How To: Recut Threads

For when a nut unscrews OK, but won’t screw back on the sightly stretched thread...

 

1: To aid tightening the wheel nut, pegs on a Sunbeam wheel spindle engage in slots in the stub axle. Excess force burrs or distorts the axle so the threads won’t start. Thread filing didn’t cure it...

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2: A screwcutting lathe can clean up a damaged thread, but there’s not much to hold. Gripping the thin flange in the chuck, a rotating centre supports it, keeping it reasonably square.

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3: Set the gears to the correct pitch (26tpi), and manually turn the chuck forward to eliminate backlash. Then centre the tool into the original thread by adjusting the compound (top) slide.

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4: When recutting, just turn the chuck by hand to keep an eye on what’s happening. You should see the swarf only on the burred area. Job done – the nut screws on easily again.

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