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Dial resizing.

bibby1

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2/3/15
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I need to take about 1.2mm off of the circumference of a dial fit for an ETA 2824. Is there any way to evenly remove material from the brass blank without completely damaging the dial?

I was thinking about taking a dowel and placing it in the hole where the cannon pinion and hour wheel sticks through and placing the dowel in my dremel, then using sandpaper; my worry is that the friction fit of a dowel in a dial hole won’t be enough to hold it in place.


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bibby1

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2/3/15
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Also, is there a name for the hole in the middle of a dial? It would behoove me to use the proper terminology.


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tripdog

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You could use a lathe. Some people have done it using various techniques with a Dremel, but the risks are high unless you practice on several 'throwaway' dials first.

I would just use a sanding stick with 400 grade paper and do it nice and slowly by hand.
 
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manodeoro

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I need to take about 1.2mm off of the circumference of a dial fit for an ETA 2824. Is there any way to evenly remove material from the brass blank without completely damaging the dial?

I was thinking about taking a dowel and placing it in the hole where the cannon pinion and hour wheel sticks through and placing the dowel in my dremel, then using sandpaper; my worry is that the friction fit of a dowel in a dial hole won’t be enough to hold it in place.


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You'd better not ... if the dial slips on thecdowel while it is turning the paint and/or varnish will be definitely damaged ...
Plus you're not certain to remove material evenly ...

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bibby1

Known Member
2/3/15
180
46
28
United states
You could use a lathe. Some people have done it using various techniques with a Dremel, but the risks are high unless you practice on several 'throwaway' dials first.

I would just use a sanding stick with 400 grade paper and do it nice and slowly by hand.

So with a sanding disk, clamp the dial gently and just move around evenly, and slowly?


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bibby1

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2/3/15
180
46
28
United states
You'd better not ... if the dial slips on thecdowel while it is turning the paint and/or varnish will be definitely damaged ...
Plus you're not certain to remove material evenly ...

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It was a super cheap dial, 22 dollars, I’m not worried, if I ruin it, it is what it is. I obviously would prefer not to, but, I also need to figure something out.


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bibby1

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2/3/15
180
46
28
United states
You'd better not ... if the dial slips on thecdowel while it is turning the paint and/or varnish will be definitely damaged ...
Plus you're not certain to remove material evenly ...

Envoyé de mon moto g(7) power en utilisant Tapatalk

Do you have any advice or experience? I’m going to try tripdogs method by hand if I can’t figure something a little faster out.


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manodeoro

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Do you have any advice or experience? I’m going to try tripdogs method by hand if I can’t figure something a little faster out.

Too bad I never took any pics while doing that (I need both hands to work) but here's how I proceed :

01 - remove all the indexes from the dial as they could be satelized while the dial will be in rotation
02 - sand a bamboo skewer to almost the diameter of the dial's center hole ... try to keep it just a little larger than the hole ... and cut it so that it exceeds about 2 or 3 cm each side of the dial
03 - push the bamboo stick "in force" inside the dial's center hole ... if "in force" enough the dial will stay perpendicular to the axis of the skewer
04 - get 2 little blocks of teflon/metal/etc ... any material on which the bamboo skeer will rotate without too much friction
05 - put a thin aluminium oxyde grinding stone on your dremel (see pic below) ... use a flexible shaft if you have one too make control easier
06 - put cotton glove fingers (cut from a glove) both on your index and ring fingers ... you'll use those 2 fingers to hold the skeewer on the blocks ... cotton cause you want the skewer to rotate easily
07 - put a leather glove finger (still cut from a glove) on your major finger ... you'll use that finger to slow down the dial if needed
08 - start the dremel ... low speed
09 - put the bamboo skewer on your blocks, with the dial between the 2 blocks, hold the 2 sides with your index and ring fingers
10 - start grinding ... the grinding stone will both rotate the dial and grind it ... use your major finger to slow the rotation if needed

Grind slowly, without applying too much pressure with the grinding stone, and check repeatedly how much material has been removed.
Proceeding that way you should get a really good result (almost perfect circle) and much faster than sanding by hand only.
When you're about too get the perfect size, just finish by hand with fine sand paper.

Hope this helps ;)


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tripdog

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So with a sanding disk, clamp the dial gently and just move around evenly, and slowly?


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Hold the dial around the edge with your fingers, and slowly work around the edge using a sanding stick, you're very unlikely to slip or damage the dial - a Dremel will be obviously be much quicker, but if you slip the dial will almost certainly be ruined.
 

bibby1

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This is all great information, I am going to get it started tonight, and post some pictures of the process.


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bibby1

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46
28
United states
I think I’m going to scribe a circle on the back of the dial with a compass first before I start this way I can see where the sanding should stop.
Guess and check seems risky


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