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View Full Version : A spot of mother of pearl inlaying.



Wal
08-12-2017, 02:22 AM
I've just recently finished this project for a local guitar builder. He tends to supply his fingerboards as flat oversized stock which I'll pocket about a millimetre deeper than the pearl thickness and then he sands down to where he needs the surface/radius etc. So as it is, it's not a finished piece, just my CNC bit.

Cutters used for the wood were 2mm (for a rough pocket with about .15mm allowance) then a 1mm followed by a .5mm for the detailing around the profiles - these were programmed as being .06mm undersized to give a bit of clearance for the mother of pearl shapes to drop in.

I superglued the pearl blanks down to a plate of aluminium, scanned that in, then (in Illustrator) positioned the vector shapes where I needed them to fall on the blanks and added a datum at the bottom left which I matched with my x/y zero in CAM and in turn zeroed off my machine at that corner too. It's reasonably accurate, but you can get a bit of a shift if what you've scanned isn't sat flat on the scan bed - here the alu plate was nearly a couple of mm off the surface due to the pearl blanks, so its relative position to the pearl blanks wasn't represented exactly in the resulting scan. At this scale it's no big deal, but if you're going right to the edge of a blank it pays to check that your tool isn't riding off the edge at some point in the cut - if it is, just tweak the x/y zero on the machine.

The nice thing about supergluing to the aluminium plate is that, once cut, you can boil the whole assembly for 5-10 minutes and once cooled the pieces separate from the plate with just a gentle nudge - exactly what you want with the more delicate pieces.

Anyway, some pics of the results:

23342 23345 23341 23344 23343 23348 23346 23347

Wal.

phill05
08-12-2017, 06:26 AM
Real nice job Wal that will look impressive on the finished piece.

Phill

EddyCurrent
08-12-2017, 09:43 AM
Yes, very nice indeed. You have to watch the dust from that and the wood, don't be breathing it in.

Wal
08-12-2017, 11:41 AM
Yes, very nice indeed. You have to watch the dust from that and the wood, don't be breathing it in.Cheers guys. Yep, I hear you Eddy - wore a respirator for the pearl, although I'm in the market for one of those dust filters - something like this:

http://www.axminster.co.uk/jet-afs-500-air-filtration-system-310483?gclid=CjwKCAiAjanRBRByEiwAKGyjZXyF8Gcnx83du FjqxYQzP4WnktiTuQKtEOZGXvcNpMMz7J7uWPiyjRoC8pQQAvD _BwE

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Lee Roberts
08-12-2017, 12:41 PM
Looks nice, not seen any mother of pearl cnc machined on here before. :thumsup:

mekanik
08-12-2017, 02:38 PM
Very nice Wal(as usual)
That filters OK but you would be better trying to catch it @ source so theres no chance of inhaling it. centrifugal setup on your vacuum might help.
Mike

the great waldo
08-12-2017, 04:52 PM
Cheers guys. Yep, I hear you Eddy - wore a respirator for the pearl, although I'm in the market for one of those dust filters - something like this:

http://www.axminster.co.uk/jet-afs-500-air-filtration-system-310483?gclid=CjwKCAiAjanRBRByEiwAKGyjZXyF8Gcnx83du FjqxYQzP4WnktiTuQKtEOZGXvcNpMMz7J7uWPiyjRoC8pQQAvD _BwE

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Hi Wal

This might save you a few bob http://www.rutlands.co.uk/pp+woodworking-workshop-equipment-dust-extractors-vacuums-air-filters+d01110 but Mekanik is right about catching the dust at scource. By the way nice work on the inlays. Do the cutters last long as the pearl is fairly abrasive.

Cheers

Andrew

Wal
08-12-2017, 05:36 PM
Hi Wal

This might save you a few bob http://www.rutlands.co.uk/pp+woodworking-workshop-equipment-dust-extractors-vacuums-air-filters+d01110 but Mekanik is right about catching the dust at scource. By the way nice work on the inlays. Do the cutters last long as the pearl is fairly abrasive.

Cheers

AndrewCheers for that link Andrew, yeah - a fair whack cheaper that..! It specifies being mounted at a height of 2m or greater. I'm in a vaulted cellar, so perhaps one of these filters isn't the best option for me. Not having given it a great deal of thought, I was hoping to pop it under an existing bench... but having my boiler etc. located down there, means that my cellar's pretty warm - a fairly constant 20℃ - I imagine the particles would be happy floating around on the warm air where that kind of filter would be most efficient in picking them off. At leg height it's probably doing its bare minimum...

I think that even a vacuum cleaner picking 'em off at source might struggle to contain these particles without a very decent filtration system - the cutters pulverize the stone and pretty much turn it into super fine talcum powder...

As pearl work is always small scale, I wonder if it's worth me making myself a little water tray fixture that traps the particles as they're cut..? Hmm... I wonder...

Wal.

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the great waldo
08-12-2017, 06:58 PM
Hi Wal

I would imagine wetting the pearl would keep the dust down and possibly increase the life of the cutters. I've been making guitars for 40 years and in the old days I used to grind abalone shells dry with a grizzly disk on a black and decker drill, Mixed up with a nice dose of nitro cellulose i'll be glad if I make my pension. Luckily I don't smoke :worked_till_5am: LOL I don~t think it matters much where you put the filter but higher up would capture more airborne dust or put the filter by the where your'e cutting maybe with a small computer fan blowing towards the filter or just get one of those cheapo 4 inch kitchen ventilators with the flexi hose that comes with it and run it outside. I use uhu blue epoxy for pearl mixed with a little polyester colouring paste and some fine ebony or whatever wood you are using dust (the dust (not too fine) stops any filler becoming to shiny if the fingerboard is polished)

Cheers

Andrew

Wal
11-12-2017, 02:12 AM
>in the old days I used to grind abalone shells dry with a grizzly disk on a black and decker drill, Mixed up with a nice dose of nitro cellulose i'll be glad if I make my pension.

Oh gawd... Yeah, I fear that spores borne on a mist of WD40 have done me no favours whatsoever since moving down into the cellar to keep the machine company... What's the old adage - 'find what you love and then let it kill you...' Doubt it was meant literally, though..!

Would love to see some of your guitar work - do you have a site?

Thanks for the tip on installing the inlay - I've yet to try one personally, the work I do gets passed back to the client who runs a guitar/bass building course up here in Manchester and he goes through the process with his students. It's usually a nice tight fit - here are a couple I did a while back:

23374 23375

Wal.

fwm891
28-01-2018, 07:55 AM
Superb stuff Wal - that's line I'm heading towards for my guitar logo's etc. I'll be picking your brains on this topic I'm sure as my design/build gets off the ground.

Francis
https://milsomguitars.weebly.com/

Wal
28-01-2018, 08:02 AM
Superb stuff Wal - that's line I'm heading towards for my guitar logo's etc. I'll be picking your brains on this topic I'm sure as my design/build gets off the ground.

Francis
https://milsomguitars.weebly.com/Hi Francis,

I'll try to drop you a line this evening - just working on a project this weekend and it's all consuming..!

Had a quick look at your site - my word, you build some beautiful guitars..!

Wal.

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the great waldo
05-11-2018, 09:28 PM
Hi Wal
Where do you get your pearl cutters from ? and what kind of speed feed rates are you using. I liked your dream or die video. Was that an arbortech turboplane that your'e using.

Cheers

Andrew

fwm891
05-11-2018, 09:50 PM
Well Wal, I've been playing around with the WorkBee for a while now here's one of the latest headstock inlays I've done...

25021

The MOP inlay was cut with 0.5 and 0.3mm end mills, the wood inlays 1.3mm end mill. Feeds @ 20k rpm for the inlay circa 1.5 mm/sec with 0.3mm depth of cut. The wood inlay pockets were cut circa 5mm / sec 1.2mm depth. I remembered you saying about super gluing your MOP to an ali sheet and soak in boiling water to release the parts. I ended up super gluing to thin MDF and soaking in boiling water. The MDF just swells up and flakes away.

Wal
06-11-2018, 12:45 AM
Andrew,

Thanks for your kind words, I'll be posting about that Dream or Die piece in the next few minutes as there are a couple of questions I have regarding grain filler... Anyway, I buy my cutters from APT in Glasgow. I use ordinary two-flute carbide cutters - the same as I use for aluminium/brass/wood. Heh - they seem to work for everything! A couple of links:

https://www.shop-apt.co.uk/end-mills-for-aluminium-standard-length-2-flute-45-helix-uncoated-carbide.html
https://www.shop-apt.co.uk/micro-diameter-end-mills-2-flute-altins-coated-ultra-fine-grain-carbide-60hrc.html

Feeds and speeds are very conservative when using the smaller cutter - less than 0.6mm and I'm running around 1-1.5mm/sec - yep, very slow but luckily inlays tend to be pretty small so it's not too much of an issue. The larger 52mm surfacing tool I use is from Wealden:

https://www.wealdentool.com/acatalog/Surface-Trim.html

Francis - that's an awesome looking headstock - that WorkBee is certainly doing the business for you! Good call on the MDF - I take it that you don't get any issues with fibres sticking to the back of the inlay pieces?

Wal.

fwm891
06-11-2018, 06:24 AM
Thanks Wal - no any fibres that do stick a light rub on fine wet-n-dry removes them - I use APT as well for my cutters - very prompt service.

the great waldo
06-11-2018, 09:02 AM
Hi Wal
Thanks for the links, i'll check them out.Your right about the slow speed. I cut my surname out on Sunday (12 Letters Polish name !) 6 passes with a 0.5mm cutter must have taken 45 mins. My cutters are a bit long so I didn't want to push them too much. The cutters on the apt site are a little short on the 0.5mm dia, only 1mm deep my pearl is usually 1.5mm thick. That surfacing cutter looks really useful.

Cheers

Andrew

Wal
06-11-2018, 09:09 AM
Hi Wal
Thanks for the links, i'll check them out.Your right about the slow speed. I cut my surname out on Sunday (12 Letters Polish name !) 6 passes with a 0.5mm cutter must have taken 45 mins. My cutters are a bit long so I didn't want to push them too much. The cutters on the apt site are a little short on the 0.5mm dia, only 1mm deep my pearl is usually 1.5mm thick. That surfacing cutter looks really useful.

Cheers

AndrewAndrew, they also stock long necks:

https://www.shop-apt.co.uk/2-flute-long-neck-rib-processing-carbide-end-mills-68hrc.html

Wal.

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the great waldo
06-11-2018, 10:29 AM
Hi Wal.
Thanks for that, I'll have to give my plastic friend a bashing.
Cheers.
Andrew