Anyone make a small hydraulic expanding mandrel?

I've got a part I'm making that I need to hold by the ID for
external post anodize machining. I'm cutting decorative
flutes with a full radius carbide saw blade, the small
diameter to reduce how far the mandrel will have to extend
beyond my indexer. Using a Hardinge Universal dividing head.
Not only is this not really ideal for a traditional 5C
expanding collet, I haven't found one that extends 2". Royal
declined to quote a special despite my assurances cutting
forces were very low.
In searching for an answer I did run across some nice
hydraulic expanding mandrels. I am sure they are out of my
price range, but got to wondering just how hard it could be
to make one. I want to hold a .592 dia along the better
portion of it's 1.3" depth, and have a thru hole in the end
I hope to use to access the screw that provides the
hydraulic pressure.
The decorative fluting is cut into contoured profiles on the
OD of the part and any significant runout results in cuts of
different lengths. Reason for thinking hydraulic expansion
is to improve the runout, and to provide better support for
the part to avoid possibility of vibration/chatter. Been
doing the prototypes on a solid mandrel with a screw/washer
through the end to clamp. Works, but not ideal.
Anyone do anything like this before? Have any better ideas?
Reply to
Jon Anderson
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Why not use a good old fashioned expanding tappered lathe mandrel? about $65 in the size you want.
Reply to
Ah, didn't clarify the situation. Part steps from the .952 dia to a 5/16-24 hole. Also, I am looking for a pretty quick load/unload cycle. Volume is low right now, but I could end up doing hundreds at a time. Thanks for the suggestion.
Reply to
Jon Anderson

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