Tuesday, January 28, 2014

Crappy crayons

Project X has a lot of book matched parts, and adjacent parts with continuing grain. There are a lot of orientations to keep track of.

I've been using Irwin lumber crayons to help keep track of all of that. And they keep breaking on me. I should know better than to buy things at a home center, but, you know... I was there, I had a need, and like many other regrettable relationships, I gave in, knowing it was really against my better judgment.

At over $1 per crayon, they should hold up better. But for a project like this, using other colors would probably help keep track, too. I'll be using crayola next time. Cheaper, more colors, and more durable. (I think... We'll see.)

Sunday, January 26, 2014

Shop Build Update: Outfeed and Dust Collection

After 4 months, I'm finally at what I'd consider full functionality. Out-feed behind the table saw is completed, and there's dust collection for all of it. I'm pretty happy with how the design shook out, too. The bridge between the saw and the MFT is made up of two parts, and both are movable.

Dust collection for the router table fence is available, if the table saw section is moved to one side:

When I use the router table for dados, most of the waste shoots straight out from the back of the cut. Before I built the bridge, it would pour out all over the MFT, and onto the floor, and everything that's set up under the MFT. (shop vac, dust, dust barrel, and circ saw) So I built a small downdraft section in the outfeed table there, which captures most of that waste. Not all, because some will come out at an angle, but I'd say a solid 90% goes down, and into the dust collector.

When I need to use the MFT, the downdraft section lifts out:

I did a litle bit of head scratching about dust collection under the router table. Most of the tables I've seen are mounted on top of a box, and there's a port underneath, somewhere. But I didn't really feel the need to make an entire box. Instead, I bolted this MDF plate in, underneath the table. There's an inch and a half between the underside of the router table and the plate. I cut a hole to clear the lift, and for the dust port. While the vast majority of the air flow actually comes up from under the plate, as opposed to through the surface of the table, that air flow carries a lot of waste along with it.

How well does the plate work? Well, I took this pile of waste that I'd swept up from the floor...

Fired up the dust collector, and pushed the waste into the opening in the table...

And this is what fell through:

Between that, the hose for the fence, and the downdraft section of the outfeed table, I'd say I'm pretty well covered.

Monday, January 20, 2014

2 step dado with the bench dog router table

Cutting dados on the table saw is straightforward, but tedious. Remove the blade, and mount dado stack. Shim or dial to desired width. Getting the width set is a chore, but it works. And for projects with a lot of the same size dados, efficiency of scale is on your side.

But when you only need to cut one or two, it takes more time to set up and break down than it does to make the cut(s). Especially with the SawStop, when it means swapping cartridges, too. Some folks will make multiple passes with the saw blade because it's faster. I've done that myself. But if you need more than three or four passes, that gets tedious, too.

This is a little bit better for wider dados... Like the ones I just cut for the out feed bridge. I use the saw blade to define the edges of the cut, and clear the waste with a straight bit in the router table, using the table saw fence to guide the cut. If multiple passes are required, (as here) they're much easier to do with the saw fence, both because it sets up faster, and because it's easier to see how much you're moving the fence. (No need to set and reset the router table fence by trial and error, no need for setup blocks.)


Apologies for the photo quality... posting via iPhone has been glitchy lately.

Friday, January 17, 2014

A note on plywood

A few years back, I made some 12 foot box beams for a long glue up. Construction was straightforward: top and bottom had grooves for the webbing, (the vertical part of the I-beam cross section) and the whole got glued and screwed. 

For those beams, I used regular, paint grade, birch faced ply. And what I found was that there was a huge variation in thickness. The ply wouldn't always fit into the grooves. 

To compensate, I rabbeted the edges of the webbing on a router table by running them between the fence and bit. The result was a consistent thickness, and a rabbet that was nonexistent in some places, and over 1/16" deep in others. That over-thickness was what had been keeping the ply from fitting into the grooves during the dry fit. Once thicknessed, everything went together fine.

The grooves in the top and bottom were of consistent depth, which meant that there would be a variation in the remaining thickness, translating into a variation in flatness of the surface. On a 12 foot span, 1/16" or more isn't a big deal. But the project I'm working on now (Henceforth, Project X, until design trademarking is worked out) will require tighter tolerances.

These box beams are only 5' long. And this time I used good Baltic birch. (As opposed to the home center equivalent, which usually has overlapped laminations, and flaky surface veneers.) No variation in thickness, and the web fits cleanly and consistently into the grooves.

I'm much happier with these beams. Project X will have some funky 3-way miter joints that transition into compound curves. That means I need accurately flat blanks glued up to work with the jigs. The process has been interesting to engineer.

More on that soon, along with the write up on the hay rake assembly.