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Poor man's 8-jaw set-tru chuck

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  • Poor man's 8-jaw set-tru chuck

    Well; not really but ER32 collets do have 8 slits & "jaws." The set-tru function comes from the collet chuck's flange bore I.D. being larger than the lathe spindles's nose taper allowing it to be slid around by 4 brass-tipped 10-32 allen screws. You snug up the chuck flange nuts, dial in a perfect runout then finish tightening the nuts. Works a treat and allows dialing in a collet that happens to be off a little or in my case when repairing existing part features that aren't perfectly concentric.

    The smallest brass I had in the shop was 1/2" dia. and really didn't want to waste that turning it down to 5/32" so I found some 1/4"-20 brass screws at Home Cheepo @ 2 for a buck & change. Way overpriced but within my budget. The alloy is unknown but machined beautifully and doesn't mar the spindle taper.

    The 3, 5/16"-24 studs came out of a dusty drawer in my toolbox and were left over from my days working on MGB's. They go right along with the British Denford ORAC lathe theme. Fortunately, the metal in the chuck is tough but machined OK with HSS tooling. Couldn't pass up the $29.99 from although now they're out of stock.


    "Accuracy is the sum total of your compensating mistakes."

    "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

  • #2
    Very cool.
    The shortest distance between two points is a circle of infinite diameter.

    Bluewater Model Engineering Society at