Pockets and inlays with different materials

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FrancisM
Posts: 5
Joined: Mon Mar 19, 2018 9:03 am
Model of CNC Machine: Oosnest WorkBee 750 x 750

Pockets and inlays with different materials

Post by FrancisM »

I'm building acoustic guitars and I use my CNC to produce the logo's (pocket/ inlay) and other parts, but my problems are usually with the pockets and inlays.
I'm usually cutting with 0.5, 0.4 or 0.3 mm end mills the pockets are usually in various hardwoods the softest being from the mahogany's through to old english bog oaks. The inlays are in sheet mother of pearl.
Cut depths for the pockets max 1.5mm with 1.3 to 1.5mm for the MoP inlays.
I find that the MoP inlays cut larger than the pockets and I can't put this down to anything other than tool deflection in the harder MoP material?
Any thoughts please.

litzluth
Vectric Craftsman
Posts: 261
Joined: Fri May 09, 2014 1:37 pm
Model of CNC Machine: Laguna IQ
Location: Pensacola FL

Re: Pockets and inlays with different materials

Post by litzluth »

I typically use a .025 or .023" endmill to cut MOP for inlays without fit issues. 3 or 4 passes on a 1.2 mm blank.
What I would recommend is that you cut your male part first, and then cut the female pocket.
That way if you need to adjust your settings you can do it without removing the part with the pocket, and simply recut.
It isn't surprising that you have a fit issue if you haven't created a pocket allowance in the female part (now, I believe called "overcut distance"). If the parts have the same dimensions it is going to be very difficult or impossible to fit them together.
I would start with a .1 mm allowance (or the inches equivalent if you are doing it that way) in the female pocket.
For me, that is usually enough to allow a part to insert but fit snugly without any visible gaps. If it is still too tight, leave the part clamped in the CNC and redo the toolpath with a slightly increased allowance.
Good luck with your guitar building.
Michael

FrancisM
Posts: 5
Joined: Mon Mar 19, 2018 9:03 am
Model of CNC Machine: Oosnest WorkBee 750 x 750

Re: Pockets and inlays with different materials

Post by FrancisM »

litzluth wrote:
Fri Jun 14, 2024 6:23 pm
I typically use a .025 or .023" endmill to cut MOP for inlays without fit issues. 3 or 4 passes on a 1.2 mm blank.
What I would recommend is that you cut your male part first, and then cut the female pocket.
That way if you need to adjust your settings you can do it without removing the part with the pocket, and simply recut.
It isn't surprising that you have a fit issue if you haven't created a pocket allowance in the female part (now, I believe called "overcut distance"). If the parts have the same dimensions it is going to be very difficult or impossible to fit them together.
I would start with a .1 mm allowance (or the inches equivalent if you are doing it that way) in the female pocket.
For me, that is usually enough to allow a part to insert but fit snugly without any visible gaps. If it is still too tight, leave the part clamped in the CNC and redo the toolpath with a slightly increased allowance.
Good luck with your guitar building.
Michael
Many thanks Michael

litzluth
Vectric Craftsman
Posts: 261
Joined: Fri May 09, 2014 1:37 pm
Model of CNC Machine: Laguna IQ
Location: Pensacola FL

Re: Pockets and inlays with different materials

Post by litzluth »

Let me know if that works for you, or if you continue to have problems.
Best,
Michael

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