Heel block - spanish guitar or mortise and tenon??

[Quinny]

Hi,

I have previously made two soprano ukes with dowelling to join the neck to the body. I am now building a tenor uke. I thought I would try the Spanish guitar method to join the neck for practice in case I make a guitar one day. Although the plans I purchased for this build use a mortise and tenon.

My main concern is that I will be unable to router/trim all the way to the neck. I presumably have to finish the last trim by hand. This is more of a concern as I plan on fitting binding so I would have to rebate the last bit by hand. I do have a Dremal which may be OK to finish the job pretty close to the neck then chisel out the last bit.

Any thoughts/advice on this??
Is there any advantage to a Spanish heel, such as a neater join of the neck? Or easier alignment of the neck?
Or is a mortise and tenon the way to go?

Thanks

Andrew

[johnparchem]

I have made my ukuleles with glued on butt joints and a single bolt (The bolt is really used as a gluing clamp). I have made classical guitars with a Spanish heel joint. You do need to hand cut for the bindings near the neck in the back. I use a scalpel and a template as a guide to make the cuts for the channels and use a chisel to remove the waste. You can also carefully use a razor saw and chisel out the waste. I was afraid to go in with a dremel.

I am not sure what the advantage of the Spanish heel would be (even in a classical guitar), other than tradition or matching the design of another Uke. It does not make anything easier.

[Allen]

All my ukes and several guitars have been built with the Spanish Heel.

I use my perspex top template to help knife in the edge of the binding / purfling, in that short area that requires a bit of hand work. Then a dremel on a base with undersized bits for the area to be removed. Cut to full depth in multiple passes.

They need to be undersized because cutting a slot with material on both sides that is critical to keep is going to want to pull the bit to one side or the other. So you need to run up the middle, then carefully sneak up to either side. It's actually a lot easier than you might think at first

[Quinny]

Thanks for the response John. I'm re-thinking the Spanish heel.
Thanks for your reply Allen. Other than a preferred choice - is there an advantage to the Spanish heel as you see it??

Andrew

[kiwigeo]

The Spanish Heel:

1. Advantages - simpler to construct cf to neck joint method.
2. Disadvantages - on a uke I don't see any disadvantages. On a larger instrument such as a classical a neck re-set may become necessary at some stage which will require taking the back off and shimming the spanish foot. That said my first ever build was an OM steel string built using the Spanish method and the neck is still good after 10 years

Up to current build all my classicals have been built using the Spanish Method. I now build after Gore et al and use a bolt on bolt down neck and have a truss rod in the neck.

[Quinny]

Thanks for the reply Martin.

My main concern is hand finishing the rebate for binding. So with a mortise and tenon joint, do you attach the neck with the back off? Or can you do it when both soundboard and back are glued on? The important point here being that if you have to bolt the neck on with the back plate off, you still have to hand finish the binding rebate on the back. What is the norm for bolting the neck on with mortise and tenon - before or after the back plate is glued??

Andrew

[johnparchem]

Normally the body is complete and finished before you bolt on the neck with a mortise and tenon. With a tight enough mortise and tenon you could just glue the neck on as well. Not much need to ever reset a Uke neck.

[Quinny]

Thanks John. I think your advice settles the issue. At my practice level, or lack of, I prefer to have all bindings completed before attaching the neck. So mortise and tenon it is.

I checked on the internet and saw two types of bolts setups. One was with a timber screw end to screw into the neck face. The other choice was to use epoxy glue to glue-in a bolt to the neck face. This method means I could hacksaw off the bolt head from a regular bolt and use it.

Any advice on how to proceed re bolts. Is there a special place to get them or just Bunnings? (I'm in Melbourne)

Thanks

Andrew

[charangohabsburg]

The Spanish Heel:

1. Advantages - simpler to construct cf to neck joint method.

Agreed. Much simpler and much quicker. The real time-saver and and sorrow-dissolver is thee absolutely fool proof built in neck angle when used in conjunction with an adequate workboard (solera) which provides the neck angle.

2. Disadvantages - on a uke I don't see any disadvantages. On a larger instrument such as a classical a neck re-set may become necessary at some stage which will require taking the back off and shimming the spanish foot. That said my first ever build was an OM steel string built using the Spanish method and the neck is still good after 10 years

When using hot hide glue it is very unlikely a neck reset will ever be needed. However, most synthetic glues will creep under tension when exposed to elevated temperatures: very slowly at around 30°C, noticeably over the years at around 40°, and disastrously fast in the famous closed car at a parking lot on a sunny afternoon where temperatures easily reach 80°C (while a hide glue joint just will laugh at 80°C).

If a neck reset has to be done on a spanish heel - guitar, the back does not need to be removed (unless the guitar is close to disintegrating). Heating up the back on the heel itself and on the rim 100 mm to each side of the heel will soften any PVA glue enough that the neck can be pushed back to the right angle, and while clamped in that position during cool-down the glue will harden again. I have done this twice in the last few years and both re-set guitars are still fine.

On the rare occasions hide glue will let go because of excessive "humidity" (I should rather say "wetness") and/or bacteria "eating away" the glue. In these rare cases (mostly on very old guitars) it is most likely that the whole guitar needs dis- and re-assembling, and cracked wood will usually be the greater issues anyway.

[lauburu]

Any advice on how to proceed re bolts

Try a furniture bolt and barrel nut - available at Bunnings etc. Looks a bit classier than a wood screw and probably easier to install.
Miguel

[kiwigeo]

Thanks for the reply Martin.

My main concern is hand finishing the rebate for binding. So with a mortise and tenon joint, do you attach the neck with the back off? Or can you do it when both soundboard and back are glued on? The important point here being that if you have to bolt the neck on with the back plate off, you still have to hand finish the binding rebate on the back. What is the norm for bolting the neck on with mortise and tenon - before or after the back plate is glued??

Andrew

With a bolt on neck the body and neck are finished as separate units. The body is fully boxed up and bound before the neck is attached.

Cutting the binding/purf channels in the neck area is an inconvenience when building Spanish method but with a sharp chisel (I use a set of narrow LMI chisels) and a Schneider Grammel its not that hard a job.

[kiwigeo]

Any advice on how to proceed re bolts

Try a furniture bolt and barrel nut - available at Bunnings etc. Looks a bit classier than a wood screw and probably easier to install.
Miguel

Another alternative is Trevor Gore's method with a brass bar in the neck heel and hex head screws through from the back of the neck block. It requires a chisel mortiser but I think it's a fool proof method for a bolt on neck.

[colburge]

Thanks John. I think your advice settles the issue. At my practice level, or lack of, I prefer to have all bindings completed before attaching the neck. So mortise and tenon it is.

I checked on the internet and saw two types of bolts setups. One was with a timber screw end to screw into the neck face. The other choice was to use epoxy glue to glue-in a bolt to the neck face. This method means I could hacksaw off the bolt head from a regular bolt and use it.

Any advice on how to proceed re bolts. Is there a special place to get them or just Bunnings? (I'm in Melbourne)

Thanks

Andrew

I like the threaded inserts rather than the barrel bolts, I have seen them at Masters, but you can also get them at McJing.

https://mcjing.com.au/Static/Images/h902.jpg

https://mcjing.com.au/categorybrowser.a ... goryid=146

Cheers


Col

[Quinny]

Thanks for the tips Miguel and the advice Martin. And thanks col, I'll check the bolts out