New Bison 4" 5C Collet Chuck Runout?

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lens42

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I got one of these Bison 4" 5C collet chucks (http://www.ecolletchucks.com/BISON/BISON-4INCH-5C-MANUAL-COLLET-CHUCK.htm). I'm seeing about 0.0015" runout, measured without a collet by indicating the inner taper in the chuck. The Bison spec is 0.0004" TIR. It turns out that this chuck mounts straight onto my lathe spindle (I have a Wabeco D3000E - if your curious: http://www.lathes.co.uk/wabeco/), so there is no back plate to add error. When I indicate on my spindle's registration flange, I see about 0.0002" (I'm eyeballing between lines to read this). I tried rotating the chuck to all three possible mounting positions on the spindle to try and find a sweet spot, but all indicate the same runout.

Do I have a dud, or am doing something wrong? The 0.0015" runout is not awful, but I was hoping for better. Also, I expect more runout will be added by collets, so this may end up worse than my 3-jaw, which was not the plan. Bison is supposed to be quality brand, but it's still an import. Does that mean their printed spec is more of guideline than a real limit? I'm trying to decide if I should try a replacement, or just return it for a refund and look for something else.
 
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