Tonyh
58 posts
Mar 10, 2013
1:10 PM
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I am often asked what is the process I use to machine my harmonica combs. So here is a detailed step by step procedure I use when machining my combs. Maybe it will be usefull to someone.
Ok so how to get from the blank piece on the left to the finished comb on the right
First I start by cutting the blank piece closer to final dimension for the comb (I use the mill for this but you could use a bandsaw or anything you have handy):
Here I'm using a regular handsaw to make the blank piece that is now the correct width a bit shorter in lenght:
I then go back to the mill to adjust thickness of the blank piece. I first start by squaring everything properly in the vice and I then use a flycutter to machine a pretty flat surface and to get the correct thickness for the comb. The first picture is when I start after everything is square:
This is when I'm done and the thickness is what I am looking for:
At this point the comb is already pretty flat thanks to the flycutter. I am now off to the lapping machine ( this is an homemade lapping machine using a glass lapping plate I just finished building). After a couple of minutes on the lapping machine on both sides the comb is VERY VERY flat. There is a weight that goes on top of the blank piece to put some pressure that is not shown in the picture so you can see something. If there is interrest I can share plans for the build of the lapping machine:
I then go back to the mill to cut the slots on the comb:
After that I use a small file to round the corners of the tines and I use very fine sandpaper to polish the comb. Here is the final product:
Hope someone will find this usefull !
Last Edited by Tonyh on Mar 10, 2013 1:15 PM
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florida-trader
267 posts
Mar 10, 2013
7:58 PM
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Very nice workmanship. I've always had a question about a lapping machine. How do control the thickness of the finished product? Is it just matter of time - how long the blank is left on the machine?
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Tom Halchak
www.BlueMoonHarmonicas.com
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Tonyh
59 posts
Mar 10, 2013
8:47 PM
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Hi Tom,
Lapping itself removes very little material since you use very fine sandpaper or grit. I usually leave the blank 5 min on each sides. This also depends alot on the sandpaper grit and the weight you put on the comb. Finer sandpaper will give better flatness but will take longer. With 5 min on each side the combs are already very very flat.
I use a light weight that I drop on top of the blank just to keep the blank touching the glass plate at all time and remaining flat during the process.
The idea is just to get a very flat surface not to remove alot of material. I find that when hand lapping no matter how well you try to put even pressure there is always one side a bit lower. With the lapping machine since the blank is spinning and the glass plate is also spinning with even pressure put on it you really get a very flat surface quite quickly.
Leaving them 5 min on each side will usually take out 0.1-0.2mm of the total thickness of the comb depending on the pressure applied.
This lapping machine is only for 1 comb at a time since I don't produce a lot of them but the principle would be the same for a larger scale lapping machine.
I hope this answers your question. I'm still experimenting with the lapping machine to figure out what works best.
Last Edited by Tonyh on Mar 10, 2013 8:50 PM
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florida-trader
270 posts
Mar 11, 2013
7:47 AM
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Thanks Tony. So, if you wanted a finished comb that was say 6mm you would use the flycutter to mill the thickness to 6.3mm or 6.4mm and let the lapping machine do the rest. Is that correct?
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Tom Halchak
www.BlueMoonHarmonicas.com
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Tonyh
60 posts
Mar 11, 2013
6:16 PM
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Yes that is the basic idea. If your surface is already pretty flat when you start you won't have to use that coarse sandpaper or grit and it will remove less material. But yes you need to machine the comb taking in account that you will make it slighly tinner with the lapping.
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HarpNinja
3244 posts
Mar 11, 2013
7:22 PM
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Tonyh,
Do you sell combs? Do you have a website?
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Mantra Customized Harmonicas
My Website
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Tonyh
61 posts
Mar 11, 2013
9:01 PM
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Hi Mike,
I'm not officially selling combs because they take so much time to do them right (1hr30 usually without the polishing steps).I'm primarly a customizer and I build these combs to fit on the custom harmonicas I make for myself or others. I live in Canada and since there is no custom comb maker up here to my knowledge it is more economic to machine them to my specification than to import them from the US. I sometime sell some on request but since I don't have a CNC mill everything takes more time and I need to charge a bit more for that. I can be reached at antoine(dot)hamel(at)outlook(dot)com
Last Edited by Tonyh on Mar 11, 2013 9:02 PM
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