Bearing blocks and staining

In preparation for getting the pressure box and lid all sealed up with shellac, I needed to get the interior stained. Before I could do that, I needed to make sure I had the rear bearing blocks glued & screwed into place, so they'd have a unstained surfaces for better glue adhesion.

I borrowed a forstner bit of the correct size to accommodate the ball bearings I planned on using and cut and drilled some bearing blocks that look a little like pipe flanges:

Once I had the bearing blocks stained and attached, I proceeded to stain the interior of the pressure box and the lid in preparation for the shellac sealing:

Now I've got to wait until the stain is fully dry...

More fun with the pressure box

When I compared the pressure box to the lid, I discovered that while the lid was almost perfectly square, the main part of the box was slightly out of square. It also rocked slightly when I set it on a flat table. In order to square up the box, I decided that some mechanical fasteners were in order - I didn't want to rely on just gluing & clamping.
So, I put the lid in place and using some hardwood scraps, I clamped the lid and the box together, side to side and end to end, to forcibly square the side/end assembly (with the already square lid):








Then I flipped the arrangement upside-down, and drilled some pilot holes for some small screws so that they would screw into the centerlines of the hardwood reinforcing strips that were glued to the lower edges of the side and end pieces:








Before gluing, I drove all the screws in to the bottom panel so that the points stuck out slightly and would "find" their pilot holes in the side/end assembly:









I then applied glue to all of the bottom-facing edges of the side/end assembly, set the bottom panel in place and tightened down all the screws:









Once the glue had dried overnight, I found that everything was square and flat, and I got a nice square fit with the box and the lid.

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Pressure Box Initial Assembly

I started putting the pressure box and lid pieces together. Getting everything to line up precisely was a bit of a challenge.

One of the first minor problems I noticed was that the shorter side pieces and tracker bar platform pieces were all just slightly too long to allow the longer sides to fit flush with the bottom and the lid top. Since I had cut them all from a single length of ripped 1/4" plywood, they were all exactly the same amount too long. (about 1/32")

The amount I needed to remove was too small to handle with the bandsaw, and I knew from previous mistakes that hand sanding the end of a thin strip of wood to remove a little length often results in an edge that's less than square.

I remedied this problem by clamping all the pieces together so I could run them over my sanding block and gradually reduce their lengths. By clamping all the pieces together I could keep the end cuts square.

 And here's how the ends looked after sanding. (the one piece that looks shorter is actually a reinforcement strip that had already been glued on to one of the plywood strips)

Once all the pieces had been sized more precisely, it was time to glue everything (almost everything) together.

(Since I'm going to be staining and shellacking the pressure box in a multi-step process, I elected to keep from gluing the bottom on at this point.)

Here's a pic of the lid pieces finally glued together:

Here's the pressure box glued together (without the bottom):

Another view of the pressure box, lid and bottom:

And stacked together to check the fit:

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Back at it!

I've been distracted for long enough and figured it was time to get back to the building….

For the last week or so, I've been focusing my attention on the pressure box.

I've been busy cutting out and gluing together all of the reinforcements and various pieces in preparation for assembly, and here are all of the pieces that I've been working on for the pressure box and the lid:

Another view:

Here's the lid put together as a dry fit to see if everything lines up correctly:

And here's a dry fit of the pressure box:

And a detail shot of the tracker bar platform pieces:

I'll still need to drill some holes for the air entry and the take-up spool shaft, as well as for the crankshaft end and the idler shaft.

It feels good to be back building!

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