[sreilly]

Well as I hone my old rusty skills and learn new ones I have started another project for my shop by way of a hanging tool cabinet. The plans I'm using are from a Woodsmith book titles Shop Cabinets & Tool Stands. In this plan the box sides are all hardwood while the door panels and back are plywood. As I'm a bit short on hardwoods at the moment and have 10 sheets of plywood I asked myself why not make it all from plywood? I have an Incra IBox Jig which I've had very little practice with but am wondering if plywood could work well for this joint? I can't imagine a reason not and research hasn't turned up any negatives but I'd like to ask those who have the experience for suggestions. And yes, I can get hardwood but I thought the ply is cheaper, already on hand, and maybe a good practice exercise that may turn out just fine. Any thoughts?

 

[sreilly]

I have two questions:

1- Are you making box joints or finger joints? To me, for joining box corners, you want to make "Box Joints". Box joints have square ended pins and are used for making box corners.. Finger joints have tapered pins and are used for joining boards end to end to make the resulting board longer.

2- What kind of plywood do you have?
You will need "void free" plywood for making boxes and cabinets using "Box Joints". Baltic Birch and Marine quality plywood has no internal voids so they do well for making boxes and cabinets. Construction plywood has internal voids and does not make good joints with the Incra I-Box jig.

I use my Unisaw with My I-Box jig because I've found that I can get cleaner cuts using my saw and the SBOX8 blade than I was able to get easily using the jig on my router table. This is because the saw blade cuts in only one direction as it passes through the work. A sacrificial piece in the I-Box jig becomes a zero clearance insert, keeping the blade from breaking the edges of the cut on the back side. When cutting with a router bit, the rotation of the bit cuts in both directions as it passes through the work. To get chip free edges on both sides of the cut, a second sacrificial piece must be added to the back side of the work as well, so both sides are protected as the cuts are made.It can be done, but I find that it's easier, faster, and produces better results if I use my I-Box jig on my table saw.

Earlier this year I made about 20 boxes from Baltic Birch plywood, joining all of the corners using my I-Box jig on my Unisaw. I had perfect results. Plywood can be used to make boxes and cabinets, if the plywood is void free and you use sacrificial pieces to prevent tear-out. If your plywood isn't this good you should find another way to join the pieces. Solid wood corners with plywood panels between is one way.

Charley

For some reason I called them finger joints when indeed they are box joints. As for tearout I didn't get any. With the Incra jig I made sacrificial fences to reduce/eliminate the tearout and that has worked extremely well. I move the fence for each new width cut. So if I'm making a 1/2" cut I'll have a new area that's not cut, lock the fence, amke my cut and continue. If I need to change the cut width I'll set the blade width, and make a new cut into the fence (on the IBox jig). My biggest issue was the joints on the test pieces were way too tight to allow any glue.

As for the plywood, I've not seen a single void or football and it's rated AA. At $56 a 4x8 sheet I seriously doubt it's Russian Birch. I'm not even sure I could find that within a reasonable drive from home. I do have the IBox jig as mentioned and was actually a little surprised to see this plan calling for box joints. However I was trying, still ma, to build as planned especially seeing how this is a shop tool cabinet. And yes, I'm using the table saw (SawStop) and my Freud SD208 dado set to make the 1/2" cuts.

I did make a trip yesterday to a woodyard 1.5 hours away in Culpeper, Va (C P Johnson) and bought some wide quartersawn poplar to use for the sides/top/bottom. My concern about less wide boards is I haven't made any cauls yet for gluing up boards yet so I wanted to get the flattest wood I could. This quartersawn could easily just be planed and skip the jointer. Of course I need to do the edges but I mean this is square evensome flat wood. I need to plan don the 4/4 to 3/4" but I expect that anyway.

I'll experiment with the ply some but will get busy prepping this poplar for use.

Thanks for the advice, especially the blades and glue. I'll make sure the blades are clean and sharp.

 

[sreilly]

Until all concerned get together and change it, like they did with Pluto's status as a planet to a planetoid, then both terms will get used for the same thing.

Oh you just had to bring Pluto into it didn't you? Stubborn me still calls it a planet. But that's a whole nother chat......

As seen in another post not long ago, terminology in the English language isn't always so clear.

Thanks again Chuck