Heel block grain direction

Timbuck · Jul 29, 2011

I've noticed that "Martin" heel blocks have the grain running horizontal..I suppose thats the strongest way to do dovetails or splines..I have been making e'm with the grain vertical up to now, and I have had a couple split down the centre when clamping

...another thing learned.

Rick Turner · Jul 29, 2011

Why not use multilamination Baltic Birch? No splitting...

Given what materials are available now, I see no reason to use obsolete methods which have obvious drawbacks. The only reason to use neck or endblocks with grain parallel to the grain of the sides is if you're worried about wood expansion and contraction with humidity changes. In reality it's a non-issue. High quality plywood blocks work fantastically well.

Timbuck · Jul 29, 2011

I agree with all what you say there Rick..it's just that i'm into vintage mahogany style "O" replicas.

Rick Turner · Jul 30, 2011

Veneer Baltic birch ply blocks with mahogany veneer. Best of both worlds...

BlackBearUkes · Jul 30, 2011

You can glue up a 3 ply mahogany block using short scrap pieces with the center section running up and down. Martin always ran the grain direction the same as the sides.

Rick Turner · Jul 30, 2011

I think Martin did that for two reasons...one, the afore mentioned theoretical issue of expansion and contraction perpendicular to the grain...which I think is really a non-issue, and two, it's much easier to trim with a block plane or to sand the top and bottom of the blocks when you're not going against end grain. That, too, is a non-issue for me as we sand the rims using a dish with sandpaper mounted to a potter's wheel.

Timbuck · Jul 30, 2011

Now I've had a think about it (thinking mass production)...I maybe it was done like that co's they had a machine set up to cut dovetails into long 2" X 1" lengths at equally spaced pitches and then they were sliced off.
Something like this.

Rick Turner · Jul 30, 2011

I highly doubt it. In production, dovetails have generally been done in the assembled body so the dovetail is cut through the sides and block all at one time. It's not that big a deal to tool up for this at any production level.

Timbuck · Jul 30, 2011

Rick Turner said:
I highly doubt it. In production, dovetails have generally been done in the assembled body so the dovetail is cut through the sides and block all at one time. It's not that big a deal to tool up for this at any production level.

I always make the block with the dovetail pre-cut...once its glued in place..Then it's easy to expose with a razor saw...I've done about 170 ukes with this method and I'm just about getting the hang of it

I have seen several videos and pictures of ready made up dovetail and spline type heel blocks at Martins...Look at this video and note the part built guitar sides(on the bench)with dovetails ready cut before assembly http://www.youtube.com/watch?v=a-m0Z90HT-k&feature=relmfu also this video in the first couple of min's in http://www.youtube.com/watch?v=OaLOsq1G_Bk&feature=relmfu
I'm building a jig based on this one at the moment, just for sopranos.

Rick Turner · Jul 31, 2011

I know that pre-dovetailed neck blocks are available...now...but I also know that the pre-dovetailed blocks are a modern innovation going back no more than about 30 years at the most. I highly doubt that Martin ukes from the classic era were done that way. It's certainly not how they made guitars then.

Sven · Aug 1, 2011

I make my blocks with the grain horizontal, it's much easier to plane the sides and blocks to height and curve that way.

Sven

Rick Turner · Aug 1, 2011

Sven, you may not have done a lot of guitar and uke repair. I've seen more than enough instruments that had side cracks going all the way around the instrument right through the end block.

Many of my design and materials choices are the result of having been a repair luthier for 47 years now. Seeing recurring problems leads me to try to figure out ways to make instruments stronger without overbuilding them. Baltic birch end blocks really makes a lot of sense. Also, I don't plane my blocks to fit the top and back. I set up a 3/4 hp electric potter's wheel as a horizontal disc sander. I drop on the appropriate radius dish with 80 grit sandpaper and get perfect rims in no time flat. The sand paper does not care about grain direction.

Heel block grain direction

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