How do I create circular pattern on a stainless steel case back ?

[mikepilk]

I want to polish the scratches out of a stainless steel watch back, but then I will need to re-apply the circular brushed pattern.

Easy enough with the correct holder and a lathe. But without those, has anyone figured out an easy way?  

Maybe superglue a bit of dowel on the back then put it in a drill ?

 

Edited October 18, 2022 by mikepilk
typo

[Neverenoughwatches]

23 minutes ago, mikepilk said:

I want to polish the scratches out of a stainless steel watch back, but then I will need to re-apply the circular brushed pattern.

Easy enough with the correct holder and a lathe. But without those, has anyone figured out an easy way?  

Maybe superglue a bit of dowel on the back then put it in a drill ?

 

Sounds feasible mike, What about a suction cup on the inside of the case back. Or one of those rubber case back removers and spin it between your palms. Whatever the bridging tool obviously needs to be a wide enough diameter to easily center it but also fit into a drill. How about sticking with hot shellac to allow you enough time to center it.

[lexacat]

If this were me, trying to get this done cheap, easy, and accurately, I'd go the dowel in the drill trick but I'd use stick on velco strips instead. That way you could easily reposition the piece to get it more centered. 

[Neverenoughwatches]

1 minute ago, Neverenoughwatches said:

Sounds feasible mike, What about a suction cup on the inside of the case back. Or one of those rubber case back removers and spin it between your palms. Whatever the bridging tool obviously needs to be a wide enough diameter to easily center it but also fit into a drill. How about sticking with hot shellac to allow you enough time to center it.

 

30 minutes ago, mikepilk said:

I want to polish the scratches out of a stainless steel watch back, but then I will need to re-apply the circular brushed pattern.

Easy enough with the correct holder and a lathe. But without those, has anyone figured out an easy way?  

Maybe superglue a bit of dowel on the back then put it in a drill ?

 

A glue gun ?, they have two adhesives to try and allow a little time. You could also apply heat from underneath to reposition it if its not centered as accurate as you need.

2 minutes ago, lexacat said:

If this were me, trying to get this done cheap, easy, and accurately, I'd go the dowel in the drill trick but I'd use stick on velco strips instead. That way you could easily reposition the piece to get it more centered. 

Haha thats spooky that was my next one  

3 minutes ago, lexacat said:

If this were me, trying to get this done cheap, easy, and accurately, I'd go the dowel in the drill trick but I'd use stick on velco strips instead. That way you could easily reposition the piece to get it more centered. 

I actually have some of that in my shed . Also have a 2" velco sanding disk that fits in a drill the velcro tape would stick onto the inside of the caseback after a little padding out. Great minds think alike eh

[mikepilk]

1 hour ago, Neverenoughwatches said:

Sounds feasible mike, What about a suction cup on the inside of the case back. Or one of those rubber case back removers and spin it between your palms. Whatever the bridging tool obviously needs to be a wide enough diameter to easily center it but also fit into a drill. How about sticking with hot shellac to allow you enough time to center it.

I like the suction cup idea.

I found one from my aquarium which was just the right size. Push fitted an electrical connector in to the hole, then mounted in the cordless drill. Spinning at low speed, and using 400 grit wet and dry. It only takes a little pressure, so you don't need a strong fixture.

And it works ! 

[AndyHull]

I've had some success simply blue-tacking the case back to the chuck of my battery drill. Open the chuck first so you have a flat face to work with.

Use a relatively generous blob of blue tack.

Once you have it centred, which is a matter of squishing the casback into the blue tack till it rotates without any chatter,  simply attack with whatever abrasive is appropriate.

500 grit emery paper seems to do a good soft circular pattern. Coarser grit gives a coarse pattern, and you can polish almost mirror smooth with finer grit and polishing pads or something like T-Cut.  You may need to re-centre from time to time, but the blue-tack keeps things surprisingly well centred. It probably helps that the drill in question has a good speed controller to keep things relatively slow and stop me launching the thing into space.

Edited October 18, 2022 by AndyHull

[Neverenoughwatches]

38 minutes ago, mikepilk said:

I like the suction cup idea.

I found one from my aquarium which was just the right size. Push fitted an electrical connector in to the hole, then mounted in the cordless drill. Spinning at low speed, and using 400 grit wet and dry. It only takes a little pressure, so you don't need a strong fixture.

And it works ! 

[mikepilk]

Blue-tacking works I've done it before.

If I want a polished finish I hold the back flat on the desk and use my Dremel with felt pads. Only takes a few minutes to grind out scratches and get a shiny finish. 

Then for a straight brushed finish I Blue-tack it to a small angle bracket, which I run along a strip of wood,  allowing me to keep a straight line as I run it along some 240 grit.

What I haven't figured out is how to get the straight lines on some cases like on one of my Bell-Matics - is it a coarse wire brush ?  (I'd only do it on Stainless Steel !)

 

Edited October 18, 2022 by mikepilk

[lexacat]

11 hours ago, mikepilk said:

What I haven't figured out is how to get the straight lines on some cases like on one of my Bell-Matics - is it a coarse wire brush ?  (I'd only do it on Stainless Steel !)

Hm. I'd think the best way would be with a stiff sanding stick (or just rigid sandpaper) by hand, and methodically following the existing grain lines.

[Neverenoughwatches]

13 hours ago, mikepilk said:

I like the suction cup idea.

I found one from my aquarium which was just the right size. Push fitted an electrical connector in to the hole, then mounted in the cordless drill. Spinning at low speed, and using 400 grit wet and dry. It only takes a little pressure, so you don't need a strong fixture.

And it works ! 

Good test bed mike, i had a similar idea for reducing crystal diameters. Edge thicknesses are around 1 mm, a reduction of 0.1mm  should do no harm  . So that gives up to a 0.2mm overall adjustment usually more than enough for a correction on crystal measurement. I've not actually tried it yet,  centering and maintaining the bevel edge on the crystal obviously a key factor to consider.