Help with jig or method ...

[steve_b]

Morning ...

I am making a 'thick' shelf for my daughters room. The frame of the hollow 1 1/2" thick shelf is about 59" x 12" and I had thought about doing the corners as per the attached image (hope it shows up) and then capping the top and bottom with 5mm birch ply.

Doing the corners as show it means standing the long part up on the table saw to run the dato thru. I have done this and wasn't happy with the fit - it is hard to keep things from moving as I pass it thru the saw. SO I could scrap what I have done and start again and treat it as a learning experience - change the corner type or make a jig to hold the part - what would be the preferred corner configuration for something like this? I thought that a locking type corner would be a good idea helping with assembly.
I have limited tools (BT3100 not much else)

If the image doesn't show - see at link....

http://www.diynetwork.com/diy/hi_too...219278,00.html



Thanks for listening...

[crokett]

A couple options:

matched router bit set or use a slot cutting but to cut the groove in the end grain. Probably would take multiple passes with router at different heights to get a wide enough slot. You might be able to use a rabbetting bit for this.

Use the dado blade in the saw but build a tenoning jig that rides on the rip fence or clamps to the SMT. It will give you a lot more stability standing the piece on end and is much safer.

[pelligrini]

If you've just got the BT, I think a tenon jig is what you're looking for. If you don't have the miter slots, then you'll want one that will work with the fence.

[cabinetman]

If you only have a table saw, you could make a triangulated support. If you have a router, that would simplify it some. If you have a drill and bits, you could dowel.
.

[radhak]

If you have a router/table, the lock miter router bit helps you get this joint very easily
(note : pictures below link to the articles):




If not, doing on the TS is best with a tall fence like this ( It might look complicated, but I could make it in an hour or so, and I'm a newbie too; Suwat's article is really easy to follow) :

[LarryG]

You could use a rabbet & dado, which is sort of a simplified version of the lock joint:



This doesn't actually lock together, but the geometry will still help hold everything in alignment during the glue-up. Can be fabricated with a router bit; or, on the table saw, using either a dado set or by "nibbling" with a blade that cuts a flat bottomed kerf (which the stock BT blade does). All pieces can be laid flat on the table and guided with the SMT.

[just started]

If you have to use the TS, you need to rig up a tall fence to support the long board in the upright position and a feather board to keep the bottom against the fence, however if you have a router the bit Radhak posted is the best way to do it.

[poolhound]

If you've just got the BT, I think a tenon jig is what you're looking for. If you don't have the miter slots, then you'll want one that will work with the fence.

Here is something that works with the fence, I have one, its not fantastic, but if you are carefull it does work. You could of course make something but if you have to use the TS this may be a quick way forward.

As others have said, from choice I would do something on the router table if you have one.

[LCHIEN]

Your preferred method you showed is using the TS to cut a joint much like the lock miter joint. As Larry G and Pelligrini said.
I feel your stated problem is how to hold the long board vertical to cut the end joint.
the DIYnetwork article does not show how to do this. Its dangerous and inaccurate if yo don't have a jig, I feel.

One jig for this is a tenoning jig, which is sold for standard cast iron saws with a miter slot. If you have the BT3100 you stated, no miter slot, so you can't use an off the shelf tenon jig.

But here's a simple way to do what you need on a properly aligned BT3:

Here's the basic idea: Make a 3-sided box about 12" x 12" x 12" out of MDF or plywood, I think 1/2" would be plenty good, 3/4" if you want to make it really solid. Make sure all sides are perfectly square, the sides should all be adjacent and at right angles to one-another. Simple butt joints should be fine, its just a jig.

Place one side (A) of the box against the miter fence. One side (B) flat on the SMT, and one side (C) facing right and parallel to the blade.

Use the T-slots in the miter fence to capture the B side to the fence.
On the C face, put a nice straight piece of 1 x 2 running vertically, about 2" from the back (close to the user) edge. You can use screws to mount this but have no screws closer to the table top than about 1-2 inches. THis will be the backer piece for the workpiece and the bottom will get chewed by the blade to the depth of your cuts and should have no screws in the sacrificial part.

As its 12" tall you can hold the piece to the against the C face and the backer with your hand, or use some clamps

This is the basic idea... I gave it to you for your consideration. You can make a number of modifications - for example I would make the thing 6" front to back instead of 12. I might use the jig-holding vertical clamps to hold the workpiece, mount the clamps to the 1x2 backer. Or I might cut some slots or holes in the C-face for clamp bars and some slots or holes in the A-face for clamps to hold to the miter fence instead of the t-bolts. You could put a 5/16-18 hex bolt (head down, knob and flat washer on top) through a horizontal (rt-left) slot in the B face to go into the center slot in the SMT, to lock the B face flat to the table.

I might make the backer board swivel to go 45 degrees (for future work on mitered joints).

[cabinetman]

You could do a splined miter (boards would be flat to the table):

.

[pelligrini]

Loring's idea would be quick and easy. I used to use a nice square wine box for doing similar cuts.

[shoottx]

I am making a 'thick' shelf for my daughters room. The frame of the hollow 1 1/2" thick shelf is about 59" x 12" and I had thought about doing the corners as per the attached image (hope it shows up) and then capping the top and bottom with 5mm birch ply. ...

In stead of trying to do a complicated corner for a shelf, use the corner approach Cabinetman offered and change design of the shelf to a torsion box.

I think this would be stronger and simpler to make .

See http://www.diynetwork.com/diy/ww_mat...278182,00.html

[LarryG]

Joinery type and methods aside, I'd like to offer one suggestion for Loring's jig, or anything similar: when building jigs and fixtures, always locate any screws that are conceivably within the path of the blade a minimum of 4" above the table top; i.e., safely out of the reach of a 10" diameter blade at maximum elevation. Because one of these days, you're going to have an application where you realize you can use an existing jig to make a particular type of cut with the blade all the way up, and ... well, you see where I'm going.

(And if you're wondering, "Is that the voice of experience talking?" -- no, not quite, but almost. I once made a shop-built tapering jig virtually identical to this one, except that for the adjustment arm I used a curved brass lid stay. As in the pictured jig, the adjustment arm extended into the blade path. Scouting around the shop for something to form the two arms of the jig, I found a couple nice, straight pieces of VG fir leftover from some project or another; they were about two feet long and 3" wide. I thought they'd make a splendid tapering jig, and they did, too, for probably three years -- because I never tapered any stock thicker than 8/4 or so, and the tapers were always short enough that the brass stay never got all that close to the blade. Then one day I needed to make some long, shallow tapers. I got the jig out and lay it on the saw table. The blade just happened to be all the way up, and as I was moving the fence over to position the jig I suddenly realized what I'd done. At that point, I had two choices: be careful, remember the limitations of the jig; or take the safer road and take it apart. I took it apart.)

[LCHIEN]

Joinery type and methods aside, I'd like to offer one suggestion for Loring's jig, or anything similar: when building jigs and fixtures, always locate any screws that are conceivably within the path of the blade a minimum of 4" above the table top; i.e., safely out of the reach of a 10" diameter blade at maximum elevation. Because one of these days, you're going to have an application where you realize you can use an existing jig to make a particular type of cut with the blade all the way up, and ... well, you see where I'm going.

4" might be a little high to provide adequate support. I'd suggest 2" and a big red line at 2" with a warning "Maximum blade height", its hard to imagine tenons more than 2" long. Brass screws if you are really worried...
or maybe 4" is OK. Try and see if there's any "give" to it.

[steve_b]

I really appreciate the responses, thank you

I had thought about torsion box construction - I'll look at that. I had even considered a foam core shelf - band the outside and cap (with 5mm top and bottom) a Styrofoam SM core - think it would work? light and stiff.

I feel that the jig that Loring described would be a good place to start - so I built one when I got home last night (surprised myself) haven't tried it out yet, just a few things to finish - but basically done - even if I don't use it for this job - I will have it for later.

I like the corner that cabinetman posted but excuse the novice question - how are you holding this as you run it thru (assuming that you use the TS for this)


Thanks for the help


Stephen