A Whole Lot a ‘Sumpthin Ain’t Right’

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Published on Monday, 06 May 2013 10:01

Written by Frank J. Pasquale

Recently I have addressed the issue of increasing production in my shop. Things are starting to grow and expand and there is a need to produce guitars more quickly. My shop is set up as a very traditional woodworking shop. The bulk of production is done with an Overarm Pin Router, Band Saw, Drill Press and Belt Sander. All the contouring and shaping is done by hand with traditional Hand Rasps and Files.

I have sought council from several woodworkers as to how to increase the production rate of my guitars and more than once the CNC machine has come up in conversation. CNC stands for   Computer Numeric Control and it operates on a guided cutting grid system that allows the computer to fully cut and rout a guitar body in about 25 minutes.

My present set-up is an Overarm Pin Router that uses hardboard templates to guide the wood along a center pin to cut and rout a guitar body in out an hour. Clearly it seems like the CNC is the way to go because I would be cutting production time almost in half. I would also have the added benefit of being able to do something else while the computer did all  the work so its value would increase exponentially and the CNC would pay for itself in no time.

This idea sounded appealing so I decided to experiment and I sent a hardboard production template to a woodshop and had a computer program designed and a production run done of one of my guitars.

I was less than impressed. It looked like one of my guitars but it just wasn’t right. I have a friend who is famous for saying “That’s a whole lot a ‘Sumpthin Ain’t Right’” and I couldn’t agree more.

First off the computer program didn’t match the template exactly so there was some significant sanding that needed to be done. I understand that this is correctable but it’s also a time consuming task. However, once the program is right it will always be right so it could be time well invested. But the real issue was the center line and the neck pocket. They just didn’t feel right when the guitar was done. Maybe it was psychological because I knew it was cut by a CNC but either way the guitar just didn’t have the “Mojo Factor”.

A final issue was the tremendous amount of “tear out” from the wood. Large chunks of wood were basically ripped out of the wood and required some serious sanding. There were even some spots where I had to fill in holes with wood filler to get them level. I would like to say I was disappointed but I wasn’t, this was exactly what I expected from a CNC machine.

A computer can do things more efficiently and quickly than a human being and can do them consistently for greater periods of time but a computer does not have craftsmanship or skill. 

I soon realized why doing things by hand produces a much better guitar than a computer ever could. It’s the wood. Every piece of wood is different.

 It’s not just enough to say that every species of wood adds different characteristics to the natural tone balance. I mean every piece of the same species of wood is different. Some pieces of wood are a dream to work with and some are not. Some woods were quite content before we came along and started drilling cutting and shaping and they do not want to get with the program so they chip and tear and are extremely sensitive.

I recently cut a batch of 10 maple neck blanks. Out of the 10 there were 2 extremely difficult pieces of wood to deal with. On these two particular pieces the router bit wanted to run and it seemed to want to want to chip out on every cut. There were soft spots in the wood and extremely dense spots in the wood and this made cutting the headstock contours a nightmare.  Like I said they were 2 difficult pieces to deal with, however those pieces usually make great guitars so they are worth the extra effort.

The way to compensate for the difficulty is by making smaller cuts and creating escape channels that give the wood more room to allow the chips to fly out without digging into the soft wood or bogging down on the denser parts. It’s a simple answer that a craftsman can adjust easily as soon as the problem begins but a machine cannot understand this problem or compensate for it so you just get tremendous amounts of tear out and stressed center lines.

I knew that CNC wasn’t for me but I still had the task of being more efficient. The answer that I got was from an old world cabinet maker who worked for 30 years making custom cabinets by hand. He taught me a better way to organize my production schedule by using production tracking sheets and I reorganized my shop to be much more production efficient.

There is a tremendous difference between mass production and efficient production. Mass production turns out product in bulk as quickly as possible, efficient production makes the best possible use of a craftsman’s skill. It’s not as fast as a computer but let’s face it, some things are worth waiting for.