Replacing bushes

Tony10Clocks

Registered User
Aug 10, 2010
1,641
8
38
63
Northant's
Country
Hello, still being new to the world of clocks, at what point do you decide to replace a bush, Excuse my ignorance, But is it when there is play in the pivot. or something else.
 

harold bain

NAWCC Member
Deceased
Nov 4, 2002
40,832
197
63
74
Whitby, Ontario, Canada
Country
Region
I think that looking for a visibly ovalled hole is where you should start as a beginner. You need to drift the hole back to it's original center before installing the bushing. Some play is OK if it isn't affecting the movement's ability to run.
 

Tony10Clocks

Registered User
Aug 10, 2010
1,641
8
38
63
Northant's
Country
Thanks Harold, Learning something new everyday, Only found out yesterday that you can't overwind a watch or clock,:eek:
 

MARK A. BUTTERWORTH

NAWCC Life Member
NAWCC Member
Jul 4, 2009
2,665
258
83
Muscatine, Iowa 52761
Country
Region
In addition, while you are feeling your way, keep in mind that a marginal hole you bushed still reduces the friction somewhat while a hole you should have bushed but didn't could cause the clock to stop and require you to disassemble again. In other words, I would err on the side of the former rather than the latter.
 

Scottie-TX

Deceased
Apr 6, 2004
936
72
0
82
Mesquite, TX
Country
Region
Also depends somewhat on which bushing is suspect. For example, excessive slop low in the train near the spring can be potentially hazardous and cause irreparable damage if it results in meshing loss.
Then, high in the train, I accept nearly zero tolerance on Escape wheel and Anchor arbor as slop there will cause poor performance of the escapement. All the rest in between are purely a judgment call.
 

Kevin W.

NAWCC Member
Apr 11, 2002
23,709
768
113
65
Nepean, Ontario, Canada
Country
Region
Also depends if you are working on a newer German made movement or a old ogee, a old ogee was made to run very loose.
 

shutterbug

Moderator
Staff member
NAWCC Member
Oct 19, 2005
49,940
3,164
113
North Carolina
Country
Region
For the newby, I'd go with Harold's advice: If the hole is nicely round, leave it. If it's clearly oval, bush it. :)
 

Willie X

Registered User
Feb 9, 2008
18,687
3,999
113
Tony,

Your question is one that I don't have a good answer for after about 54 years working with clocks.

Generally the smaller and finer clocks, will tolerate only a little pivot wear where larger more robust movements will run even with very pronounced wear.

And ... there are many exceptions! I've seen modern German and older French clocks, both finely made, with hugely worn out holes that still ran. I've also encountered American big wheel eight-days that stop with slight to moderate wear. Their one-day sisters will often run until the pivots snap off!

A pretty good rule is to surface clean the movement using a soft brush and solvent. Then, look downward into the movement while you snap the 2nd wheel back and forth with your finger, using a good amount of force. Any arbors that are jumping around need attention.

Sorry, but this is about the best answer that I can come up with.

Willie X
 

Tony10Clocks

Registered User
Aug 10, 2010
1,641
8
38
63
Northant's
Country
Thanks for all the reply's. All interesting stuff. I think for the time being if it runs i'll leave it.
Cheers
Tony
 

R&A

Registered User
Oct 21, 2008
4,218
110
63
Country
We might want to also let you know. You have to take the power off the springs before you inspect the wear on the pivots. When the movement has no power, you can move the gears forward and back. The wear on the plates will be easier to see, the pivot will jump back and forth with the train in that motion, moving it back and forth. After cleaning do this again, you will see that the wear maybe greater after the dirt is removed.

H/C
 

Dave B

Banned
Jun 7, 2008
2,389
12
0
Westminster. MD
Country
Heritage-Clocks;499904 said:
After cleaning do this again, you will see that the wear maybe greater after the dirt is removed.

H/C

Which is why I always completely clean a movement and polish all the pivots before deciding which bushings to replace. You would be surprised how often just cleaning up worn pivots will reduce their diameter to the point that a bushing which looked good suddenly has too much slop.
 

R&A

Registered User
Oct 21, 2008
4,218
110
63
Country
Dave B;500133 said:
Which is why I always completely clean a movement and polish all the pivots before deciding which bushings to replace. You would be surprised how often just cleaning up worn pivots will reduce their diameter to the point that a bushing which looked good suddenly has too much slop.



I agree with you. I never bush until I have polished all the pivots that need it. And after polishing recheck the slop in the plates. Then bush. Matter of fact I check the slop three times.

H/C
 
Last edited:

shutterbug

Moderator
Staff member
NAWCC Member
Oct 19, 2005
49,940
3,164
113
North Carolina
Country
Region
My method is to mark the bushings that need replacing on a separate sheet of paper before doing anything. After a good clean, I inspect the pivots and wheels and make any needed repairs. If any pivots required a large amount of material removed, I note that - and if the corresponding bushing is not slated for replacement check it for proper fit. Then put in the new bushings and put it back together. Works well for me. Don't like to do things twice.
 

Dave B

Banned
Jun 7, 2008
2,389
12
0
Westminster. MD
Country
shutterbug;500919 said:
My method is to mark the bushings that need replacing on a separate sheet of paper before doing anything. After a good clean, I inspect the pivots and wheels and make any needed repairs. If any pivots required a large amount of material removed, I note that - and if the corresponding bushing is not slated for replacement check it for proper fit. Then put in the new bushings and put it back together. Works well for me. Don't like to do things twice.

I guess it comes down to whatever we find works for us. I don't mind fitting the arbors back after cleaning and polishing them, so that I can take a hard look at the bushings. I have occasionally tried by simply writing things down, at the outset, but discovered that does not work as well for me.
 

Dave B

Banned
Jun 7, 2008
2,389
12
0
Westminster. MD
Country
Incidentally, after many years of doing bushing work by hand, a couple of years ago I sprung the bucks to buy a machine. Cash being what it is, I went for the Bergeon, instead of opting for one of the higher priced ones. By and large, I have been happy with it, but recently, I got into a whole spate of plates that were odd thicknesses. Heretofore, I have been chucking bushings up in the 8mm lathe and taking a face cut on them to make them the proper thickness for the plate, but that is time consuming.
Pivotcutters are expensive, and I decided I could get around that by making an adapter to hold Dremel end mills in the Bergeon machine.

I had a piece of 304 stainless stock in the junk bin, so made it from that. Using my Unimat 3, I turned a step to fit the diameter of the Bergeon machine. I then chucked the stock in a collet on my Peerless 8mm lathe, and drilled a 1/8" diameter hole in the opposite end, to take the Dremel shanks. My Unimat tailstock is not as accurate for end drilling as using collets in the Peerless. Mounting the piece in a vee block, I used the Unimat to cross drill and tap for a 4-40 set screw. I could have gone smaller, but I wanted something that I could tighten against the shank of the mill. The 4-40 also has the added advantage of using a 1/16" hex key. If I prang this one by gronking down too heavily on it, I can easily get a replacement key at any automotive parts store. The final step was to mill a flat across the end of the adapter, to match those used by Bergeon for their tools.

Now, I can install the bushing to stand proud of the front of the plate, then, using the flat stump, reverse the plate, and center it in the machine, and use an end mill to cut the bushing down flush, and use a cone, round, or pear-shaped end mill to re-form the oil sink, matching the shape of the originals. 74506.jpg 74507.jpg 74508.jpg
 
Know Your NAWCC Forums Rules!
RULES & GUIDELINES

NAWCC Forums

Forum statistics

Threads
181,423
Messages
1,583,013
Members
54,807
Latest member
LolasMom23
Encyclopedia Pages
918
Total wiki contributions
3,131
Last edit
Swiss Fake by Kent
Top