Half Nut Repair

[bazmak]

Using spot heating and cooling to stretch and shink material to remove distortion etc i think is a dying art.Used to use it to remove dents etc in sheetmetal but not easy as the oldtimers made it look

 

[goldstar31]

Like Bazmak, I could do it. The old boys used wet asbestos, made finger holes and a oxygen acetylene torch to heat it up to red heat.
Alternatively, using stretching and shrinking hammers could be used cold to remove what was known as 'oil drumming'

Passed the 'drum shop' which was part of International Paints on Felling Shore to pick up the repair bits for my sit on mower!

More of all our yesterdays, and Spitfire elliptical wings were made this way.



Almost impossible to describe further but my father, his brothers and old grandpa Sam were all blacksmiths.

Probably the way to start to understand the principle is to bend a bit of steel bar cold in the vice and then heat it up red hot and sprinkle water on the wrong side. Interesting and not for the armchair experts!

Norm

 

[Hopper]

You did pretty good getting it back that true. I've seen the leadscrew flipping trick down with pins before but never welded. Good job!

 

[ShopShoe]

Here in the U.S., one of the gurus of shaft straightening is Keith Fenner. Go to Youtube and search for "keith fenner shaft straight" and you'll find some videos of him doing it. He runs a job shop and does many types of repairs which involve lots of variety in skills.

I've done the shrinking with sheet metal in car restoration, but I did not do enough of it to get good at it. The main thing I found out is that having an oxyacetylene torch is a wonderful thing.

Best of luck and kudos to those who use heat to move metal.

--ShopShoe

 

[restore49]

This explains better than I could. Still have my Fathers wood paddles and taulk pads from when he lead filled truck body panels. I hung pipes from the short and long ends to get in the ball park then less weight as I closed in on straight. With long heavy shafts its own weight works in your favor.

Tried to attach U tube of Keith Spot Straighten shaft.