Gear cracks:

[ralberto2001]

Hi everyone! Nice to talk to everyone
again. Been busy at work, but got to work on
Gilbert clock alittle each day.
It had bent arbors that I straightened,and
Polished the pivots, then thought
I was ready to put together and check
Pivot holes. I am sure it will need some
bushing work too! Well, I found
another problem!

There are two gears with cracks in them.
Here is the pictures. I tried to use the
Loupe with camera, but you will see Loupe
and gears. Hope I did good!
I will probably try and make somemore.
Anyway, thanks Richard

[namonllor1953]

Say Richard,
Wouldn’t you know it, I’ve got the exact same situation on the clock I’m working on. I polished the verge as per Bernie’s suggestion tried to have a go of it and it stopped after a few tick-tocks. I took it apart once again and discovered the cracked pinion.
Spent some time today in the machine shop prepairing the tooling I’m going to need to create a new pinion gear. I’ve also got to figure out how to remove the broken gear and replace with the new gear, without damaging the arbor. Probably have to make some sort of small gear puller.
Best of luck,
Ren

[ralberto2001]

Hey Ren, Thanks for your reply!
That is so weird! but I guess it can be a normal thing sometimes.
I am trying to come up with a way to make somemore gears to. I looked for some 10 tooth gears
at Timesavers, and Merritts, but did not see anything. Oh well I think that I can make some.
I have never taken Pinions off, but I believe that they are press fitted. I looked it up on the internet.
I know that Timesaver’s sell’s a pinion puller, but it is expensive. I know that I will find something.
Anyway, good luck with yours as well, and thanks again. Richard

[chris mabbott]

Guys, great photos. Ya know I was looking at this and the first thing that popped into my brain cavity was…. Make a cast replica 💡

Not sure why this came to me but I wonder if it would work for a small pinion like this, I don’t see why not.
What is the material, steel or brass?

Here’s a link to basic casting. Whereas I wouldn’t use sand because it leaves sand casting marks and looks ugly, but you can purchase casting clay which is smooth and leaves a clean appearance. A gear would be easy to make, even the center hole. It would require a little polishing after but..

[ralberto2001]

Hey Chris! That is a very good idea!
I will look into that as well. Thanks! Richard.

[ralberto2001]

I am sorry Chris! You asked what material it was.
I don’t believe that it is brass. I was going to grab some copper dowels.
I thought it was made out of that.
Richard

[bernie weishapl]

The pinion gear in my gilberts are all brass. They definitely are not copper. I had to have one cut for one of my clocks and it was cut from brass. He drilled it smaller so I could adjust the it when I replace it on the shaft. They are a press fit.

[ralberto2001]

Hey Bernie! My clock probably is as well.
I am just guessing. I will grab some brass rods and try my hand at it.
If I fail miserably I will try something else.
I will get something done so I may proceed on to the next step.
One thing is for sure, this is definally a learning experience.
Thanks, Richard

[namonllor1953]

Hi Chris,
Thanks for the input. I too thought of casting but the pinion is so small I didn’t think it a good idea to cast it. I’ve done a bit of research on the repair o/replacing of clock pinions and have come across other options. The first is using pinion wire ( http://www.rushgears.com/catpages/pinionwire.pdf ). The second is machining the pinion as talked about in The Clock Repairer’s Handbook by Laurie Penman (which is why I was getting the tool set-ups done yesterday in the shop).

Any advice as to how to remove the old pinion??
Here’s a second photo of the other side.

Thank you,
Ren

[arutha]

Is it possible just to turn the old pinion off in a lathe? If you want to save the pinion I would try some gentle heat as the brass should expand faster than the steel and then a bit of gentle levering. If there is room to get anything under the pinion you could just then hammer the arbor through it using a small piece of wood or a brass punch to protect the top of the arbor, if you are very posh you could try your nice brass hammer.
Paul.

[chris mabbott]

Hey Ren,

I’ve seen modelers cast really tiny parts from aluminum, brass, tin, silver etc and they turned out nice. I think this is what the casting clay is for, because of the small parts, sand is to coarse. when the clay is soft, press your gear into the putty, which should air harden after a while.. leaving a nice impression of your part. For a gear, you don’t need two halves, I think. Anyway, if you use brass, it’s easy to trim away any overflow on the lathe.
I haven’t done this but I hear what others say about casting figures/equipment for military dioramas. some of the guys make a template out of balsa wood for tank rollers, they need about 20 of them, so they make the first from the wood template, the rest they make using the first cast example.

I agree with Paul, use heat, but you might want to put the piece in the freezer for a couple of hours first to shrink the steel, because the brass will expand faster while the steel remains reduced.
Have your piece setup and ready for removal prior to applying the heat. You don’t want it to migrate to the steel part, so quick & accurate are the key words..

[arutha]

The other thing you could try once you have the pinion off is to silver solder it. Make sure you only use just enough heat to melt the solder. I would imagine soft solder would be too soft but then it is only a motion work pinion?
Paul.

[willofiam]

Hey guys, not the best fix but it will work as Paul says you can silver solder them, the trick is to make sure you dont end up with solder in the teeth 🙄 also it will stop the clock if the split is not brought back tight making the one area wider than the rest (hope that makes sense as I try to explain) causing stoppage in its meshing with the motion works wheel. thats the main reason you want to take it off, to be able to get it together tight while soldering.

Ren I use a punch and the bench block or a vice to dive it apart, check to see if there is a pin thru the drive pinion into the arbor (some have this) otherwise you can just grab it with some pliers and twist off (with one that is cracked sometimes they will come right off) the punch fits just over the pivot. you may have to remove the lift lever to do this so you want to make sure you get it back on in the same spot or else you strike will go off at the wrong time, though you can adjust it after the pinion repair.

If you dont have a lathe or a milling machine, find a piece of brass thick enough or cut off some from a rod. drill a hole so it will be a tight fit onto the arbor (not too tight or you will break it again) DONT press it on yet….using the old pinion bolt the old and the new together. the reason I say bolt it that you can move the two from tooth to tooth using a good section of the old as a template….cut and file to match (a long time ago before milling thats how they did it, right Bob? remember?) and WHALLA 😯 nice new drive pinion..Pretty quick explanation but I hope that all makes some sense.

.I am sure there are many variations to accomplishing this task, this is the way I did my first one but now I have more machinery and would do it a bit different, use your imagination and I am sure you guys will get it!!!!.
William

[ralberto2001]

Hey William, That is another good method! Thanks for the Advice.
Books and video’s are nice, but with out you Guy’s Experience it would be very very hard!
Thanks so much for all yaw’s expert advice. I really appreciate it. Now I have some methods to try
and one is going to work.
Thanks again, Richard

[willofiam]

well I forgot to mention that some of those pinions have recesses on them so you would probably need a lathe or figure something out with a drill press or email me and I’ll make you one or someone on here smarter than me can give you a better idea.

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