Results 1 to 8 of 8

Thread: The case for CNC cut inlay work

  1. #1
    Join Date
    Aug 2008
    Location
    Wales, UK
    Posts
    5,236

    Default The case for CNC cut inlay work

    Hand cut and machine cut inlays are part od the same family but effectively different 'species'. Here are some extracts from a conversation I am having on my Facebook page and in a forum:

    I've been working a lot with shell inlayed into brown wood - mgurure to be precise and IR. As anyone doing inlay work will know, if you don't get the tolerances right, the inlay will have a 'defining outline' which often reveals itself as a black line - rather like the work of Jamie Hamley. So for newbies using CNC technology for inlay work this is what I have found out:
    1: The tolerance for pearl is 0.025mm/001".
    2: To get sharp external corners the pocket must be 'relieved'
    3: Precise Bits is the best company for fine cutters - their speeds and feeds recommendations are so helpful to someone like me who cannot do math. Gurian are agent for them but you can buy direct.
    4: CNC technology allows you to use sub 1mm thick material which is both cost effective and conservationist - my logos are cut from 0.7mmm thick shell rather than the standard 1.2mm or 1.5mm.
    5: Using epoxy to fix inlays is messy and unnecessary if you get 1 and 2 right.

    In response to a comparison to hand cutting and my work using 'brown wood', a really hard gig when inlaying:
    ..... unless you are Larry Robinson, shows the gaps which is why hand inlayers use ebony... My gig is inlaying into brown wood and pushing the CNC to the limit. It requires absolute tolerances and after work with a sharp scalpel. I use cutters that are either 0.4mm or 0.6mm to do all the fine work and am exploring 0.8mm - 1mm for the main clearing of the pockets to speed the process up. Speeds and feeds are all well and good but like any other job, you still have to 'read the wood'!

    It requires meticulous surveying and measuring of the drawing and converting all internal radii, often amounting to 100+ to be radiused to that of the final cutter. Tang wide pockets have to be cut where the fret is positioned over a pice of inlay. The hardest thing is getting the sequence of operations right. The way I do it ties the machine up for almost a day per fretboard! This also is as technically demanding as any hand cutting and in my opinion, because of the levels of accuracy, demonstrates an equality though different level/type of skill to hand cutting. Imagine how many more Larson Bros instruments would have been made with the Dyer tree of life if they had access to CNC technologies? Their instruments may have to turned out symmetrical in the first place....
    Last edited by Pete Howlett; 07-31-2019 at 11:03 PM.

  2. #2
    Join Date
    Jul 2011
    Location
    central CA
    Posts
    663

    Default

    The programming of inlays like your vine on your latest example would be a daunting task. Getting the tolerances correct is another matter all together.
    KUDOS for your perseverance to get yourself to this point. I programmed for years on our own products which were relatively simple compared to this, IMO, and I don't believe I could get this done.
    Daunting. What you and Allen are doing with the CNC is amazing to me.
    Well Done!
    My Real name is Terry Harris

  3. #3
    Join Date
    Apr 2008
    Location
    Kapolei, Hawaii
    Posts
    1,843

    Default

    The one thing that put held me off inlaying a LOT is the strive for perfection in joints, which is impossible to be CNC perfect by hand. Because there's so much CNC inlay (compared to 10 years ago, give or take), the "standard" for perfection is there. But it doesn't just happen by itself, as Pete mentions. That skill to program is different from building, but a developed skill nevertheless.

    Fortunately, I was briefly schooled on wabi-sabi, which now makes hand inlay even more enjoyable, albeit non-efficient and nowhere near the perfection of CNC.

    I appreciate the skill it takes to do both.

    Engraving- yet another skill entirely.

  4. #4
    Join Date
    Feb 2008
    Location
    Big Island, Hawaii
    Posts
    5,196

    Default

    More and more, builders are becoming programmers.
    Chuck Moore
    Moore Bettah Ukuleles
    http://www.moorebettahukes.com

  5. #5
    Join Date
    Mar 2009
    Location
    Stockton on Tees..North East UK.
    Posts
    5,078

    Default

    Same thing happened in the printing trade, skilled type setters replaced by young bright lads on computers who never had a clue about the old ways...In the shipyards large CNC burning machines cut out the plates once done by hand by skilled platers etc: etc:...Time marches on
    http://ukulele-innovation.tripod.com ebay i/d squarepeg_3000 Email timmsken@hotmail.com

    If you can believe that moving images and sound, can fly through empty space across the universe and be seen and heard on a box in your living room ?.. then you can believe in anything.

  6. #6
    Join Date
    Aug 2008
    Location
    Wales, UK
    Posts
    5,236

    Default

    You're right Chuck and everyone else. But take a step back - I don't see anyone building entirely by hand like Sven and I doubt many have got a complete set of hand planes and chisels that they know how to sharpen, or a set of hand stitched rasps that are used to hand shape a neck (the process many people want to be done by machine that I prefer doing by hand). Progress is grasping the technology of the day. For me, it's a way of countering the effect of PD which is gradually eroding my fine motor skills, ability to concentrate, maintain balance and spatial awareness. I need technology to fill the widening gap. As for programming skills. I use a powerful intuitive software package called Cut 2D and its sister package ProCarve. The drawing interface is made for someone non technical like me. It has two elements drawing and tool path creation. My student this week made her own single letter logo in abhor. She had quite good computer skills but nevertheless, not many building courses out there that can offer this service to their pupils. Great moment when the head plate came out of the sander fully formed with tuner location holes accurately placed and perfect symmetry - challenges for every student making an instrument form the first time.

    As you know, for a long time I advocated hand skills - I still hand bend, hand plane seams and prepare stock. These processes are essential in developing motor skills and muscle memory and you really have to do your 10,000 hours before you can own the title 'luthier'. That I cannot stand at my bench with a #7 shooting plane prepping necks all day means I have to find other ways of being efficient so instead of hand cutting and drilling for position dots a fingerboard, I set up my machine and 45 minutes later I have one with bespoke elliptical position markers, accurately profiled and ready to go. I can fine-line a headstock with 1mm lines for my super tenor model and 0.9mm lines for my tenors and .0.85mm for my concerts, all with pocket fret slots and custom inlay if the client wants it. Half step changes in detail are important 'scaling' decisions that form the central part of my design ethos. I can use powerful software to maintain the style of a bridge or inlay yet reduce it by 15% or increase it so it is perfectly scaled to the instrument it is going on. Being able to control the design elements that most people comment on and look for is neither compromise or lazy - takes just a much time an energy to do this stuff. The only difference is, you only have to do it once and that has got to make sense to anyone running a business.
    Last edited by Pete Howlett; 08-02-2019 at 10:50 AM.

  7. #7
    Join Date
    Sep 2013
    Location
    Hawaii Island
    Posts
    166

    Default

    Seems like discussions of CNC/Laser machine abilities come up often enough that the UU should start a separate forum for those who care. In this increasingly programmers world, I'm sure this computer machine stuff is interesting to many and they would probably appreciate having their own place to hang out.

  8. #8
    Join Date
    Dec 2008
    Location
    Stockholm, Sweden
    Posts
    1,398

    Default

    Quote Originally Posted by Pete Howlett View Post
    You're right Chuck and everyone else. But take a step back - I don't see anyone building entirely by hand like Sven and I doubt many have got a complete set of hand planes and chisels that they know how to sharpen ...
    Fanx Pete. I really admire your skills and your dedication, and lately your ability to adapt to your new condition and limitations. You have helped me so much the last ten years, since UkeTalk, and you continue to inspire me.

    That said, I feel I must admit to using the drumsander sometimes.
    Building blog - http://www.argapa.blogspot.com
    Music and atrocities - http://www.goodcopbadcop.se

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •