 This is part two of our wedged triple through tenons discussion by that we mean we've got triple tenons they are through tenons and they're going to get wedged with some black walnut wedges. In the first part we discussed cutting the mortises and getting them essentially ready. This is an end view of our workpiece here and so if I was looking at it from this direction I see one of these you would have three of these but I don't want to confuse the illustration so I'm only showing one. So here's my A point that's my entry point. When you're getting your mortises ready as a final step you need to make sure that the part of the mortises where the tenon is going to first fit in is larger than where it's going to come out on the other side. It can be equal to if you're a really really good craftsman but I would recommend you make it slightly larger. So I want my entry to be larger than where it exits so I want in this diagram here I want A to be greater than or equal to B1 where I'm going to exit. I cannot push a piece of tenon into a small A and somehow get it magically to expand to fill up a larger B. I can get a tenon to go into a larger A and then as it exits to be just the right size for B. So that's what you're after. Make sure, check them all, make sure that you've met that rule that A is greater than B. Secondly you probably don't want to try to have perfectly square or 90 degree walls. That's rough wood, you got glue in there, things are going to fill up, it's going to get hard to push things through if those walls are exactly the size of the tenon. There's nothing wrong with making the walls convex meaning that they're bowing out into the workpiece. The absolute last thing you want to do is have concave walls where your openings are bigger than like in the middle of your mortise. So go ahead and make them convex, make them bow out to give yourself room for glue and non-friction. So that's the second rule. When you're cutting the tenon here really critical spot is right here where the tenon is meeting on the outside edge of your workpiece. So you want to work on that tenon and keep measuring with your calipers until B2 which is the part of the tenon that's maybe a quarter of an inch, half of an inch inside from the end. This is designed to be a quarter of an inch or longer sticking out and this is going to get cut off. So I want the part where it gets cut off to be perfectly the same size. So I need to work with my chisels, with my sanding, with my files and everything to get this part of my tenon equal exactly to this part. I get a big equal sign here. Get B2 the width here to be equal to B1. I haven't said anything about the width over here yet or maybe even the width of D. This is the critical territory. B2 has to be chiseled away, filed away, sanded away, use your calipers to measure it. No sense in trying to stick it in there and stick it in there when it's too big compared. You're just wasting time. Use your calipers. Alright when you get B2 to be exactly to B1, leave those two alone. Don't carve away on this face to make a little bit larger opening because things aren't fitting. Don't sand it down in this critical territory because things aren't sliding through. They're not sliding through for some other reason. You've got jagged little things in the corners of your mortises. Your walls are a little bit concave instead of convex. Your other parts of the tenon aren't small enough yet. So let's get to that. With the rest of the tenon, there's nothing wrong with C being smaller than B2. In fact, as you probably want to do that and so it's okay to have those B where up here near the cheek, this is thinner at C than it is at B2. And certainly it's okay to have D be thinner than B2. It's also okay to round off the edges here so that there's less friction beyond your forbidden territory. So you can go in and chisel off and round off the edges of your tenon. Just don't do that in that magical half inch that you want to be fitting exactly. It's also all right to round off the ends here and camper them and get them so that they're not catching on any little jagged edges inside. You want to be able to push this thing through in a critical glue up time. So I guess again the only thing I would emphasize is don't keep just chopping away at your full blown tenon the entire length of it because something's not fitting. So don't carve away at the critical area once you've got that to be the size it should be. Work on other things. One last thing about the preparation of your mortises. Here I'm showing as if you're looking at the face of this. You want to you're going to taper those so that there's more room at the top or where it's going to you're going to put in the wedges. More room up here than there is down here in this in this mortise. But here's what's critical. You want to do that extra space but you want it to be angled almost all the way down to the bottom in a straight line. It's a very common mistake to say oh well I got to have the top just a little bit wider for wedges and then just use your chisel and just go a little ways down but not almost to the bottom. I would take the half an inch or so from the bottom and make sure that you get this chiseled all the way down. If you can put a ruler inside this face and touch this edge if there's a big gap here then you haven't done it properly. If you do this then when you go to drive that wedge in across here there's absolutely no even though you've done a relief line or a cut line and put a little drill hole down at the bottom of your tenon there's no place for it to go and so in order to get a triangular wedge to go further and further down you need to have these side walls be slanted almost all the way down otherwise it the wedge will just stop going in and you won't get enough spread to close up the gap if you'll follow these rules I think you'll find that this is not all that intimidating and you can make things fit nice and tight on your triple wedge through tenons. Small workshop guy signing off.