Keyways

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Bob D.
Posts: 381
Joined: Thu Jun 21, 2012 10:43 pm
Location: Saco, ME. USA

Re: Keyways

Post by Bob D. »

I ended up going with all woodruff keys and keyseats. Used specs from the Machinery Handbook. The proper cutter yielded a slight press fit of the key into the keyseat. It stays in place well. The key ways were broached to a depth that doesn't allow much clearance at the top of the key. It is not going to rock up much more than a few thou. Has already been together and apart a few times with no issues.
Here is a peek at the madness showing the bare axle and two of the 3 Woodruff key seats.

Bob D.
Attachments
IMG_1655.JPG
3/4" Juliet II 0-4-0
3/4" Purinton Mogul "Pogo"
3/4" Hall Class 10 wheeler
3/4" Evans Caribou/Buffalo 2-8-0
3/4" Sweet Violet 0-4-0
3/4" Hunslet 4-6-0
3/4" Kozo A3. Delayed construction project

1 1/2" A5 Camelback 0-4-0
tetramachine
Posts: 236
Joined: Sun Mar 19, 2006 6:27 pm
Location: NJ
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Re: Keyways

Post by tetramachine »

When the time comes to cut the keyways in the bores, You will find that the bushings and broaches will conform to the NEMA standards. So you won't find a std. bushing that uses a B size broach, at a 1 3/16" bore. That needs a C size broach, and the smallest keyway is 3/16 with a C broach. You can make your own bushings to fit a B broach, but keep in mind that the length of the cut, is dependent on the size of the tooth gullet of each size size broach. A B broach is 1.5" length, a C broach is 2.5'
My wheels don't slow me down
Bob D.
Posts: 381
Joined: Thu Jun 21, 2012 10:43 pm
Location: Saco, ME. USA

Re: Keyways

Post by Bob D. »

I just made my own bushing to fit the broach I had. Was easy since I had a stub piece of the axle. Add shims behind the cutter until the proper depth is achieved. I went with the 3/16" as I had the tooling and met my load requirements. This is broaching the dual drive sprocket hub. The gnarly Spacely Sprocket at the bottom of the stack just lives on the press........

Bob D.
Attachments
IMG_1653.JPG
IMG_1652.JPG
IMG_1660.JPG
3/4" Juliet II 0-4-0
3/4" Purinton Mogul "Pogo"
3/4" Hall Class 10 wheeler
3/4" Evans Caribou/Buffalo 2-8-0
3/4" Sweet Violet 0-4-0
3/4" Hunslet 4-6-0
3/4" Kozo A3. Delayed construction project

1 1/2" A5 Camelback 0-4-0
jpfalt
Posts: 982
Joined: Sun Jan 05, 2003 12:55 pm

Re: Keyways

Post by jpfalt »

A properly fit woodruff key is set up so the set screw is offset from the center f the key radius. That way the set screw rotates the key in it's pocket so that the set screw and opposite end of the key clamp the hub in place with approximately twice the clamping force of the set screw alone. This makes for a more robust lock between the shaft and hub.
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