Boxford Shaper - clapper box wear

My Mk2 Boxford shaper seems to have some wear in the clapper box taper pin which under certain conditions, allows the clapper to lift and the tool glides over the work or chatters.

I have tapped the taper pivot pin in as far as possible but I suspect the pin is too badly worn to take up the play.

I'm tempted to turn/grind up a replacement but before I do, can anyone explain why the clapper pivots on a taper pin and not a straight one?

I suspect it is to allow for wear adjustment but clarification would be good.

Also, does anyone know what the correct taper is, I can make to 'fit' but having the correct taper as a starting point will help.

cheers

Graeme

May help

**LINK**

“The taper pin is designed to be a tight (non-moving) fit on the mount sides and a loose (but shake-free) fit on the clapper.

http://www.model-engineer.co.uk/forums/postings.asp?th=73662

Edited By Ady1 on 13/05/2014 11:44:50

I have a boxford shaper operators manual but it has no parts list, only general stuff, and doesn't even mention the clapper box pin

If the pin were parallel then there would have to be a working tolerance between the two, which would mean there would be movement between the two. A taper pin allows the clapper box to move without any movement against the pin. Over the years a degree of wear may occur between the hardened pin and the cast iron clapper box, in which case the two parts, the clapper box and the tool slide should be visited with a taper reamer to re-instate a continuous fit before fitting a new pin.