Block grain direction

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Pat.Hawkins
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Block grain direction

Post by Pat.Hawkins » Sun Oct 01, 2017 5:44 pm

Hi Folks,
Does it matter which way the grain runs on the two body blocks?

Should they follow the direction of the sides?
Or be at ninety degrees to the sides?

Thanks for a great forum.

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Allen
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Re: Block grain direction

Post by Allen » Sun Oct 01, 2017 6:08 pm

I look at it from a repair prospective. If it gets dropped what's the most likely scenario? If it's going to split a side, then you want something that's going to help stop that. I've had to repair a few guitars over the years that the split went right away around through the tail block when the grain was running same as the sides.

I make tail blocks from plywood. Solves that problem. Neck blocks are solid timber just because people look at them. I go with grain from sound board to back.
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Mark McLean
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Re: Block grain direction

Post by Mark McLean » Sun Oct 01, 2017 11:17 pm

Yep, making the end block from plywood makes a lot of sense for the reasons that Allen said. However, it might offend a purist builder, or a snob owner who thinks that solid wood has some sort of magic properties and plywood cheapens their instrument. If you succumb to that arguement, then at least having a solid block with grain perpendicular to the sides is going to better resist cracking.

I am less sure of what is best for the neck block. You could again argue for ply as the most dimensionally stable and crack resistant. But I have not seen many guitars with plywood neck blocks. Is there some reason not to - I can't think of one. It seems pretty standard to use a solid block, most often mahogany, and to have the grain perpendicular to the sides, so that the back and soundboard are glued to the end grain

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Mark McLean
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Re: Block grain direction

Post by Mark McLean » Sun Oct 01, 2017 11:39 pm

So, does anyone have experience with plywood neck blocks?

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Allen
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Re: Block grain direction

Post by Allen » Mon Oct 02, 2017 6:48 am

I've seen some use plywood blocks but use veneer off cuts from the sides to dress them up. I have on occasion used veneer from the sides on the tail block for the same reason.
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Mark McLean
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Re: Block grain direction

Post by Mark McLean » Mon Oct 02, 2017 8:05 am

That is a great idea. I have been using plywood heel blocks and they work well - but look like plywood. Sounds like a perfect cosmetic solution to clad them with some offcuts from the sides.

jeffhigh
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Re: Block grain direction

Post by jeffhigh » Mon Oct 02, 2017 8:38 am

One issue with using blocks with grain perpendicular to the sides, is that you end up gluing endgrain to the soundboard and to the back.
I tend to laminate blocks myself, with vertical grain to the inside to resist splitting.

Pat.Hawkins
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Re: Block grain direction

Post by Pat.Hawkins » Mon Oct 02, 2017 9:45 am

Thank you for the great replies.

I'll do a ply tail block.

I have some straight celery top.
Would that be ok for bracing and neck block?
Cheers

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rocket
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Re: Block grain direction

Post by rocket » Mon Oct 02, 2017 11:00 am

I had been using solid mahogany or Sitka blocks parallel to the sides but have changed recently to ply tail block as seen here but still got the solid neck block parallel for the better gluing to the plates.
In view of this discussion I'll give the ply a go in the neck position on the next build.

Cheers
Rod
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blackalex1952
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Re: Block grain direction

Post by blackalex1952 » Mon Oct 02, 2017 8:04 pm

My take on tail blocks...plywood is best as it will withstand accidents where the end pin is driven inwards by an impact of some sort.
My take on head blocks...I run the grain at around a 15 degree or more angle to the grain of the sides. This gives a good glue surface for the back and soundboard, or the fingerboard pocket extension on a bolt on neck. It also gives a cross grain reinforcement to the sides.
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