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Mar 8, 2021 - 4:21:41 PM
1632 posts since 4/13/2017

I have a question

I am about to build a pantograph, using a Dremel FlexShaft as the cutter tool. My main purpose for it will be cutting out fretboards, headstock covers, bridges, truss rod covers, and routing inlay cavities.

However

I would also like to cut pearl with it eventually. Are there any bits available for a Dremel that will allow it to effectively and precisely cut pearl, or does the Dremel spin too fast to cut pearl?

Mar 8, 2021 - 5:51:36 PM
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Fathand

Canada

11713 posts since 2/7/2008

My Dremel purchased in the 1980s included some instructions for "dental use".

If it will drill teeth it will cut pearl. Sometimes you can talk your dentist into giving you worn out bits that are still suitable for cutting wood.

I did cut some pearl freehand with a dremel once and was not happy with the result (sloppy).

Buy 3mm or 1/8" shaft milling machine bits on Amazon for Dremel use. Cheaper and last longer.

Note that cutting out fingerboards will be much easier with a router, pattern bit and a template made of MDF or similar. Pegheads can be cut the same way if not overly ornate. A dremel is frustratingly underpowered for this work.

Mar 8, 2021 - 5:54:26 PM
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13472 posts since 6/29/2005

The speed of a Dremel is variable, but I think the little tiny bits you'd use to cut MOP would overheat and break—I recently broke one just drilling a hole in MOP.

Most people use a jeweler's saw to cut the MOP shapes.  You can put jeweler's saw blades in a scroll saw and cut pearl, but they overheat and break in a short time, so you go through a lot of blades.

Mar 8, 2021 - 6:00:21 PM
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7915 posts since 1/7/2005

Like most others, I prefer a jeweler's saw for cutting out the pearl. And like most others, I find the Dremel well suited for cutting the matching inlay cavities. If I made enough banjos, I would probably look into a pantograph, or CNC.

DD

Mar 8, 2021 - 6:30:55 PM

1632 posts since 4/13/2017

quote:
Originally posted by Fathand

My Dremel purchased in the 1980s included some instructions for "dental use".

If it will drill teeth it will cut pearl. Sometimes you can talk your dentist into giving you worn out bits that are still suitable for cutting wood.

I did cut some pearl freehand with a dremel once and was not happy with the result (sloppy).

Buy 3mm or 1/8" shaft milling machine bits on Amazon for Dremel use. Cheaper and last longer.

Note that cutting out fingerboards will be much easier with a router, pattern bit and a template made of MDF or similar. Pegheads can be cut the same way if not overly ornate. A dremel is frustratingly underpowered for this work.


Is this something like you were talking about for the milling bits? At this price, I wouldn't imagine they'd be quality, but at price, they're almost disposable.

https://www.amazon.com/JIUWU-Tungsten-Carbide-Engraving-Milling/dp/B00SMDP72S/ref=sr_1_2?dchild=1&keywords=milling+machine+bits+1%2F8%22+shaft+engraving&qid=1615256927&sr=8-2

Mar 8, 2021 - 8:59:38 PM

Fathand

Canada

11713 posts since 2/7/2008

Yes I bought some like that but a set of assorted sizes. I've been using them to rout out guitar tops for rosettes.

Much sharper than typical dremel bits. The thin ones are delicate, go easy.

Mar 9, 2021 - 5:25:17 AM

13472 posts since 6/29/2005

The pantograph would be useful if you were making a lot of banjos with the same inlay design, but very slow if you made a number of different designs, since you would have to make a different template for each one.

As Dan has said, the Dremel is a very useful tool for routing out the cavities.

Mar 9, 2021 - 5:35:57 AM

rmcdow

USA

908 posts since 11/8/2014
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I use a flex shaft with diamond grit faced bits for fine shaping MOP pieces. When cutting the patterns from it, instead of a steel jeweler's saw blade, I use a diamond impregnated blade, as it is much better for turning the corners you find in inlay work, and it also works well for fine shaping. A small diamond faced file, with fine grit, works for the fine shaping as well. I have found that the diamond grit faced tooling works better for MOP as it doesn't chip out the edges of the MOP as carbide or steel tooling sometimes does.

Mar 9, 2021 - 5:49:38 AM

rmcdow

USA

908 posts since 11/8/2014
Online Now

A friend of mine just bought a Shaper CNC router:
store-us.shapertools.com/
It is pretty impressive, and works by bringing a vector drawing into the system, then following the outline the best that you can. The CNC makes all the corrections for you when you deviate from the line, and you end up with a perfectly cut out part or cavity. They are not cheap; you can buy a very nice banjo for the money you would spend on one of these, but if you want to get into production of inlays, I haven't seen anything that works as well as this does.
shapertools.com

Mar 9, 2021 - 6:25:12 AM

beegee

USA

22268 posts since 7/6/2005

I think a limited-production shop would be better-served by hand-cutting or buying pre-cut inlays until volume dictated an investment in high-tech machinery. Unless said shop is just burdened down by excessive dollars.

My experience with Dremel and pearl is that Dremels are very unforgiving and pearl, with its layering and grain tends to be rather fragile in the presence of high-speed bits. I use small abrasive discs in my Dremel(or Foredom) and diamond nail files to smooth rough spots on pearl inlays.

Edited by - beegee on 03/09/2021 06:31:20

Mar 9, 2021 - 6:54:34 AM

1632 posts since 4/13/2017

My main reason for doing this is money. I can buy precut inlays from Custom Inlay, but I would like to be able to get a better profit from my stuff. Plus, this summer I am going to have tons of free time, and I figured that the more things I could learn to do myself, the better my profit will be.

Yeah, my time involved is definitely going to be a lot higher, but once I make a pattern for each inlay type, I won't have to make it again, and, I have the patience of Job, and I know the satisfaction I'd get from cutting my own inlays would be worth it all.

Mar 9, 2021 - 7:06:14 AM

rmcdow

USA

908 posts since 11/8/2014
Online Now

quote:
Originally posted by beegee

I think a limited-production shop would be better-served by hand-cutting or buying pre-cut inlays until volume dictated an investment in high-tech machinery. Unless said shop is just burdened down by excessive dollars.

My experience with Dremel and pearl is that Dremels are very unforgiving and pearl, with its layering and grain tends to be rather fragile in the presence of high-speed bits. I use small abrasive discs in my Dremel(or Foredom) and diamond nail files to smooth rough spots on pearl inlays.


I agree with all this.  I'll just go over to my friend's shop and use his machine if I need to.  I have a Servo brand CNC milling machine, but hardly use it for CNC work, as I find that I can be more accurate with hand work, and a microscope if necessary (for those really tiny watch parts I sometimes work with).  When in CA, I had an Alexander 2D pantograph and another smaller pantograph for jewelry engraving.  Pantographs are a very handy tool to have to accurately reduce and duplicate the size of a part, but I wouldn't buy one again, as there are much more advanced ways of doing the same thing now, with better results.  The Shaper Origin is expensive, and like you say it might be a good thing to have once you are burdened by dollars burning a hole in your pocket.

Rockler and other woodworking suppliers has an inlay bit with a removable sleeve on it.  It allows you to trace the inside (for a pocket) or the outside (for the part) when doing inlay.  Completely manual.  It uses very small bits.  I've never used it, the same friend gave it to me, but I can see how it can be used to create a part and a pocket that the part would fit into.  

https://www.rockler.com/inlay-bushing-and-bit-with-removable-collar?country=US&sid=V91040&promo=shopping&utm_source=google&utm_medium=cpc&utm_term=&utm_content=&utm_campaign=PL&gclid=EAIaIQobChMIiteq2L2j7wIVFo3ICh1RkgtlEAYYASABEgLTIfD_BwE

Mar 11, 2021 - 3:19:26 AM
Players Union Member

Helix

USA

13789 posts since 8/30/2006

There is an old thread here about mounting the dremel upside down in your vise and putting a thin plate on top of your router base, so you have a spinning bit to push Pearl against. I've done it, it works, go slow.

Mar 11, 2021 - 2:56:39 PM

7915 posts since 1/7/2005

For cutting out pearl pieces, I can do much if it using my 1" belt sander. You would be surprised at some of the tiny places you can get into when feeding the workpiece into the side of the sanding belt. What I can't quite reach, I switch to the jewelers saw. 

Several companies are marketing mini-belt sanders made of machined aluminum. They would probably be extremely handy for shaping pearl, or metal inlays--as well as nuts and bridges--etc.etc. 

How they can build the little sanders for the small prices I can't understand. How would you like to make one of these for $50 bucks?

https://www.ebay.com/itm/202861674265?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=202861674265&targetid=1098102009964&device=c&mktype=pla&googleloc=9032155&poi=&campaignid=11774733487&mkgroupid=113829509425&rlsatarget=pla-1098102009964&abcId=9300474&merchantid=223114833&gclid=EAIaIQobChMI2dq8pKmp7wIVCxmtBh135wEYEAQYBCABEgLvvvD_BwE

DD

Mar 12, 2021 - 2:38:52 AM

15012 posts since 2/7/2003

If you are going to cut pearl with a bit it must be small to do the tight radiuses and as said it will heat up and break quickly pearl is like glass not like teeth.

I have experience with this with the largest oldest pearl cutting company in the business, they failed for years until they invested in expensive bits only found in Germany did I say expensive.

Mar 14, 2021 - 4:45:22 PM
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rmcdow

USA

908 posts since 11/8/2014
Online Now

quote:
Originally posted by desert rose

If you are going to cut pearl with a bit it must be small to do the tight radiuses and as said it will heat up and break quickly pearl is like glass not like teeth.

I have experience with this with the largest oldest pearl cutting company in the business, they failed for years until they invested in expensive bits only found in Germany did I say expensive.


I agree about MOP heating up.  My father used to take the mussel shells left from the WW2 button factory in Memphis, cut them into squares, then make them spherical in a machine he built.  He had a color sorter that would grade them, after which he sold these to Mikimoto to use for the nuclei of their cultured pearls.  All the cutting, grinding, and polishing had to take place under a steam or bed of water, or. the MOP would start to flake apart from the heat.  I use water even when hand sawing or finishing the edges of MOP for this reason. It cuts down on the minute splitting of the MOP that pretty much ruins the edges of the chatoyancy.

Mar 22, 2021 - 8:42:11 PM

SOBX

USA

3 posts since 1/30/2021

What rmcdow said.

I've cut it for chessboard inlay but my experience was the stuff was so hard, if you dry-cut it, the bit lasts a very short time. Even with the diamond bits, it heats up the bits to the point of melting the epoxy that glues the diamond dust to the bit.

The only way i found to do it without the MOP "eating" bits is to use the flex attachment and cut the MOP in a dish of water to keep the bit cool.

You could technically do it without the flex attachment but I'm not comfortable with using a power tool that close to water. The flex attachment allows me to clamp the dremel gently in a padded vise and operate the tool a safe distance from the water.

Edited by - SOBX on 03/22/2021 20:42:58

Mar 27, 2021 - 7:41:27 PM

1820 posts since 11/18/2010

CNC's are cheap now. If you are CAD-proficient at all, it's the only way to go.  Even if you are not, it's worth learning.  My buddy Joe Mendel was paying about $40/each to have his inlays hand-cut by some outfit and wanted to know if I'd CNC them.  I told him I'd teach him to run a CNC.  He bought a little one with a water-cooled spindle and I set up an old Dell Core2 XP computer to run it with Mach 3.  It paid for itself in a few months since the total investment was about $1300.  I used a combination of WinTopo Free (raster-to-vector conversion), Autocad, and Mastercam to convert the original hand-cut inlays to a usable CAD file.  I scanned the original inlays to begin the process.  I've also generated CAD models from a couple hand drawings this way, though it is tricky.  We used .02" carbide running about 8,000 or 9,000 rpm to cut all of these.  You can get several inlays out of each bit.

Edited by - David Cunningham on 03/27/2021 19:44:09

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