The Oakes Family

Middle Plate: With the rear plate cut out, next up is the middle plate. The outer edge is cut, including the large notch at the bottom. I’m planning next to cut the front plate out around the edge before crossing out both the front and middle plates. (2 hours)

 

A quick test on a piece of scrap with different grades of sand paper and steel wool have shown that a good finish can be achieved on the aluminum plates. I’m confident that the aluminum / brass construction will look great when complete.

Front Plate: This plate is slowly taking form, in a similar manner to the first two.

The front plate is now cut out and at last I have all three plates ready to move onto the next step. (2 hours)

 

Drilling: The four 0.125in holes near the corners are drilled and dowelled to keep the plates held together in alignment. I’ve chosen to put all three plates together to file level and smooth the main outer edges. Later, I’ll pop out the brass dowel and put just the front two plates together to cross out these two plates.

 

I step-drilled the front plate starting with a small center drill to make sure the drill didn’t wander, working up to the 0.125in bit. I then marked up the center of the holes on the second plate and sighted the alignment through the holes in the top plate, clamping it tight, then using it as a guide for the drill. (1 hour)

 

After each step, I pushed in a small dowel cut from a length of 0.125in brass rod. This ensures the holes align and reduces the chance of the plates slipping.

 

Filing: I clamped the plates inbetween two pieces of wood in a bench vice and got to filing the edges smooth. Marking each edge with a black marker gives a good idea of where more work is needed - just make sure the keep the file level and keep going until all the black is gone.

 

Every couple of minutes, stop filing, brush out the file with a wire brush and recoat the file with chalk. This keeps the aluminum chips out of the teeth and helps it bite more consistently. (1 hour)

 

The front two plates were separated, the remaining areas crossed out (4 hours) and filed smooth (1 hour).

 

Pillar Test: I bought a piece of half-inch cold-rolled steel rod, four feet long for $7. This will become the pillars between the plates and the suspension post for the pendulum. Each pillar needs to be machined in the lathe to make a collar to fit snuggly into the plate pillar holes, center drilled, tapped and then drilled perpendicular to the axis. This is followed by brushing for a satin finish and oiling. I spent a little while testing out my machining techniques, using a test hole drilled in scrap aluminum sheet and a small section of steel rod. (1 hour)

 

I probably need to make a tool to assist with tapping, making use of the tailstock, to ensure a straight tap and reduce the risk of breakage. A small length of threaded bronze is used between the pillars to hold them tight on the middle plate.

I picked up a few supplies to complete the pillars and screws - 1/8″ and 1/4″ bronze rods ($8), associated drills, taps and dies, a couple of slitting saws for the mill, and a cut-off blade for the lathe.

Drilling the Plates: In order to make the pillars the right diameter on the ends, the plates need drilling, as well as a few test scraps against which the pillars can be tested for a snug fit. This is now completed, using a small center drill, then a 9/32″ drill, followed by a new 5/16″ (0.315″) bit. (1 hour)

 

I also tested drilling the plate bushing holes on scrap. I have a 6.2mm (0.244) drill bit that provides a perfectly-sized bushing hole for press-fitting the 0.25in broze rod bushings.

 

Pillars: I’m starting to work through the first end of the pillars. I’m pleased with the results so far - a nice accurate fit. They asked for 0.310″, and that is what they got! (1 hour)

 

Total for November: 14 hours + $15
Total so far: 19 hours + $17