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Neck creep and intonation (PICS)
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Author:  snood [ Tue Apr 10, 2007 7:59 am ]
Post subject: 
Hiya everyone,

For those that do not know I am nearing the end of my 1st guitar which is a SM 000 kit with a dovetail joint.

I have used the internal mold and so my rim was not nice and square resulting in a pretty difficult neck set. (Larry I think you may have had the same thing buddy)

Any way after hours of flossing my cheeks I have managed to get a fairly workable neck set as shown below:



and...



The height over the bridge is a little shade over 1/16th and is nice and staright (L>R).



BUT:
The efforts that i have made to achieve this set has meant that the 12th fret has crept towards the end of the guitar by between 5.5 and 6.0mm as shown below:



and...



Not a problem i hear you cry, the bridge is set to the 12th fret plus 7/64ths correction, simply move the bridge back towards the end of the guitar.

Mmm as Crazymanmichael kindly pointed out to me earlier today (thank you soo much I did not appreciate this) such a large adjustment may meen that the bridge will no longer be positioned adequately over the bridge plate.

I have measured the distance between the bottom of the soundhole and the bridge plate neck and tail edges using a piece of tape placed inside the guitar.

I put my hand into the guitar with a piece of low tack tape and 'felt' my way to each edge. I have imprinted the edge to be measured whilst sticking the tape to the bridge plate. Then I have pulled the tape taught and marked the position of the bottom of the soundholde. I have done this 3 times for each bridge plate edge and taken an average.

Obviously there is a small error due to the sine of the angle the tape makes with the soundboard due to the tape 'riding' over the braces and not being flush with the underside of the soundboard but it was the best i could think of at the time.

Anyway here are the measurements:



Front of bridge (in correct posn) 9.00cm
Back of bridge (in correct posn)   11.60cm

Front of bridge plate 9.20cm (I measured 9.20cm 3 times)
Back of bridge plate 13.10cm (I measured 12.95, 13.30 and 13.05cm)

So from these measurements it appears that the front of the bridge is right over the front edge of the bridge plate and that the back of the bridge has plenty of room.

Is this acceptable?
If not what solutions can you suggest?

Cuuuurazzzymanmichael and I kind of came to the conclusion that I could 'build-up' the cheeks of my dovetail and re-set using hardwood material that I have lying around. In fact i could do this using some rosewood (tough to work with maybe) and make it a nice-ish feature perhaps. The extra material would not need to be thick and so flossing may not be soo bad.

Any suggestions always very much appreciated.

Thanks for looking (as Hesh always says....sooo polite )


Oh also do any UK OLFers fancy a meet-up somewhere. I noticed that our US cousins have done this (maybe we have too) just a thought everyone.

Barry
Author:  TonyKarol [ Tue Apr 10, 2007 8:13 am ]
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A better way to check the bridge patch is this - turn out the lights while having a small flashlight inside the guitar - you will be able to see exactly where the patch is. If your above numbers are correct, then you could leave the neck as is. However, IMO, if you move the neck back 5-6mm, and the leading edge of the bridge is now 5 mm in front of the patch, I would say you patch is in the wrong spot, and dont bother moving the neck at all. The patch should be fully under the bridge (at least they are in ll my guitars). something else to check is if the bridge in its further bcak position still sits ove rthe X brace - if it does, good, if not, you have more trouble waiting to happen.
Author:  JohnAbercrombie [ Tue Apr 10, 2007 8:20 am ]
Post subject: 
Barry-
I'm no expert, but it sounds like you should be fine moving the bridge.
You can sometimes see what's happening with bracing by putting a bright light (fluorescent is cooler) inside the guitar and turning off the room lights. However, it sounds like you have figured out the position of the bridge plate quite well.

BTW, if you add material to the cheeks, it shouldn't affect the neck angle as long as the thickness of the added material is consistent.

Your neck fit looks very clean, BTW.

Cheers

John
Author:  snood [ Tue Apr 10, 2007 8:28 am ]
Post subject: 
OMG guys thanks so much.

TonyK your right, **** indeed if i correct the neck (12th) the bridge plate will deffinately be out of place.
I will do the light test (why didnt i think of that I am a physicist too hahahaha) and come back with some more definate measurements.

JohnA
I would plan to add consistent material as well as i could to limit the amount of re-setting (and work).
You're too kind and thanks

Barry
Author:  Sam Price [ Tue Apr 10, 2007 8:38 am ]
Post subject: 
Snood, might be a good idea to start a new thread on the possibility of a UK meet, to see what interest there is.   
By the way, your work is very clean!!
Author:  snood [ Tue Apr 10, 2007 8:45 am ]
Post subject: 
Sam
Yeah will do it may get lost in the noise on this one :)
Thanks for the compliment too.

I have taken some pics from inside the guitar which should show you all my set-up more clearly (I hope). I havent made any more measurements as it is still not clearly defined where the bridge plate exactly is.







Thanks again
Author:  snood [ Tue Apr 10, 2007 8:50 am ]
Post subject: 
Hesh,

Wow what a cool story!

Indeed politeness costs nothing unless of course you are an old man!

Author:  KenH [ Tue Apr 10, 2007 10:58 am ]
Post subject: 



Never say that you cant teach an olddog new tricks !!


This is an interesting thread and VERY educational. Thanks for sharing it all and for the excellent pictures! I'll be sure to keep this trick in my bag of tricks and tips in case I run into this in the future.


 
Author:  snood [ Tue Apr 10, 2007 7:49 pm ]
Post subject: 
As you can see above i have posted more pics. I am finding it very difficult to find/measure the location of the bridge using the excellent lamp proc. (you may be able to tell from the pics??) The apparent misalignment fore and aft is probably due to the lamp alignment and shadowing. When i constructed the bracing i know everything was very evry square and true. Also I followed the brdige plate posn from the plans very closely.....strange (maybe i didnt)

Anyway I would appreciate second opinions in light of these new pics.

Thanks

Barry
Author:  curtis [ Tue Apr 10, 2007 11:06 pm ]
Post subject: 

hey homie, (please excuse me if i'm being an idiot if i'm missing something here) why not mark the scale length plus a few mil for compensation and see whre it comes to on the bridge plate?


 


Hesh - the Hemingway story is really cool, i've ben a big Hemingway fan for years - i dont suppose you kept the dollar? that be a great thing to work into a guitar somehow.. "the old man and the 'c'"!


 
Author:  curtis [ Tue Apr 10, 2007 11:10 pm ]
Post subject: 
'c' as in chord by the way (as you can tell our yrs of endless benny hill tv shows have left us brits with a world leading sense of humour - or so we like to think!)
Author:  curtis [ Tue Apr 10, 2007 11:21 pm ]
Post subject: 

[QUOTE=Hesh1956]
A CT scan would be price prohibitive....
[/QUOTE]


my wife's about to start lecturing in all that stuff at Uni here (medical physics/ imaging) - she has her own machines for 'research' ...maybe there's a thing there...
Author:  snood [ Tue Apr 10, 2007 11:42 pm ]
Post subject: 
Hahahaha yeah Kato could have a look see for me. Mind you she would have to take it to hospital (Hope maybe?) they wouldnt do it at Uni.

Anyway i forgot to take the bridge off last night during my illumination tests and so it obscurs the posn of the bridge plate.

I will have another go tonight and post back my findings.

Barry
Author:  snood [ Tue Apr 10, 2007 11:52 pm ]
Post subject: 
Idiot...hehehehe joking fez joking

This is what i am trying to do but as the bridge plate is on the inside it is a little bit more difficult.

Besides once the measurement is found i need to find out what tol. is acceptable (opinions etc..)
Ali should be posting your prezzie today to SC BTW
Author:  Pwoolson [ Wed Apr 11, 2007 12:14 am ]
Post subject: 
As Curtis said, I think we're all over thinking the issue. Here's what I'd do:
Measure the scale in the middle of the fingerboard (between the d and g strings) and make a mark on the top at the said scale. Then measure from the front of your saddle slot to the pin holes of your bridge. Put a mark at that location on the top as well. Now, shine a light to see if these two marks fall on the bridge plate. If so, you are golden, if not then you might have some more work to do.
Author:  snood [ Wed Apr 11, 2007 1:23 am ]
Post subject: 
Paul,
Many thanks for the post much appreciated.

This is in fact what I have been doing since the begining of the post. The trouble is in measuring the bridge plate position as it is inside the geetar. The light proc. works really well but because i am stoopid i didnt take the bridge off first and so the bridge plate position is obscured. Also the light/lamp proc. means that edge positions are ambiguous due to shadowing.

No matter though i am sure all will be good in the end.
As Hesh has said I think that I am gonna be ok............phew

Author:  curtis [ Wed Apr 11, 2007 1:39 am ]
Post subject: 

i think you've got the skills to sort this out Baz - we've got a nice new table saw in the shop if you want to have a REALLY good look inside tho


looking fwd to seeing the next step / result (plus i think Kato has actually got CT and X ray m/c's in her dept...its not unthinkable - especially in the summer hols. might make a nice avatar if nothing else )
Author:  snood [ Wed Apr 11, 2007 1:45 am ]
Post subject: 
Just the thought Curtis makes my heart stop!
You wiat until you start your #1 son hehehe.

CT my guitar in the Salford summer????
Hell yeah buddy.
I may even get in thier with it!

Barry.
Author:  Steve Saville [ Wed Apr 11, 2007 2:01 am ]
Post subject: 
Barry,
What wood is your bridge plate made from? It looks like it might be maple. It also looks like it might be a soft wood?   
Author:  snood [ Wed Apr 11, 2007 2:21 am ]
Post subject: 
Steve,

It is maple as supplied in the SM 000 kit.

Barry
Author:  snood [ Wed Apr 11, 2007 6:42 pm ]
Post subject: 
Hi everyone,

I have measured up and indeed the front edge of the bridge is right on the front edge of the maple bridge plate. The back edge of the bridge is well clear of the back edge of the maple brdige plate...

Is this ok?

Thanks,
Barry.
Author:  Alain Desforges [ Wed Apr 11, 2007 10:35 pm ]
Post subject: 
Then it should be fine... How about the X? Will the bridge still intersect it? I'm thinking it should. If it was already over-lapping correctly and not just at the tip of the 'wings' then 6mm shouldn't be that bad.

Now I'm willing to bet that on no.2 (because, of course, there will be another) you'll make that bridge plate a bit bigger?

Great pics by the way. That always helps understand the matter at hand.

Hesh! You met Papa!!! Man, that is too Cool!!!
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