Progress on Metal Inlay Box

China Woody

John
Senior User
A while ago I asked some questions about inlaying metal in wood. I feel comfortable enough now to give it a try.
Step 1: Cut & patina the 3inch brass medallion that will be inset on the box lid.
Step 2: Cut & patina the (6) 1-inch medallions that will be inlaid around the outside of the 12-sided box.
Step 3: Cut the box itself. The lid and the side medallions will be fitted to the box.
Step 4: Cut the lid. Once I know the exact finished dimensions in the lid cutout and the cavity for the medallion in the lid, I can go ahead and test final cut dimensions, so the metal and lid fit properly.

So far I have cut and applied the patina to the 3-inch lid medallion. It came out pretty well -- I'll attach a photo.
The side medallions are cutting now. The photo shows the CNC machine cutting all six medallions from one piece of 1-inch wide, 6-inch long, 1/8inch thick brass stock.
The other photo is the 6 X 6 X 1.25 walnut block that will be cut for the box itself. The preview images show how that is supposed to come out.
 

Attachments

  • 3inch Brass Lid Insert.JPG
    3inch Brass Lid Insert.JPG
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  • 1-inch Side Medallions.JPG
    1-inch Side Medallions.JPG
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  • 6X6X1.25 Walnut Block.jpg
    6X6X1.25 Walnut Block.jpg
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  • Preview of Box, 1.jpg
    Preview of Box, 1.jpg
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  • Preview of Box, 2.jpg
    Preview of Box, 2.jpg
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JNCarr

Joe
User
Nice! I'd say you have the brass cutting down pretty well.
Looking forward to seeing it completed.
 

China Woody

John
Senior User
Next step was to perfect the cutting of the 6 small tokens that will be inlaid in the sides of the box. On the third attempt the fates were smiling, and I was able to complete the pattern, feeds and speeds to cut all six in one go, from a 1 X 6.5 inch piece of 1/8 inch brass. Next is to cut the box itself.
 

Attachments

  • Inlay Tokens, 1.JPG
    Inlay Tokens, 1.JPG
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  • Inlay Tokens, 2.JPG
    Inlay Tokens, 2.JPG
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China Woody

John
Senior User
Well, Murphy's Law is not a thing of the past -- old Murphy is still out there doing his thing.
Pretty much everything that could go wrong, has, but finally I yelled at the machine enough to make it work right. The 12-sided base to the box is now done. It's still rough, right off the CNC, but with some cleanup should work well.
Next, drill the pockets for the inlaid medallions, then cut the lid. Progress.
 

Attachments

  • IMG-2133.JPG
    IMG-2133.JPG
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JNCarr

Joe
User
Very nice - the design works REALLY well.
A few questions -
Are the interior sides sloped or straight?
Was there a reason to not mill the medallion pockets on the CNC? Bit not long enough?
Was the exterior CNCed or sawed?
What stepover did you use on the pocket cut - looks like a little less would have eliminated those ridges (of course some of that will be hidden by the medallion pockets). Just curious.
 

China Woody

John
Senior User
Very nice - the design works REALLY well.
A few questions -
Are the interior sides sloped or straight?
Was there a reason to not mill the medallion pockets on the CNC? Bit not long enough?
Was the exterior CNCed or sawed?
What stepover did you use on the pocket cut - looks like a little less would have eliminated those ridges (of course some of that will be hidden by the medallion pockets). Just curious.
Thanks. No, the interior walls are straight up and down, done with a 1/4" end mill. I couldn't mill the medallion pockets because the box is 5 inches across, and I don't have that much Z height. The exterior is done with the same 1/4" end mill. Yes, the stepover could have been a little tighter. I didn't worry about it because a quick swipe with some sand paper cleans the marks right away. I'll have to post a pic of the box after a few minutes of tidying-up.
Good questions.
 

China Woody

John
Senior User
I've now lightly sanded the box, given it a couple coats of Danish oil, then three coats of satin lacquer.
It turns out the hardest part of that process was the shallow holes around the periphery, where the metal tokens were to be installed.
In a more traditional box, constructed with discrete boards joined together, I would have just had the CNC machine drill the holes, then assembled the pieces. With this piece, however, it is monolithic -- cut from a solid block of walnut. That means that to have the CNC cut the holes, I would have needed a CNC machine with 8 or 9 inches of "Z" axis height. Even if my simple little X-Carve machine could have done that -- which it could not, even with the Z-axis upgrade, I would have had to clamp down the piece on its edge, drilled a hole, then clamped the next one, and so on, for the 6 required holes. So this is one case where putting it on the drill press and using a Forstner bit turned out to be a better choice.
I was able to cut the metal tokens for a snug fit in the 7/8 inch hole, and used just a small amount of wood glue to secure the pieces in the holes. I thought of using epoxy, but because the tokens fit snugly, and all they have to do for the rest of their lives is to remain in the shallow holes, I figured I would be OK.
I left the bottom cavities on the box a little rough, because they will get a piece of felt specially cut to make them look nice -- I'll describe the fairly easy way I have developed to do that next time.
Tomorrow -- cutting the lid so that it fits the box, and has a cavity to inlay that large 3 inch brass medallion.
 

Attachments

  • Side Tokens Installed.JPG
    Side Tokens Installed.JPG
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China Woody

John
Senior User
One thing I forgot to mention in my post above, about cutting the holes around the sides of the box. I haven't done enough drill press work to realize that it takes a good deal of pressure to cut a 7/8 inch hole in dry walnut. With the insides of the box cut on the CNC machine, I clamped it up on its side in a drill press vice and tried to drill the shallow holes. It was frustrating that no matter what I tried, the holes would not come out square (hmm.. square holes -- but you know what I mean) -- one side of the hole was always deeper than the other. I spent an hour making sure that the drill press table was exactly perpendicular to the chuck, then I discovered the problem. As you can see in the photo of the cut box, the edges are cut fairly thin -- yup, when the Forstner came down, the thin side of the box wall was flexing, while the wall near the bottom was not, hence the uneven cut. To fix the problem, I made a new box blank and had the CNC cut the 12 outside edges, but not hollow out the inside compartments. That left a solid block of wood on the drill press, and the holes were cut perfectly. Then back on the CNC to finish the cuts. Still lots of tricks for old dogs to learn.
 

JNCarr

Joe
User
That is looking great!
A thought on drilling the medallion pockets --- it might have been simpler to CNC a second lid with a little deeper internal lip (to give it a little more seating inside the box) and clamp that onto the body to bolster the opening during drilling. That way you only have to datum the body to the CNC once.
 

China Woody

John
Senior User
That is looking great!
A thought on drilling the medallion pockets --- it might have been simpler to CNC a second lid with a little deeper internal lip (to give it a little more seating inside the box) and clamp that onto the body to bolster the opening during drilling. That way you only have to datum the body to the CNC once.
Ahh -- great minds thinking alike :)
I'm glad you mentioned that. Making a "working" lid to insert into the body before drilling the holes, to keep the edge stiff for drilling, would have been my first go-to. But this time, I decided to change the pocket structure of the box, so had to cut a new box anyway. Next time I will likely do exactly as you suggest. Thanks for pointing out this alternative solution.
 

China Woody

John
Senior User
Well, I'm getting close. After competing with holiday activities, I was able to get back to the box, and nearly finish it.
Photo 1 - shows the completed exterior. Once all the inlay was done, I gave the walnut three coats of Tung oil, letting it sit for 10 minutes or so after application, then wiping off the residue. Then 3 coats of semi-gloss lacquer, followed by a coat of Renaissance wax polish.
Photo 2 - shows the lid inlay in detail. I decided to add a cut in the walnut around the brass inlay, to add a little more interest to the lid.
Photo 3 - shows the almost finished interior. I usually use a felt cut from peel-and-stick sheets that come with adhesive on them. I tried once using glue on plain felt, and the glue scrunched up the material. Using the felt with its own adhesive gets around that problem. At the moment the felt inserts are just sitting in the box, one green, one black -- I take votes from family members on what color they think the felt should be. So far it looks like the green is going to win, because it ties in the greenish cast in the brass medallions. So, cut one more green insert, then stick them both down, and the thing is finished.
Photo 4 - because I plan to make multiples of the box, I make a simple cutting jig that I call a "felt cutter." I start with the pocket toolpath that was used to cut the inside of the box, then make a simple profile toolpath, which is essentially a mirror image of the pocket. The little piece of 3/16 plywood then acts as template to cut the felt with a razer blade.

Next -- version 2 of the box, made with a different medallion image, and cut from Padauk.
 

Attachments

  • Medallion Box 1.JPG
    Medallion Box 1.JPG
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  • Medallion Box 2.JPG
    Medallion Box 2.JPG
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  • Medallion Box 3.JPG
    Medallion Box 3.JPG
    1 MB · Views: 27
  • Medallion Box 4.JPG
    Medallion Box 4.JPG
    1.2 MB · Views: 27

ptt49er

Phillip
Corporate Member
Could you have mounted the box on your CNC in such a way that the face being machined for the medalion pockets was within the z-axis of your machine? Essentially putting the body of the box through the bed of the router? Maybe lifting the machine higher or a hole in the table?

Box looks great!
 

China Woody

John
Senior User
Could you have mounted the box on your CNC in such a way that the face being machined for the medalion pockets was within the z-axis of your machine? Essentially putting the body of the box through the bed of the router? Maybe lifting the machine higher or a hole in the table?

Box looks great!
Phillip, I imagine most anything is possible. The X-Carve, even with the Z-axis extension, still only has about 4-5 inches of z clearance, and the box is nearly 6-inches in diameter. If this were a production piece, say the first of 100 copies, boring the side holes on the drill press would become fairly tedious. In that case it might make sense to figure some way to clamp the workpiece below the normal height of the machine. But I would guess that in the end I will make 4 or 5 of these things, then move on to the next interesting thing.
Good question. Thanks.
 

mkepke

Mark
Senior User
Phillip, I imagine most anything is possible. The X-Carve, even with the Z-axis extension, still only has about 4-5 inches of z clearance, and the box is nearly 6-inches in diameter. If this were a production piece, say the first of 100 copies, boring the side holes on the drill press would become fairly tedious. In that case it might make sense to figure some way to clamp the workpiece below the normal height of the machine. But I would guess that in the end I will make 4 or 5 of these things, then move on to the next interesting thing.
Good question. Thanks.
Yeah, with having to manually rotate and align the box six times, I don’t see a big time savings drilling the holes on the CNC

Or…maybe it’s time to add a rotary axis :)

Neat process.
-Mark
 

China Woody

John
Senior User
Yeah, with having to manually rotate and align the box six times, I don’t see a big time savings drilling the holes on the CNC

Or…maybe it’s time to add a rotary axis :)

Neat process.
-Mark
Hmmm...rotary axis. Now your talking :)
 
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