size of set screw to hold gear to shaft?

Nov 12, 2006 30 Replies

I wouldn't use set screws. They do work in and get lose under real and continuous load. What's so difficult with the pinning? Mount the parts, drill through gear and shaft and drive in a pin. Use the pins that have a C-shaped cross-section and are made out of rolled sheet. Primitive and effective. No reaming nor tight tolerances, just a hammer. :-))

Nick

So 50% (roughly!) of the torque will be side load. Side load on a screw!? Do you really want that? I wouldn't!

Nick

On Mon, 13 Nov 2006 05:28:53 GMT, with neither quill nor qualm, Gunner quickly quoth:

It was a roll pin from the HF kit ($4 on sale) which saved the band saw so I could use it a bit. Speaking of which, did you ever have a chance to see if you had gears for that baby? Mail 'em with your Alice clips if you ever find them, too, wot? All that desert camo cloth is still sitting on a shelf.

-- Chipmunks roasting on an open fire...

Why do you consider a taper pin "essentially permanent"? Always mark a particular end with a tinny punch mark and they are easily removable with a drift. ...lew...

Because of bitter experience. Actually, these were steel taper pins in aluminum, and I think they'd been in about 50 years. I did repeated heat/cool cycles, penetrating oil for weeks, made a custom puller, drilled/tapped the big ends and pulled like a mofo. Of 6, one came out and the other 5 broke about halfway down so only the big end came out. I threw the part (a 15" steady rest) away and sold the lathe. Ever since, I've been scared of trying to pull taper pins. That's why.

Grant

The Clausinc/Metosa lathes we have are only a few years old and they have brass taper pins connecting the carriage drive rod to the gear box, good thing too. :-) ...lew...

And you couldn't reach the small end to drive them out? Well, they have to reach through and not end in a dead end hole.

Nick

Does the equipment that I made last weekend count? If so, then last weekend :-)

Mark

OH! OH! OH! Now I see. :-) Sorry for bringing it up. :-) ...lew...

Yeah, steel taper pins in aluminium would probably turn a bit permanent the fist time someone breathed near them :-(. Never had any problems with steel and cast iron though.

Mark Rand RTFM

Roll pins (as we call them) will tend to batter and open up their hole if they are used in aluminum in high torque/high impact applications.

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