Does anyone know a method for turning eccentric banking screws? I have been able to make them in a standard screw-making manner, then bending the banking pins to achieve the eccentric effect, but surely there has to be a trick to actually making one properly. Any thoughts?

Mike Miller
NAWCC Member# 154831
NAWCC-IHC Charter Member# 27

Mike,

I've never done this, but I think it would work. Select the size of brass wire you will use and turn the stump to the size you need. If it is to be threaded, this would be the time to do it. Also, cut the screw driver slot at this point. Then, drill a hole slightly larger than you require for the banking pin stock in a wax chuck, of a size the you have a collet chuck for. Mount the banking pin stock in the wax chuck and shellac it in place, off centre. Put the wax chuck in your lathe and carefully turn the off-centre pin on the stock, warm the wax chuck to remove the stock, and clean it up. Maybe someone has a simpler way? I'd be glad to hear it.

Regards,
Doug S.

What Doug suggests would work fine, but the job could also be accomplished using a three or four-jaw lathe chuck.

With a four-jaw chuck, the jaws can be adjusted off center to allow the proper offset. With a three-jaw chuck, a small spacer can be placed between the work and one of the jaws to achieve the correct offset.

Personally, I'd use a three-jaw chuck and spacer, which should produce relatively uniform results, but there's more than one way to skin a cat!

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Steve Maddox
President, NAWCC Chapter #62
North Little Rock, Arkansas

Thanks Doug and Steve!

Both sound like very good ways of accomplishing this. Alas, I don't have a jawed chuck for my lathe (hint... anyone looking to sell one ), so the wax chuck will have to sufice for now. If I manage to acomplish anything worth sharing, I'll post a picture!

Mike Miller
NAWCC Member# 154831
NAWCC-IHC Charter Member# 27

Mike,

I have used Steve's four-jawed chuck method of turning eccentric, adjustable bearings for a tower clock anchor, and it works well. If there is such a thing as a four-jawed chuck small enough to turn something as small as a banking pin, I dont have one. As I said in my original answer, I've never used that method to turn an eccentric banking pin, so I look forward to your report as to whether it will work or not.

Doug S.