CNC for musical instrument inlay

[jemmyell]

Hi,

Are others on this forum using CNC for musical instrument or fine woodworking inlay applications? I am using a Liberty CNC 20" x 19" router table, Vector CAD / CAM and Mach1 CNC controller on Windows 2000. I am attaching a picture of a 'State of Texas' fret marker prototype for a project I am currently working on. The material is Green Standard Abalam.

[jemmyell]

Ok, second attempt at attaching a picture!

[jemmyell]

Hi,

These are fret markers cut from natural .050 thick Mother-of-Pearl

[jemmyell]

Hi,

These are fret markers that work for both the side of the fingerboard and the face. They are both 1/4" wide and 3/8".

[jemmyell]

Ok, the last picture of stuff I have done is of a Martin-style heel plate for a DreadNought guitar. The material is .060 Ivory.

[CNCadmin]

Very nice work!

[DICKEYBIRD]

Hey jemmyell,

You being a CNC type luthier guy and all, I have a question. I inherited my father's '67 Martin guitar and when I found out what they're worth I almost choked! Anyway, it's in good (although much played) condition except for the obligatory cracked rosewood bridge partially delaminated from the top syndrome.

I was thinking of carefully removing the bridge with a thin blade, gluing and clamping it back together with aliphatic glue, clamping it in my CNC router and routing out 2 or 3 small hourglass shaped pockets in the back side and gluing in 3 matching hard maple or rosewood (if I can get it) "dutchmen" across the crack....then machining the bottom perfectly flat before carefully gluing & clamping it back onto the top with aliphatic glue.

Whatcha think?

Thanks!
Milton Dickey

[jemmyell]

Hi Milton!

Nice to make your acquaintance!

What I think is that your instrument is FAR too valuable both monetarily and sentimentally to attempt a bridge repair / replacement by yourself. An instrument of this era probably needs hide glue on the bridge, not aliphatic resin, which is too flexible. You should have a new bridge made by a luthier or supplied by Martin. These are typically slightly oversize so they can cover up the minor misalignment that is inevitable when replacing the bridge. The bridge PROBABLY needs to be moved slightly anyways to avoid a neck reset in an instrument of this age. Putting a new bridge on and routing the saddle slot in place will allow for greatly improved intonation and playability. Please use a Martin authorized repairman, since ALL Martins have a lifetime warranty and your repair will probably be free! Contact the factory with your serial number to inquire. Feel free to contact me off list if you have any questions, or need help contacting Martin about your guitar.

[handersen]

Hi James,

Nice work, did you cut the state of Texas on the first try?

What do you use as a hold down for such small pieces?

What size bit do you cut it with, does it explode (the shells)?

I have read that Mother Of Pearl and Shell dust causes fever, pneumonia-like disease, is that right? I've seen alot of Mother Of Pearl on e-bay and was wondering how hard it is to work.

Thanks for the pictures, inspiring, you got me thinking.

Harry

[jemmyell]

Hi Harry!

<Nice work, did you cut the state of Texas on the first try?>

Yes, the design was done in VectorCADCAM from a TrueType font in the shape of the state of Texas. The customer (CrossRoads customs) supplied the font as an example. Luckily, I was able to use it directly.

<What do you use as a hold down for such small pieces?>

The Abalam sheet it was cut from is 2.75 x 4.75. It is superglued to a sheet of masonite which is held down by clamps from Rockler woodworking fastened in a T-Track on the MDF table of my Liberty router.

<What size bit do you cut it with, does it explode (the shells)?>

I use the special Mother of Pearl cutting bits from PreciseCut. They are .031 in diameter. You CANNOT tolerate ANY chipping of the finished part. I don't get any with the setup I am describing.

<I have read that Mother Of Pearl and Shell dust causes fever, pneumonia-like disease, is that right? I've seen alot of Mother Of Pearl on e-bay and was wondering how hard it is to work. >

MOP is NOT toxic, but it IS dangerous. Getting the dust trapped in your lungs will eventually cause silicosis, an incurable condition similar to emphysema. Wear a GOOD toxic dust mask at least, not one of those silly things with elastic bands. I use a painter's mask suitable for nitrocellulose lacquer with prefilters.

Please consider using a Porter-Cable laminate trimmer motor instead of a dremel for the spindle. It will add a small amount of extra cost, but coupled with micro-tools from PreciseCut and one of their ultra-precision 1/8" tool collets, the results will be truly professional. Having a TIR (Total Indicated Runout) of less than .0015 is the key to NOT breaking small bits. You also have to control the acceleration during the cutting cycle. Very rapid accelerations also will break bits. Once I got my replacement collet from PreciseCut and I tuned my acceleration, I haven't broken a bit since.

I am using Mach1 as my CNC controller. It is a child of EMC (sort of) since Art Fenerty uses the NIST interpreter as the GCODE interpreter core for Mach1. Very affordable, and the ONLY REAL Windows-based software-only CNC controller available.

I hope this is a good start on your 1000 questions! <GRIN>

-James Leonard

[CNCadmin]

Any updates?

[CAMmando]

Great stuff guys.

Im in the design and scavanging stage of building a router and was thinking of this exact application. I hadnt considered the safety aspects you mentioned.