New at inlay, with questions...

I'm working on my first inlay project (mother of pearl), practicing on East Indian Rosewood and planning to do the actual peghead veneer in W. African Ebony. Didn't choose to try the shell cutting so I simply planned to do the easier task -routing the pockets. HAH!

I got my logo back from DePaule Supply, and found the letters to be of varying thicknesses (14 thousands of an inch on the extreme) sometimes varying 8 thousandths in the same letter. I could carefully cut the channels for each letter to match as best I can the thickness of each one. Or I wonder if a better plan would be to double-stick tape them to a board and gang sand them to a more uniform thickness? My thinking is to split any remaining differences from that sanding by routing the channels deep enough so that as little shell-surface sanding would have to be done. (Mind you, I may be overthinking something I know nothing about --that's never happened before...!)

I also found that the letters I received weren't an accurate match to the original drawing. I had hoped to cut the channels using a CNC router. After cutting the pockets for the letters, I experimented with tailoring them with a Dremel. I wasn't finding this workable and finally checked the inlay against the drawing and saw that there is some difference; to the extent that using the CNC process off of the original drawings isn't saving much time and effort at all. So I may simply work on cutting the pockets in without the CNC.

Another question: I read about the possibility of cutting shell out with a CNC router. If that is do-able, I would give it a try. Do any of you do that? Where do you buy your mother of pearl blanks?

Thanks!!

You didn't say what the average over-all thickness of the shell is. It is common to have varying thicknesses with shell as this is a natural substance. You should have plenty of extra "meat" so that thickness variance isn't an issue. What I do is cut the inlay pocket just deep enough so that the thinnest part will be just proud or ideally, just flush with the surface and the thicker parts will be proud. Then I can sand everything flush and I'm done.

I know nothing of using a CNC cutter and just do it by hand with a dremel tool with a downcut bit (1/16 and 1/32) on a SMD router base. Here is the thing Chuck, when you use ebony you can really mess up the cut (with a little practice you can get amazingly accurate) and nobody will know because you use the ebony dust - in glue trick and any gnarly margins totally disappear into the blackness. Ebony is very forgiving in this way.

I'm no inlay expert and I get acceptable results so don't overthink the thing and just do it. Maybe one of the experts will weigh in with advice.

It seems like it shouldn't be any harder to program a CNC to cut shell than to rout the pockets. I know nothing about either, but I watched the shell layout process at Huss & Dalton many times. Each pattern was routed very lightly into a board of synthetic stuff (can't remember the name), so as long as the shell blank covered the rout it would be big enough for the piece. Superglue was used to hold the blank in place. The board had to be precisely set on the CNC table each time. The completed board was placed in a tray of solvent overnight, shell patterns down. A lid covered the tray. The pieces seldom fell off after soaking but popped off with minimal breakage. Their cost per logo fell from $25 apiece for hand cut to less than $3. They purchased shell by the pound. I don't know who supplied them.

Chuck

This is something I know a lot about. First, DePaul is a great supplier but because everything is done literally by hand, do not expect consistency.

As far as doing inlay work on the CNC this is what I do:

Prepare a drawing in your software package - this represents the 'pocket' you will inlay into. Since I use two cutter for inlay work, 0.635mm or 25 thou for 'hogging' out the centre portion of the inlay and a 0.395mm or 16 thou for fine tuning the perimeter. All internal and external points are radiused to 0.2mm.
Offset the drawing and transpose onto a separate drawing layer and reduce this by 0.075mm or 3 thou- this gives you clearance for setting your pearl. Cutters obtained from Precise Bits USA. They have a speeds and feeds chart. Get pearl from Australia... laminate from China (quarter of the price of Ablam and just as good).

And that is it. If you have a CNC you will know what to do next - cut the pearl then cut the pockets. Here are some examples of my work. You can pm me if you need further help.

Hey Chuck, In a world where hand craftsmanship is slowly being lost by machine work, I suggest you do this by hand. CNC machines are great for production work but overkill for individual inlays. Routing the pockets can be done in the same amount of time it takes to read this thread. Sequoia offers some great advice. I’ll add the I temporarily glue the pieces in place using Just a dab of Duco Cement and tracing the outline with a fine mechanical drawing pencil. Pop off the piece And rout up to the line. I usually dye my CA black but ebony dust works well too. Fast and easy.

Moore Bettah Ukuleles said:

tracing the outline with a fine mechanical drawing pencil. Pop off the piece And rout up to the line. I usually dye my CA black but ebony dust works well too. Fast and easy.

Click to expand...

What I do is pin the piece down and outline it with a sharp #11 scalpel blade and then put white chalk dust in the indentations. Makes seeing the line soooooo much easier and seeing the line is key. I also use an aquarium pump to blow away the dust. Ease up to your line slowly with a 1/32 inch bit and you can get it amazingly accurate. The key is being able to see your line and things can get obscured with wood dust in the heat of the moment and you can go over your line. It really isn't that hard and I agree CNC is primarily for production work.

Picture of one of my first inlays years ago. Shell from DePaul.

One little tip if you rout the pockets manually with a dremel type router, is to use the "flag" trick. I used to use an aquarium pump to blow away the dust, like Sequoia , until I discovered that attaching a small "flag" of masking tape to the Dremel bit around the flat part of the shank, does a great job of blowing away the dust. No need for pumps.

mikeyb2 said:

One little tip if you rout the pockets manually with a dremel type router, is to use the "flag" trick. I used to use an aquarium pump to blow away the dust, like Sequoia , until I discovered that attaching a small "flag" of masking tape to the Dremel bit around the flat part of the shank, does a great job of blowing away the dust. No need for pumps.

Click to expand...

That is an excellent idea! I was doing a lot of blowing of sawdust as I practiced today. I will try that!

sequoia said:

What I do is pin the piece down and outline it with a sharp #11 scalpel blade and then put white chalk dust in the indentations. Makes seeing the line soooooo much easier and seeing the line is key. I also use an aquarium pump to blow away the dust. Ease up to your line slowly with a 1/32 inch bit and you can get it amazingly accurate. The key is being able to see your line and things can get obscured with wood dust in the heat of the moment and you can go over your line. It really isn't that hard and I agree CNC is primarily for production work.

Picture of one of my first inlays years ago. Shell from DePaul.

View attachment 128093

Click to expand...

I like the idea! Where do you find these scalpels?

In this practice run, I used a thin strip of double stick tape to try and get the letters lined up accurately and then tried my best with an exacto knife with little success. So I tried pencil with not much better results.

Moore Bettah Ukuleles said:

"Routing the pockets can be done in the same amount of time it takes to read this thread."

Easy for you to say, Chuck! ;-) I'm a slow reader, but not that slow!

I have been practicing getting these letters cut in using a Dremel first with a 1/16th inch bit, then switched to a 1/32 inch bit, finally experimented with a .020" bit, to see if I could break it. (No success there.)

I have probably sat hunched over that router for 5 hours today and I'm afraid the results are quite disappointing. (Photo)



"I temporarily glue the pieces in place using Just a dab of Duco Cement and tracing the outline with a fine mechanical drawing pencil. Pop off the piece And rout up to the line. I usually dye my CA black but ebony dust works well too. Fast and easy."

Click to expand...

I see where some people use a dab of CA glue to put the inlay in place to mark out around it. I also read that that's risky because you can break inlays into pieces trying to get them off the wood. I would rather not try that.

But you are using a different type of cement with good results so I will try that. This inlay spans just 2 inches in height. The T looking piece is 1/2 inch tall, tip of foot to top of crossbar. Probably smaller stuff than a rookie should mess with. But that's never slowed me down yet.

Pete Howlett said:

Chuck

This is something I know a lot about. First, DePaul is a great supplier but because everything is done literally by hand, do not expect consistency.

As far as doing inlay work on the CNC this is what I do:

Prepare a drawing in your software package - this represents the 'pocket' you will inlay into. Since I use two cutter for inlay work, 0.635mm or 25 thou for 'hogging' out the centre portion of the inlay and a 0.395mm or 16 thou for fine tuning the perimeter. All internal and external points are radiused to 0.2mm.
Offset the drawing and transpose onto a separate drawing layer and reduce this by 0.075mm or 3 thou- this gives you clearance for setting your pearl. Cutters obtained from Precise Bits USA. They have a speeds and feeds chart. Get pearl from Australia... laminate from China (quarter of the price of Ablam and just as good).

And that is it. If you have a CNC you will know what to do next - cut the pearl then cut the pockets. Here are some examples of my work. You can pm me if you need further help.

View attachment 128088

View attachment 128089

View attachment 128090

Click to expand...

Thank you, Pete, for some excellent tips! At this point I am going to try to manually create the pockets. I may experiment with shell at some point using a CNC machine. The consistency of doing lettering with a CNC is attractive to me. But I will stash your wisdom in a file for future reference.

jcalkin said:

It seems like it shouldn't be any harder to program a CNC to cut shell than to rout the pockets. I know nothing about either, but I watched the shell layout process at Huss & Dalton many times. Each pattern was routed very lightly into a board of synthetic stuff (can't remember the name), so as long as the shell blank covered the rout it would be big enough for the piece. Superglue was used to hold the blank in place. The board had to be precisely set on the CNC table each time. The completed board was placed in a tray of solvent overnight, shell patterns down. A lid covered the tray. The pieces seldom fell off after soaking but popped off with minimal breakage. Their cost per logo fell from $25 apiece for hand cut to less than $3. They purchased shell by the pound. I don't know who supplied them.

Click to expand...

Thank you! I watched a video on using a CNC to cut shell and I think it was a sheet of phenolic material that the shell was glued onto. Didn't realize that you can dissolve CA glue with acetone until I watched that video.

Some good thoughts here!

sequoia said:

You didn't say what the average over-all thickness of the shell is. It is common to have varying thicknesses with shell as this is a natural substance. You should have plenty of extra "meat" so that thickness variance isn't an issue. What I do is cut the inlay pocket just deep enough so that the thinnest part will be just proud or ideally, just flush with the surface and the thicker parts will be proud. Then I can sand everything flush and I'm done.

I know nothing of using a CNC cutter and just do it by hand with a dremel tool with a downcut bit (1/16 and 1/32) on a SMD router base. Here is the thing Chuck, when you use ebony you can really mess up the cut (with a little practice you can get amazingly accurate) and nobody will know because you use the ebony dust - in glue trick and any gnarly margins totally disappear into the blackness. Ebony is very forgiving in this way.

I'm no inlay expert and I get acceptable results so don't overthink the thing and just do it. Maybe one of the experts will weigh in with advice.

Click to expand...

Thanks, Sequoia! Good stuff. I'm seeing where people use epoxy and some sort of dye. One gentleman that I am communicating with suggested I cut the pockets for the individual pieces to match the thickest one. Then glue a flat toothpick across the surface of each letter and suspend the letters in the pockets in epoxy. Gently queeze the letters in so that they're all at the surface. Once the glue is hardened sand the toothpicks off.

ChuckBarnett said:

One gentleman that I am communicating with suggested I cut the pockets for the individual pieces to match the thickest one. Then glue a flat toothpick across the surface of each letter and suspend the letters in the pockets in epoxy. Gently queeze the letters in so that they're all at the surface. Once the glue is hardened sand the toothpicks off.

Click to expand...

I think that is sorta goofy. It ain't that hard and you risk making a hellava mess as well as spending an inordinate amount of time playing with toothpicks and glue. Suspending shell in an epoxy matrix to get level???.. Your picture of your attempt looked pretty good to my eye as a first effort. Those bigger margins will disappear with glue and wood dust. You will still see them if you look really close, but nobody else will and with ebony those are totally gone.

ChuckBarnett said:

I like the idea! Where do you find these scalpels?

Click to expand...

They are not scalpels they are just the blades and they will jack into a standard exacto handle. These things are an absolute must around the shop for doing fine work. They are extremely thin where an exacto blade is too thick and too dull. They sell them in packs of 100 I believe. I found my last pack of all places in a recycle bin. Pharmacies might have them.

Also good for gently picking out splinters (common in wood working) and for doing the occasional emergency appendectomy on a family member. You can buy them on Amazon:

https://www.amazon.com/IMS-CBLD11-S...K34SC05KEC0&psc=1&refRID=9XGP4A9KAK34SC05KEC0

sequoia said:

What I do is pin the piece down and outline it with a sharp #11 scalpel blade and then put white chalk dust in the indentations. Makes seeing the line soooooo much easier and seeing the line is key. I also use an aquarium pump to blow away the dust. Ease up to your line slowly with a 1/32 inch bit and you can get it amazingly accurate. The key is being able to see your line and things can get obscured with wood dust in the heat of the moment and you can go over your line. It really isn't that hard and I agree CNC is primarily for production work.

Picture of one of my first inlays years ago. Shell from DePaul.

View attachment 128093

Click to expand...

Cut and wrap a piece of 1/4” tape around the shaft of your bit. That’ll create a flag that will keep the dust away as you rout.
I’ve tried the the scribe and chalk method or outlining but have found my way quicker and less messy. My router base has a LED light built into it and I use OptiVisors.

Moore Bettah Ukuleles said:

My router base has a LED light built into it and I use OptiVisors.

Click to expand...

Totally. Being able to see what you are doing is 90% of the job.

Quick question on installing frets after inlaying (mop). Will the fret barbs crack the shell inlay when installing the frets? If so, are the shell inlays clearances from the fret slot first, how?
Thanks

I don't do much inlay, but there are a couple of ways to deal with the pearl at the slots. One is to cut individual pieces that leave the fret slot open. This may be the cleanest way, and maybe the only way if you have a lot of fine pieces of pearl that can chip out if you saw through them,but takes more precision cutting and planning. The other, and more common probably, is to use needle files to widen and taper the slot you have sawn through the pearl. Not the whole slot, just the pearl part.
I have attached some photos of another way of marking the design out on the wood. Getting a very clear line is difficult. Pencils work, but not very good. I cover the area of the inlay with a couple of thick coats of tempura paint, and let it dry completely. I use yellow, but other colors would work. It sands right off easily and I have had no problems with getting color in the wood pores. I stick the piece of cut pearl down with a tiny drop of super glue. Then I go around the pattern with a very sharp awl a couple of times. After that I remove the pearl, which usually will pop right off the tempura. If the piece does not come off easily, I use a heat gun, but be careful because you can easily burn the wood. Finally I take my scalpel blade and deeper the design line. Then it is just a matter of routing out the design cavity using the largest bit for most of the work, and a small bit for the final cleanup to the line. Routing is done on very slow speed so prevent the bit from digging in and running away. I learned from Chuck Moore that good, strong light coming from behind me makes the lines easiest to see. Makes a lot of difference for me. Enjoy your inlaying.

mikeyb2 said:

One little tip if you rout the pockets manually with a dremel type router, is to use the "flag" trick. I used to use an aquarium pump to blow away the dust, like Sequoia , until I discovered that attaching a small "flag" of masking tape to the Dremel bit around the flat part of the shank, does a great job of blowing away the dust. No need for pumps.

Click to expand...

+1 works great!