Stabilizing pins.

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Stabilizing pins.

This topic has 10 replies, 5 voices, and was last updated 10 August 2014 at 19:40 by Ian P.

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5 August 2014 at 22:23 #15720
speelwerk
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@speelwerk
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5 August 2014 at 22:23 #159845
speelwerk
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@speelwerk
I am looking for something to stabilize small diameter pins (0.20 mm and smaller) during grinding musical box cylinders. I now use shellac but it takes a long time to set. I have used water based wood glue which works fine but the water in it makes the pins starting to rust. Pins stick out ca. 1.2 mm and the final length is around 0.60mm. Ideally it is easy to apply without using heat, is not water based, sets quick and is also easy to remove. Thanks, Niko.
5 August 2014 at 23:34 #159850
Michael Gilligan
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@michaelgilligan61133
Niko,

Lakeside 70C Cement might be worth a try … it is used in Lapidary, and for other small workholding.

I must admit that was surprised when you said that Shellac takes a long time to set … Watchmakers and lens-makers use it for chucking components … are you melting it with heat, or dissolving it?

MichaelG.

.

Sorry, I mis-read your post … You said you wanted something that works without using heat.

Edited By Michael Gilligan on 05/08/2014 23:36:25
6 August 2014 at 10:38 #159864
speelwerk
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@speelwerk
Thanks Michael for the link, sadly I cannot use it because of the filler inside the tube, it melts around the same temperature. Niko.
6 August 2014 at 11:12 #159868
Ady1
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@ady1
Ideally it is easy to apply without using heat, is not water based, sets quick and is also easy to remove.

Sounds like you need some form of resin (which is what shellac is)

Might be worth experimenting with a poly resin

or a varnish

or a solvent based resin

Edited By Ady1 on 06/08/2014 11:25:35
6 August 2014 at 14:06 #159904
mark costello 1
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@markcostello1
Would a super glue work? Then get dissolved off later.
10 August 2014 at 12:19 #160354
speelwerk
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@speelwerk
Thanks for all the advice, I let the shellac dry for a week before I ground the pins yesterday with a positive result as you can see in the picture. The cylinder has ca. 5000 pins of 0.20 mm diameter, height is now ca. 0.65 mm. If you grind these small diameter pins without stabilizing them the change of breakage is very great which is very frustrating. Niko.
10 August 2014 at 16:13 #160375
Michael Gilligan
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@michaelgilligan61133
Great result, Niko

MichaelG.
10 August 2014 at 17:22 #160386
Ian P
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@ianp
Niko

When you first posted the question I did try and think of something that would suit the purpose, but I failed. Having seen the picture of the drums and pins I can see the nature of the problem. (and the quality of your work!)

I suppose if the grinding system took extremely light cuts you might get away with unsupported pins, but it would be a very slow process.

One avenue of material that might be worth investigating is to coat the drum in a layer of 'Pollyfilla' or some other gypsum based product. No heat is involved and it would hold the pins rigid whilst being easy to grind away (bit messy though). I am not sure how you would remove it after grinding (unless it could be dissolved in some way).

Out of interest, do you drill and insert the pins manually using the grid lines as a guide?

Some of the pins have a very close horizontal spacing, presumably that must be much less than the spacing of the tines. How does that work?

Ian P
10 August 2014 at 17:40 #160390
speelwerk
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@speelwerk
Ian

This is the cylinder from a musical box made between 1820-25, the grid lines are specific for this maker. The old pins are removed in a bath sulphuric acid leaving the holes vacant for the new pins which are placed by hand . This cylinder has 3 revolutions with tunes, after one revolution it shifts ca. 0.38 mm to the next line pins, after 2 shifts it returns to the first position. Polyfilla crossed my mind, but the problem is how to remove it, thinking what they must have used in the past I came to shellac. Cuts are very light (<0.02mm), but if you have this small diameter pins they get in vibration and you get a stress fracture at the base, larger diameters you can do without stabilizing.

Niko.

Edited By speelwerk on 10/08/2014 17:41:01
10 August 2014 at 19:40 #160400
Ian P
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@ianp
Niko

'Lateral movement' Ah, I remember now!

When I was very young there was a musical box at my grandparents house that we were allowed to play with. I am sure it may have had about 8 tunes. It was in a beautiful ornate (Japanned?) box with bevelled glass windows in the top and front. The 'comb' like thing was about 150mm wide (about a quarter of the tips were already broken).

Nobody in the family ever knew what happened to it after my grandparents died and I had forgotten about it until I saw your picture.

Ian P
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