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American PW straightening pivot

Doug Davies

Registered User
May 23, 2006
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I am planning to try to straighten the seconds hand pivot on a Howard N size using a method De Carle recommends, involving drawing the pivot straight with "warm" pliers. Has anyone tried this? Any advice on how "warm" the pliers should be? Seems to me the purpose is to bring down the hardness of the pivot, so they should be quite hot. I have a spare part, so this is just a learning experience. Thanks.
 

doug sinclair

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Aug 27, 2000
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Calgary, Alberta
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Doug,

As metal bends one way, it hardens. When you try to bend it back to the correct position, it continues to harden! The risk of it breaking increases! The way most often recommended is to take the temper out of the arbor, straighten, then re-temper the arbor. On a tiny steel part like a fourth wheel arbor, heating with a flame cannot be done with the wheel on the arbor. That, plus heating a small part like that and allowing it to cool quickly once the heat is removed, only adds to the problem because the arbor is tempered in the process! I have used a pallet stove successfully. The arbor (with the wheel) is clamped in the pallet stove and the tail piece of the heavy brass pallet stove is heated until the arbor becomes hot. The pallet stove keeps the arbor HOT long enough that the temper is removed from the arbor. The pivot then is far more likely to respond without breaking. Once the pivot is straight, the process is repeated, quenching the warm arbor to re-temper it, then polishing of the pivots. Anyone else with a helpful suggestion?
 

LarFure

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Nov 30, 2003
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www.lfure.us
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I have used DeCarle's method of drawing a pivot straight with some success. The only difference being that I used a tweezers that I shaped in the prescribed way instead of a pliers. Take your time while doing this and heat the tweezers/pliers often. If you use this method on a balance pivot make sure you burnish the facets out of the pivot when you have it straightened out.
 

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