My main interest is restoring vintage watches and the restoration of the case has always been a story by it self.
Buffing out scratches is "easy" but you often end up with a case that has rounded corners and in worst case - a watch with a somewhat deformed case.
I also used different methods for getting the brushed surface back om cases and the worst one - the sun burst was made using a simple jigg - alot of patience and time!
As a mechanical engineer I love machines, and it was time to get a new one for the work shop.
My first go was using a disc sander as base and building a fixture for it.
I made an order for some goodies.....
A 12" disc sander with a cast iron base and tiltable table
Hooking it up I noticed that the disc was not spinning as I wanted - time to measure the "wobble"!
0.25mm difference along the edge of the disc - not good!
Getting the disc lose was a mission in it self - but with a homemade "puller" I finally got it off!
Got it set up in my lathe (had to cut it down to 10" as this is the maximum diameter my lathe can handle) and got the surface within acceptable values.
Last edited by McGyver; 4th February 2015 at 14:07.
Took a short cut again and got a small cross table
Made a simple "cradle" for the table that could be attached to the disc sander so the disc and table had the same reference point.
I also made a small tiltable table
....and a "chuck" with adaptors from 26mm up to 31mm
Here you se everything set up for a first test run
Last edited by McGyver; 4th February 2015 at 14:07.
The result of the initial tests using an old case . The case has been polished MANY times during its life => I had to remove alot of material to get a flat surface again!
There was to much "wobble" and I had to compensate for it by hand - time to see what could be done.
I got the motor axel out and put it up in the lathe - made some adjustments and put things back together again - still wobble in the disc!
After many hours making new discs, adaptor etc. I finally gave up and went for something different.
I have this small mill in my workshop
It has a spindle that can be tilted 90deg and a 6 speed gearbox - with a motor dimmer I can adjust the speed almost down to zero! :)
made a new disc with a sutibla adaptor for the mill.
Things set up for a first test of this configuration.
The test object this time - an old Seiko that has been polished so you almost have to use a microscope to se the remains of the original sunburst brushing!
And the result
Not perfect - but it's getting better......
Excellent results and a very enjoyable post :)
As I was reading the first post I was thinking that you'd probably end up binning the sander and sure enough... :D
Neat solution, reusing your existing kit appeals to my efficiency. Good job all round :)
I use the mill quite alot so I'm currently trying this third version
It's a 12" disc with a homemade construction for the bearings powered by a 40V DC-motor.
Initial tests show that the disc now turns much smoother and controlling the rpm with the voltage for the DC-motor + the dimensions of the belt drive shows potential.
That's how far I have come with this version........
Wow! You need to stick around here McGyver, proper bodging skills on display!
Really enjoyed reading the above. Love the skills and the tools.
Brilliant! Looking forward to the continuation.
Living up to your name rather well there ;)
Good stuff. Some proper McGyver ingenuity going on there. The finish looks excellent.
Very impressive work and a lovely finish. That old Seiko looks great.
I vote sticky.
Very impressive skills there sir!!!
Beautiful done!
Fantastic results.
I don't quite understand how the arrangement produces the sunburst - do you rotate the case a few degrees by hand, finish, rotate, finish, rotate, finish etc...
Thanks
Chris
The case is presented to the spinning disc at 270deg as close to the edge as possible and at the horizontal center using the table for the right "tilt". My "chuck" can rotate and the case is then rotated 360deg to achieve the sunburst pattern.Originally Posted by h780
As the length of the case in contact with the disc is so short the brushing will be almost straight, but it will NOT be perfectly straight!
The larger the disc is the straighter the lines/brushing you get and that is why I wanted a 305mm/12" disc! :)
Excellent
Many thanks. I think I get it. Does the case remain in contact with the disc while you rotate it?
Chris
Yes - the case is rotated and has contact the whole 360deg!
If you look at the STS video (40s -> ) you can see how it's done!
https://www.youtube.com/watch?v=7j9ThJZpH6o
Last edited by McGyver; 5th February 2015 at 12:56.
excellent thread,most interesting and enjoyable.thankyou.
Wow amazing building skills and the finishing skills to match , great read look
Forward to seeing some more case refinishing !
Nice work,Sir.
where did you pick up the cross table please? could use that with my pillar drill...
Engineering initiative at it's best!
Great thread. I really enjoyed reading this, it's fantastic to see the excellent results that can be achieved with some ingenuity and skill. Hat's off to you :-)
V.interesting!
Building a lapping machine never crossed my mind...until now.
Paul
I really like your approach to things! Great post!
Very impressive, I want one!
Thanks all - have made some new parts for the belt drive - will post pictures when I have them fitted!
Right now I'm thinking about a sutible setup for the table so that the hight can be adjusted.
I got mine from Conrad.de - It's from Proxxon and quite easy to find - at least here in Sweden!
Excellent work there OP. Re the Proxxon slide table, we discussed them a while ago in the Digital Photography section with a view to adapt to take a camera mount in order to take a series of macro photographs to be stacked for great depth of field.They were pretty widely available, and allow for very fine adjustments, measured in microns for macrophotographic use. I never got around to buying one as something else took my attention............. and my ££££s!
F.T.F.A.
New wheels for the transmission made.
First try lapping a case with the machine!
Not perfect - but I'm a noob so I hope I'll get better at this! :)
That's brilliant!
I don`t have the skills or equipment to build something like this, but I`d be interested in buying one. It would be helpful for me to have this capability. Depending on the watch, I can do sunburst finishes quite well using the edge of a coarse Garryflex block, but the lapping machine will always be the best way.
It shows what can be done with a bit of thought and improvisation, I`m v. impressed.
Paul
Last edited by walkerwek1958; 10th February 2015 at 23:19.
excellent post and the results look very impressive.
INGENIOUS!!
Great post and a brilliant bit of engineering.
Well done sir
What a difference! Superb stuff
Nice!!!
Thanks all!
I've done some minor modifications to the setup with a "help wheel" to make the disc more stable and flex less .
I have also ordered new sandingdiscs with 120, 240 & 320 grain (carborundum) as the silicon ones I have (finer grain) tend to leave residue that makes the surface look a bit sandblasted.
Here are two of the test watches
Why do you use such a small drive belt. Does it not stretch / contract under load and chage the disc speed, or are you relying on 'flywheel mass effect' ?
I had a bunch of O-rings in my workshop - "supply and demand"! ;)
It gets a bit stretched just at start up (~1s) but after that it's not a problem and i actually think it helps to put less strain on the DC-motor.
I normally only run the disc at 60-80rpm and have found no problem with the small size of the drive "belt" - but it's an easy change if there should be one in the future.
Interesting. I am a little prone to over engineering :-)
McGyver
Just my ignorance but how does one get the radial starburst?
Do you set an angle and then rotate on?
Do you set angle and then push on and off then rotate off?
What happens when case has more of a curve to it?
You can find my (try) to explain the procedure in post #15
Will post a film as soon as I get everything up and running as I want! ( have a 0.1mm "wobble" in my discs that I have to fix in some way)
The cases I have done all have a flat surface for the sunburst pattern. if you have a curved case the procedure becomes a bit more complicated as the fixture then has to follow the curve of the case in some way - nothing I have tried!
Why did you not try to use your lathe in the first place? Ok, you use it a lot otherwise but that might have been my first try.
Nevertheless awesome work.
Thanks!
My lathe can take a disc of maximum 240mm and I wanted 300mm to get the "scratches" as straight as possible.
I also use the lathe to make parts almost on a daily basis => I wanted a machine that could be used only for lapping ( + building machines is fun! )
I have just started to experiment with DIY anodizing of aluminium - will perhaps ad some colour to the machine in the future!
Wow just love your work. Nice results too.
Stumbled across this thread and I must say this is very cool!
Great ingenuity and engineering skills, fantastic results too.
New discs with 120 to 600 grit has finally arrived - so will try to lapp some more cases soon!
Here is a Heuer case that was quite messed up from the start - I had to remove some dents.
Last edited by McGyver; 6th May 2015 at 13:40.
That heuer looks great, very crisp edges and nice graining. That's a great skill to have particularly as you assembled what you need yourself.
There is no way I would ever do this myself (lack of machinery and skills!) but your work looks great. Well done!
Nice work.
You could try truing the disc in situ by mounting a lathe tool on you table.
Dave
Omega Seamaster 70's
Before lapping........
.....and after
It had "dented corners" due to being polished a few times to many - did not want to take of to much material so left them as they are!
Lapping is fun and I constantly get new ideas for jigs etc. - now I just have to find the time to build them! :)
Last edited by McGyver; 3rd September 2015 at 08:42.
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