Gibson MK72 neck reset

[Dave Sparrow]

Hi all

I have an MK72 on my bench needing a neck reset but it appears to have other issues that I don't really understand and thought that someone here might be able to help.  My scant knowledge of these particular guitars is limited to "they're somewhat unstable" so I'm just a bit hesitant in case this turns into a seriously major (too costly) undertaking for the owner. 

1. There's evidence of movement around the heel (lacquer cracking) but I'm unable to get even my finest feeler gauge in anywhere so it does seem solid.
2. There some separation of the sides and binding where they meet under the heel suggesting (along with the lacquer cracking) that there's a problem with the heel block but internal investigations haven't shown any separation or splits. 
3. There's a gap under the fingerboard extension of about 0.015" but the neck certainly hasn't moved up by that amount - a few microns at most suggested by the lacquer cracking. 
4. The glue in the gap under the fingerboard is "stranding" suggesting either bad fit initially which has failed or could it be that the fingerboard has warped (it is three pieces!?) 
5. The soundboard falls away drastically towards the heel.  If it were flat, it would have been in line with the bottom of the fingerboard.  Is this bad manufacturing with the possibility that there was originally a shim to fill the gap? See also 4.
6. I'm assuming by the period in which it was made and that the heel block extends all the way to the end of the fingerboard, there's a tenon under the fingerboard extension, what problems might I face when detaching the neck?  Any special tips?

Thanks in advance

Dave

[Thomas James]

IMHO. This is a guitar where structural repair jobs should be avoided. It will be a detour to the the land of - I wish I just said no thank you. Fraught with bad design that will not allow a good return on time invested.

[Dave Sparrow]

Ha ha!  Thanks Thomas.  That was my thinking too..Unfortunately there's not a lot of information available about these guitars but what there is, most isn't very good.