Martin D-18 neck reset?
 

After you get the neck off and you have shaved the tang and sides of the neck so the set is correct how do you compensate for the fingerboard now being raised off of the top of the guitar?

If the reset angle is so dramatic that it causes a lot of air space over the extension then you just need to make a wedged shape shim. Use rosewood for a rosewood board or ebony for an ebony board and you can make it almost invisible.

Typically thought the amount of change in the neck angle does not result in such a dramatic change. In that case it's ok to just glue down the extension and have a bit of fall away. In many cases when I do a reset there is a need for a refret too and if that's the case you can set the neck glue it in and replane out that very minor difference.

Anything more then 1/16th inch airspace is when I consider making a shim to make up the difference.

Great question. I look forward to the response. my tech skills are limited to simple set ups but I would think that if there is a significant gap it has to be filled with a shim of some type.

Edit....redir answered the question before my response but it guess i was on the right path.

Agreed, on guitars where i know a major shim 1-2mm will end up having to be fitted i will recommend to the customer we overset the neck, glue the extension straight down to the body and then plane and refret the guitar, this way you get a perfectly flat fretboard with a nice low action and no fallaway or shim

Steve

neck reset without removing neck?
 

I did watch a Youtube vid of a guy "resetting" a neck w/o removing it.

He said that often times when some might think a neck has to be removed to reset it you can just correct the depression the fingerboard has made in the top. I'm not stating this very well and I don't know how to ad the youtube link but I searched Youtube for the cost of resetting a neck and it came up. YouTube, https://youtu.be/UTVzGM1Znv8. John Miner.

He braced the top of the neck to keep it flat, stuffed 95% of the interior of the guitar with rags to keep steam from loosening the interior bracing, steamed inside on both sides and close to the neck block, put some downward pressure on the nut (removed) end of the neck which put upward pressure on the fingerboard/top of the guitar to over compensate for some of the defect, steamed it a couple more times and let it sit for 3 weeks.

It made pretty good sense to me but this method was probably for minimal correction.

This is a very viable option to try if you listen to what he is saying. If care is taken about blocking the rest of the inside and all the parts that you don't want to change, and do it no more than 30 seconds it might work out for you. You can always do it again if it didn't move it the right amount you need.
As always, use super caution and really plan out what you want and are going to do before you do it.

https://www.youtube.com/watch?v=UTVz...ature=youtu.be

Ron