Babbitt Bushings for Clocks?

[R. Croswell]

This topic has come up before, whether Babbitt could be used for clock bushings. I'm not sure that there was any general agreement, although Babbitt has been used for many years for bearings in all sorts of machinery. Well, I'm currently servicing this Riley Whiting wooden works movement that had 12 bushings made from what I'm pretty sure is Babbitt. They apparently worked long enough to show some wear. They are not all the same thickness, and except for one square one, are tapered and pressed in. I used a screw to pull them. (The owner prefers a different material.) So it does look like Babbitt has been used more or less successfully by at least one clock repairer. I believe there are better choices for bushings like this, but we now have an answer to the question.

RC

 

[shutterbug]

I wonder how long they were in there? That would be helpful info. Does he remember when it was serviced last? Or did he acquire it after the fact?

 

[R. Croswell]

I do not have any additional history. I'm not suggesting that Babbitt be used for clock bushings, just reporting that at least someone did. The pivots in this movement were not shiny, in fact they were dull and a bit "frosty" looking. I don't have the equipment for analysis but it almost looks like material from the bushings had been transferred to the pivots. The pivots were dry, and of course Babbitt bearings, at least those I have seen in other applications, require lubrication. This is a wooden movement and in my opinion any bushing material that requires oil is a step backward from the original wooden pivot holes. This movement is getting a complete set of Delrin-AF bushings and will be as maintenance free as possible.

Just wondering if and where anyone else may have encountered Babbitt bushings in clocks. I don't work on tower clocks, but that seems like a possible application for properly lubricated Babbitt machinery bearings. Just wondering as I've only seen one tower clock. I was in the courthouse bell tower for an unrelated purpose and was only interested in getting down before the hour struck on that massive bell.

RC

 

[Rockin Ronnie]

I am anxious to see what approach you will be taking on the movement as I have a Daniel Pratt that is waiting to be worked on.
Ron

 

[R. Croswell]

I am anxious to see what approach you will be taking on the movement as I have a Daniel Pratt that is waiting to be worked on.
Ron

Ron, there wasn't anything special about this one except the Babbitt bushings that were removed. These were fairly large, like is often the case even with wooden bushings. One was squarish and fairly thick and irregular and left a deep scar. I filled around the new Delrin-AF bushing with JB-Weld. It isn't easily visible and made a strong repair. The movement was in pretty good condition and the strike side had never been bushed so I used smaller bushings there. I think the pictures tell most of the story. The time side winding arbor had some bad places where it contacts the pivot hole so I used a thin steel sleeve over that section. The owner did not supply the pendulum and suspension so I used one I had here for the test run. Movement ran without any apparent issues on the first try.

I got a little snookered for a while on this one until I realized what was wrong. Apparently the owner, or someone on his behalf, had taken this movement apart. All the wheels were were in place but the two strike control levers were loose in the box. I noticed the three teeth that needed to be replaced on the time side great wheel. I did the repairs and was starting to put things back together and something didn't seem right. The count wheel will run 12, 11, 10,-----2, 1 and the escape wheel wants to turn backward. Well whoever put it together got the main wheels in the wrong place. Thankfully I discovered the problem before the final assembly.'

The movement was already pretty clean and it appears that the plates and wheels had been coated with something, probably turpentine and linseed oil or something similar. That makes things look pretty but is a practice I do not approve of. On the edge of the movement is a very old strip of paper with an early date and words that are difficult to read. It had previously been varnished over. I was asked to preserve that label and I believe it survived OK.

RC

EDIT: Most of the pictures have captions that, at least on my computer, are not visible unless the image is enlarged full screen.

 

[Rockin Ronnie]

On the great wheel tooth re[pair, you used Cherry wood. A source or an equivalent wood? Were the teeth hand cut?

Ron

 

[R. Croswell]

On the great wheel tooth re[pair, you used Cherry wood. A source or an equivalent wood? Were the teeth hand cut?

Ron

As for the cherry wood, I have a friend that gave me a "lifetime supply" of small scraps that I believe came from a vocational training center when it closed. I believe there are sources of various species of wood in most areas and on-line. Check out custom woodworking shops and furniture makers for scraps. I've heard of others salvaging wood from old broken furniture. Cherry seems to be the most often mentioned, but I have used maple. I think any fine grain and fairly hard wood would work. If you want a better color match, would salvaged from other broken gears can also be used.'

Yes, the teeth are hand cut. There are two ways that I find that work for me. The "technical way" is to chuck the wheel (with the blank in place and turned to the correct diameter) and attach a dividing plate to the spindle corresponding to the number of teeth of the wheel. The leading edge of a good tooth is lined up with the lathe tool. The plate is advanced to the position of the first tooth to be cut and the carriage moved to- lightly score the location on the blank. Repeat for each tooth, then do the same for the trailing edge. These marks outline where the tip of the tooth will go. Remove from the lathe. Use a straight edge along the "front" edge of a good tooth and draw a light pencil line past the middle of the wheel. The distance from the center defines the radius of a circle. A line from the tooth tip of each new tooth will be tangent to this circle. Draw a pencil line on the blank for that side of each tooth. Go back to a good tooth and do the same thing for the other side. Because the teeth slant, a different diameter circle is defined for the line defining the other face of the tooth. It's then just a matter of cutting out the teeth and carefully checking the spacing with a caliper as the final size is filed or shaped with a Dremel sanding disk.

For this movement the time and strike wheels are identical opposites. T just turned a plug to center the two back to back and used the good teeth on the opposite wheel as the guide to cut out the new teeth.

RC

 

[John MacArthur]

This topic has come up before, whether Babbitt could be used for clock bushings.

Ivory was used for bushings by various repairers over the years in this kind of clock. It is hard to get now, though. I'm trying some experiments with PEEK, poly ethyl ester ketone, as that has been used by Frodshams for some bushings in the repro Harrison clock at Greenwich. It is supposed to have similar self lubricity to Teflon without the deformation under load. This experiment is not on a repair, but on an experimental movement. We'll see what happens.
Johnny

 

[R. Croswell]

Ivory was used for bushings by various repairers over the years in this kind of clock. It is hard to get now, though. I'm trying some experiments with PEEK, poly ethyl ester ketone, as that has been used by Frodshams for some bushings in the repro Harrison clock at Greenwich. It is supposed to have similar self lubricity to Teflon without the deformation under load. This experiment is not on a repair, but on an experimental movement. We'll see what happens.
Johnny

Will stay tuned. The problem with new materials is that it takes so long to get meaningful results,

RC

 

[John MacArthur]

Yes RC, and I'm quite conservative in that respect. However, I'm always curious. The idea being of course to find a material for bearings that require no lubrication. I doubt if the PEEK would be appropriate for pallets, where the most deleterious friction change occurs due to lubricant deterioration.
Johnny

 

[Jim DuBois]

No matter how well-executed a repair might be done, some are just very wrong! These were all inside the plates and showed almost not at all when assembled, so I left them as any correction would look worse than this. The plates were carved out under the patches. How not to rebush! This, unfortunately, happened on this clock that is extremely rare and most like pre-revolutionary war. Rack and snail strike, brass dial.

 

[R. Croswell]

No matter how well-executed a repair might be done, some are just very wrong! These were all inside the plates and showed almost not at all when assembled, so I left them as any correction would look worse than this. The plates were carved out under the patches. How not to rebush! This, unfortunately, happened on this clock that is extremely rare and most like pre-revolutionary war. Rack and snail strike, brass dial.

View attachment 627107 View attachment 627108 View attachment 627109

Not much choice except to leave it as is. The fix could be worse than the "problem". Looks like someone spent a lot of time doing it wrong. I don't like brass repairs for wooden pivot holes. It adds the requirement for oil and, at least in this example, is not easily reversible.

RC