Late wedge failure -- split

[Bob Coates]

Went to select a vase to give to friend and found this. 2 wedges for some unknown reason decided to split and spread to pine wedge on either side. The split goes through to inside by shining a light on outside. 12 rings of the same wood and so far they are the only 2 in 1 ring that split. I believe that the wedges that split are maple. Any idea why?CloseSploit.jpgWholeSplit.jpg

[Alex Zeller]

Where did you get the wood? I've made a few segmented turnings out of short cutoffs. But I realized that these cutoffs usually were the ends of boards and on occasion had some hidden checking. Also they usually sit on the cement floor in my shop for months or longer and I think they pick up moisture.

[Jim Morgan]

Ah, that's a shame.

That looks like beech to me, which moves at about twice the rate of a typical pine (11.9% tangential vs. 6.1% for EWP). It also looks like the splits were along glue lines, perhaps not well glued in the first place.

[Bob Coates]

Thanks guys,
James,
That could be possible, that wood had been from previously glued sections(not me).
Alex,
That wood was given to me 3 or 4 years ago as a glue up block of 8 x 8 has slowly been use for other vases. It may have been cracked. It was strange that the two were side by side without any signs of others.

Cut the split out and re-glued the halves together, will see if any more cracks develope.

[John Kananis]

Bob, how did you go about sawing a line across the piece?

[Kevin Jenness]

For sure the splits were caused by moisture content change between assembly and now. Mixing two woods with different rates of movement didn't help. Those particular pieces may have been wetter than their mates in the initial glue-up for some reason.

[Bob Coates]

Kevin,
Put the vase on jaw chuck and used a home made cone chuck to lightly hold top. Then used my special made reciprocating saw blade paring tool to separate the two pieces. Flattened matting pieces and re glued. Because of the tapper of the vase there is perhaps a 1/32 miss alignment of the wedges. I still found it strange that 2 wedges out of all the others and side by side split.