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Looking around for a replacement, for a bell collar thumbscrew for my 1941 Holton, I can see why it has been getting along with 2 for lo these many years, before I got it anyway. The thread is 1/4-24 (looks to me anyway), which apparently was not that uncommon before WWII but hasn't been used since. I found a screw for a Duesenberg generator shaft, but not really interested in that because, for one thing, it's steel. The repair shop around the corner offered to re-tap the screw receiver, I suppose for 1/4-20. I'm thinking I might be able to find a machine shop to make the darn screw. Anyone ever do that? Would I need to bring a spec for the brass, so it isn't harder than the female threads? It has been a while since I visited a machine shop, and I'm not sure they haven't all been displaced by fancy restaurants, but last time it was fairly painless.

Send me the measurements of a good one or a clear profile picture and I can do it on the lathe in brass or other metal. I may have a 1/4-24 die or I can single point it. No guaranty that I can match the knurl. Brass is not particular about compatibility, I know that I have some 360 on hand.

The only place where I've ever seen a 1/4-24 thread used is on the Model T ring gear, where it's screwed (with brass screws) to the flywheel with the magneto magnets -

https://www.modeltford.com/item/3278.aspx" target="_blank

90 cents each, should you be interested in cutting and brazing.

roweenie wrote:The only place where I've ever seen a 1/4-24 thread used is on the Model T ring gear, where it's screwed (with brass screws) to the flywheel with the magneto magnets -

https://www.modeltford.com/item/3278.aspx" target="_blank" target="_blank" target="_blank" target="_blank

90 cents each, should you be interested in cutting and brazing.

Thanks! I got a couple of those, and managed to bang together something usable. The top was a nut, $1.49 at the hardware store up the street, with the seat filed off, and 1/4 x 20 threads. I cut off the threaded end of the magnet bolt, ran the nut on as far as it would go, and filled the hole with solder.


It's a little longer than it should be - when I cut the bolt, I was hoping I could run the nut on farther - but works OK. (It looks small, and in fact the thread diameter is a hair less than 1/4", but the visible difference is just perspective.)

(And of course thanks to all the rest of you.)

Nice job - glad to have been of service