Wheel Chucks and thier purpose:?

[James1983]

Hello again,

I am such a newb. I just got a set of 25 collets from a retired watchmaker and so far so good. decent range of collets from 12 - 50. I also have two "wheel chuck collets" what the heck are these sunken style step collets for?

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[Bob Tascione]

Hi James1983,
Wheel chucks are multiple step collets used for holding watch gears or round blanks for boring etc. It's important to use one that is very close in size to the O.D. of the gear to prevent damage to the teeth or distortion to the gear. Cement chucks and for larger gears even face plates can be used in place of these wheel chucks.
Hope this helps,
Bob

[James1983]

So they are meant to hold gears for watches? by the actual teeth? what purpose would you need to hold a gear like that in a lathe?

thanks for the info, now just wondering why? lol

[Bob Tascione]

One reason would be to bore a hole to a larger diameter to fit the shoulder of a new pinion. Also can be used to repair a distorted hole or drilling a hole into a disk or into a piece of round stock that is too short to grab in a normal collet. Can be used for facing a small round part. Yes you can hold a gear by closing around the teeth with the proper sized wheel chuck. The fit between gear and chuck must be nearly perfect. If the wrong size chuck is used then damage to the gear teeth is possible. Sets of 10 chucks are common for watch repair as this range will accommodate most watch gears. In my opinion cement chucks are a safer way to go but will take longer to set up and center.

Hope this helps James1983,
Bob