Clamping bolt + thrust plate

[Martin Bonner]

I have an old radial-arm saw. There is a large base-bar, and then a carrier which holds a wooden base on which the workpiece sits. The carrier can move back and forth along the base bar, and is clamped in place.

See

The knob which clamps the base in place is broken in two ways:

1. The actual plastic knob is cracked, so it spins on the metal thread.
2. The threaded metal should push onto a metal thrust plate which actually clamps onto the base bar - but I've lost the thrust plate.

I could easily replace the knob+thread with a 50mm M10 bolt and just use a spanner to fasten/unfasten. Replacing the thrust plate is a bit trickier.

Anyone got any ideas where to find a suitable replacement (or what to google for).

[Bob Minchin]

you can buy the knob with male and female threads as standard parts

look for star knob

As for the thrust plate you have the advantage in knowing what it looked like before you lost it(!) but just a piece of thick steel cut to fit might do.

[Martin Bonner]

Thank you! "Star knob" yields much better (cheaper) results (ie Axminster).

The thrust plate was an oversized version of the thing on the end of a G-cramp (about 20mm across). I think a piece of steel is the way to go. I might get a hole with a thread put in it.

[Bob Minchin]

The clamp end is known as an elephants foot for obvious reasons but generally not available as a standard part. You do NOT want to thread this as just as on the clamp, it stays still whilst the screw rotates. Imitate the g clamp. file the end of the thread to form a necked ball on the end, drill a hole in the steel about 25% deeper than the ball and peen over the edges of the hole to retain the ball. Oil the ball & socket for smooth action.

[newshound]

Should work, or just canibalise a cheap G clamp?