Tuesday, September 30, 2008

Inlay and Rosette Tricks

I'm always looking for a quicker and more accurate way to inlay without visible gaps. Inlaying a straight-edged design does help, but as always, the room for error is basically a couple thousandths. In other words, not much. The inlay either fills the mortise right up to the edge or it doesn't. Lots of fancy inlay is done on darker fingerboards like rosewood or ebony. Filling gaps in these woods is easy. Just overfill with epoxy and let the dark wood hide the errors. Inlay in lighter woods like walnut poses a challenge, and inlaying soundboards of soft spruce calls for a light touch and extreme accuracy. My technique isn't unique. However, I do have a little trick I use that improves my results. I always tack glue my inlay to the substrate with a tiny drop of CA glue. It won't budge while I scribe with a #11 Xacto blade. And it pops off quite easily afterwards.

I route the majority of the mortise with a 3/32" spiral bit, then sneak into the corners with a 1/32" bit. These little buggers are really fragile, but they cut very smoothly and allow me to get into tight corners. I clean up the very tip of the corner with the #11 Xacto.

And here's where my little trick comes in. I use a highly polished jeweler's burnisher to compress and spread the aris of the mortise wall. 99% of the time this takes care of any iffy spots in the fit. If a particular area is off by more, I'll use some extra pressure and try to smoosh the wood fibers a tad more.

The burnished areas are visible around the perimeter of the mortise. These will get scraped and sanded flat after the inlay is glued.

A matching caul puts pressure evenly on the inlay.

This is ivory in walnut.

For rosettes with inlaid central calligraphy, getting the pattern on the blank in the correct position can be tricky. There is no room for error when the border of the inlay is a 2mm circle surrounded by 2mm walnut. Any deviation from the pattern will be obvious.

I cut some tiny windows into the pattern to line up exactly where the pattern should lay. Once I position it exactly I tape one edge to the blank, flip it over, spray with 3m Super 77, flip it back and press it down. The tape acts like a hinge, returning the pattern to exact spot.

This dark walnut rosette is made from several plies of alternating grain veneer, epoxied together and cured in a press. This plywood makes for easy, predictable cutting since the "grain" of the wood is the same in every direction. And obviously it makes the rosette very strong.

After cutting the pattern, but before removing the paper.

The finished rosette. Walnut and ivory.


  1. 30 September 2008

    Mr. (Khalaf) Abraham:

    Can you please give us more information about your "router" setup and your source for those bits?


    Phil Lang

  2. Phil,

    I use a shop made base with my dremel. The bits I got from a friend, but you can get upcut spiral bits in these sizes if you search around a little. I'm actually running out of bits, so I need to do some searching myself. Using downcut sprial bits in these sizes is problematic. The chips don't eject and the bits heats up. So I use upcuts for narrow grooves, and downcuts for cleaning the egde of wider mortises.

  3. How timely! I am just now tackling some simple inlay on a project. Thank you for the tips. Is there a comparable tool to use in place of a jeweler's burnisher or is it the ideal tool?

  4. What fantastic craftsmanship. The walnut rosette is exquisitely detailed. It's always a pleasure to drop by and check in on you. — Keith

  5. The jeweler's burnisher is what I've always used. The idea is to compress and distort the wood, so anything smooth and slightly rounded should work. The jeweler's burnisher is a handy shape and size. I also use it for turning a burr on a cabinet scraper.

    Thanks Keith. As I said before, Woodtreks is a great site. I watch all your videos. Thanks for dropping a line.

  6. Who knew you could even get 1/32 router bits! Great post Jameel and your work never ceases to amaze me. Great tip on the burnisher too.

  7. you said u use a dremel but ive never seen one like that. it looks like a pneumatic tool. if so what kind and what psi and rpm do you think you r cutting at. what size magnifier light do u have and what type of bulb is in it. have you ever used colored epoxy as an inlay (inlace).oh BTW great work.

  8. Dave, It's an older flex shaft for a Dremel. It's actually a pretty pitiful tool. I'm planning to get a better one soon, like a Foredom or Wecheer. I'm not sure what the diopter is on the Optivisor. They make several versions. The light is just an 10" I think, widely available with a fluorescent bulb. Nothing special. I've never used epoxy as an inlay material, and never will. I've repaired 2 ouds with epoxy fingerboards, and it's a nightmare.

  9. A web site that has 1/32" router bits is http://www.precisebits.com/


  10. Jameel,

    You're doing it all wrong. Just joking. I really like all the impressive pictures you have on your site. Nice work.

    You did say that you are always looking for a more efficient way to inlay. Might I suggest:

    1)Would it be easier (less chance for slipping with knife) to trace inside a "female" star pattern rather than outside a "male" star pattern?

    2) Rather than "tweak" the star points with a 1/32" router bit, why not drill them with a 1/32" bit before routing with the 3/32" bit.

    3) You could really speed things up by drilling the center of the star cavity with a 3/8", 1/2", whatever, mortising bit.

    I would like to hear your feedback. Keep up the excellent work and most of all have fun doing it.


  11. Allan,

    Thanks. Your ideas are interesting. The 1/32 bit is just to remove as much waste as possible. I actually tweak the points with a knife. Drilling out the waste wouldn't really save time. It only takes a few seconds to route out most of the inside with a 1/8" bit. A large forstner drill wouldn't allow nearly enough depth control. Your floor inlays medallions are very nice, by the way.

  12. Yea, I guess the forstner bit wouldn't be much help in your situation.

    The more I think about it, the more I realize that my application is quite different. If I need to remove material it is a full 5/16" thick/deep therefore it would take a little longer and require more passes with the router.

    e.g. To repair (that is remove) a band on a medallion I have to remove material that is 5/16" thick and any where from 1 1/2" to 2" wide and ?" long.

    I can remove most of the band rather quickly and efficiently by drilling with a larger diameter forstner bit and the drill press. This leaves minimal wood to remove with a router bit and jig setup.

    I can now cut with router set at full 5/16" depth since I am only skimming the edge of the cavity and removing minimal material.

    Thanks for your kind comments.

    Allan Mc Donald


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