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PostPosted: Tue Jul 09, 2013 3:28 pm 
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Walnut
Walnut

Joined: Mon Jul 08, 2013 4:48 pm
Posts: 1
Country: france
Focus: Build
Status: Amateur
Hi,

Hope someone here can help.

After quite a long time in the making,I thought I was nearing the completion of a National type,wood bodied,round neck resonator guitar,but no!! A "problem" has arisen that is baffling me somewhat,still it does make this building process even more interesting.

The build up until now has gone well,but having just fitted the cone,bridge and strings I am in difficulty sorting out the string heights in relation to the bridge and coverplate.The strings end up near to the top of the bridge and the coverplate will not fit ! Let me explain.

The guitar is a biscuit bridge model with a scale length of 25"(635mm.)The neck has a 1.5° angle,and joins the body at the 12th.fret.The Beard cone and coverplate come from Stew-Mac,the coverplate handrest/bridge cover has a clearance height of 3/4" (20mm.)from guitar top to underside of the bridge cover.

O.K. heres the math(s). With half the scale length,that is, 12.5"(317.5mm.) from the neck edge of the body(12th.fret) to bridge and a 1.5° neck angle, using tangent theory(its all on the net) the height above the soundboard at the bridge will be 11/32"(8.3mm)approx.,the fretboard and frets are 9/32"(7mm")approx. in height,and with a string clearance of 1/8"(3.2mm)at the 12th fret that makes it double at tha bridge=1/4"(6.4mm)approx.

All this means that I am working near the top of the bridge(with the risk of pulling the bridge out of square).This can be reduced by raising the cone,maybe,but it does not change the height of the strings above the soundboard.The height of the strings(underneath) to top, are 11/32" + 9/32" + 1/4" = 7/8"(22mm.);Plus string thickness and a bit to secure them,say 1/16"(1.5mm),that means overall bridge height above the soundboard is 15/16"(23.5mm). As I only have 3/4" clearance on the coverplate,then logically its not possible.Is it?Have I got to change the neck angle(isn't 1.5° about right?),have I got to change the coverplate(is 3/4" clearance standard?)or have I got it all hopelessly wrong??

This is maybe a bit longwinded,and for that I apologise, but I didn't find it easy to explain.I'll gladly try and make it clearer if anyone has any questions

Anyone who can shed light on this,please reply. Thanks Chris Broad


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PostPosted: Mon Sep 02, 2013 9:47 pm 
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Mahogany
Mahogany

Joined: Fri Oct 01, 2010 11:30 pm
Posts: 55
Country: usa
Focus: Build
Status: Amateur
I may not be fallowing you, but here is what I think you are saying. If you put it together as is, you will be able to get the action set to the height you want with the biscuit bridge, but you will not be able to put the cover on without the cover contacting the strings. If this is the case a neck reset sounds like it is in order. If you are more concerned with getting your project done, than you are with its being authentic to the plan, you do have the option of building a spacer that raises the height of the cover so that it clears the strings.


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PostPosted: Fri Sep 13, 2013 10:25 am 
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Koa
Koa

Joined: Thu Nov 04, 2010 1:46 pm
Posts: 865
First name: Freeman
Last Name: Keller
Focus: Build
Status: Amateur
Chris, normally the cone well for a biscuit is one inch deep. That should give the cover plate clearance over the saddle part of the biscuit. The top of resonator guitars are flat (ie. no dome like an acoustic). With a resonator you have very little adjustment of the action at the saddle, you do most of it with the neck angle. I don't know how you built yours, but most have a neck stick and you shim the stick to change the angle. If you built with a dovetail or bolted neck joint (I use bolted) then you will need to reset the neck or, I guess as Butterschotchblond suggests, shim the cover plate. You could also punch the rivets out of the hand rest on the coverplate and either put a shim under it or bend the hand rest to get more clearance.

fwiw, I always suggest to people building a resonator that they get cone(s) and coverplates and confirm these heights before they ever start. Building to an angle like 1.5 degrees may or may not be correct because of the flat top.


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