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dbane883

Lapping Machine project. Stage 1

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Contrary to popular belief, Rolex, AP, Patek do not use Dremels and mini buffing wheels acquired at Home Depot to polish their cases. They all use special "lapping" machines which look something like this:

47dca32f8374720b95879d97f72ba323.jpg

a6c838bcd4a9160632ec26c18b248ed0.jpg

Very simply, it's a vertically mounted, variable speed disk grinder whereby various abrasives can be applied to create anything from satin starburst patterns to mirror finishes.

The horizontal rails are mounted perpendicular to the spinning disc plates and a special contraption rides freely on the rails and looks like this:

266e6c3f7bb20a40a10510d0a7c490cf.jpg

This holder is similar to a high end pan/tilt camera mount and holds the watch case to the abrasive at a specific angle. Once set in place, the case can be manually rotated.

An angled work rest can also be attached for other polishing requirements:

ed34330de9446b50e711b3fc47601693.jpg

These machines are very rare and start at about $25k USD and go up to $50k or so depending on the attachments. This is not exactly walking around money for me, so as such, I have embarked on building my own "ghetto" version.

I'll be using a 3/4hp Leeson motor controlled with a KB speed controller.

I happened to be in Ohio the other week and dropped off at Beaumont Metal works to pick up a heavy duty grinder work rest.

The base unit will start off looking like this:

eeea48c9bf9b465ae7fa574f37811810.jpg

I managed to get ahold of some 16mm SS rods used for CNC milling and will be fabricating a mount for them. I will also be fabricating the angled case holder which will be the most challenging part.

Will let you know how it goes when (and if) I complete this time-wasting project :).

Wish me luck.

To see one of these in action, this video is a good example. Watch closely at the 2:00-2:15 mark:

http://m.youtube.com/watch?v=zn0UHZuOEeY

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Good luck!  It'll be fun following your progress.

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This is really cool. Lots of modding possibilities. Can't wait to see what you will do with it.

Sent from my droptop using telepathy.

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Should be able to put a really sharp and crisp bevel on the top edge of the lugs with something like that!

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Should be able to put a really sharp and crisp bevel on the top edge of the lugs with something like that!

It's gonna require a different type of case holder but yes, that's in the plan.

Crisp lug bevels are the hardest part about case polishing.

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this will be interesting :D

 

this "inside the rolex factory" video shows a home depot style buffing machine being used, no?

 

@45secs

 

 

i always understood lapping was an additional part to using the buffing wheel of a multi step process ?

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this "inside the rolex factory" video shows a home depot style buffing machine being used, no?

i always understood lapping was an additional part to using the buffing wheel of a multi step process ?

You're correct. The tapered spindle type of buffing wheels are still used for debuting, final buff, satin effects etc. I was referring to the Dremel mini buffing accessories like this:

a4adc323c0dedf0858bca6012f1eac07.jpg

However some watches, like the Grand Seikos (arguably the best case polishing ever), does not use a traditional buffing wheel at all. It's all done uses continually finer abrasives in the so- called "Zaratsu" method of polishing katana blades.

8dadb6a81a718e1671f34098eaa1b406.jpg

My goal is to replicate the process the Grand Seiko polishing masters use. Not sure what abrasives they use yet, but I've amassed a small collection of PSA backed abrasive discs for experimentation. The finest I have is a 0.05 micron lapping disc, typically used to polish the terminations/connectors for optical fiber. I think 3M makes even finer lapping film than that, but sourcing those in an 8" diameter is the least of my issues right now.

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i ve tried to replicate a perfect factory polish using several grits, from say 320 -12,000. one after another, then with some high gloss rouge on two different material buffing wheels, and even some diamond paste. for some reason i can not, never could achieve the same results as straight from the factory. so i m very interested to see your results.

 

maybe my buffing wheels were getting too hot and causing some swirling or something. i am not sure

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i ve tried to replicate a perfect factory polish using several grits, from say 320 -12,000. one after another, then with some high gloss rouge on two different material buffing wheels, and even some diamond paste. for some reason i can not, never could achieve the same results as straight from the factory. so i m very interested to see your results.

 

maybe my buffing wheels were getting too hot and causing some swirling or something. i am not sure

Buffing wheels (usually made of compressed felt) are generally very uneven and the bumps will heat the metal at different rates.  At the microsopic level, there is some supercavitation going on and the uneven buffing wheel will create some gouging as some parts of the metal is heated more than others.  The contact patch of a spinning felt buffing wheel is actually very small..so if a small gouge develops, it will tend to get bigger, not smaller the more one applies the case to the buffing wheel.  Kinda like how moguls develop on a ski hill...As skiiers go around one small bump, and as the sun heats up the hill at different rates due to shadows, the moguls will get bigger and bigger.  The final buff of rouge should be relatively quick and prolonging the polishing makes it worse, not better if you want a mirror finish. 

 

 I think the principle of the lapping wheel/case holder is to distribute the pressure more evenly.  If the angle of the case is not maintained, there will be uneven pressure resulting in imperfect results.

 

what a weirdo

 

Bite me J :).  Find a watch yet?

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Buffing wheels (usually made of compressed felt) are generally very uneven and the bumps will heat the metal at different rates.  At the microsopic level, there is some supercavitation going on and the uneven buffing wheel will create some gouging as some parts of the metal is heated more than others.  The contact patch of a spinning felt buffing wheel is actually very small..so if a small gouge develops, it will tend to get bigger, not smaller the more one applies the case to the buffing wheel.  Kinda like how moguls develop on a ski hill...As skiiers go around one small bump, and as the sun heats up the hill at different rates due to shadows, the moguls will get bigger and bigger.  The final buff of rouge should be relatively quick and prolonging the polishing makes it worse, not better if you want a mirror finish. 

 

 I think the principle of the lapping wheel/case holder is to distribute the pressure more evenly.  If the angle of the case is not maintained, there will be uneven pressure resulting in imperfect results.

 

 

Bite me J :).  Find a watch yet?

low blow you bastard ;)

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Funny, I am still using the dremel method and have tried like a hundred different pads and methods to get that mirrored finish.  This is educational and makes sense.  I have noticed that using a brand new pad with rouge and mothers mag wheel polish and just a quick buff works the best for finishing which goes with what you stated.  keeps the heat down.  Spent several hours reshaping my 16750 case yesterday in fact and it looks much better than it did.  

Very interested to see the progress with your project.   

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Hopefully in the near future I will see my 5513 case on that:)

Sent from my droptop using telepathy.

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