In search of inlay technique

[Doug Shaker]

I usually do a reconstituted-stone decorative inlay in the headstock of my guitars. I think I do a reasonable job of cutting out the stone. I make several photocopies of my design, then cut out the parts that I want from the photocopies, glue the little bits of paper to the stone, then try to cut on the line. Then I take the stone, clean it up with sandpaper a little, and glue it to one of the copies in the place that it would ordinarily go.

After I have all the bits cut out, I glue a copy of the design to the headstock and use a Dremel tool to rout out the cavity for the inlay. However, I seem to have trouble keeping exactly within the borders when I am doing the routing. Often there is a resistant bit of wood and, when I get through it, there is soft wood behind it and the router bit goes too far into the wood on that side.

I use tinted epoxy to glue the pieces in so, nominally, the errors are not too bad, at least if you don't know how to spot the errors. But, man, I would like to do better at accurately routing out the cavity.

Anyone have any advice on accurate routing?

[Gordon Bellerose]

When I am routing for inlay, the temptation is always to go too deep on the first pass. This has caused me grief in the past too.
I use the smallest bit I have, (1/32) and go very shallow for the first pass along the edges; just grazing the surface.
Secondly, I go just a bit deeper with the same bit.
I find that tracing the outline in this fashion has two benefits.
1. It is easier to do the outer edges without the bit chewing into the wood and making the error you talk about.
2. The small bits don't break as often.

Inlay is a job that requires being awake and fresh. Not a job for late in the evening.
Don't work too long at it. I go for an hour or less at a time. After that I rest, or leave it for tomorrow.

And you're correct. The right color epoxy is of prime importance. Hides those nasty errors.

[Barry Daniels]

A new, sharp bit will have less of the tendency to jump into softer material. Also, there are high speed rotary tools that cut a lot smoother.

[Rodger Knox]

When I attended Dave Nichols Inlay seminar at an AISA symposium, I concluded that the tool makes a lot of difference. He used some type of ultra high speed air tool. With the precision base, following the markings was not a challenge like it is with a dremel.

[Barry Daniels]

Here is the tool I use. It runs on air and goes 65,000 rpm. It feels like it melts through wood.

[David King]

I'd also suggest choosing your headstock veneer material carefully so that it's of uniform density if possible and not too hard.
I always cut the outline to full depth with a chisel and or small gouges first exactly on the line. This really helps me from going over.

[Doug Shaker]

OK, I had been using a slower speed on my Dremel. I will switch to a higher speed.
I expect I was going too deep at first, too. [Not the first time that I have unwittingly sacrificed quality for speed. My history of orange-peel finish problems bears testimony.]
Also, I will try cutting the outline with a marking knife or a chisel before doing the routing.

All good suggestions. Thank you!

[Gordon Bellerose]

Here is the tool I use. It runs on air and goes 65,000 rpm. It feels like it melts through wood.

Barry,
Can you tell me more about this tool?
What brand?
How much air does it use?
Is there a precision base for it?
What kind of chuck does it have?

[Barry Daniels]

Give me a day or two and I'll get you that info.

[David King]

You might also try some of the solid carbide cutters from http://precisebits.com , that's where the rest of the guitar industry seems to go.

[Barry Daniels]

Gordon, sorry it took so long. My machine is made by Air Turbine Tools of Boca Raton, Florida. It is a model 201SV.

http://www.airturbinetools.com/hand_tools/specs/201sv.html

I originally bought it from MSC or McMaster Carr (I can't remember which one), but neither one currently carries this line.

[Barry Daniels]

It doesn't use much air at all. My pancake compressor keeps up with it fine. You can get it with several different size collet style chucks. I have the 1/8" diameter. There is no precision base so I modified a Stew-Mac base to fit. The tool has a 5/8" diameter housing so it is easy to make holders.

[Barry Daniels]

The turbine is a real precision tool. There is virtually zero run out. With the tool running, you can touch the side of the collet and it doesn't have any chatter. It feels like it is not moving at all.

I recently put together a Collin's style saddle mill to use with this turbine.

In the upper right corner of the photo, you can see the inline air control valve that comes with the turbine. You slide it to turn the air on and it basically provides a soft start.

[David King]

Now that is a very slick contraption Barry! Are those window cranks?

[Barry Daniels]

No, I made those cranks out of solid brass on my lathe. Those were the one concession to make the jig pretty.

The jig contains five linear slides and two ball screws that I procured from eBay. It moves very smoothly.

[Gordon Bellerose]

That is a nice inlay rig Barry. I will have a look here in Canada for that unit, or something similar.
Thanks for posting.

[Matthew Lau]

Hey Barry,

I might copy you and build a similar rig for my NSK setup.
To those of you guys out there, sometimes you can find dental handpeices that will work.
There are a whole ton of belt driven dinosaurs out there that never die...they are nowhere as nice as my NSK ultimate XL, but work worlds better than a dremel.

-Matt

[Bryan Bear]

Hey Barry,

I might copy you and build a similar rig for my NSK setup.
To those of you guys out there, sometimes you can find dental handpeices that will work.
There are a whole ton of belt driven dinosaurs out there that never die...they are nowhere as nice as my NSK ultimate XL, but work worlds better than a dremel.

-Matt

From time to time I think about having one of those old school belt drive things in my shop, if for no other reason than it would look really cool. I have no idea where to even look for one nor would I want to spend a bunch of money, but it would be cool to stumble across one for cheap.

[David King]

And when your customers want to stick around and watch you work I think strapping them into an antique dentist chair might be the perfect compliment.

[Bryan Bear]

Customers? What are those?