Hand hole slightly larger than pinion - what's a better way to fix?

[SudoHalt]

Hey there,

I bought a Mondaine railways watch a few years back, but unfortunately it came with this factory defect in which the minute and hour hands have holes that are slightly oversized.

Compared to the features of the minute hand and its pinion, for the hour hand and its pinion

• hour pinion is larger,
• hour hand is short
• The "protrusion" of the hand hole hole being longer.

What I am trying to imply is that the hour hand will not fall out of place due to impacts.

• On the other hand, for the minute hand:
• the hand is heavier
• the hand got a larger moment about the pinion
• The pinion shaft is tiny
• And the protrusion from the hole of the minute hand is tiny
• On top of all of that, the hole is slightly oversized.

Any impact, even if you bang it on a desk accidentally, pushes the minute hand out of place, and it freely floats between the second and the hour hand. I humbly reassembled the minute hand 3 years ago, only for it to come off at the next bang on the desk, which you could imagine as a daily ritual.

Fast forward to all the mess that happened with the watch (crystal broke, damaged movement, etc), I replaced the movement and got to the reassembly job.

I tried to tighten the hole of the minute hand by pushing the small protrusion from the hole inwards. This strategy worked pretty well for the hour hand. But for the minute hand it is just tiny.

Then I got a wonderful idea.

Glue?

How about I go suicidal and I glue the hands to the pinion? I used GS Crystal Cement. Hour hand was a piece of cake. Minute hand was a disaster for this job. There simply isn't much area for the glue to bind the hand on the pinion. I gave the watch a knock on my knee and the minute hand was off again.

In the 8 hours that followed, I kept trying gluing again, but to no avail. Then I moved to Super Glue. I almost damaged the replacement movement, and there really wasn't enough area to safely bind the hand on the pinion. At that point, I realized I was being insane.

Or Glue two hands together?

I then attempted to glue the "minute hand" that came with the replacement movement, to the underside of the original minute hand. I then attempted to attach the assembly to the minute pinion. The hand was just too heavy and the assembly got knocked off right after the first impact. On top of that, it blocked the second hand from being assembled in the first place.

The Sewing kit

At that point, 12 hours from the start, I got small sprinkles of superglue scattered over the dial, and I couldn't care less about how the outcome looks like. I just wanted it to work. I remembered there is this fiber-like thing that is used to seal pipes to prevent leakage. So how about I use a string to tighten the hole of the minute hand?

I took a black-colored string from the sewing kit. It was made of two strings twisted together. I split the string into its two individual ones. I took one of them and I passed it through the minute hand hole, and I fastened it. I made sure both free ends are protruding from the side of the hand. I used GS Crystal cement to make sure the free ends stay in that position and don't interfere with the other hands. I then cut the overhanging parts, leaving a protrusion of a string from the side by something slightly above 1mm.

Surprisingly, this worked. The hand visibly swings up and down by over a milimeter in each direction, but it hasn't been knocked out of place yet. I have bent the hands in a bizarre way such that the minute hand doesn't stick to the indices or either hand.

In theory, the swinging makes a lot of sense as to why it exists. But also in my theory, the hand wouldn't fall off again. I believe this theory is flawed and the hand could fall off again.

What else can I attempt in case the minute hand decides to fall off again? Or if I can go back in time, what is the right way to do it?

 

Edited March 13, 2020 by SudoHalt

[watchweasol]

Hi you seem to have got in a bit of a pickle here ,  I would recommend measuring the hour wheel and cannon , then replacing the hands with a new set. No string , glue.  If that's out of the question buy a set of hole closing punches and close the holes in the hands for a better fit.  Have a look at Esslingers web site in the USA they have tutorial  one including measuring and fitting watch hands which you may find instructive               Cheers.

[vinn3]

yes;  "hand closeing tool"      this could be just a hammer and anvil.   a jury rig.,  But it is the measurment of the hole to get a press fit,  is the art.   vin

[Vacherin]

Amazingly beautiful clock design that. Very modern, so Swiss. Still popular in Switzerland. Every train station has one. Never seen the hands fall off yet!

I would have tried a Jerry rigged hole closing tool first. The walls of the hole near the edges of the hand would have got really thin if I did it, and the hand would snap in two, or go a funny shape as it starts to snap on one side. Hopefully you are better than me. Try and move metal from the sides near the long parts of the hand. Bodge wise, I would have tried a smidgen of car thread loc, put it in the bore then try and wipe it all off leaving an inperceptible amount as it is not possible to remove it all.

 

[SudoHalt]

The hammer and anvil sounds crazy, but I can see myself trying that! Maybe the needles from the sewing kit will help me in "undoing" a very small hole size.

The hole closing punching tool is an amazing idea, didn't even know it existed. Too bad it's way out of my budget. Do you know of any place which would sell such tools independently? I mean, if I wanted just the appropriate size of the minute hand hole instead of a whole set of hole closing tools.

Out of curiosity, is there a difference between measuring the pinion sizes and checking them up in the technical documentation? The movement is a Ronda 513/515, and according to the Datasheet, it got 120/70/20 sized hands. I am not really interested in replacing the hands, unless I can find something that looks fairly similar. Where could I find such replacements? The ones on Esslinger are a little bit far off from what I would like.

[vinn3]

Quote

 

    the best way to answer the questions is "read a book on watch repair and clock repair."  you can down load some these on the internet..       vin

[watchweasol]

Hi  Right , the watch is a ronda 513/515 movement and hands are 120/70/20.  So in theory any hands with those measurements will fit.    Watch material suppliers the likes of Cousins uk , AG Thomas, Gleave&co in the UK   Jules Borel, Esslinger, Timesavers, USA and Perrins of Canada will all have on list hundreds of hand patterns for you to check. If thats not what you want and want to use the origional hands you will have to fill in the origional holes and re drill new ones to size. This will take a great deal of skill plus the tools to do the job. Its a question over the level of work and the economic cost.  To be cost effective replace the hands, I believe without checking the style is Baton.

[SudoHalt]

1 hour ago, watchweasol said:

If thats not what you want and want to use the origional hands you will have to fill in the origional holes and re drill new ones to size.

I just remembered something! In some activity at the university, one guy taught me I can bond two pieces of steel together by filing their surfaces, soldering them together with the aid of solder paste. Then I will have to find a way to drill out that lead fill. I might think of that as a last, last resort!

On the other hand, baton hands aren't too bad really! Thanks!

[watchweasol]

Hi   The same method of soldering can be used on brass. If you get some brass foil and cut it  clean one side and apply solder paste evenly do the same to the other bit and apply heat and pressure  you will solder the pieces together. then cut the shape.  Not impossible but a fair bit of work to do.  cheers.

[rodabod]

I do this job regularly using a jeweling set. Don’t use a hammer and a staking set....