Grain orientation wedged round M&T

[William Fretwell]

Mark, wood is elastic, you don’t go from ‘snugging up the joint’ to destroying the cells, there is an elastic compression first. If there was not then all wedges and shims would be tapped in delicately to just touch. The metal wedges holding hammer heads in place would not work, the wedges holding my workbench legs tight would destroy themselves. There is an elastic range which when exceeded causes some crushing in a gradual way.

Not sure how to re-explain the grain thing.

Suffice to say picture 1 is how I would make the joint.

[Mark Hennebury]

William, sketch this out for me, because it makes no sense.

"Driving the wedge against the grain of the tenon will have the greatest resistance and longevity of the joint ie: the least damage of wood fibres." Please explain that.
"To avoid possible splitting of the mortise the wedge is driven to put pressure on the end grain of the tenon. " Please explain that.
"If the tenon grain aligns with the mortice grain these conditions are met for the wedge." Please explain that.
"As for the glue joint in picture 2 it is essentially end grain to end grain all the way round, the worst glue joint." Please explain that.
"In picture 1 there is far more edge grain glue joint, a better glue joint." Please explain that.

None of these statements make any sense at all.
If you think that they do then explain it, sketch it out, draw the grain direction and show me.

Once the wedge is driven you can’t assume it’s just part of the tenon and normal seasonal movement will continue. The wood is now in compression, at least 15%. You also can’t assume the compression is in one direction, on this scale as the wood is forced out the circle compresses each half also.

Driving the wedge against the grain of the tenon will have the greatest resistance and longevity of the joint ie: the least damage of wood fibres. To avoid possible splitting of the mortise the wedge is driven to put pressure on the end grain of the tenon. If the tenon grain aligns with the mortice grain these conditions are met for the wedge.

As for the glue joint in picture 2 it is essentially end grain to end grain all the way round, the worst glue joint.

In picture 1 there is far more edge grain glue joint, a better glue joint.

On this scale the compression of the wedge dominates.

[Mark Hennebury]

There might be a good reason that you cant explain the " grain thing"

Mark, wood is elastic, you don’t go from ‘snugging up the joint’ to destroying the cells, there is an elastic compression first. If there was not then all wedges and shims would be tapped in delicately to just touch. The metal wedges holding hammer heads in place would not work, the wedges holding my workbench legs tight would destroy themselves. There is an elastic range which when exceeded causes some crushing in a gradual way.

Not sure how to re-explain the grain thing.

Suffice to say picture 1 is how I would make the joint.

[William Fretwell]

Private message sent.

[John Keeton]

For what it is worth, in his videos Buchanan does explain why he favors his method and if you research vintage Windsor chairs Buchanan’s method has a 250 year old (at least!) history of application. Buchanan also applies glue to only one side of the wedge and explains why in his videos. I find solid merit in his approach.

[Mark Hennebury]

I did a quick online search and snipped this from Bruce Hoadley's research on dowels.
I don't know if it's right or wrong, but It is inline with what I said about growth ring orientation.

R. Bruce Hoadley (1933 – October 15, 2019)^[1] was Professor Emeritus of Building and Construction Materials in the Department of Environmental Conservation at the University of Massachusetts Amherst.^[2]His main research interests were wood identification and dimensional changes due to wood-moisture relationships. He is known to the general public primarily as the author of popular books on the anatomy, properties and processing of wood, and for his work as a contributing editor and technical consultant for Fine Woodworking magazine. His expertise in wood identification has been utilized in analysis of antique furniture and art objects for Sotheby's^[3] and major museums.^[2]
His book Identifying Wood: Accurate results with simple tools is an accessible introduction to the topic,^[4] and his Understanding Wood is a comprehensive treatment of wood technology. The first edition of this work sold over 130,000 copies.^[5]

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