I’d like to make live edge tables from wide (22-24″) white pine 2″ thick slabs. They’ve been air dried for 2 years. I’d like to use the tables in a 3-season cottage (northern Ontario) so there will be a lot of wood movement.
If I cut dados in the bottom of the slab, say 1/2-3/4″ deep, across the grain in several locations, and glue hardwood strips into them, will this stop the wood from splitting? While these slabs are pretty stable (basically quarter sawn), I’m concerned about possible cupping or splitting. There are no splits now so putting bowties in would be kind of pointless.
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Replies
Gluing strips across the grain of the slabs is very likely to CAUSE splits, rather than prevent them. Anything that restricts the seasonal movement across the grain of the slabs is likely to cause splits as the wood shrinks. To prevent cupping, you want to attach stretchers across the grain with screws, with tight holes in the middle of the slab, and slots for the screws to move with the slab expansion/contraction at all other locations. If you don't want to use screws, your other (much more difficult) option is to use stretchers with sliding dovetail tops that fit in dovetail grooves across the bottom of the slab. If the slab has dried to its current state without cupping, it is unlikely to cup much with seasonal moisture changes.
I agree with jharveyb. The stretchers need to be fairly thick (maybe 1" thick, but that's just my opinion) or they will just bend if the top tries to cup. If you don't want to have the stretchers show for some reason, you could rout out a 20" long pocket on the underside of the 2" thick top for the stretchers, making sure that there is a little bit of room for movement at the stretcher ends.
For cupping some people route grooves in the slab bottom and insert c-channel. The c-channel needs to have slots, not holes, which allow the wood to expand and contract. Here's the guy at Blacktail Studio doing it on Facebook and YouTube. https://www.facebook.com/share/r/18Pp75knPy/ https://www.youtube.com/watch?v=FqQUlLJOTMg
If its a 3 seasons cottage it will not undergoe the extreme dryness of Heathed homes in the north therefore, being air dried it is probably the most stable state that you would wish.
Agree with jharveyb.
Beefy sliding dovetails would be great. This technique seems appropriate if you want it totally hidden (link below)
https://www.instagram.com/reel/DE-huYauf70/?igsh=MWNmNnMwZW01bHgycg==
Neat idea, might try it out. "Split sliding dovetails"?