Turning Aluminum at 1400??

I'm surprised anyone makes a small lathe with such a low maximum speed, the Myford Super 7 was capable of over 2000rpm and is a very old design.
 
T Bredehoft said:
Speeds are specified for those who need to spend as little time as possible, (production).
Those of us who play in the shop are not required to use the fastest speed. There is no penalty or reason not to go slower than the max. Finish will not suffer.

Edit: Speeds, not feeds. CSR kicking in. Mia Culpa.
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Exactly, I was pointing out to the OP that slower is not a problem. 1700 RPMs at 1/2" diameter is 220 FPM.

I rarely run a lathe above 2000 RPMs with a 3 jaw chuck because this vaporizes the coolant, a collet chuck is a different ball game however, it has no fan blades (-:
 
Slower is fine if slow is fine for you.
I've always had so many things on the go that it's been advantageous not to go slow just for the sake of going slow, I've never enjoyed doing anything in a sub-optimal way and I always enjoy learning and applying new things.
That's not going to change if I retire unless I complete all the projects on my list, and it's a long and growing list :D
 
I understand the desire to be as “efficient” as possible. However, I am retired and am not pressed to finish a project in the shortest amount of time. I recently purchased a mill and will use it along with this lathe to do small projects in my shop at the farm. I just want to make sure I am not eliminating the possibility to work on small diameter aluminum stock with a maximum of 1400 RPM.
 
I run a 12x36 and rarely go into the high speed ranges due to a slightly annoying belt change. As such my top speed is 550 rpm. I do 100% of my aluminum turning with carbide aluminum specific inserts and get great results. When doing very small work I might hop up to 1200 rpm but that's rare.
 
Alu is soft as butter and will cut with most-any tools at whatever rpm, and doc.
Finishes are decent, not great.

High rpm has a big flywheel effect, and can result in exceptional finishes and accuracies.
The spindle stabilises, and thus the workpiece vibrates less, at high rpm.

It wont matter for hsm homeshop users, and any final sizing is easily done with abrasives.

I use ccmt 21.51 inserts for tool steels (98%) and everything else like alu and brass.

Biggest improvement ever was a 0-100% analogue feed and spindle speed override on a real servo motor spindle.
After some time, my rpms went way, way up, and the results got even better.

But you do not really need a variable speed spindle for alu, at all, nor for steel - for decent results.

New ccmt inserts will leave mirror-like finishes on alu and tool steel, for a while.
The edges wear and the finish suffers, over time.
On alu the edges last very much longer.

I bought a 100-pack of inserts maybe 6-7 years ago and half are gone.
Around 2000 hours of cutting time in tool steels, mostly big stuff like 200x200x70-50mm blocks, in a 10" 4-jaw.
12x24 lathe, chester craftsman.
 
I'm a big fan of the positive rake high polish inserts specifically for aluminum like the CCGX and TCGX.
 
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