Feed screw

[Bobm90]

Hi guys,
It seems like I always come here for correct reliable answers because I know you guys have em.
I am trying to find a die to chase the threads on a feed screw for my Edison Home Model B, I measure it with a micrometer and get .615 actual, this is almost ⅝ (which is .625) I think the threads per inch are 100, of course I find no such die that size. Do anyone of you know the correct size of these feed screws, I would think they would all be the same, or would anyone know where to buy a good feed screw, ½ nut and ½ holder for this machine. Thanks in advance for your input.
Bob

[phonospud]

The thread Edison used was a buttress profile thread, it’s is not a standard 60 degree profile thread. Years ago I had a feed screw blown up on an optical comparator by a tap and die company. If you rethread it with the wrong profile, you will ruin it. A 60 degree profile will not work on this application.

[edisonclassm]

Darren is absolutely correct

[tomb]

I have used the half nut several running times lubed with W 40 to try to regroove or clean them out. It worked for me several times . Tom

[JerryVan]

I have used the half nut several running times lubed with W 40 to try to regroove or clean them out. It worked for me several times . Tom

Good that it worked for you. However, you're just as likely to regroove the half nut as you are the feed screw.

I have cleared small nicks with a small, extremely fine file, with the edge sharpened like a knife. Takes great patience and a good jeweler's loupe.

[Curt A]

I agree with Jerry's use of a small file. I have used a small diamond file to correct rust defects by running the machine and holding the file against the rotating feedscrew like a lathe...

[Inigo]

In any case it seems t to be a delicate operation... Any bump and the screw will be ruined!