill at 4,000 RPM and feed it fast, close to rapid traverse. If you have a VMC with a 10,000 - 12,000 rpm spindle run it redline at 120 IPM. It will look just fine.:cool: