a new clock repair tool

[doug sinclair]

Clocksmiths,

Over all the many years I have repaired clocks, one particular problem has oft come back to haunt me. Perhaps it has happened to you. Upon re-bushing a clock, you find it necessary to rebush the strike side third wheel bearing in the back plate. Once the clock is assembled, you proceed to the strike side third wheel extended pivot at the front plate to press the gathering pallet on, and you push the bushing out of the back plate! has it happened to you?

The tool

 

[doug sinclair]

Clocksmiths,

Over all the many years I have repaired clocks, one particular problem has oft come back to haunt me. Perhaps it has happened to you. Upon re-bushing a clock, you find it necessary to rebush the strike side third wheel bearing in the back plate. Once the clock is assembled, you proceed to the strike side third wheel extended pivot at the front plate to press the gathering pallet on, and you push the bushing out of the back plate! has it happened to you?

The tool

 

[doug sinclair]

Clockers,

The application

I took a piece of 3/4" square aluminum stock, squared up the ends on my lathe, centre-bored it all the way through, tapped the hole with a 1/4" x 26 tpi NC tap. Then I took a carriage bolt, 1/4 : x 26 tpi NC of appropriate length and turned the head off of it. I then made a bronze cap (brass would do) that was a press fit over the top of the carriage bolt. This is used as it greatly reduces the risk of "mushrooming" a pivot if you have to "convince" the gathering pallet on with a few taps. With the movement on assembly pegs, slide the tool under the bushing you are preserving, raise the stump with the bronze cap by unscrewing it until it contacts the bushing (or the pivot as shown). Now you are safe pressing the arbor down on the new bushing. What do you think?

 

[Tom Chaudoir]

Hi Doug,

This came up some time ago on the clocks mailing list. If memory serves, I was the one who asked how to deal with the situation. The consensus was to put "something" under the pivot that wouldn't hurt it. Hardwood would do, or brass, etc.

Yours is an excellent answer to the problem. I intend to shamelessly copy your tool. Thanks!

P.S. Now that I think of it, the tool might also be used when setting bushings in hard to reach places, such as near posts etc. I'm liking it more and more.

Regards,

 

[doug sinclair]

Tom,

Another excellent application for this tool would be in the instance of Urgos cable-drive, three-train movements on which the drive gear for the centre shaft and hour wheel is a drive wheel on an extended pivot of the time side third wheel in front of the front plate. This gear has a very strong, three-fingered tension spring beneath it, and it is retained by a washer and "e"-clip. If you bush the back pivot on that wheel, you risk pushing the bushing out of the back plate when you compress the spring to install the washer and e-clip. Actually, I struggled with one of those movements, earlier today. I got the friction gear back on, but what a struggle. I thought at that time that there HAS to be a better way. I designed this tool in my head, and after supper, I went and made it. If only I had made it yesterday, or last month, or last year!

 

[Mike Phelan]

Hey - that is a Good Idea, Doug. Guess what I am going to make soon........

 

[bcaclock]

Hi Doug,
This once again proves that "Necessity is the Mother of invention". I will make one also.

Thanks, Bob Brown

 

[doug sinclair]

David,

A friend of mine who took the course on clock restoration at West Dean (England) about ten years ago, does his bushings on his 17th and 18th century clocks differently than those of us that spend our time working on 19th and 20th century stuff. His bushings are rivetted in, and likely would never push out. Perhaps that is how you do yours. My bushings are pressed in, and they can be pressed out again. It hasn't happened often with me, but avoiding having a bushing come out can be a time consuming and clumsy part of clock repair. Makeshift methods of avoiding this problem are a nuisance. This method is positive, cheap, convenient, quick, and the tool can be used for other purposes, as described by Tom Chaudoir, above. So, anyway, if you see no particular use for this tool, don't make one.

 

[Mike Phelan]

All
I have knocked out bushes fitted by others - I broach mine from inside, turn bushes up from scrap, slightly tapered, so they probably would not come out.
However, I would prefer supporting the GP wheel pivot or centre arbor with Doug's tool rather than hitting the shoulder against the back plate or bush. Some cannon pinions on Napoleons are tight, and the rear centre hole is top of the wear stakes and often bushed

 

[Rick Alhadeff]

Just finished making one - great idea! It's similar to a milling jack used to support the center of the milled stock to prevent deflection. I decided to drill a small pivot sized hole in the brass cap to allow the pivot to not be touched but support the bushing. Many thanks for the idea.

 

[doug sinclair]

Rick,

I haven't even used this tool for its intended purpose, yet. But from the sound of the modification you've made to the original idea, it just might be an improvement. Some pivot material is definitely a bit on the soft side . Thanks for the idea. Let me know how it works for you.

 

[doug sinclair]

David,

I count 6 respondents to my original post, including you. Five of whom will make, or have already made this tool. I'll count you out as an investor when I take this tool to market!

 

[Mike Phelan]

Doug, just a thought!!! If you drill a series of holes in the base plate and make 4 pegs say 1 inch high and 1 peg with the centre drilled for the pivot you might have a universal tool that may suit different clock plates, Dave

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[doug sinclair]

All,

Let's make this a message board project. How about everyone taking the basic idea, improving on it as suits their particular requirements, and get back with pictures of the tool in action?

 

[David Holk]

Doug,

Sounds like you should have patented this thing.

David

 

[doug sinclair]

All,

I gave this tool its first practical test today. I was working on an Urgos weighted triple chime today. It is one I had rebuilt several years ago. This particular movement has an extension of the time train second wheel that sticks out in front of the front plate. The time train drive wheel fits on that arbor, and it has an aggressive three-pronged spring beneath it. This all is held in place with a counter sunk washer and an e-clip. The bushing on the other end of the arbor had been re-bushed. The e-clip had let go, and the assembly came apart.

To assemble this unit required a lot of pressure to retract the three-pronged spring. The danger is that the bushing at the back won't hold. So, today, for the first time, I used the tool to support the arbor while I compressed the spring, and the tool did its job perfectly.

 

[Dave Robertson (no relati]

most of the time I just use a small staking block with the size of the bushing and tap it on that way, on that arbor and on the time arbor when replacing the activating gear for the strike on an old german movement or british movement. It really helps to have 4 hands, we usually use team work on that deal. If I'm being lazy I'll just use a anvil and put the pivot end on it... kinda scary for mushrooming tho, but if yer gentle... of course many times on the time arbor that's not possible...

 

[steve.shroyer]

Hi all,
I stumbled onto this post looking for help for a different problem but thought I'd put my two cents worth in here in case anyone else happens in here as well. I too have knocked a few bushings out this way. The way I solved the problem was to take a short length of thin mainspring stock and cut a "v" notch in one end. There is usually enough end shake to slip this between the shoulder of the arbor and the back plate. Friction holds it in place while I tap the gathering pallet home. Only took me a few minutes to make and I have not popped a bushing out since.

 

[Talyinka]

This Shaw-something site supposed to hold the photos for this thread states that they don't exist there. Would it be possible to upload them to this site, please?

Thanks

 

[bangster]

This is a nine year old thread. It's unlikely that any of its pics can be retrieved.

Please pay attention to time frame, when adding replies to outdated threads. You probably won't get any back. Yoda

bangster
moderator

 

[doug sinclair]

I will post a picture of the tool, either this evening, or tomorrow. I like the suggestion of Steve Shroyer in which he cuts a notch in a mainspring and inserts the "V" between the shoulder of the pivot and the plate.

 

[bangster]

Good on you, Doug! It seldom happens.

 

[doug sinclair]

Bangster,

Call me an habitual poster!

 

[shimmystep]

Call me an habitual poster!

You're an habitual poster

 

[doug sinclair]

Two pictures. One, of the tool which is simply a 1 1/2" piece of aluminum stock drilled and tapped. A carriage bolt with the top cut off and a brass cap fitted over the top end to protect the pivot. Height adjustable. The second picture is of a clock movement on movement stands. The tool is adjusted to a height suitable to fit well, underneath the bushing you wish to preserve. Then do what you have to do to the upper pivot. For example, pressing on a gathering pallet.

 

[leeinv66]

This is a nine year old thread. It's unlikely that any of its pics can be retrieved.

Please pay attention to time frame, when adding replies to outdated threads. You probably won't get any back. Yoda

bangster
moderator

Naysayer

 

[Talyinka]

Two pictures.

Thank you.

 

[dAz57]

I use the same as Steve's, I make mine from a feeler gauge which is nice and flat and polished, cut a long V slot then polish to make sure there are no burrs or sharp edges, been using one for more than 20 years, works well

 

[binman]

dAz57 how thick is the feeler gauge?

 

[Albert Rambaud]

See this post from a while back.

Hello everyone. I have here a tool similar to the one posted by Doug Sinclair earlier in useful hints and tricks. It is an arbor screw jack form of tool to help you support the arbor of a bushed wheel. This prevents the bushing from being pressed out of the movement plate when a gathering pallet or other item is pressed or drifted on the other end of the arbor. My tool is a little fancier in appearance but that is not the difference. The difference is in the metal at the top of the screw that makes contact with the end of the pivot. The cap is made from copper pressed onto a steel cap screw. The movement is supported by bench assembly posts and the screw jack copper cap is put under the movement in light direct contact with the arbor end being addressed. An old clockmaker/gunsmith in Denver, CO, named Ben Spann enlightened me about this device and the properties of copper. Copper, even more so than brass, will lend itself as a sacrificial metal in the fact that it will grip/support and lightly give but not mar or deform steel. He demonstrated this with a pair of copper jaw pliers on a blued gun barrel. The copper left light copper marking but was easily wiped off and left no marks or permanent scarring. The bluing on the barrel was untouched. Ben said the same is true for the screw jack arbor support copper end cap. The copper will support the end of the arbor it makes contact with but will not mushroom the end of the arbor. When pressing or lightly drifting a gathering pallet on the arbor it makes direct contact with the copper under pressure. The arbor tip will leave a small impression in the copper without damaging or mushrooming the arbor tip. This is where the term sacrificial metal comes from. The purpose of the arbor support screw jack is to support the arbor directly and not the bushing itself. If the busing itself only was being supported the shoulder of the arbor will make contact with the bushing and possibly mar it and cause distortion with possible end shake problems. Copper is tricky to machine since it is a little gummy and does not form chips well. A very sharp tool is a must when turning on a lathe. Iknow this is a tool but helpfull in the clock catagory as well.​

Attached Thumbnails

 

[David S]

Albert just so that I am clear. You have not bored a clearance hole in the end of your arbor for pivot clearance? I have worked on some clocks that seem to have very long pivots sticking out from the plate. I think I would have to do some experimenting before I would be comfortable with just supporting the end of the pivot.

 

[shutterbug]

Albert just so that I am clear. You have not bored a clearance hole in the end of your arbor for pivot clearance? I have worked on some clocks that seem to have very long pivots sticking out from the plate. I think I would have to do some experimenting before I would be comfortable with just supporting the end of the pivot.

I think the idea is valid. If you wanted, you could drill a small hole for a protruding pivot. The idea is to hold the new bushing in place while you work on the other end

 

[David S]

SB I don't think that is what Albert is saying. As I understand it he doesn't want to touch the bushing, and that the "soft" copper won't damage the protruding pivot. But let's wait for him to respond.

 

[shutterbug]

SB I don't think that is what Albert is saying. As I understand it he doesn't want to touch the bushing, and that the "soft" copper won't damage the protruding pivot. But let's wait for him to respond.

Maybe. But if you aren't touching the bushing, I don't think the tool is functional

 

[David S]

Maybe. But if you aren't touching the bushing, I don't think the tool is functional

Sure it is.. if the arbor supports the tip of the pivot then you can press on the pallet. Rather than have the shoulder of the pivot arbor press onto the bushing and have the bushing supported by the other tool.

 

[shutterbug]

Oh, I see. Maybe a little dangerous for the pivot though. I guess you can't argue with success though

 

[doug sinclair]

A brass cap has always served me well. I have never had to use this tool at a time when I needed to hammer something into place at the position opposite to the tool. Pressing on a gathering pallet, or fitting a friction clutch to the front mounted drive wheel of an Urgos tall clock movement is the only time I have used this tool. I have never had a problem with distorting or mushrooming a pivot. Were I to have to actually hammer, using this tool as a support, I have done something wrong! I agree that copper might be a good choice to replace the brass, if circumstances demanded it. A small hole in the protective pad would allow the bushing to bear the strain rather than the pivot. However you want to do it, you have my blessing!