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Reso cone warning!

I just did my first build using a lightning reso cone from Gitty and at the end found I had a problem with intonation. I laid everything out first as I always do, used a 24" scale. I was very careful to measure twice and cut once for the hole to hold the cone. All done and string it up and something is not right, intonation is off. I used a medium action since I wanted to do both slide and finger notes, it is fully fretted. I know it will go a bit sharp if the action is too high. So , to get the intonation to be correct , I had to slide the discuit/ saddle back by a bit over 1/4", so now the biscuit is not centered on the cone "nipple" like it should be but teetering on the edge. I think I will make a new biscuit/saddle on an oval shape (maybe rectangle) and screw it to the cone so it does not tip off the edge of the "nipple". I've done resonators before but never one where moving the biscuit causes a problem. I guess the moral of the story is I needed to figure in some "compensation" in my calculation of where to mount the cone on the box for my scale length.

Anyone else run into this??

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Permalink Reply by David L. on November 13, 2017 at 11:47am

Stew Mac has a calculator that gives you the extra length you need to help intonation.
http://www.stewmac.com/FretCalculator

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Permalink Reply by Bluesheart on November 13, 2017 at 11:56am

Cool, thanks, that looks helpful however I had to move it over 1/4" in this case, where the calc only indicated a few thousands. Prob due to my action, I also used heavy strings, maybe that makes it worse?

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Permalink Reply by Randy S. Bretz on November 13, 2017 at 12:22pm

I was never big on a floating biscuit for a cone, thats why I use a short 1/4" dowel rod out the bottom of the biscuit plate and thru a drilled hole in the center of the cone. Then I measure the scale length from nut to biscuit saddle. That gives me spot to cut the cone hole in the lid. You can also adjust the pitch of the neck a few degree`s downward and adjust the action off the biscuit saddle.

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Permalink Reply by David L. on November 13, 2017 at 2:30pm

Hi heavy strings need a longer bit added - all of my acoustics and electric guitars have slanted bridge saddles with the bass side having more compensation length than the treble side.

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Permalink Reply by Richard Dean on November 13, 2017 at 12:35pm

You'll also notice, the height of the action can also change the intonation, when I was adjusting my last builds action, I had to re-adjust the bridge placement each time. Now I know it wasn't a res, but the same applies. I'm building a res as well, I have the Thunder cone, but I'm making a bolt on neck, and I was thinking of making the neck slightly adjustable by a 1/4" so I can compensate for the intonation, but was thinking, instead of sliding the biscuit forwards or backwards, you should be able to just turn it on axis(rotate counter clockwise), as usually the high string is set more forward than the low pitch, and the middle would stay where it is as usually needed.

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Permalink Reply by Bluesheart on November 13, 2017 at 4:15pm

Yep, I do turn it so there is longer space on the bass side. The thing I did not anticipate is the area on the cone that you can move around on is very small. When I slide the biscuit back far enough to get intonation, 2/3 of it is now in the air, no longer in contact with the cone.I've not run into it before because of the kind of reso, like a dog dish for example , has a pretty large flat area to move the bridge around on, not the case here. I'm sure I will end up lowering the action a bit, which will help. In this case "the middle would stay where it is" is no good cause where it is is about 1/4" from where it SHOULD be....

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Permalink Reply by 3 String Guitars on November 13, 2017 at 7:15pm

I have actually had the problem before....just remove the strings and tail piec, and loosen the screws on the cone and slide it back just a bit, if you have not made the cone hole so big there should be a 1/4 inch to sldie the hole cone back....you might need to take the cone out and on the back part of the body round out the hole so the cone can go back a bit, you only need to move it a liitle

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Permalink Reply by Bluesheart on November 14, 2017 at 12:38pm

Um, that is a good idea, though it will leave screw holes in the top where the cone was first mounted(I'm not using a cover, yet). I think I'll leave the cone a come up with a "cantilever" bridge.

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Permalink Reply by Richard Dean on November 13, 2017 at 6:41pm

Well, thanks for the heads up, not sure what everyone else has been doing to this point, but I may mount the neck temporarily fretless, wind a couple strings, then mark each fret position with a tuner, might cut down on the amount of adjustment needed at the biscuit

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Permalink Reply by 3 String Guitars on November 13, 2017 at 7:12pm

I play "Red Dog's"...problem averted!

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Permalink Reply by Richard Dean on November 13, 2017 at 7:20pm

Well that's just cheating, having someone else build it for you lol...how ya doing Beetle?

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Permalink Reply by Taffy Evans on November 13, 2017 at 8:56pm

Hi, I'm thinking that with such a short scale the strings would have less tension on them anyway, so heavier strings would be needed [to allow for slide playing] and may not cause as much intonation problems as you may think, depending on the action of course.

I also think I would fret the neck, string up the guitar [two outside strings will do] and with a tuner available, slide a saddle [with the action height desired] along the top until tuner shows the sweet spot.

It works, its what I do. But maybe a bit late now. Soooo, if your frets are correct I'd go for the "move the whole cone solution".

Cheers Taff