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Attachment runout

Posted: Thu May 30, 2019 1:11 pm
by moggymatt
General question on attachment runout.
My arbor has zero runout. That's fantastic.
My 6" cast faceplate had .001 to
002, set screw loose or tight, and its diameter is rough. That's fantastic.

My Oneway scroll chuck has about the same, .001 to .002, along its widest diameter. Love it. But that's with the set screw loose. Tighten the set screw and the runout almost doubles.

My Nova scroll chuck, on an adapter that extends the chuck further than the Oneway, has less than .001 runout when the set screw is loose, but .003 - .005 runout when the set screw is tightened


Never occurred to me to even check until my current project.

Anybody else ever check or get similar results?

Re: Attachment runout

Posted: Thu May 30, 2019 6:13 pm
by Hobbyman2
up until I replaced my quill I had major issues , especially when applying cutting pressure .
since then everything seems to be ok , as far as chucks go I only have the one barracuda chuck , it appears to be with in .001 - .002 , my thoughts are it has to have some give so the quill shaft will slide in, then when ya tighten down the set screw it shows the difference ? JMO I could be wrong ?

Re: Attachment runout

Posted: Thu May 30, 2019 6:55 pm
by jsburger
There has to be some clearance (a few thou?) in the bore of the chuck so it slides on easily. When you tighten the set screw it pulls the chuck to one side by 1/2 the clearance. You also don't know the accuracy of the diameter your measuring the run out on.

I certainly would not loose any sleep over it.

Re: Attachment runout

Posted: Thu May 30, 2019 10:01 pm
by sehast
Adapters are are always suspect for creating runout. One or two thousandths is no big deal but .005" is kind of a lot. I would take a close look at the adapter and maybe consider replacing it if you can't reliably get at least .003" runout.