[Newbie] 3C collets

GrayTech

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I got some 3C collets in a tool lot I bought while visiting Poland and would like to find out how common they are and which machines use them. I don't currently have anything that takes 3C (I currently use ER32 and ER20 in my lathe and mill). I have 2 sets of metric 4, 6, 8, 9, 10mm.
 
Thanks for that guys.
Looking around at 3C collets to make up a complete metric set but 3C collets seem to be pricey, maybe I should just pass them on to someone who's machine is set up for them. I was thinking of making a 3C cutter holder for my tool grinder, as I don't currently have many metric ER collets. I already have sets by 64ths of imperial in ER32 and ER20. Also probably wiser to standardize and get metric sets of ER32s and ER20s as they're pretty cheap and I'm already set up to use these in mill, lathe, tool & cutter grinder and collet blocks.
 
My Craftsman 12x36 lathe came with I believe a complete set of 3C collets. I have never used them. There is an MT3 adapter that holds the collets in the spindle and a draw bar to tighten the collets. What lathes can use them would depend on the adapter to fit the spindle.
 
Personally, I think you probably be best off reselling them on eBay. People with Atlas lathes need to use them, anything else is much more likely to use 5C collets for workholding.

ER collets are cheap and convenient, but they're really designed for tool holding, not work holding. They require a lot more insertion in the collet to hold properly without damaging the collet, and aren't really set up to use a backstop like 5C collets are.

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I used a set of 3C collets on my Grizzly G4000 (9x20) lathe. Bought an MT3 adapter and a closer from Grizzly. Had to adapt the closer, but that was pretty easy. If you have a lathe that takes ER collets, especially one with a spindle bore larger than about 13/16", you're probably money ahead to sell the collets.
 
Smaller south bend, logan and atlas lathes often take 3c or 3at collets. Basically any lathe that has the smaller hole thru the spindle, like 3/4" or 25/32", would likely take them.
 
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