Looking for an alternative ETA7750 oscillating-weight bolt tool.

[Endeavor]

Dear All;

I've to change out a bearing of an ETA7750 oscillating weight. The bearing is hold in place by what is called an "oscillating weight bolt" (1491), it's a kind of a flat washer.

To aid fixing the "bolt" to the bearing there is a special tool (6823) on the market;

So far, the tools I've seen are rather expensive for a job I've to perform seldom to near never again.

Disconnection the bolt from the old bearing was easy enough but pressing / turning the bolt back on may be a bit more of a challenge.

Has anybody some tricks on their sleeve (method or DIY-tool) to connect this "bolt" without the need of this expensive special tool ?

Hope to hear .......

 

[spectre6000]

This is not the "right" answer, but it looks like you could treat it like a... I can't think of the name of the thing... A blind nut with slots in the side... Secure the movement/rotor, then take a pair of screw drivers, or peg wood if it's not too tight and you don't want to risk scratches, in opposing slots and push. If it were large scale on an engine or some other industrial machine, you'd drop a drift or something in the slot, and hammer it loose.

Edited October 2, 2021 by spectre6000

[Endeavor]

Thanks for your contribution

That's how I removed the "bolt" (I still find it a strange name for something which looks like spring-washer), two peg-woods in either side slots and rotated. Which direction you rotate is irrelevant. The "bolt" is like a square which, once rotated, locks in four places.

With the weight and bearing in place, resting on a stacking-block, I tried to do the reverse, but next to rotation one has to press the "bolt" all along the circumference down to slip into the (4x) slot. It's the rotation combined with the circumference pressure down which makes it hard(er) to lock. Obviously the tool makes it and easy job; push down and rotate.

Now thinking out loud; perhaps a (modified?) cheap hollow hole-punch may do the trick.... (?) Perhaps, without modification the friction may be just enough to turn the bolt? Will tomorrow look into that idea .....

Any other suggestion are also welcome .......

 

Edited October 2, 2021 by Endeavor

[watchweasol]

A suitable sizes leather punch (used for cutting holes in leather) you would need to grind the profile tosuit the "bolt"

[Endeavor]

Followed up on my last night suggested idea and as @watchweasol subsequently doubled; a 5.5mm hollow hole-punch fits very neatly over the "neck" of the bearing and once in place & pressed down, leaving plenty of room to insert a pointed peg-wood into one of the "bolt"-slots to assist rotation. Press down and rotate with the peg-wood; works as a treat and, since I had the punches, with no additional tool cost

No modification to the punch needed.

Problem solved and one more trick in the bag

Thanks all

 

 

Edited October 3, 2021 by Endeavor

[watchweasol]

Brilliant some times thinking out of the box works. I am a great believer in diy sououtions in stead of slavishly buying expensive tools for a "one off" 

[Endeavor]

@watchweasol Indeed 

Hence most of my "watch"-tools are just simple hand-tools .......

"Necessity is the mother of invention"

 

Edited October 3, 2021 by Endeavor

[watchweasol]

Right on. If you haven't got one then make it or modify something to do the job.  A fellow thinker.

[Plato]

On 10/2/2021 at 12:05 PM, Endeavor said:

So far, the tools I've seen are rather expensive for a job I've to perform seldom to near never again.

Does anyone offer a watchmaking tool rental service? Could be a good business idea.

[Endeavor]

9 minutes ago, Plato said:

Does anyone offer a watchmaking tool rental service? Could be a good business idea.

Not sure if that will work/is cost efficient with "modern" high registered shipping cost. It most likely also requires an amount to be deposited in case the tool get damaged or simply doesn't get returned.....

Edited October 3, 2021 by Endeavor

[Plato]

Yeah, I didn't think it through.

[Endeavor]

3 hours ago, Plato said:

Yeah, I didn't think it through.

[spectre6000]

Those one off tools are a curse! They always seem to fall under two categories: Use it once and never use it again, or use it once, need it later and forget you already have it, and order it a second time, use it, then discover you already had one when you go to put it away to never be used again.

[Kalanag]

I just designed and 3D printed a tool for the ETA 2892 bearing.

It is on the edge of the capabilities of a standard printer but works after some minor cleanup.

 

Edited August 25, 2022 by Kalanag