Neck rest problems on Framus Archtop

[Andrew Armstrong]

Hello I need some learned advice...

I have a Framus Sorello arch top acoustic jazz guitar. The action was way high and the adjustable bridge was as low as it could go including I removed the height adjusting thumb wheels. So it needed a neck re-set. I removed the neck and got about the re-set. To get it where it needed to be required adding some thin veneer material to either the tenon or the mortice of the dove tail joint to pull the heel into the body. I did this and diligently sanded and scrapped till I had what I thought was a tight fit and the right neck angle. All looked good and I re-glued the neck using hot hide glue - something I have little experience with. After I strung it all up it appeared fine till 24 hrs later I noticed the heel had pulled away from the body effectively meaning the neck was moving back to where is was before the re-set. I was back to square one. Clearly the shims were not thick enough to set the neck mechanically in the right place (although it felt ok before the glue up) and the glue couldn't overcome the tension allowing the neck to flex up.

So, I swore several times, gnashed my teeth and then I took a deep breath. I concluded that the hide glue was a mistake (or I had not mixed it right) and removed the neck again. Now every time you remove a neck there is some damage done somewhere and the finish or various structural joints suffer. Any way I got it off again with minimal damage and went through the whole process again, fresh shims (glued in) and lots and lots and lots of trial fits to make sure I had a really good fit, the right angle and the neck wasn't (apparently) flexing in the joint. This time I decided to go back to what I know and used TiteBond Original rather than hot hide glue. Glued it and clamped it and left it to sit for about a week to make sure the glue was fully set. Re-strung it and it felt great, nice action.

24 hrs later ................

OK, I could probably remove the thumb wheels again and I have got the K&K Arch top pick up transducers installed under the floating bridge which adds about 1mm to the bridge height and so I can remove them and probably get a playable action but there is this horrible gap of about 1.5mm between the heel and the body and I simply can't live with that.

So the neck will have to come off for a 3rd time. But I will have to burn the guitar if I don't get it fixed this time . What is the secret to getting a perfectly fitting, mechanically tight dovetail neck joint fit? I reckon the glue is simply to stop it from coming apart when there is no string tension and it shouldn't affect the stability or strength of the joint in operation.

If you want photos I can post them but they are not immediately available. I hope my description is sufficient for you to understand the situation.

Please help because I really couldn't burn a guitar.

Andrew

[Barry Daniels]

There maybe something else going on like a split in the head block.

[Mario Proulx]

This next time, re-string it with the dovetail dry. No glue! A well-fitted dovetail doesn't need the glue; the glue is there simply to prevent the neck from being knocked-off. So, string it up, watching the neck joint as you bring it to tension, and if it moves at all, stop, pop it back off, and work on your shims once again. Once it remains stable for a day or three, -then- apply glue and call it done.

[Michael Lewis]

Try chalk fitting. Rub chalk in the mortice and carefully put the neck in place with as little contact between the neck and body as possible. Press the neck into the joint and then gently remove it and look for the high spots on the tenon, they will have chalk on them. Carefully scrape the high spots away and try it again, and again, and again until you get chalk over most of the tenon. You will need to refresh the chalk frequently.

I now use Saral transfer paper from the yardage shop. I cut it in strips as wide as the tenon and face the chalky side to the tenon as the neck is fitted into the mortice, press the neck into the body with a cam clamp and carefully take the neck out without touching any of the paper. This gives the best indication of contact between the mating surfaces of any method I have tried. Saral transfer paper comes in colors and white. Colors are fine for very light colored wood but white is best for darker woods like mahogany.

The joint must fit well in the contact surfaces of the mortice and tenon, the cheeks of the heel, and the fingerboard support to the soundboard. All this and you have to keep the alignment of the center line, neck pitch, and roll under control as you fit the tenon. It all has to come together at one position (when the fingerboard support meets the sound board) and everything line up properly, or you start over.

[Andrew Armstrong]

Thanks for that advice Michael and Mario. Funny how both ideas has occurred to me at some level but I had just dismissed them and thought it wouldn't (or shouldn't) be that hard. Gotta love a learning experience