Woodruf (halfmoon) Key question

[MPH 12]

How nessary is it to use the dog eared keys instead of reg. ones in places like the BGB input shaft. The one on the B-112 been running with no set screw for who knows how long. it's a little hammered out, I have a better one but not a new one. Not available locally. Dog eared on the right.

Thanks for any info

[MDB 134]

Trying to remember....I don't think any of the one I have worked on have the dog eared keys. a regular one should work just fine. JMO

[RayS 79]

I rebuilt a BGB for HB 212 two months ago with new keys from the Simplicity dealer and the ones that I got from him were standard keys without the dog ears.

[Ronald Hribar 91]

I belive the key without the dog ears is fine. However I would drill and tap sprocket and put at least preferably two set screws in. There may not be room to do so.

[GWGAllisfan 159]

I've never even seen a dog-eared like that. How rare are they?

[comet66 0]

I'm not familiar with this particular application, but the only place I have come across the dog eared key, is when the gear it locates slid on the shaft. The moon portion of course kept the key from sliding with the gear. The ears on either side, kept the key from rocking out of the keyway when the gear was at one end or the other. I don't know if this is the only reason for this design or not. This one was in a two speed gear box on an industrial machine in a factory. I don't remember now just what my journeyman called it, (39 years ago). I hope this makes sense. If the gear stays stationary on the shaft, I don't know why you would need that style.

[D-17_Dave 12]

The dog ears are just to help w/ th instalation of the sheave. Some applications with a somewhat loose groove will let the key roll out of the grove if not watched closely when slideing the pulley or sheave up on the shaft. Other than that there is no diff. as the pulley traps the key in place so it doesn't matter where the set screw seats on it.

[MPH 12]

Thanks guys, think I'll just a new one in. Thought maybe the extra surface contact inside the yoke was important. Ron, the yoke is taped for a setscrew and the treads are good, it was just MIA.

[firefoxz1 4]

Thanks John(comet66). That makes a lot of sense about the ears and never thought of that. Funny how when you here something it just goes click in your head like "that's it".

[HubbardRA 19]

The last time I replaced a dog eared key, I bought a larger size woodruff (same thickness) that was the same width as the dog ears. Then I ground the round part of the key to fit the cut in the shaft. In other words, I made a dog ear key from a larger size woodruff.