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Pratt and Whitney Model C 16/30

johnoder

Diamond
Joined
Jul 16, 2004
Location
Houston, TX USA
Sometime during its 20 plus years here, this 12 X 30 had its ratio box off to fix a sheared key - so I know that gear box comes off.:)
It left here in 2005

(this is from 1950, so the bare beginnings of the "squareish" head Model C - ass opposed to the "slope head" originals)


good little lathe
 
Last edited:

binzer

Plastic
Joined
Apr 25, 2022
After doing some research today on a couple model b lathes, I can now understand what this dog tooth looks like. It was tough to see clearly in the parts listing. Added the first two pics from another post. link below.


So now when I turn the drive rod I can feel the dog tooth in reverse and not in forward. Although when I help the detent out (attached pic in red circle) and keep firm pressure on the clutch, I can feel the dog tooth in forward - mind you I think I can feel some rounded edges. Is it possible this wear is actually caused by the detent spring wearing out over time and not holding the correct pressure allowing it to slip back?

I am going to remove the detent and change the spring to something stronger and see how that does, but I still think tearing down the ratio box to get to that forward dog tooth is the right thing to do. Even if I can reform some square edges on it at the least.
 

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  • Dog tooth 1.JPG
    Dog tooth 1.JPG
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  • Dog tooth 2.JPG
    Dog tooth 2.JPG
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  • PIC6a.jpg
    PIC6a.jpg
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