re:- another question.

Nov 28, 2003 4 Replies

Why not make a new shaft ? I'm afraid that I have always had reservations about welding power transmission shafts, the heat applied has unpredictable effects on the hardness of the material. My company did a similar job on a



300 hp slip ring motor shaft a couple of years ago, the motor was driving a primary crusher in a quarry. The crusher ran up to speed OK but as soon as stone went in the shaft snapped like a carrot, and that was 41/2"diameter EN8!!

Hardy surprising as EN8 is a thru hardening steel and it isn't advisable to weld it. A lot of people make the mistake of welding and quenching which can have all sort of adverse effects on parent metals. If you weld and allow to cool naturally this takes all stress out the material and stops any local hardening taking place. ___

Duct tape is like the Force. It has a light side and a dark side, and it holds the universe together.

My concern would be unexpected results from local annealing or hardening, but as it's been running in less than perfect conditions for years (!), I think I'd do it your way Roland.

If I liked him a lot, I'd measure it up and idly look around for steel to run up another if it wasn't too difficult. Materiel? I love half shafts - easily available at cheap prices in a range of sizes, already end in a frequently useful flange and made of tough - but not brittle - steel.

Regards,

Kim Siddorn, eschewing banality

In message , John Stevenson writes

I'd have to take issue with the 'takes all stress out" part. Why would fabricators use stress relief, especially on thicker sections, otherwise?

I worked in the metallic fabrication industry as an NDT technician for fifteen years and have lost count of the number of oil production platform components I've had to re-test after they'd come out of a

48-hour soak at 600C in the stress-relief oven.

Regards

Pete

Having now stripped it I think making a new shaft will be less work, after all once the shaft is set up for keyway milling one's as easy as two. The original appears to be 45mm black mild. Replacement from EN16? ttfn Roland

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