New Luthier Tips du Jour video - CNC and Lutherie

[Robbie O'Brien]

Welcome to 2023 Here is the first Luthier Tips du Jour video of the year. - The topic is CNC and lutherie
This video as well as all my other videos are available via my website, https://lutherieacademy.com/videos , LMI's website or on Youtube.
Don't forget to subscribe to my channel if you want to get the latest Luthier Tips du Jour videos when they are released.

youtu.be/EJKNIn8Gv-4

[peter.coombe]

Just 6 months ago I decided to get more serious about CNC (I had a small and very problematic Chinese machine bought to cut the "Coombe" headstock logo) and took advantage of the tax advantage that ended on 1st July 2022 and purchased a Stepcraft M700 with the ballscrew option and aluminum table. Serious money for me, but still in the hobby range for CNC, although it is high end hobby. Made in Germany. After the problems with the Chinese machine, which was mainly to dip the toe into the CNC world, I wanted a complete solution and local support, and I got it. I also have limited space, so it had to fit into the space. 1x1m of which there are many options is too big. I opted for the kit version so would have a detailed knowledge of how it was put together and would know what to do to fix any problems. They estimated 10hrs to assemble, but that assumes you know what you are doing and don't make any mistakes. I did not know what I was doing and made a couple of mistakes and had to back track, so took about 15 hrs. The kit is very high quality, everything fitted perfectly and there was nothing missing out of over 1000 parts and the assembly book is 100 pages and excellent. One problem was resolved by the local support. Working perfectly, and in another dimension as far a quality is concerned compared to the Chinese rubbish.

My initial aim was to use the machine to do things that were hard to do, or impossible to do by hand, and also wanted to eliminate some outsourcing such as making tailpieces (outsourcing sucks). I am also getting longer in the tooth with eyesight not as good as it once was. Things like the cutting oval sound holes and oval rosettes I have done for nearly 30 years, but none are a perfect oval, and most have a bit of wobble that drives me insane, but nobody else seems to notice. Perfect oval every time, piece of cake with the CNC. Also cutting the grooves in mandolin fingerboards for the brass pins is a pain and gaps have always had to be filled with glue. Piece of cake with the CNC, perfect fit every time, no gaps. One mistake a lot of people in the mandolin world make is to try and run a marathon before they can walk with CNC. So there has been lots of questions about carving 3D F5 mandolin plates on a CNC as a starting point for using CNC. Probably the most difficult thing to do out of all the other things that are possible. So, I have Vectra software 2D carve only. There are plenty of things to keep me busy in the 2D world for the time being. Walk first, and the machine is more likely to be used productively. The software was a bit daunting at first, but once I got my head around it, it is quite easy to use, and I am getting quicker by the day. Just the other day I needed to cut a wooden plug 13mm in diameter to fill an endpin hole in a repair. Thought about it, no plug cutter, no hole saw is 13mm in diameter, so how to make it. Idiot, use the CNC, piece of cake on the CNC, and it was. Perfect fit first time. One thing I did learn was that it is very rare for it to work the first time, rare to work the 2nd time, 3rd time might be lucky. So, the old practice on scrap is essential. The bin is full of bits of chopped up scrap MDF.

So, absolutely no regrets. I am just scratching the surface of what is possible so far. There are many things that will never be done on the CNC because it is easier and quicker to do by hand. Some things will be done just because of the accuracy. For example, mandolin tuners come 4 on a strip so the holes have to be drilled dead straight in line and accurately spaced. Very difficult to do every time by hand, but easy peasy on the CNC. So, headstock overlays will now be cut on the CNC before gluing and they will have pilot holes drilled for the tuner post holes. I can now get the holes drilled accurate to within 0.1mm. Modern high end mandolin tuners are made to very small tolerances and don't work well if the holes are not accurately drilled. I did buy the Stew Mac gismo, but that was a waste of money, results were no better than how I had been doing it. The first headstock overlay took hours to program, but the second took a fraction of that time because the bugs had been worked out and I could cut and paste some of it. I am currently working on a new tailpiece design.

[kiwigeo]

Thanks for the video Robbie and thanks Peter for a detailed run down on your experiences with CNC

[Allen]

When I decided I wanted to be a full time builder I had been doing some time / process testing to work out where I could save time, increase accuracy etc. to be more productive so it would be possible to replace the income from the day job. Didn't take long to come up with a list of huge time wasters and the obviouse solution was to go with a CNC. But were to start?

Doing more research everything out there was either for industrial applications far larger than what a small luthier shop required, or specifically for sign makers that just didn't have the Z hight that we require. So I built my own very industrial CNC because there was absolutely nothing available in the size I wanted at the time. It was either Chinese toys, some kit's out of the USA or prebuilt machines that were very expensive and built for 110V. Importing them was just out of the question. Certainly no high quality kits back then.

I had no idea how difficult a job it would be and knowing what I know now I'm sure I wouldn't have taken that leap. So many things from the engineering, electrical, and software and programing all having to work together. In hind sight a very well built kit is the way to go and if you are thinking of going down this route, don't skimp. It's just not worth the time and effort if the mechanics, electronics and software isn't capable.

And when it comes to CNC learning the CAD/CAM software is a huge learning curve. I'd been recommended to start dabbling in the CAD software well before getting a machine to become familiar with how to draw out a part in 3D. And as Pete says, you have to learn to walk before you can run. Doing anything in 3D is an order of magnatude more challenging than cutting out something like a peg head veneer.

I tested out all of the software options on the market at the time and it's very different process depending on the software you choose. Because my prefered platform is Mac OS the choices were a bit limited. At the time there were a couple of options, and probably sitll that case. I settled on Fusion360 and used it from the very first Beta testing. If you are on either Windows or especially Mac OS, I highly recommend it.

My most common jobs for the CNC are in 2D, sound hole / rosettes, peg head veneers including logo and purfling lines, truss rod slots. In 3D fret boards with compound radius, purfling lines with fret slots that follow the surface radius, and bridges.

[peter.coombe]

I actually contacted Multicam and went as far as getting a quote on their smallest machine. Industrial quality machine, designed to run all day every day, weighs around 400kg. The offer was quite good, included delivery, installation and 6 weeks training course. However, to justify the cost I would have had to set up a CNC machining business making parts for other people. Would have taken the rest of my life to pay for itself otherwise. I thought about it for 3 minutes, nope to making things for other people, the machine was gross overkill otherwise, so nope. The salesman tried very hard to convince me to set up a CNC machining business, but was unsuccessful. Some years ago I did import a CNC kit from north America, as Alen said nothing was available here, but that was a disaster. The manufacturer quoted 3 months to delivery to my door, actual delivery time was 2 years! I was super pissed off. The supplier then disappeared. The kit came with no instructions. I made probably 5 attempts to set it up and came to the same conclusion every time - this is a shit load of work and no guarantee I will ever get it working. Any problems and I am on my own. It did not use off the shelf parts, so if anything did not work I was stuffed. Not worth risking the time. So, it is still in the workshop in the carton, under the Stepcraft.

[simso]

I embraced cnc many years ago.

Ask away if you have any questions re fabricating parts, pretty much covered it all by now.

Also pretty awesome for making inlays, custom one offs, still a lot of work involved in making of the part, its just a different type of work, eg programming, drawing etc

I find however making things like fretboards, necks are far quicker done by hand and conventional machinery / jigs than cnc unless of course you want custom inlaid fretbaords etc

My main cnc unit is 2 metres wide by 3 metres long (cut bed size) with auto tool changing

The smallest cnc I have is a 300 by 300 cut bed