Lathe RPM and Proper Cutting Speed

[Phil3]

My 1946 vintage Southbend 9A lathe is the 6 speed version, which means its top speed is pretty low. I measured it at about 580 rpm. Since I typically machine aluminum and small stock that is 2" down to .375 in diameter, should I try and get an optional used dual pulley setup for the lathe that bumps its top speed to about 1200 rpm? Besides the work progress being slow at the lower rpm, am I hurting my finish going slow vs the faster cutting that aluminum will tolerate? The dual pulley setup is about $200 with shipping, and I need to get a new drive pulley for the motor and a belt. So figure $250 all said and done.

- Phil

 

[GK1918]

I think you should leave it alone, sounds like mine has the same rpms as yours. I dont have problems with brass or
alum. just slow down the feed rate. Or thats my way.

 

[FarFar]

My Boxford sits on a piece of rock and is driven by a VFD.
Yesterday my newest Tangential holder with a homeground piece of carbide did 20 minutes of cutting 1.5mm(1/16inch) deep with a feed of 0.0027 inch per rev.Revs were 1300 rpm and mild steel of unknown origin 3 inch diameter.
Block of rock,VFD and motor cost 350 USDollars.
You cannot do anything like it with normal setup.

 

[Maglin]

Where did you get your 1/4" carbide square tooling? I would love to have a 1/4" square and 1/4" round carbide tool for my tangential. I get so tired of sharpening it all the time. I use mine on steel a lot and when I'm ready for the finish pass I throw a stone on it to give me that perfect surface finish. BTW I actually use the round tool more than the square until I need to machine to a shoulder that needs to be square.

 

[FarFar]

Hello Maglin

My 5 mm square carbide tool bitt was made by wiresparking EDM from an old and broken 8 mm milling bit.

You can buy square and round carbide sticks from

wilke-tools.com

Kind regards

Farfar