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I have a decent wood working background, grew up making things with my dad. Haven’t done much lately, but looking to get back into it a lot. Anyway, that has nothing to do with the question but a little background.
I am wanting to make a chest, the first aspect of my design is that it is tapered and has either finger joints (first choice cosmetically) or dovetails (second choice) at the corners. So basically I have a 24″x36″ top and 16″x28″ bottom 21″ tall. I have been racking my brain trying to figure out how to produce the required layout work. I thought I figured out how to make a jig to do most on a table saw, but then laying it out in a 3d CAD package it doesn’t fit up. Is there magic information I can use to figure these compound angles and then produce it in real life (maybe theres a jig that already does this?) I’d appreciate any pointers, web sites, or reference works that would help me out.
Thanks in advance,
Jeremy
Replies
* It's very advanced craftsmanship that's called for I'm afraid. I've done the joinery myself a couple of times in the past. I like to think that I'm a reasonable craftsman, and I can testify from personal experience that this joint is tough to do. The only other joint I cut that comes close in terms of difficulty is the double twisted dovetail, which is a dovetail that locks in two directions at once. The blue link below is the same image. No need to click on it, and it may be a bit large.
You're talking about a hopper. If you'll tell me what angle the sides slope in from the top plane, I'll tell you what the dihedral angle is, and what the true slope of the sides edges are in relation to the top plane. I could draw out what's needed from your description to find that angle. I'm just saving myself some effort, and being lazy. Or you might try this online calculator,
Compound Cuts There are more calculators out there on the net. Their main failing is that they give you the information for compound mitres, not the raw data which is what you need to be able to calculate your various angles for a jointed hopper.
Once you've got that information you could do a through dovetailed hopper as illustrated here. There is no jig that I know of to do this kind of work on a table saw, or any other machine. The only jig I'm aware of is the one between the ears.
This came from Ernest Joyce, The Encyclopedia of Furnituremaking. Excellent resource that I highly reccomend. ISBN 0 8069 7142 8. Sliante.
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*Well, that figures that I would choose a difficult joint for an initially simple project. Oh well, it'll make it that much more of an heirloom I guess. My initial idea for a table saw jig may still work I just may have to massage the angles via that calculator. I'm gonna try to attach my jig idea. I'd appreciate any who point out any blatant errors. Note the rear "fence" is tilted away from perpendicular at an appropriately small angle.
*I'm pretty sure your tilted sawblade (dado?) is cutting an inappropriate angle at the top of its cut, i.e., the shoulder line of the finger joint is being cut at the wrong angle. You need a blade with a bevelled tip profile. Actually, you need two, one to do two of the diagonally opposite corners, and its mirror image to do the other two corners. You can cut some of the meat, but you'll need to finish the joint by hand. You'll also need two jigs that are mirror images. Don't hold me to my opinion too tightly. I'm not looking overly close at the problem because I'm rushing through my lunch hour and may be missing something. I'm working off memory too where I've encountered the job first hand, and the point I've made seems familiar. Sliante.
*Yes you are correct, with a dado I would have a lot of fixing up. What I'm thinking is using a thin kerf blade with multiple passes per "finger" thus it should only leave a little chamfer to square up by hand in one corner (of each finger), and flattening up the top of the cut. I have re-thought the angles and believe I have it all working out (nominally via computer) though I'm not exactly sure how I'm gonna get the tight angle tolerances I'd need. I had already discovered I'd need a mirror image jig for the opposing sides. Any way I'm sure I'll run many scrap pieces through to test my setup. Thanks for your input.
*Jeremy:For a one off job,Its hard to beat the basic joint making equipment,saw,mallet and chisel. PAT
*I tend to agree with you Major. ;-) That would be my approach for this one off job, even if I preferred the final look to be a box lock, which is what Jeremy's wanting. I could probably cut it by hand and have it assembled before most people have even half made a jig that almost certainly won't fully eliminate hand work anyway. But as I commented earlier (very) advanced hand skills are needed, and perhaps Jeremy doesn't feel quite confident enough with his hand skills. It would be nice to have his abilities with a draughting programme though! Sliante
*b Kabu Kalli,Shibidan, Wamara: Has anybody had any experience with these woods. I saw them at Woodcraftin Orlando.I have never heard or seen these 3.Shibidan has some figure like good walnut,kabu kalli has greatly increased figure,wamara is fantastic figure.Wamara sold for around, 154$(+,-)for a 7-8ftx2"x8-10" piece.Wondering how this wood planes out,cuts,band and table saw.What finisheswould work.Are these "oily" woodsfdrake
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