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Fabrication of longer Hour wheel pipe and Cannon pinion


RWG Technical

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Many times when you are making a custom build, the dial is much thicker than the original dial, and you need longer cannon/hour wheels to allow the hands to clear the dial. Buying new parts would be the easy solution, if they were available... since they are not available, the solution to the problem is to fabricate new parts.

Here's an overall view of the Cannon pinion and Hour wheel from a Cortbert 616 as delivered, as you'll see further down, they are much too short for our new dial thickness...

As delivered

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The specifications were to raise the cannon pinion and hour wheel (2 sets) high enough to clear a 1.7mm and 2.7mm dial thickness respectively.

I am not going to show all the machining and fabrication steps required to make these new parts, it is a lenghty, time consuming, and demanding process, with tolerances in the +- 0.01mm. I will show the end results of my efforts, I hope you like it and find it interesting.

ORIGINAL on the LEFT, NEW on the RIGHT

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Various views of the longer cannon and hour wheel pipe.

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Here are the two new sets all finished and ready to send out.

_1014394.jpg

Thanks for reading.

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Actually...I didn't cut new teeth on the hour wheel, I cut OFF the old pipe, fabricated a new one, and brazed the new pipe to the old hour wheel gear...

How's that for craftmanship?

Now I have you thinking don't I... :)

I wouldn't call it craftmanship, that's just frightfully clever! :)

Skipping the crucial part of reproducing the teeth makes it cheaper and the parts have to be fitting as they are the originals... (where's the hats off smiley :) )

-Andei

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Would this fix work on the 2893-2 movement to get the hands high enough to clear the dial indices on a GMT master IIc? That seems to be the biggest sticking point preventing a movement swap from a 2836-2 to a 2893-2

Beautiful work as usual .:thumbsupsmileyanim: :thumbsupsmileyanim:

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Would this fix work on the 2893-2 movement to get the hands high enough to clear the dial indices on a GMT master IIc? That seems to be the biggest sticking point preventing a movement swap from a 2836-2 to a 2893-2

Beautiful work as usual .:thumbsupsmileyanim: :thumbsupsmileyanim:

The parts are very small on that size of movements and it would be a real challenge to make them. Given it's a recent movement there is no need to fabricate new ones anyway.... ETA makes a large variety of lenghts and there are some that are really long, so replacement with new parts should be the solution.

The biggest problem with this type of swap is always the location of the stem, it doesn't line up with the case tube and is the no-go issue and not correctable.

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The parts are very small on that size of movements and it would be a real challenge to make them. Given it's a recent movement there is no need to fabricate new ones anyway.... ETA makes a large variety of lenghts and there are some that are really long, so replacement with new parts should be the solution.

The biggest problem with this type of swap is always the location of the stem, it doesn't line up with the case tube and is the no-go issue and not correctable.

i understand. i thought the problem was with the hands, but the case not accepting the movement certainly is a no-go situation. thanks very much for clearing that up for me.

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I am not going to show all the machining and fabrication steps required to make these new parts, it is a lenghty, time consuming, and demanding process, with tolerances in the +- 0.01mm. I will show the end results of my efforts, I hope you like it and find it interesting.

Oh come on Z, From one machinist to another, would love to see the process... :clapping: Would love to just have watchmakers lathe. :drinks:

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