How do I repair the damage I've done to a Forestville mantel gear?

Richard Kennett

Registered User
May 30, 2014
57
6
8
Country
Region
4.jpg 1.jpg 2.jpg 3.jpg 5.jpg 6.jpg

This gear is driven by the centre time mainspring wheel (see photo of open movement where I point to the wheel with the back end of a black and red tipped screwdriver). The brass wheel has torn away from its pinion on the steel rod. How I did that is another story! Any suggestions about whether, with some work, I can repair this, or is the part toast? Thanks
 

AndyH

Registered User
Aug 25, 2020
48
6
8
55
Country
Any suggestions about whether, with some work, I can repair this, or is the part toast? Thanks
If I am interpreting the photos correctly, the problem is "just" that the wheel has become detached from the turned shoulder of the pinion?

If that's the case is the wheel still a reasonably snug fit on the pinion? If so you should be able to use a punch to secure it again by riveting.

Andy
 

Willie X

Registered User
Feb 9, 2008
16,556
2,630
113
There was an good discussion about this a few weeks back. Maybe someone can find it for you. Willie X
 

Mike Mall

Registered User
Oct 27, 2021
247
77
28
Country
It was about a music box - but the same question, and a few opinions.

Pinion Repair
 

Richard Kennett

Registered User
May 30, 2014
57
6
8
Country
Region
If I am interpreting the photos correctly, the problem is "just" that the wheel has become detached from the turned shoulder of the pinion?

If that's the case is the wheel still a reasonably snug fit on the pinion? If so you should be able to use a punch to secure it again by riveting.

Andy
Hi Andy. No, it is no longer a snug fit but quite loose. In one thread of this forum, it suggests, I turn over the brass gear and deliberately avoid finding the original meshed points. Find where there's some friction and resistance, then punch it. I'll try that. Thanks.
 

Jerry Kieffer

NAWCC Fellow
NAWCC Member
May 31, 2005
3,105
690
113
wisconsin
Country
View attachment 710628 View attachment 710629 View attachment 710630 View attachment 710631 View attachment 710632 View attachment 710633

This gear is driven by the centre time mainspring wheel (see photo of open movement where I point to the wheel with the back end of a black and red tipped screwdriver). The brass wheel has torn away from its pinion on the steel rod. How I did that is another story! Any suggestions about whether, with some work, I can repair this, or is the part toast? Thanks
Richard
I would suggest as indicated in the following quick and crude sketch.

Jerry Kieffer

35899ECD-1B7C-4005-B36F-D10E2F48717B_1_201_a.jpeg
 
  • Like
Reactions: Old Rivers

Willie X

Registered User
Feb 9, 2008
16,556
2,630
113
I can supply a photo of that "round nose hollow punch", if you like.

It's the tool that Jim mentioned in that older thread. Jerry has mention this also.

The second wheel is highly stressed. So, if you get anything less than a really good bite, using the punch and proper backer. I would again recommend the soft solder.

Note, trying to fill the big gaps with solder will result in a big mess. The solder will run through and fill up the pinion teeth! Use about 4 tiny bits of solder spaced evenly around the pinion to wheel junction. Clean and flux well, then apply the heat to the pinion (from below) with the pinion down and the wheel level.

Look up 'jewelers method' of soldering. Using this method, any excess solder can be easily scraped away but if done well no cleanup will be necessary.

Willie X
 

Richard Kennett

Registered User
May 30, 2014
57
6
8
Country
Region
View attachment 710628 View attachment 710629 View attachment 710630 View attachment 710631 View attachment 710632 View attachment 710633

This gear is driven by the centre time mainspring wheel (see photo of open movement where I point to the wheel with the back end of a black and red tipped screwdriver). The brass wheel has torn away from its pinion on the steel rod. How I did that is another story! Any suggestions about whether, with some work, I can repair this, or is the part toast? Thanks
View attachment 710628 View attachment 710629 View attachment 710630 View attachment 710631 View attachment 710632 View attachment 710633

This gear is driven by the centre time mainspring wheel (see photo of open movement where I point to the wheel with the back end of a black and red tipped screwdriver). The brass wheel has torn away from its pinion on the steel rod. How I did that is another story! Any suggestions about whether, with some work, I can repair this, or is the part toast? Thanks
With the help of another clock repairer, he punched the hole in the brass so that it closed its diameter just enough to make the steel pinion fit in more snuggly, so that there was some bite. Then we dripped tiny amounts of Loctite (I forget the spelling) over the union. I'll give it 24 hours and test it. Thanks everyone for your help.
 
  • Like
Reactions: Jonas and Mike Mall

Mike Mall

Registered User
Oct 27, 2021
247
77
28
Country
My bet is you have it.
Loctite goes against tradition, but it is modern tech, meeting old school.
Some may call it "glue", but it has been proven for holding many mechanical things together for many years.
Caveat - "when used the right way" - clean parts, right materials etc...
 

R. Croswell

Registered User
Apr 4, 2006
11,632
1,630
113
Trappe, Md.
www.greenfieldclockshop.com
Country
Region
...... he punched the hole in the brass so that it closed its diameter just enough to make the steel pinion fit in more snuggly, so that there was some bite. Then we dripped tiny amounts of Loctite (I forget the spelling) over the union.
My guess is that you may be revisiting this repair. Simply punching the hole will not close it uniformly all the way to the center. It may seem to "fit in more snuggly", but it won't have the grip it originally had. I doubt that the Loctite will contribute significantly, especially applied after assembly. Loctite doesn't work well where there is a large gap, or where parts are pressed tight where there is zero clearance for penetration but it won't hurt anything. You can add a bit more "grip" by punching the brass between the splines with a small round end punch, but like closing the hole, this does not lock the entire length of the spline. This 2nd. wheel is heavily loaded and short of replacing the wheel and pinion, most repair methods are not likely to restore 100% of the original strength, although it may be sufficient for gentle use.

You said; The brass wheel has torn away from its pinion on the steel rod. How I did that is another story! So what did happen? Under the same circumstances the repaired wheel will surely fail again. The first part of such repairs is to fix what caused the failure in the first place.

Good luck

RC
 

Forum statistics

Threads
174,396
Messages
1,523,873
Members
52,192
Latest member
danarog
Encyclopedia Pages
1,063
Total wiki contributions
2,971
Last page
Hard Life for Wristwatches by Roy Gardner