Pivot hole bushing

[PlasmaParticipant @plasma]

Hello all.

I’m no clock repairer but was asked to cast an eye over a pretty standard mantel clock by a friend.

Its a Bentima or Perivale movement with Westminster chimes.

One of the pinion holes in the chiming train is badly worn and needs bushing.

Can anyone tell me the best type of drill to use for boring the oversize pivot hole for a bushing?

I’ve seen images of something that looks like a D bit but tapered. I am guessing so that it gently opens up the hole in the backplate.

I’m pretty sure that it’s a repair I can carry out, with the right tools and knowledge.

May just keep this old bird ticking for a while longer.

Mick

[Michael GilliganParticipant @michaelgilligan61133]

First thing … unless you have a dedicated bushing tool … is to ‘draw’ the egg-shaped  hole using a round needle-file, so that it is a symmetrical ellipse.

It can then be much more easily opened-up with a drill or a five-sided broach.

MichaelG.

.

Ref. https://www.cousinsuk.com/sku/details/bushing-tools/b0290

[Paul LousickParticipant @paullousick59116]

The bushing tool in the link would be good but £1,295.00 purchase price is a bit too expensive for a one off repair.

You may be able to just ream the existing hole to suit the bush (or drill undersize and ream). Either for a press fit or sliding fit and fix in place with Loctite.

 

[Paul Lousick]

On Paul Lousick Said:
The bushing tool in the link would be good but £1,295.00 purchase price is a bit too expensive for a one off repair.

[…]

But I showed it to illustrate the design-concept … easily adapted if you wanted to make one.

MichaelG.

[Author]

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