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Jay's 2016 Challenge entry
http://luthiersforum.com/forum/viewtopic.php?f=10145&t=47888
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Author:  truckjohn [ Sat Dec 31, 2016 3:05 pm ]
Post subject:  Re: Jay's 2016 Challenge entry

Congrats on being first to finish.

Thanks for showing your pic of the way you clear the finish off the top. I may try that this time - as I generally scribe and scrape. It's hard to do that without putting at least one ding or scratch on the top from the chisel and scraper.

That came out very pretty. Any chance you can post a sound file.

Author:  J De Rocher [ Sat Dec 31, 2016 8:46 pm ]
Post subject:  Re: Jay's 2016 Challenge entry

I'll try to record something and post it tomorrow.

If you do use the Jasco method, just be sure to not apply the Jasco right up to the edge of the tape mask. At least for the blue tape I'm using to make the mask, there can be a bit of seepage just under the edge of the tape here and there which will show outside the footprint of the bridge. That's why I leave the 1/8" margin without Jasco on it and then scrape that off with the square-ended x-acto blade.

I use a piece of scrap wood cut to a sharp taper as a sort of spatula to scoop up Jasco after it has set for 15 minutes (wear gloves) and wipe it onto a paper towel and go back for more. After scraping the last bit of the finish off in that 1/8" margin up to the tape edge, I lightly sand the bare footprint area with adhesive-backed 220 sand paper on a small wood block that fits inside the footprint and call it done.

Author:  J De Rocher [ Sun Jan 01, 2017 8:44 pm ]
Post subject:  Re: Jay's 2016 Challenge entry

Ok, here goes. I recorded a short version of West Coast Blues to give an idea of how it sounds. It was recorded on my i-phone so nothing fancy....

https://www.youtube.com/watch?v=VLQf0zAioSY

Author:  JoeM [ Mon Jan 02, 2017 12:36 pm ]
Post subject:  Re: Jay's 2016 Challenge entry

Beautiful guitar, and very nice playing too. Is that the Blind Blake version? I want to learn some Blind Blake songs this year myself.

Great work!

Author:  J De Rocher [ Mon Jan 02, 2017 10:00 pm ]
Post subject:  Re: Jay's 2016 Challenge entry

You're right, it's a Blind Blake song. I got this version from an instructional DVD by Jorma Kaukonen. If you want to learn this version, his video is well worth getting. It's on the first DVD of a three DVD set from Homespun Video. There's also a great version of Hesitation Blues on that DVD.

Author:  JoeM [ Tue Jan 03, 2017 12:41 am ]
Post subject:  Re: Jay's 2016 Challenge entry

J De Rocher wrote:
You're right, it's a Blind Blake song. I got this version from an instructional DVD by Jorma Kaukonen. If you want to learn this version, his video is well worth getting. It's on the first DVD of a three DVD set from Homespun Video. There's also a great version of Hesitation Blues on that DVD.


Cool, I'll order the DVD. I got "The Guitar of Blind Blake taught by Woody Mann" (GuitarVideos.com) for Christmas.

Author:  JoeM [ Tue Jan 03, 2017 11:03 am ]
Post subject:  Re: Jay's 2016 Challenge entry

J De Rocher wrote:
As a final note, I took the suggestion made by Alan Carruth and seconded by DennisK in a separate thread to try reducing the height of the saddle to reduce the torque on the bridge. I was able to reduce the height by almost 1/32" and still have it play clean fingerstyle which is how my daughter plays exclusively. That reduced the bridge rotation angle from 2.28 degrees with the original set of 12-53 strings to 1.79 degrees with the 11-52 set that's on it now. That greatly reduced the deformation of the top that I had been concerned about and it sounds noticeably better than with the extra-light 10-47 set I had put on it as a precaution. Good thing too, because I really did not like those thin strings both for tone or for playability.


I'm curious about this --how did you measure the rotation? What is an acceptable amount of rotation? What do you think caused the excessive rotation? Top thickness? Bracing?

Author:  J De Rocher [ Tue Jan 03, 2017 12:55 pm ]
Post subject:  Re: Jay's 2016 Challenge entry

JoeM wrote:
J De Rocher wrote:
As a final note, I took the suggestion made by Alan Carruth and seconded by DennisK in a separate thread to try reducing the height of the saddle to reduce the torque on the bridge. I was able to reduce the height by almost 1/32" and still have it play clean fingerstyle which is how my daughter plays exclusively. That reduced the bridge rotation angle from 2.28 degrees with the original set of 12-53 strings to 1.79 degrees with the 11-52 set that's on it now. That greatly reduced the deformation of the top that I had been concerned about and it sounds noticeably better than with the extra-light 10-47 set I had put on it as a precaution. Good thing too, because I really did not like those thin strings both for tone or for playability.


I'm curious about this --how did you measure the rotation? What is an acceptable amount of rotation? What do you think caused the excessive rotation? Top thickness? Bracing?



The guitar was laying on its back on the bench with the neck on a neck rest so it wouldn't move. I used a small laser pointer resting on the flat top surface of the bridge and pointed at a vertical ruler positioned 24 inches away from the bridge in line with the direction of the strings. I noted where the laser dot fell on the ruler scale without the strings and then put on strings, tuned it up to pitch, and noted where the laser dot fell on the ruler scale. The difference in height on the ruler between the dots and the 24 inch distance from the laser pointer to the ruler form two sides of a right triangle so I solved for the angle at the bridge formed by the path of the laser with and without the strings.

I posted a separate thread asking about the excessive rotation to get forum members' ideas about the cause. I suspected that I thinned the top too much and/or positioned the bridge with too little overlap of the bridge ends over the x-braces. Several people agreed with those possibilities. Tim Mullen also raised the possibility that the x-braces were too aggressively carved north of the saddle line which would allow the bridge to rotate more than desired. Alan Carruth and DennisK also brought up the height of the saddle above the top as a possible contributor. DennisK pointed out that the Gore/Gilet book recommends 2 degrees of bridge rotation as a good number. You can see that thread here: http://luthiersforum.com/forum/viewtopic.php?f=10101&t=48762

For the next one of these parlor-size guitars I build, I plan to thickness the top to a lower deflection number than I did on this guitar and move the x-braces a bit to give more overlap with the bridge ends.

Author:  truckjohn [ Wed Jan 04, 2017 12:10 am ]
Post subject:  Re: Jay's 2016 Challenge entry

That's a nice guitar you have there.

I find that on little guitars - I prefer the sound of a thinner top and more bridge overlap of both the X and the finger braces.. I also like to cap or tie in everything north of the sound hole to get the most out of the bracing structure. To my hearing, they are warmer, louder, and have a fuller sound..... Unless of course you are aiming for a very bright and boxy guitar..... Which is the sound most of the little factory guitars hit. It's pretty easy to get a big 'ole dread too boomy/bassy/woofy sounding.... Much harder on one of these little things.

Thanks

Author:  J De Rocher [ Wed Jan 04, 2017 12:29 am ]
Post subject:  Re: Jay's 2016 Challenge entry

Thanks for those suggestions. In my case, I'm definitely not aiming for a very bright sounding guitar. Do you have a preference for either scalloped or tapered x-braces on small guitars?

Author:  truckjohn [ Wed Jan 04, 2017 12:55 am ]
Post subject:  Re: Jay's 2016 Challenge entry

My X bracing usually ends up tapered because there's just not that much bracing between the bridge saddle and the bottom of the lower bout... Especially if you start off at 1/2" tall. Compared to a dread - the lower bout bracing in a little guitar looks pretty willowy... But it also doesn't need to support that giant span. Just by virtue of the width - everything else being the same, a 12" wide lower bout is 33% stiffer than a 16" lower bout. So you can go thinner on everything just to get back to the same stiffness you had on the dread.

Author:  Bryan Bear [ Mon Jun 19, 2017 10:18 am ]
Post subject:  Re: Jay's 2016 Challenge entry

Bumping the finished entries up to the top. . .

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