Rotary tool

[ClaudioCavalli]

The next tool on my list is a rotary tool to fix a couple of scratched up crystals.  I've been reading up on watch forums on what tool people use and I see a lot of people use Dremel and Proxxon rotary tools (Did you guys see their mini lathes?  Wow!!).  However, I see that their minimum speeds are 2,000 rpm or so.  Isn't this too much for polishing?  No room for error?  I was looking at something like a Grobet rotary rool (See here) but they do not have specs for lowest speed on their web site.  However, similar tools on Amazon go down to 500 rpm.  Does anybody know if the Grobet goes down to 500 rpm as well?  Wouldn't this speed be better and more forgiving for polishing plexiglass crystals?

thank you

claudio

[HectorLooi]

That looks like a Chinese made Foredom motor. If it is a Chinese made foot pedal, you will have problems with it in about a month's time. 

But no big issue as you can build your own benchtop speed control quite easily.

[ClaudioCavalli]

Oh well,  I thought it was US made.

[HectorLooi]

The Chinese made motors are pretty good too. I've been using one for the last 6 months. 

I think the electronic foot pedals for sewing machines may work as a substitute but it would require a bit of rewiring. The problem with the Chinese Foredom pedal is that the potentiometer has a very short travel of about 1 cm only. The sewing machine pedal has a potentiometer at least twice as long.

Flexshaft motors can go down to quite a low speed but it wouldn't have much torque at these speeds.

Polishing is a lot of trial and error. The required speed depends on the material being polished, the polishing compound used and the type of polishing tool used. (eg. Silicone rubber abrasives, soft felt, hard felt, wool mop, muslin mop, etc)

The amount of pressure used also depends on the above variables. Some require high pressure, others require a light touch.

It's a science as well as an art. Have fun! 

[VWatchie]

On 12/26/2023 at 5:41 AM, ClaudioCavalli said:

I've been reading up on watch forums on what tool people use and I see a lot of people use Dremel and Proxxon rotary tools (Did you guys see their mini lathes?  Wow!!).

I haven't had the best of experiences with a rotary tool for polishing.

I've had a lot more success using a dedicated polishing machine so I'd recommend that.

 

[LittleWatchShop]

On 12/25/2023 at 10:41 PM, ClaudioCavalli said:

Grobet rotary rool

Looks a lot like my old Vigor.  Works fine for me.