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CNC made acoustic
http://mowrystrings.luthiersforum.com/forum/viewtopic.php?f=10106&t=20171		 Page 1 of 1
Author:  Parser [ Wed Dec 24, 2008 4:42 pm ]
Post subject:  CNC made acoustic
Hey guys...thought I'd show my latest....lot of CNC work on this (neck, rosette, inlay, fret slots, braces, side profiles, etc..)

Even though I do like to use the CNC (I have a K2 KG3925 machine in my home shop) where it makes the most sense, I still put a lot of emphasis on hand voicing the top as well as general fit and finish.

I still have plenty to learn, but I was pretty happy with how this one came out and as such..I sold it so that I can buy more wood!

Here are the specs:

*25.4" scale length
*sitka top with east indian rosewood rosette inlays, movingui back and sides from Ken H's stash
*movingui yellow lab inlay & position markers
*curly maple/rosewood laminated binding
*genuine mahogany neck w/LMI truss rod
*Z-poxy pore fill with Tru-Oil finish. The Tru-Oil worked OK...but I'm going to try Target USL on the one I'm building right now..

I braced this one pretty heavily...the X braces are almost 1/2" wide and the bridge plate was extra long. I actually had to shave the bridge plate down a bit in order to get a nice tap tone from the top. This one sounded pretty good all around, but I thought it had a bit extra in the trebles (maybe due to the stiffer top?).

Anyhow, here are the pics:

Image

Image

Image
Author:  Hesh [ Wed Dec 24, 2008 5:22 pm ]
Post subject:  Re: CNC made acoustic
Hey Trevor your guitar looks fantastic!!!!! Way-to-go!!!! [:Y:] [clap] [clap] [clap] [clap] [clap] [clap]
Author:  Parser [ Wed Dec 24, 2008 6:05 pm ]
Post subject:  Re: CNC made acoustic
Thank you Hesh! and rest assured there is plenty of room for improvement...! :D
Author:  James W B [ Wed Dec 24, 2008 6:25 pm ]
Post subject:  Re: CNC made acoustic
You lazy dog you.LOOKS GREAT.
James
Author:  Tim McKnight [ Wed Dec 24, 2008 7:39 pm ]
Post subject:  Re: CNC made acoustic
Great job. How bout a close up of the rosette?


One more question though, what CAD program did you use to get all of those awesome V shaped lines in that yellar wood? laughing6-hehe
Author:  Parser [ Wed Dec 24, 2008 8:22 pm ]
Post subject:  Re: CNC made acoustic
Here's the rosette...I did a "chevron" match from two pieces of rosewood in each block.

Image

One thing I learned about Movingui is that it is easily stained by wood glue. Good cleanup is a must..! You can see a bit of a stain around one of the back braces in this pic.

Trev
Author:  Anthony Lembo [ Thu Dec 25, 2008 10:42 am ]
Post subject:  Re: CNC made acoustic
Nice job!

I like the dog on the fretboard. :D

How did you hold those small pieces down on the CNC?

Anthony
Author:  WaddyThomson [ Thu Dec 25, 2008 5:39 pm ]
Post subject:  Re: CNC made acoustic
Very nice looking guitar, Trevor. Congratulations! [clap] [clap] [clap] [clap] [clap]
Author:  Parser [ Thu Dec 25, 2008 8:57 pm ]
Post subject:  Re: CNC made acoustic
Thanks guys...

I held the inlay while it was being cut using double stick tape. I jumbled the arrangement of the different parts so that the grain direction would vary and break up the pattern a bit.

Pretty much everything I cut as of now is held using double stick tape....one day I'll hook up some vacuum...that DS tape gets expensive! (I use the stuff from Highland Woodworking)
Author:  Tim McKnight [ Fri Dec 26, 2008 9:37 am ]
Post subject:  Re: CNC made acoustic
Love the rosette Trev. It reminds me of a Somogyi-esqe influnce

As for the interior glue stain, take a small piece of 320 and sand it out. It will make it much less noticeable.

Try the indoor outdoor carpet tape sold at your local home improvement store. It will hold just as well and it is probably less expensive. Another trick I learned on small stuff is to routh the design into thicker wood. After you are done run some masking tape along the top of your newly cut pieces and then set the wood up on your saw and re-saw the thickness down to the depth of the routed figures holding the tape side against the fence.
Author:  Parser [ Fri Dec 26, 2008 1:40 pm ]
Post subject:  Re: CNC made acoustic
Thanks Tim...I do appreciate Somogyi's design work.

What I usually do for wood inlays is pretty similar to what you have mentioned...I will use the CNC to cut the pattern to within about .010" of the bottom of the piece of wood. Then, I'll mount tape to the top of the part as you suggested...and then just go over to the belt sander and sand off the bit of extra material on the bottom.

Wood is a much easier material to deal with than shell. I'm going to try to do more wood inlays and less shell in the future.

Best,
Trev
Author:  npalen [ Sun Dec 28, 2008 10:23 am ]
Post subject:  Re: CNC made acoustic
Nice work, Trevor!!!!!!
Author:  Dennis Leahy [ Mon Dec 29, 2008 7:10 pm ]
Post subject:  Re: CNC made acoustic
Woo hoo! Nice, with a capital "N"!

That final photo (soundhole closeup) would make a good avatar pic.

Can you outline your process on bending the Movangui sides? Any minor cracking or "faceting", or did you have clear sailing?

Dennis
Author:  Parser [ Mon Dec 29, 2008 7:38 pm ]
Post subject:  Re: CNC made acoustic
I thought the movingui worked pretty similar to indian rosewood...it bent pretty easily with medium to medium-high heat. It was really nice to work with...my only complaint about it was that it stained easily with the Titebond I used on the bindings and the back braces. I had to sand a bit more than I usually like to in order to get it out of the sides. The grain really popped with both the epoxy and the tru-oil.

Some other interesting things about this guitar that I didn't mention the first time:
~the back is actually cylindrical with a 18' radius...not the normal spherical shape. I sand the sides using a sandpaper lined "trough" with this radius built into it.

~the sides were profiled so that after they were bent, they formed this 18' cylindrical form along the bottom. I used the command "unrollsrf" in rhino to generate the true side profile. This has worked really well...it's great to bend the sides and not have to mess around too much with them to make them fit the form that you want the back to fit to! I put a small tab on the side right at the middle of the waist...I use this to line the sides up in the correct position on the bender.

~the neck joint is a straight mortise & tenon joint (screwed & glued). I made a nifty neck tenon jig that has interchangeable jig plates for different tenons...it's adjustable by 1/4 degree increments which seems to be a good degree of accuracy when setting the neck angle. I do it by the numbers to get it close and then do the normal cheek flossing/chiseling to fit the neck to the body. Maybe one day I'll have something like what the guys down at Collings are using....this thing seems to be the ticket:
Image

(the image above is from the Frets.com site...hopefully I'm not infringing on anyone by posting the link!)
Author:  KenH [ Mon Dec 29, 2008 9:05 pm ]
Post subject:  Re: CNC made acoustic
Beautiful work Parser! Makes me want to build with the sister set of that wood :)
Author:  Parser [ Mon Dec 29, 2008 9:27 pm ]
Post subject:  Re: CNC made acoustic
Thanks Ken, I'll look forward to seeing her!
Best,
Trev
Author:  Fleck [ Sun Jan 11, 2009 4:56 pm ]
Post subject:  Re: CNC made acoustic
Nice.... I really like your bridge contours.
Mike Fleck
Author:  Jeremy Vonk [ Wed Jan 14, 2009 6:53 am ]
Post subject:  Re: CNC made acoustic
Wow! Really nicely done! I haven't been on the board for a couple of weeks and I come back to find this...I'm glad I checked in.
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