Box-joint jig for octagonal boxes

When Gecko posted his octagonal box, see http://www.woodworkforums.ubeaut.com...ad.php?t=39338 , I was gobsmacked, like most of the Aussie forum members. I very much doubt that I shall be able to make a box anything like as impressive as his, but I have taken a first step. I have made an adaptation of my micro-adjustable box-joint jig (see http://docs.google.com/View?docid=dgdcspjt_23cstzv4 for the standard version) to make the 45° box joints required for an octagonal box.

Like the standard version of this jig, the new version has the ability to use interchangeable index-pin boards, to enable different sizes of box joints to be made. So far I have only made one with a 6.54 mm thick index pin which exactly matches the width of the slot cut by the two outer blades of my dado set.

The pictures show the front and rear views of the jig.

Rocker

Didn't waste any time getting into that Rocker! ;) Good job as always. :) I'm assuming you can still get a clamp onto the workpiece? - can't see what's up the guts in the pics.

It is not necessary to clamp the workpiece to the jig. The index pin and finger pressure are all that is required.

I have realized that the jig also has potential for zigzag joinery. Here is a 45° prototype joint that I made with it this morning. I am not yet sure whether it would be feasible to make a zigzag chair frame using this joinery; but I will do some experimentation.

Rocker

Quote:

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Originally Posted by Rocker

I am not yet sure whether it would be feasible to make a zigzag chair frame using this joinery; but I will do some experimentation.

Rocker

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No experiments, just make the thing.

Please? :D


Another thing I will want in the future...:rolleyes:


The distant future, but future all the same. ;)

Brilliant stuff, Rocker.

I'd be very interested in some more details: exactly what do you adjust with those screws (it looks like the tilt angle is also adjustable)?

First thanks for the kind words about my box but I am sure what you come up with will blow mine away. I really like the micro-adjusment you have on that. One of these days I will try something like that when the one I have stops being accurate due to use.

Quote:

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Originally Posted by zenwood

Brilliant stuff, Rocker.

I'd be very interested in some more details: exactly what do you adjust with those screws (it looks like the tilt angle is also adjustable)?

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Zenwood,

All is revealed in the online article on my jig, whose url is given in the first post in this thread. You will need to print it out to see the diagrams properly, since they are illegible on screen. The only difference in this jig is that the detachable index-pin board is tilted at 45° instead of being vertical, as in the original version. The tilt angle is not adjustable.

Rocker

Rocker

These jigs are great. I suppose you would be able to adapt them to work on a router table if you didn't have a tablesaw with dado capacity. Do you see any probs with doing this?

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Originally Posted by djstimber

Rocker

These jigs are great. I suppose you would be able to adapt them to work on a router table if you didn't have a tablesaw with dado capacity. Do you see any probs with doing this?

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The only possible problem that I see for adapting the jig for the router table is that router tables normally only have one mitre slot. The fact that my jig rides in both mitre slots on the table-saw bench completely eliminates any slop in the movement, which is crucial to the effective operation of the jig. However, Gecko's jig is used on a router table, so it must be feasible to overcome the problem.

Rocker

What I did to overcome the one miter slot issue is to have a "runner" that hangs over the edge of the table and rides against the edge of the table.

Quote:

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Originally Posted by Schtoo

No experiments, just make the thing.

Please? :D


Another thing I will want in the future...:rolleyes:


The distant future, but future all the same. ;)

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Schtoo,

The main problem that I foresee in using the jig to make a chair frame, where I would be using much thicker (40 mm) stock, is that the jig has no provision for ensuring that the edges of the workpiece are precisely perpendicular to the base of the jig, so that the slots that are cut may not turn out to be exactly parallel to one another. Such errors are likely to be negligible when cutting fingers in wide thin stock, such as for box sides, but in narrow, thick stock, such as is used for chair frames, I am afraid that such inaccuracies might well be much more significant and might prevent the joints from being assembled.

Rocker

Quote:

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Originally Posted by Rocker

Zenwood,

All is revealed in the online article on my jig

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Brilliant stuff Rocker. Your pre-emptive thoroughness shines through again. Many thanks.