[tjbaudio]

I have a bunch of aluminum parts I would like to turn using a lath. All about 2” to 4” in diameter and 2” to 3” long. Lots of copies of each part. This has the potential of being on going product runs for me. Fairly wide tolerances. Surface finish is more important than final size. These may get powder coated or anodized. The only critical tolerances on the parts are some pipe threads and that I will do with a tap or some other thread cutter in a separate operation.

At this point all I have is an SX2 mini mill Mostly converted to CNC. It can do the parts I want but it is VERY slow at it. I have experimented with attaching the parts to the spindle and using the XY table to hold the tools. It works fairly well. I get a good finish but it is still pretty slow going. A thought I had was to use an external spindle belt driven by a 1 or 2+ HP motor. I could mount the mill and aux spindle assembly to a rigid work surface. The spindle would be horizontal to the table. The table would have a few tools mounted to it in a custom holder at the center line of the spindle. I am thinking just a couple of drills and some carbide inserts in boring bars.

I know long term a VMC or other CNC machine may be a better choice. However, I am thinking the machine I have has the precision needed for the parts, just not the horse power. Any thoughts on the idea of a high power spindle using the table of a bench top mill as a tool holder?

[Fastest1]

Use the mill as a lathe? Why not? Swap the axis' and work away. Plenty have done it very well. Why not use a thread mill too to take care of the threads all in one operation?

[tjbaudio]

Why not use a thread mill too to take care of the threads all in one operation?

I was not thinking of a spindle that had any sort of indexing or even much of a speed control. Just a cheep 1750 rpm motor belt driving a spindle. A HP or 2 so I can take relatively fast/heavy cuts.

I envision doing the thread milling with a thread cutter in the original spindle and the part mounted to the table with a fixture or jig. The cool thing about the parts I am making is ALL could be turned as blanks with the high power spindle and then coated. They will need a second opp any way and the threading can happen then, based on what option is ordered.

I guess I was more concerned with can the XY table handle the forces generated by holding a tool. Especially knowing the aux spindle would be FAR more powerful than the original machine.

[bogiestl]

Uh... Didn't you just describe a thing called a "lathe?" (grin - I know you did in the first line, but... seems to me you're trying to adapt something rather than do it right the first time)

You can try to set something up with a headstock and a table to hold the tools, but I'd want 'em bolted to a nice heavy piece of steel... Or see if you can find an old Hardinge 2nd operation lathe, and then try rigging a table to the big dovetail... But you might be best off just rigging one of the 12x36 lathes, given the 4" diameter workpieces.