.007" diameter reduction on Aluminum

[martik777]

Need to reduce some 5/8" 6061 to .618 for a length of 2" - 100 pieces. My chuck has about .004-.005 runout but I also have an ER collet chuck I can use
How would you do this?

 

[machPete99]

If you can set your ER collet chuck to run true that would probably be a good option. Maybe mount it in a 4 jaw if you have one, otherwise shim it as needed.

 

[Mitch Alsup]

Generally extruded 6061 is only visually round.
I have seen 6061 rod more than 0.007" out of round (mainly 3/4 and 1" stuff.

Collet chuck is faster if you can throw away a few pieces.

 

[Batmanacw]

I'd used the collet chuck but the stock isn't perfect. I'd check each part out by the end with an indicator and bump it true if needed before turning. I have an indicator I dovetailed to fit my qctp.

 

[Aukai]

I do not know about the smaller diameter stuff, but extruded may not clean up at .007.

 

[martik777]

Measured it at .622 to .624 so it's going to be tight. Maybe a big file?

 

[Aukai]

Are you using CCGT inserts? You could also use emery cloth.

 

[martik777]

DCMT inserts or just sharp HSS

Some 120 grit emery works but takes some time to get even

 

[Aukai]

I'm sure you already know, aluminum clogs emery, I keep it cleaned off with WD-40, and it goes pretty quick.

 

[markba633csi]

If your collet system is fairly accurate I would use that. Especially if you need to do several pieces
-M