Neck Relief, Neck Angle, Bridge Height and Action question

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RocknRollShakeUp
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Mon Jul 08, 2019 8:56 am

timtam wrote:
Sun Jul 07, 2019 5:40 pm
RocknRollShakeUp wrote:
Sun Jul 07, 2019 12:34 pm
BTW, does anyone know what fraction of a degree one gets with the use of a single ply of the typical cereal cardboard box shim? Probably not, but some hardcore dudes out there have those apparatuses that can measure neck angles and could have measured pre and most cardboard shimming :).
Trigonometry ....

tan(angle) = rise_in_pocket / pocket_length

eg
rise_in_pocket = 1 mm (ie 1mm thickness, uncompressible, at one end of pocket)
pocket _length = 76mm

angle = atan(1/76) = 0.75 degs
Nice! Thanks for for that!

So now I wonder how compressible that cardboard is. But that darn fangled trigonometry definitely helps us know what we are getting into! Thanks again!

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Matt_A
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by Matt_A » Mon Jul 08, 2019 9:11 am

mylar is not compressible and available in many precise thicknesses:
https://www.grafixplastics.com/grafix-p ... mat_thick/

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timtam
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by timtam » Mon Jul 08, 2019 5:21 pm

RocknRollShakeUp wrote:
Mon Jul 08, 2019 8:56 am
timtam wrote:
Sun Jul 07, 2019 5:40 pm
RocknRollShakeUp wrote:
Sun Jul 07, 2019 12:34 pm
BTW, does anyone know what fraction of a degree one gets with the use of a single ply of the typical cereal cardboard box shim? Probably not, but some hardcore dudes out there have those apparatuses that can measure neck angles and could have measured pre and most cardboard shimming :).
Trigonometry ....

tan(angle) = rise_in_pocket / pocket_length

eg
rise_in_pocket = 1 mm (ie 1mm thickness, uncompressible, at one end of pocket)
pocket _length = 76mm

angle = atan(1/76) = 0.75 degs
Nice! Thanks for for that!

So now I wonder how compressible that cardboard is. But that darn fangled trigonometry definitely helps us know what we are getting into! Thanks again!
To be clear, I recommend full pocket tapered shims over a small strip shim at one end of the pocket. However one of the Stewmac shims costs close to $30 by the time it gets to me (and they're a PITA to make). :(
https://www.stewmac.com/Materials_and_S ... uitar.html

There is a school of thought that narrow shims eventually lead to a 'ski jump' at the end of the neck, eg ..
https://hazeguitars.com/blog/neck-shimm ... t-research

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RocknRollShakeUp
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Tue Jul 09, 2019 8:23 am

timtam wrote:
Mon Jul 08, 2019 5:21 pm
RocknRollShakeUp wrote:
Mon Jul 08, 2019 8:56 am
timtam wrote:
Sun Jul 07, 2019 5:40 pm


Trigonometry ....

tan(angle) = rise_in_pocket / pocket_length

eg
rise_in_pocket = 1 mm (ie 1mm thickness, uncompressible, at one end of pocket)
pocket _length = 76mm

angle = atan(1/76) = 0.75 degs
Nice! Thanks for for that!

So now I wonder how compressible that cardboard is. But that darn fangled trigonometry definitely helps us know what we are getting into! Thanks again!
To be clear, I recommend full pocket tapered shims over a small strip shim at one end of the pocket. However one of the Stewmac shims costs close to $30 by the time it gets to me (and they're a PITA to make). :(
https://www.stewmac.com/Materials_and_S ... uitar.html

There is a school of thought that narrow shims eventually lead to a 'ski jump' at the end of the neck, eg ..
https://hazeguitars.com/blog/neck-shimm ... t-research
My Closet Classic 64 Reissue got a Stew Mac Shim as it is a very traditional and accurate low neck angle reproduction :) . I put in a .5 degree shim and now the neck angle is very similar to my Wildwood 10 JM without a shim. But anyway, I really liked that StewMac shim. It makes it so easy.

I have read about the "ski jump" phenomenon. I've never had a guitar that had the traditional type cardboard or other material partial shims, and one wonders about how much a problem this is. However if it is not a full pocket shim like the Stew Mac I wonder if in fact it is better to use something compressible like cardboard, to the extent that cardboard is compressible, which I would think it is a little bit.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Tue Jul 09, 2019 8:25 am

Matt_A wrote:
Mon Jul 08, 2019 9:11 am
mylar is not compressible and available in many precise thicknesses:
https://www.grafixplastics.com/grafix-p ... mat_thick/
Very interesting. I guess if one isn't afraid of the whole ski jump thing developing, this would make for good and precise shim material.

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Matt_A
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by Matt_A » Tue Jul 09, 2019 9:05 am

RocknRollShakeUp wrote:
Tue Jul 09, 2019 8:25 am
Matt_A wrote:
Mon Jul 08, 2019 9:11 am
mylar is not compressible and available in many precise thicknesses:
https://www.grafixplastics.com/grafix-p ... mat_thick/
Very interesting. I guess if one isn't afraid of the whole ski jump thing developing, this would make for good and precise shim material.
I've seen it used in neck shims, but I wouldn't stack more than two or three layers before looking at something else. It's perfect when you just need a tiny tweak to the angle, I think. There are better materials when a more drastic mod is called for.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by Danley » Tue Jul 09, 2019 10:11 am

I think the ski-jump problem becomes more evident when people really tighten down necks - which is not necessary. ‘Snug’ is enough. It’s more important that the end of your neck is tight against the body than that it’s got a death grip on the screws, and to accomplish that to just need to slightly loosen the screws under string pressure, and re-snug (G&L recommended doing this for a long time.)
King Buzzo: I love when people come up to me and say “Your guitar sound was better on Stoner Witch, when you used a Les Paul. “...I used a Fender Mustang reissue on that, dumbass!

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RocknRollShakeUp
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Tue Jul 09, 2019 10:23 pm

Matt_A wrote:
Tue Jul 09, 2019 9:05 am
RocknRollShakeUp wrote:
Tue Jul 09, 2019 8:25 am
Matt_A wrote:
Mon Jul 08, 2019 9:11 am
mylar is not compressible and available in many precise thicknesses:
https://www.grafixplastics.com/grafix-p ... mat_thick/
Very interesting. I guess if one isn't afraid of the whole ski jump thing developing, this would make for good and precise shim material.
I've seen it used in neck shims, but I wouldn't stack more than two or three layers before looking at something else. It's perfect when you just need a tiny tweak to the angle, I think. There are better materials when a more drastic mod is called for.
Makes sense.

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RocknRollShakeUp
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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Tue Jul 09, 2019 10:24 pm

Danley wrote:
Tue Jul 09, 2019 10:11 am
I think the ski-jump problem becomes more evident when people really tighten down necks - which is not necessary. ‘Snug’ is enough. It’s more important that the end of your neck is tight against the body than that it’s got a death grip on the screws, and to accomplish that to just need to slightly loosen the screws under string pressure, and re-snug (G&L recommended doing this for a long time.)
I totally agree and follow the same practices.

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by jorri » Fri Jul 12, 2019 4:31 am

RocknRollShakeUp wrote:
Mon Jul 08, 2019 8:56 am
timtam wrote:
Sun Jul 07, 2019 5:40 pm
RocknRollShakeUp wrote:
Sun Jul 07, 2019 12:34 pm
BTW, does anyone know what fraction of a degree one gets with the use of a single ply of the typical cereal cardboard box shim? Probably not, but some hardcore dudes out there have those apparatuses that can measure neck angles and could have measured pre and most cardboard shimming :).
Trigonometry ....

tan(angle) = rise_in_pocket / pocket_length

eg
rise_in_pocket = 1 mm (ie 1mm thickness, uncompressible, at one end of pocket)
pocket _length = 76mm

angle = atan(1/76) = 0.75 degs
Nice! Thanks for for that!

So now I wonder how compressible that cardboard is. But that darn fangled trigonometry definitely helps us know what we are getting into! Thanks again!
More useful is to work out the rise in bridge height, and that only involves scaling up a triangle= multiplication. Its also easier. I measured something around 6-7cm neck pocket and 26cm to bridge. so you multiply shim height 26/7 to get rise in bridge height . Doesn't need to be that accurate, btw i have an overhanging fretboard so wasn't that accurate to see where the neck pocket ends, there will be inaccuracies as the shim compresses anyway with an amount of unpredictability..

I added a second business card because i had to rewire everything too. After what i said, I do get less buzz. I've also lowered the nut a little but the general feel changed with the shim. Previously i had used hard shims for a similar height, made of wood veneer for 'teh resonanz' and that caused buzz because it warped the last frets- i think. So with a bit of matte card handy from a packet which contained a slide switch, i just used that- twice as wide as the other piece of business card in there and the tiniest dab of PVA to stop it moving if i take the neck off..

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Re: Neck Relief, Neck Angle, Bridge Height and Action question

Post by RocknRollShakeUp » Mon Jul 15, 2019 6:22 pm

jorri wrote:
Fri Jul 12, 2019 4:31 am
RocknRollShakeUp wrote:
Mon Jul 08, 2019 8:56 am
timtam wrote:
Sun Jul 07, 2019 5:40 pm


Trigonometry ....

tan(angle) = rise_in_pocket / pocket_length

eg
rise_in_pocket = 1 mm (ie 1mm thickness, uncompressible, at one end of pocket)
pocket _length = 76mm

angle = atan(1/76) = 0.75 degs
Nice! Thanks for for that!

So now I wonder how compressible that cardboard is. But that darn fangled trigonometry definitely helps us know what we are getting into! Thanks again!
More useful is to work out the rise in bridge height, and that only involves scaling up a triangle= multiplication. Its also easier. I measured something around 6-7cm neck pocket and 26cm to bridge. so you multiply shim height 26/7 to get rise in bridge height . Doesn't need to be that accurate, btw i have an overhanging fretboard so wasn't that accurate to see where the neck pocket ends, there will be inaccuracies as the shim compresses anyway with an amount of unpredictability..

I added a second business card because i had to rewire everything too. After what i said, I do get less buzz. I've also lowered the nut a little but the general feel changed with the shim. Previously i had used hard shims for a similar height, made of wood veneer for 'teh resonanz' and that caused buzz because it warped the last frets- i think. So with a bit of matte card handy from a packet which contained a slide switch, i just used that- twice as wide as the other piece of business card in there and the tiniest dab of PVA to stop it moving if i take the neck off..
good data thanks for sharing

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