I've had a few neck re-sets through the workshop recently (lucky me). I always take a photo of the join once it's apart in case I do one the same again. It's handy to know what angle/depth to drill the streaming holes.
Does anyone else do this?
Is it possible to have a gallery page on this forum to show them all? - might be a useful resource for us.
Just a thought
Thanks Doc, challenges like this one are good teachers. It's not always easy or comfortable wading through a difficult lesson but I came out the other end successful, a bit more knowledgeable and felt better about the whole experience when it was over. That said, I was rather happy to see it finally go away.
We have a couple of good art stores where I live and some good junk shops. I always keep my eye out for useful looking palette knives or anything else that might look useful for instrument work. One has to be careful though and only use stainless steel for diss-assembly projects. I learned on my own that regular steel can leave bad mineral stains, which also made me learn more about Oxalic Acid. Mistakes are not necessarily such a bad thing.
If you get a chance, I wouldn't mind seeing an image of your dental palette knife.
You got me thinking about this stubborn neck-joint too much and I've another nincompoop idea. FOR THE EXTREME CASE ONLY:
So, we know that heat alone will release the glue bond; we see this in the lifting of the fingerboard extension. We're talking about this insanely tight joint where the open pocket is unlocatible even when having to remove the extension for full visibility. This is an extreme case and involves a heat source that is only thought in my head now.
It's pretty straightforward. Initially, I thought of heating the block. It's is a considerable amount of wood to penetrate through to the glue bond but it could be useful. With that, since the extension has been cut and there is visual of the dovetail extension; I'm thinking of just drilling straight down the centre of the triangle of the dovetail. Start small, drilling 1-1/2" downward with say..a 1/8" bit and work upwards to, maybe 1/2". I'm thinking getting as close to the walls of the triangle of the dovetail triangle as possible...a few mm away. A tapered bit would even work better...
This is where the heating source comes into play.
Something that could maintain consistent heat, like a cylindrical (or tapered cylindrical) heat blanket 1/2" in diameter and 1-1/2"- 2" deep (I don't think it would matter if it protuded) inserted into the hole, would be ideal. Metal cylinders of various sizes and chemical composition are available and could be heated to an appropriate temperature and inserted into the hole as an alternative.
With the neck clamped in a vise, all the heat sources going, I'm thinking just shifting the body side to side extremely cautiously and let the heat do its thing.
This could take an extremely long time but may possibly work and is fairly non-invasive.
In the end, there is just a hole to plug with a dowel in the dovetail extension. A pretty straightforward operation.
Nincompoop, hairbrained idea over...HA
This is a good discussion. Paul, I have removed necks on two Norlin era Gibson J-40s. Both were basket case freebies: on one, the joint was just as you encountered, a 'straight' dovetail, and it was very hard to remove. The other was a more or less standard dovetail, but the top was installed over the dovetail-surprise! Those guitars were built at about the same time, '71-'72. I think, if asked to do one as a paying reset job, I would decline.
But older vintage Gibsons do come my way for repair, just haven't yet needed to do a reset. Hence my interest and questions.
The pictures and info on the Guild are helpful, too.
Not a nincompoop idea.
I had looked at heat cartridges before after seeing a thread on the MIMF (Musical Instrument Makers Forum) several years ago. Their use was demonstrated for removing banjo neck sticks from the neck heel. The heel cap was removed, a hole drilled and an appropriate size/heat cartridge inserted. I just Googled "heat cartridges" and copied the image link. There are hundreds of sizes and applications available.
I never popped for a rig but may look at them again. It's the type of tool that you might need once in a great while. You probably need a decent controller as well. I suppose one job like the Gibson Gospel, if it worked, would pay for itself in time savings.
I'll get a photo of my specific pallet when I'm back in my shop Monday but the following photo is of a similar tool but mine only has one pallet end (like the upper end). The pallet is about 1-1/2" long, maybe 1/2" wide into a typical dental handle. It's very high quality stainless, very hard.
Thanks for the link on the heat cartridge. That was pretty much exactly what I was thinking. Relieving to know another had something similar in mind. I'm no nincompoop afterall :) I'll have to look into the MIMF.
This reminds me of Don Teeter's book. He used a re-workerd stainless steel butter knife jammed into a hole cut with little saw behind the dovetail. Then heated the handle with torch. This was aided with a solution of water and alcohol.
Dave, any specifics on how your J40 project with the straight dovetail came apart? Did yours have a gap between the dovetail and neck block mortise and steam apart?
Doc, that looks like a mini butter knife. Palette knives sometimes just don't seem to have enough backbone and want bend or buckle. I have some dental tools, they are hard but also brittle, I have busted a number of them.
The MIMF has slowed down quite a bit but still have a good number of experienced contributors. They also have a good searchable archive too.
It is indeed somewhat like a tiny butter knife but tapers evenly from the top to bottom as apposed to side to side. I also sharpened/thinned down the bottom edge. An old butter knife is actually my main opening knife for violins, given to me some years ago during my first apprenticeship. My dental tool isn't brittle in the least however; I've used it hammering with the plastic knob of a fretting hammer to break the joint of a violin neck set when the top and fingerboard are removed or to help release the top of a violin from its neck block. One of my most guarded tools. It doesn't even show a bend crinkle anywhere from over-flexing. I'll see if mine has a manufacturers stamp on Monday.
Paul, I'm afraid I don't remember more specifics about that removal(i.e. if there was a gap between dovetail and mortise). It did eventually steam apart, very reluctantly. I took it apart about 8 years ago, intending to rebuild the body with a new top & neck..it's still on my project list!
No sorries necessary Doc, hope your back in the Pink!
Looks pretty handy if it won't break or buckle with use like you say. My experience with dental tools has been break city. Thanks for taking the time to post the image.
Hi Paul & Doc.
I checked with my brother-in-law who is a DMD.
Those are called "Dental Cement Spatulas" and are between $5-$10 on most Dental Supply sites.
Hope that helps :)
He also said there's a HUGE difference between bargain basement 'dental tools' and the ones Dentist's actually use. He said a good 'mid-line' selection would yield a tool with longevity :)
Take care guys & have a super weekend :)