Inlay Basics

[Rocketmaniac]

Hello,

I'd like to start getting into the inlay feature of my Black Diamond edition Shark. So, some basic questions....

1. Normal material depths? (the female part 3/4"..... the male inlay 1/4"?)

2. How do you cut the male inlay without cutting into your CNC table? Do you put scrap wood underneath? Or do you NEVER totally cut through the inlay wood? (and if you cut totally through, how do you "hold" the piece as its cut?)

3. The best bits to use for inlay work?

Thanks in advance for any help,

Randy

[4DThinker]

I use thicker wood for the male inlay. Never cut through. Glue it on the female half, then bandsaw them apart after the glue has dried.

I generally cut the female part to a flat depth of .1 inch. The male negative gets cut with a start of .1" and a cut depth of .1". It's the start depth part that fist in the female recesses, leaving a .1" gap between them when glued. This is perfect for resawing through on the band saw.

[Consultingwoodworker]

I made the inlay here a while back using the Shark Pro.

This one is 1/32" thick veneer inlayed into 1/4" material as the lid for a small presentation box. It is a map of the islands of Venice.

I have been doing CNC inlays for years, and have learned several tricks:

1st, while you will be using the same vectors for both the male and female parts, you MUST offset so that the male is slightly smaller than the female pocket. It is best if both parts are offset. I have found that about 0.014" is a good starting point, 0.007 for each part. VCarve has an 'inlay' tool path that allows you to enter the offset. You should test the settings on scrap before cutting your final wood.

2nd, pay attention to the corners. Your bit, no matter how small cannot make pointed inside corners. So your male part must not have any sharp points.

3rd, I have found that a 1/32" ball end mill is perfect for cutting both the pocket and the inlay. Since the bit has a slight taper, it creates a pocket with a slight taper toward the bottom. Cut the inlay part upside down using the same 1/32 ball end bit, and the inlay will also be slightly tapered making a wedge fit. This will really hide any tiny imperfections in the fit.

In answer to your question about how to cut the inlay, use a spoil board. I use a light tack spray adhesive to glue the inlay onto a flat scrap. This way it stays still while cutting but can be easily separated without risking the fragile veneer.

To insure good depth control you should already have an MDF spoil board mounted to your Shark bed. Cut a piece that is within your working envelope. You need to be able to run a bit over the entire surface to flatten it and make it parallel to the plane of the head.



I make mine with T-Slots every three inches. I first cut 3/8" on the TS, then follow up with Rockler's T-Slot bit. I bolt the spoil board to the bed using nylon bolts so that if I accidentally hit one with the bit, no problem. This photo is not great, but you can see that I clamp right on the spoil board instead of using the main bed.

Ralph

[Bob]

Be sure to check out this technique.
http://www.vectric.com/WebSite/Vectric/ ... inlay.html
Bob

[Rocketmaniac]

Hey, Thanks for the replies,

(I got side tracked with other projects.... including repairing my shop after a big storm torn off part of the metal roof)

After just getting back into learning "inlays" and I only have one question....... Where do I find the "OFFSET"? is it under the "Machine Vectors" in the Male inlay and the "clear pocket" in the female inlay?


Thanks,


Randy

[Consultingwoodworker]

Under toolpaths, one of your choices is 'Inlay'. There you can choose to mill the pocket or the inlay part. Use the tool offset there, it is set up to make the pocket larger and the inlay smaller.

Ralph

[Rocketmaniac]

Ive made a few test cuts, lol, with no "accidents". I still need to practice more and make a better "spoil bed" system (maybe with T-slots)

My new questions (mainly for Consultingwoodworker (Ralph)) but I welcome any and all replies

1. The 1/32" bit? Where did you get it? Cost?

2. How thick is the "spoil" bed?

3. 3/8" cut first? Does this mean the main opening? The part open to the top surface?

4. What size T-slot from Rockler did you use?

5. Did you use a handheld router to make the cuts in questions 3 & 4?



I have to find a different spray adhesive, as the one I got "adheres" a little too much (broke a couple of my test inlays)... And Ive already learned the lesson about sharp corners of the male inset/inlay!!

But, here is my first inlay project results, not perfect but Im pleased so far.

Thanks,

Randy

[Consultingwoodworker]

A good start!

I have been buying my carving bits from "Think and Tinker.com ", but Amana now offers them as does Rockler. It is a ball nosed bit, but the shank is tapered like a sharpened pencil. 1/32 or 1/16 will work fine.

The 3/8" cut in the spoil board is a dado. The T-Slot bit from Rockler has a 3/8" neck that it not a cutting edge, it only cuts the wider slot, so you need to pre-cut the 3/8" opening.

I use 3/4" MDF for the spoil board.

The Rockler T-Track bit that I use is #26099 and happens to be on sale right now.

Lastly, yes, I generally cut the 3/8" dados on my TS, and hand rout the t-slot. The 3/8" neck of the router bit rides inside the dado, so no fence or guide is needed, it follows the slot automatically.

Once the spoil board is mounted to the machine, it is planed down so it is parallel to the plane of the head.

Ralph

[drueth]

Rocketmanic

From this thread you can see there are two way to do an inlay. When I first read about the way to do it using that information that Bob posted here I could not stop until I was able to do it. What I found is no mater which way you do it you must have everything set up and working correctly or you will have a problem and not get a good inlay. This also includes measuring the geometry of the bit you will use to make the cuts. I have found many EM are under sized and also V bits may be under or over on the angle. I have used the V bit method and have had some good and bad outcomes. It all depends on how fine a detail you want to cut. And the wood you pick to use fro the two parts. If the wood is prone to chipping out you will also have a problem.
Pic 1 is using mahogany and maple. I had problems with the male maple inlay chipping
Pic 2 are using maple and walnut and came out ok
Pic 3 Not really an inlay but something I tried using clear casting resin to make up for my lack of skill and knowledge

[Rocketmaniac]

Rocketmanic

From this thread you can see there are two way to do an inlay.

I can see that the V-bit method may be better for inlays with more detail. I actually made an order last night from Rockler, including a T-slot bit and 90 degree V-bit (I totally blew my woodworking tool/toys budget for sure!!)

Thinking about what you said about bits being over or under-sized.... I measured my 1/16" straight bit and found that it was .0555" (a full .007" undersized!!). I guess I need to measure all of my bits and edit my tool database. I have a fairly nice digital caliper, but what is the best way to measure the angle of bits?

To help visualize how detailed the inlay is in Pic #1, how wide/tall is the whole project? (nice work BTW!!)

Randy