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View Full Version : Using a CNC ?



jaunedeau
04-08-2009, 11:03 PM
Hi,

In the woodworkers club I joint, they have a small CNC, which can cut up to 400x300mm (about 12"x16"). They don't have any 8mm carbide helicoidal bit that I think you would use to carve the neck (I can order one for $30), and don't have the software to transform 3D shapes into a set of cut lines. But they sure have all the perfect bits for cutting back and top and even cutting inlays and grove for frets on the fretboard.

So my question is : which are the part that you think are interesting to do with a CNC on a ukulele in my case (my "case" is that I'm a computer guy, and designing a fretboard on autocad seems simpler to me than cutting the grove withe 0.5mm precision).

Another question is about the top : if I choose to cut it with the CNC, should I do it perfect size, or should I add 5mm and finish everything with a router ?

Regards,
John.

Timbuck
04-08-2009, 11:33 PM
I own 2 CNC machines and I find them of little use in ukulele making.
http://i219.photobucket.com/albums/cc143/shiregreenbod/PICT0950.jpg
A router with a template is much quicker to set up...CNC Would be ok for carving necks if you wanted to make a lot Thats if you can get hold of 3D software...But you've got to be good at editing G code and such as well

Pete Howlett
04-08-2009, 11:51 PM
CNC - why? This is a production tool and will not give you what I suspect you are looking for. It's great for inlays but necks? Just go to taylor's Factory Friday video series and see how they use a router/spindle head to do necks... You really ought to think 'inside' the box on your first build instead of looking for short cuts.:old:

jaunedeau
04-09-2009, 12:25 AM
>A router with a template is much quicker to set up...

Maybe the cnc is then good for making the templates precisely ?

>CNC - why? This is a production tool and will not give you what I suspect you are looking for.

You are right, spending time working on some piece of wood is more what I want to do. On the other side, I'm really more skilled and trained with computer than I am with woodworking, so using a CNC sounds more reassuring, specialy if there are some difficult parts to make.

Using the CNC would be a compromise between gluing a kit and doing everything from scratch. But I don't know if some part are really better done with the CNC. If I hade the bits and 3D tools and ukulele 3D drawing, I think I would do the pre-shape of the neck with the CNC. Is there any good candidate ?

John.

Timbuck
04-09-2009, 12:47 AM
"Master Template making" thats the best thing for CNC machine's... they are very accurate .

wearymicrobe
04-09-2009, 07:30 AM
Make templates not parts.

I could not get CNC to work on a small scale, and I write/debug code pretty good.

Moore Bettah Ukuleles
04-09-2009, 07:46 AM
CNC - why?

EXACTLY! I believe in incorporating character and a soul into the instruments I build. Something that can't be done with automated production machinery. It's one of the differences between a Steve Grimes custom guitar and a Taylor for instance.

Pete Howlett
04-09-2009, 08:31 AM
I do not want in anyway to be either critical or curmudgeonly but this is not the first time you have raised this issue. I think you ought to sit down and really think out what you want to get out of this project you are embakring upon. You have received a shed load of advice, most of which you have ignored and seem to want an 'easy way out' to building. It will be no surprise to you that there is no easy way and there certainly isn't a bridge between a kit build and building from scratch that involves punching a it of code into a computer!

'Luthery', and I blench at the word and the appellation giving to what I consider to be ukulele building, is not something you just 'pick up'. It is a very quirky 'craft' that has so many layers of skill and dozens of operations, production shops easily break them down and assign dedicated workers to do them. Building with a kit is as 'skilled' as making from scratch - just a different skill-set and experience and it is a recommended route to getting into building from scratch. Using a CNC machine to make templates will only serve a small purpose -

So let's look at the hand build I do on my tenors (no machine bending):

Today I hand bent a set of cherry sides in 20 minutes into a form I had made without templates. I hand shaped the end blocks working with a #4 Stanley smoother and nothing else finishing off on a disc sander - a precision tool believ it or not! The joints were shot using my #4 and a shooting board I had made - amazing how many of my students can't use this very simple tool... and this was all before I sanded and matched the sides, shot the back joint, fly cut the soundhole and rosette channel, hand shaped and sized the tone bars. Hand cut the cross banding notches for the back brace... it goes on and on and we are just getting the body together. It doesn't include the operations on the headstock spending most of the day gently sanding and filling all of the burr cores on the burr elm headplate...

Break it down and there is a hundred operations that look very simple but all require hand/eye co-ordination. These are operations that cannot be done by machine.

And hey, I had fun! This is an extreme build that I forgot about and needs to be ready for a birthday... Oh well. Video is coming out soon.

Moore Bettah Ukuleles
04-09-2009, 09:37 AM
BRAVO Pete. If it means being "curmudgeonly", add me to the list. I do things the way I do them because I find it enjoyable and very challenging. I look at the Taylor videos and how they simply push a button to get the job done and I am left so cold. I would never own such a lifeless instrument. To each his own however. I don't know what you call that type of assembly operation but it sure isn't "lutherie". (A word I embrace BTW)

Pete Howlett
04-09-2009, 10:44 AM
I'm glad you embrace it Chuck - you are probably big enough to do so: :bowdown:

I cannot play Taylor guitars - I just beat the hell out of them and sound cowers down by the tail block, too frightened to come out. However, there are some great lessons to be learned in the videos which I love to watch. Much like Collings, Santa Cruz and all those small production companies, their guitars look great but they have no soul. It also has something to do with the insistance on a 25.5" scale length when the ideal for fingerpicking is 24.75" - 24.9" - all of their instruments seem to be aimed at the plectrum players' market. There is something completely undefineable about hand built instruments - you can spot them a mile off and they sound like they really care about what they are about!:shaka:

Bluke
04-09-2009, 01:35 PM
I own nine top end CNC machining centers at my shop. I use them for production and some prototyping. I can do anything on them. However, I do not build instruments. I create parts for satellites and surgical tools, etc. I DO love handmade guitars and ukes, and own many of them. I also own Taylors, Santa Cruz, and Martins, and they are fine instruments. Santa Cruz Guitar Company actually does hand build all their instruments, but uses some CNC work on repetitive cutting operations. I've been there, I know Richard, and I certainly don't consider his instruments 'CNC manufactured". It's just a tool. Like a table saw, router, or sander, all of which the mojo handbuilders use daily. Craftsmanship is in the builder, and the assembly and finish. If you are a craftsman AND a businessman, then you know profit is in the equation and that means efficiency. How many one man shops do you know that actually make any money, or are better off than the last job they had? Probably none, like every starving musician you know. But their instruments are fabulous!

Pete Howlett
04-09-2009, 01:45 PM
Interesting perspective Bluke and yes - like all craftsmen down the centuries we are a financially poor but morally intact bunch.

I don't think I overstated my case regarding thoseguitar manufacturers I cited. I really think their work lacks personality as mine did when I was banging out 8 - 12 a month! Also, the insistance on that long scale which tightens up the whole instrument sucks... for me it does anyway:eek:

I'd love a CNC router to do some particularly pesky operations - I am currently working on a harp-uke and trying to figure out how to do the sub-base headstock is going to require some fairly intense jig making to assure accuracy. If I could have worked off a CAD baseline then it would be easy. As it is I am going to have to hand build my router templates... Oh well, done it before...

Bradford
04-09-2009, 07:30 PM
Here is my take on the subject. Wood is not an engineered material. A CNC carving machine can make parts to .0001 of an inch tolerance, but who is to say exactly what thickness a particular top should be. I prefer to tap it, flex it and feel it. It is an intuitive process honed over many years. The number of variables involved is huge. That is what makes it an art as well as a science.

Brad

jaunedeau
04-09-2009, 11:19 PM
Pete,

thanks for you message, which made me understand that if I really listen to the reasons which push me to make a ukulele (instead of buying a better and maybe cheaper one), I must stop being afraid of trying to do it.

There is one point where I don't follow you, and it's about how you describbe the tools. The taylor video definitively made me understand that what I want to do is not to use a CNC for this project, but I don't considere tools or machines to be any evil thing. Believe it or not, but for now I can put more soul and art in a line of code or in most thing I do with a computer that I could put in anything I do with wood. I've been playing with computers for 20 years, but I still have 50 ou 60 year to learn to play with raps and planers. Ok, if I really want to learn, I have to forget about the CNC and accept to spoil my first fingerboard :)

Thanks,
John.

Timbuck
04-10-2009, 01:25 AM
Every new Journey Begins with a single step.:D

Pete Howlett
04-10-2009, 01:37 AM
Believe it or not, most novice builders rarely ruin their first build - you tend to take it so carefully that mistakes are often small and very corrctable. Use your CNC to make things like:

Fret distance rule
Jig for nut spacing : see Ken's wonderful gizmo here (http://ukulelecosmos.com/phpBB3/viewtopic.php?f=9&t=11035/):
Form templates