Verge crown wheel attachment

[bobolink]

I need to remove the brass fitting that hold the crown wheel to the verge arbor. I have removed the crown itself which I didn’t show in the photos but need to remove the brass hub the crown fits over from the arbor.   
Does anyone know what if this might be press fit or threaded on?   Before muscle it off trying to figure our best way to remove it. 

Thanks

bob

[AndyGSi]

Looked to me like it's brazed or soldered.

[bobolink]

Thanks. It’s possible. But Very difficult to tell if it’s brazed.  The picture doesn’t show what look like the one or two thread like grooves in the steel at the end of the brass. But that could be anything.  I’m going to see if I can get a better photo and post it. 

[watchweasol]

I would have thought it was probably screwed on,  like the pallets in some French clocks to facilitate adjustment. but that’s not to say I hasn’t been got at before.   And soldered or brazed.

[RichardHarris123]

Does it need to be removed? 

[oldhippy]

It looks to me that it could be shellac that has been used. I can tell you it certainly is not screwed on.  As Richard says does it need to be removed. Is it the height that is wrong causing problems with escaping? 

[nevenbekriev]

Actually, this is joint that is not meant to be disassembled. I am not sure if it is brazed or some other way is used, but inside the brass thing the steel axle as part of the pinion is not round. It has hexagon walls or small teeth that have remained from the pinion wire turned to pinion. The length of this hexagon or toothed portion is smaller than the brass thing and the brass fully covers it. Removing of the brass thing is not possible without destroying it. The easiest way to do it is to squeeze the brass thing to the point of deformation, then turn to 90 degr and squeeze again and do it until it breaks.

What happened? Why is it needed to be removed?

[bobolink]

In drilling out the bad p toivot on the crown wheel end  a tip of the carbide bit broke off inside the shaft.  So work to try to drill it out possibly with small diamond core  .20mm core bit.  But before trying that I was thinking if pulling the brass arbor would provide better access t that is no longer an option. Thanks Neven.   I learned that the Chinese carbide bits are very weak.  I did make some bits in the past from carbide dental burrs that were better but thought to try the cheap eBay carbide bits and this is what I get for it. 

[RichardHarris123]

Are you saying that the pivot here is broken? 

[bobolink]

Richard. Yes pivot was broken and in drilling it out to replace the pivot it the carbide drill broke inside.  It isn’t in great shape but I believe I can salvage it if I can clear it. 

[bobolink]

I finslly was sblecto get s high mag pic lookin down at the hole  it isn’t pretty at this magnification.  

[nevenbekriev]

OK, my advice will be to destroy the brass part as I said in first message. Then grind a groove as shown with blue using dremel  with dental separator disk. Thus You will have access to the broken tip and will be able to get rid of it.

The next thing to do is to turn the pinion on lathe to get rid of that toothed portion and have clean and very slightly tapered end. Then, pivot inserted, turned and burnished to fit the hole of the bearing. Then, new brass bushing for the wheel is to be turned and riveted to the wheel. The hole in the bushing has to be wit a little smaller diam and after the riveting, the hole should be broached to tight fit the pinion. Then the wheel to be pressed in place and it's position adjusted to correctly mesh with the verge.

This is very important for the wheel to be as much true rotating as possible.

Edited March 17 by nevenbekriev

[bobolink]

Thank you for the detailed guidance.  I have two questions. 
If the steel is too damaged under the brass can I cut it off and add longer base to the pivot than you normally would? See the drawing I added. 
Also must the brass be pinned or is there another way to retain it?

thanks

bob

[nevenbekriev]

Yes, this is possible. But it will be easier and simpler to make as in the drawing

[bobolink]

Thank you!   Also must the brass piece be pinned or is there another way to retain it?

[nevenbekriev]

I am not sure what 'pinned' means in this case. But if the place where it must sit is slightly tapered and the hole of the brass piece is again slightly tapered by the broaching, it will stay firmly in place just like a roller table on balance staff. If needed (in case the hole is broached more than needed and the piece is not tight enough), it can be soldered to the arbor.

Another good idea is not to use this brass piece, but to make it out of steel and as one whole thing with the pivoted cap that has hole where the shortened arbor will be pressed.

[bobolink]

I removed the brass piece as suggested by squeezing it. Came off easily. Turns out it loos like it’s soldered after all. Probably should have tried heat first.  But it’s ok now can try making the all steel version. 

[bobolink]

Just got back to this and followed one of the recommendations Neven made a cut a piece/pivot out of steel that slipped over the shaft.  (I still have to shorten the pivot itself.  See picture.  

My question is what is the best way to attach the crown to the steel.  In the old one it was all brass so you slipped it on and with a few dimples on the inside of the crown would attach it firmly.  Now the collar is steel and the crown is of course still brass.  It is a snug slip/twist on fit right now but is that enough?

Thanks

Bob

 

[nevenbekriev]

Hi Bob, looks nice!

If it fits tight, You can apply some locktite and just press it. But the traditional way is to rivet the part above the brass wheel. For this purpose You will  need to turn something lie a collar, just like the rivet on the balance staffs.