Pivot hole bushing

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Pivot hole bushing

This topic has 5 replies, 5 voices, and was last updated 26 February 2025 at 08:49 by Dell.

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25 February 2025 at 22:58 #785879
Plasma
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@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
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25 February 2025 at 23:38 #785887
Michael Gilligan
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@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
26 February 2025 at 01:19 #785895
Paul Lousick
Participant
@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.
26 February 2025 at 05:01 #785896
Michael Gilligan
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@michaelgilligan61133
On 26 February 2025 at 01:19 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.
26 February 2025 at 08:35 #785939
Andrew Crow
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@andrewcrow91475
On 26 February 2025 at 05:01 Michael Gilligan Said:

On 26 February 2025 at 01:19 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.

Also have a look at the attachment for the GHT pillar tool in the Workshop Techniques book.

Andy
26 February 2025 at 08:49 #785943
Dell
Participant
@dell
I am a clockmaker and It’s easy enough to bush by hand but I do it on my mill , I use a tool to align the hole with a tapered tool then clamp it down then I use tapered reamer to open hole , if you don’t want to get the tapered reamer then as Michael said file the hole on the opposite side of the wear and drill hole with a short spot drill first so hole is central then with size drill you need , the bush needs to be a press fit into plate and if you are making bush drill hole smaller than pivot in bush and broach out after fitting .

if you need any more help PM me

Dell
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