Tuesday, October 29, 2013

Sabbatical Entry 3

Well considering it's been over a month since I've had a chance to do a blog post it's safe to say I've been keeping busy.  The weekly schedule I set for myself has worked well but the further into the sabbatical more overlap develops between the things I'm working on.  I find one week an area needs more attention and the following week the pendulum shifts back the other way. 

The fall semester mid-term has come and gone already and I was able to come in and do a couple lectures in our Guitar Overview course using all new handouts and PowerPoint presentations.  All the hours spent on those appears to have paid off with only a few minor glitches popping up.  It will be interesting to see how the new content helps students prepare for the spring electric construction builds.

CAD and CNC Work

The computer drafting course has been moving along briskly as we pretty much wrapped up the Level 1 training manual a few weeks ago.  At first it seemed I was in for a big leap when I started blueprinting a dreadnought acoustic guitar.  However once I got working on it things started to fall into place.  Throughout the process I realized the training manual and instruction had served me well but like anything, once you go from arranged exercises to starting from scratch, there are things you simply have to figure out for yourself.

We took the dreadnought outline we created in an early exercise and then began to create our own blueprint using another as a guide.  I went with the same bracing pattern on the example drawing but decided to use a little different scale length and  neck specs from a Gibson J-60 I've had for many years.

Here the blueprint is starting to take shape.  I started with the body outline, located and drew a soundhole then moved onto the bracing.  It's amazing how much control you have over everything created in Rhino.

I kept working on the drawing until I couldn't avoid creating a side template any longer.  I put it off because it gets us into 3D modeling and doing some different functions that weren't as comfortable to me as the 2D drawing.  We need to "extrude" the outline to create sides but also create a radius dish and use that to trim the top and back edges of the sides.  An acoustic guitar doesn't have a truly flat back and even if the top is built without any radius, over time it will change under the tension of the strings.

In the "perspective" viewport it becomes clear that this is a three dimensional object.  Using a radius dish we can trim the sides to a specific dimension and then roll the surfaces out to have a very accurate side outline.
Another shot of the radius dish in place so it's almost ready to be "trimmed".
The radius dish has been selected as the cutting object and next I'll click on the parts of the sides I want "gone".
Here I've clicked on one half of the body to trim it.  I'll repeat the process on the other side so I end up with the "back" of the body trimmed to shape.  There are some extra lines and outline in the picture I didn't notice when I captured this image.
I like this screen capture because you can see the blueprint I'm working on in the background.  I've already done the top edge so it's time to roll out one of the sides so I can get back to my blueprint in two dimensions.
You can see what would be the treble side highlighted in yellow.  To the right of that you see the "rolled out" side in 2D.  That will become a template a person can use to trace onto a piece of wood and get the profile cut out before bending the wood into an actual guitar side or "rib".
I've placed the side template on the blueprint and added 1/2" to each end so there's a little extra wood when the side is actually bent.  In the lower right I've placed a bitmap made from a simple tracing of a half template I made twenty years ago as a student!  I was able to draw a line accurately on the image to then make a symmetrical headstock outline.
By this point in the process I was feeling very comfortable drawing in 2D using Rhino.  Of course that comfort didn't last long as we've moved onto modeling a complete 3D dreadnought guitar.  So, now I'm back to that uncertain anxiety trying to figure it out.  Confidence builds with each successful step though.  More on that in a future post...

Over the last few weeks I nailed down some travel plans and it took more time than I expected.  This past weekend I actually ventured down to Des Moines Iowa to spend a couple days at The Lutherie Shop and Bilt Guitars.  You can find their websites at www.thelutherieshop.com and www.biltguitars.com.  A very special thanks to Tim, Scott and Bill for letting me invade their space for a couple days to see them in action.  These guys are true pro's and Tim is a graduate of the guitar program back in 1998.  I was able to watch them work, take lots of photos, ask a lot of questions and observe the work flow and project management. 

 Tim put me to work sanding out an electric body so they could get it in the spray booth.  I had to earn my keep!  Apparently that particular guitar is off to a guy named Wes in a band called Limp Bizkit. 

In the two days I was there Tim and Bill wrapped up three builds they've been working on.  There were two more guitars in the finishing process and yet another two guitars ready for sealer.  These guys don't mess around!

Two of the three guitars that were completed during my visit.  These guys are building some very cool retro inspired guitars.

Over the past month I've also been working on new packets of information for the Advanced Finishing class and have been working on editing new videos for the Electric Construction class.  These are pretty big projects but I know it'll be worth the effort.  I haven't forgotten about the electronics study and am actually getting ready to start working on several amps, pedals and pickups in the coming weeks.  Time to see if all this book study is paying off.  The guitar program has an amp we haven't used for several years because it stopped working within a couple of dusty school years.  So, I'm going to tear that thing apart and see what I can find.  The rest of the projects are my own amps and pedals so I'll save those for the weekends.  It turns out I have five wah pedals I didn't know I had.  Apparently it's "easier" to buy a new pedal than it is to order the parts and fix what I already have??? 

So that's it for now, back to working on some three dimensional dreadnought bracing!