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Hi all,

I am just about finished with my first build which is a Martin 000 kit from StewMac. Today i shaped the neck and installed a really cool rosewood hell cap (looks lush)

I used the StewMac interior cardboard mould and consequently the sides are not quite true. This means that the neck is overset. The amount of material to be removed from the fingerboard side of the dovetail cheeks will be about 5-10mm.

This will obviously affect the intonation and so before i set this neck i thought it prudent to throw it open to the forum.

My own thoughts are either:
A
Remove material to set neck
This will move the 12 fret towards the bridge throwing out the intonation.
Then move the bridge back by the same amount (not installed yet)

B
Build up material using extra mahogany and set the neck keeing the 12th fret and bridge in thier correct positions.

I would be very very grateful for your opinions and options for me to progress with my build.

Many thanks and Happy Easter everyone :)

Barry.

Barry,

Wow. That sounds like a lot. Bear in mind that a change of 5 - 10 mm at the cheeks translates to about four times that amount at the bridge. What method did you use to ascertain that you need that amount of adjustment?

_________________
now known around here as Pat Foster
_________________
http://www.patfosterguitars.com

I'm not sure what you mean by 'overset'. Can you explain or (if possible) post a pic showing the situation?

I also agree with Pat about the need for explaining your diagnosis.

Hang around here for a day before making shavings- you will probably get the answers you need!

Cheers

John

[QUOTE=snood]
I used the StewMac interior cardboard mould and consequently the sides are not quite true.
[/QUOTE]

Do you mean that the body length is not what the plans specify? Where is the discrepancy - between the soundhole and the neck/body join, or somewhere else?
Still scratching my head on this one!

John

If the neck is overset, my understanding is there is too much back tilt on the neck. My solution would be to remove neck and reset by trimming upper cheeks of heel. As has already been stated, removal of only a small amount off the cheeks results in a much larger change in neck angle. Unless a huge amount of material is removed your 12 fret position isnt going to change by a huge amount and since bridge placement should be indexed off the fretboard not the position of the 12th fret there shouldnt be a problem with intonation.

Correction to last post.... "Trim the upper cheek of the tenon"

you were right the first time martin!!!

Thanks everyone.
Martin you are right of course. The neck being overset means that a straight edge held along the top of the frets ends up around 15mm above the bridge saddle (or were it should be as it is not installed yet) Underset would mean that the straight edge along the frets would fall just below the ideal bridge saddle position.

Overset is more of a problem in that removal of wood from the upper part of the cheeks will walk the 12th fret slightly toward the bridge therefore changing the intonation unless the bridge is moved and set 'to the neck posn' This is fine except with such a large overset i need to work out i guess if the subsequent bridge move does not 'frop' the bridge off of the bridge plate.

Martin you are spot in that the amount (because of trig) will / might be small. Therefore,I will calculate and see if this is the case. If so i will set as normal and adjust the bridge posn accordingly. If not i will 'build' up the dovetail to take the extra gap and set as normal keeping the 12th fret in the ideal posn.

many thanks to you all
Barry

Barry, if it's any consolation..my first dovetail M and T neck job took me and 2 months and I went through two necks before I got it right.

Ahhhh

Just read:

http://www.luthiersforum.com/forum/forum_posts.asp?TID=10445 &KW=neck+angle#forumTop

All is now now clear.

Thanks.
B

Ok people:

I have spent 7hrs today yes 7hrs setting the neck on my first build. At the start the neck was way too high over the bridge by approx 15mm!!!!

The neck is now set at 3mm (0.118") over the bridge centre based on a fretted FB. Also the FB is straight (side to side) and I have a really nice fit to the sides (been flossing my cheeks for ages )

The only bad thing is that the 12th fret has krept forward by approx 4mm and so the bridge will need to go towards the end of the guitar by the same amount to set the intonation right. Hopefully (yet to check the plans!) the bridge wont 'fall off' the maple plate under the sound board

Anyway i think things will be ok (please chip in if you have any issues with what i have done/achieved)

Barry

Ps Come on the Brits in the Masters hehehehehe

Thanks Hesh.
#2 will be made with a propper outside mould so the sides should remain square throughout the build. The learning experience has been awesome.

I want to build a binding jig too probably similar to Dave Whites and Don Williams. Which laminate trimmer fits best do you know. I heare a lot of poeple talking about Makitas but i was wondering if a particular model is favoured?

I guess I should ask Dave really but seen as you are online at the mo......

Cool
Just sent him a PM

...and the inlay buddy

[QUOTE=snood] Thanks Hesh.
#2 will be made with a propper outside mould so the sides should remain square throughout the build. The learning experience has been awesome.


[/QUOTE]

Its important to get the front of the upper bout flat before doing your neck. I build open style on a workboard so my heel blocks aren't always as square as youd get in a mold. That said it doesnt matter if the block is a bit off square as long as the upper bout surface on which the heel sits against is flat.

Fitting a dovetail M and T is a nightmare the first time around....shimming and trimming the tenon is something you just have to get a feel for...looking at the fit in the mortise and then knowing where to remove material and where to shim.

I sometimes think people attempt dovetail M and T joints for the same reasons that people go base jumping. If it wasn't either very difficult or very dangerous they wouldnt do it