Technique

Using a vibratory tumbler

Until recently I did all the cleaning and polishing of clock parts by hand! This meant every small nut, screw and wheel was held in hand and polished with fine wire brush in a Dremel miniature drill. It was tedious and painful trying to hold such small pieces. I therefore spent some time figuring out a better way to do it without damage to my ageing joints.

After a few months of searching I found a company willing to let me trial a vibratory tumbler and some media. I had already discounted barrel tumblers of the type used to polish gem stones etc, as being too harsh in their action to be let loose on small and delicate Bulle and Eureka parts. But the vibratory tumbler looked a lot gentler in its action. Having spoken to the kind people at Sharmic who were helpful in discussing my needs, they suggested a Raytech AV18 tumbler and fine media such as walnut husk or crushed maize orb. After trying both I settled on Maize Orb which could be supplied in varying grades.

I then needed to find a way of separating out the small parts from the maize after processing. I concluded that a fine mesh sieve with a grating of 1.18mm in combination with maize orb graded to pass through a 1.10mm sieve would be ideal, as the smallest part diameter is 1.5mm.

I therefore purchased a 200mm diameter 1.18mm sieve from Glenammer Engineering, and the AV18 tumbler along with GM20 Maize orb from Sharmic. A stainless steel bowl was made to fit under the sieve and collect the orb after passing through the mesh. I was then ready for a trial.

I could see no reason to use any form of lubrication for the orb and so left it dry and filled the tumbler. Because this was a trial I counted and photographed all the parts of a Bulle which I had just retrieved from the ultrasonic cleaner. If anything went missing then I would at least know exactly what I would be looking for. I switched on and watched the parts disappear into the orb. After a few seconds a cycle started to manifest itself as the parts both rotated vertically and horizontally in the bowl.

The results

I decided to check the results every hour for three hours. I could see after the first check that the parts were looking a lot better than when I put them in. And after three they had all been buffed to a high degree.

It was an easy job to tip the orb and components through the sieve and into the waiting container. I was relieved to find that all the parts were retained by the sieve with all the orb passed through to the container. As a famous journalist once said on the Harriers taking off for a sortie in the Falklands, “I counted them all out and I counted them all back again”.

I carefully examined all the parts and found no damage whatsoever, but each had received a nice polish. Perfect.

I now use this system to clean both Bulle and Eureka parts. I have also tried extending the time in the tumbler up to 24 hours. The extended time does a little better at removing some stains but I found that 5 hours was probably about right. It must be noted that the orb is not very abrasive and will only buff the parts. If you have ever used an ultrasonic cleaner then you’ll know that parts still need to be buffed with a brush or cloth to remove “water marks” etc. The tumbler in conjunction with the orb does a beautiful job and does no harm to the parts. I must also add that I have been using the same batch of maize orb for the last two years with no degradation in its polishing ability.

The only manual labour required now is spending a few minutes with a needle removing orb from the screw head slots and from other small crevices and holes. A can of air is also useful at this time.

Although I used the product from the companies mentioned I assume similar equipment and orb can be sourced elsewhere: www.sharmic.co.uk, www.glenammer.com, www.raytechmetalfinishing.com.

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