The machine shop modifications to the cast aluminum transmission frame were successfully executed. It fits and works exactly as the original part.
A little Mill Wax restored the shine to the spoolbox and the drawer frame cleaned up nicely. A few of the removable bottom panels could use repainting but higher priorities prevail. Next, all restored pneumatics were assembled into the drawer. Some careful study and comparison was done between my disassembly sketches and the tubing diagrams I had obtained. This drawer was in original condition and almost completely intact. I was able to make a detailed sketch of all unbroken tubing connections before disassembling it. Between David Saul’s 1925 drawer diagram and the popular Amphion tubing diagram, I was able to account for those few broken or missing tubes which were mostly on the bass end of the drawer. This, being a late 1926 type 8 drawer, did not exactly match either of the two diagrams mentioned above. The main difference is in how the reroll circuit components are connected. There is a 5/32 tee fitting with a .046" orifice installed but it is located in such a way as to delay the reroll signal from the tracker bar to the roll accelerator. I believe this is done to give the transmission time to shift into the reroll position before the air motor can begin to accelerate. The pump cutout is no longer teed to the accelerator. It is connected directly to the slide valve on the transmission shift lever. (see sketch provided)
Some additional study was done of my tubing sketches of the piano belly. There were more missing and broken tubes in this area and my sketches contained a number of question marks particularly in the area of the feedthrough blocks on each end of the primary chest. With the aid of the tubing diagrams and my hand sketches, I was able to account for 100% of the missing tube connections. My drawing of these feedthrough blocks has been included in the photo album.
After seeing a number of other Ampico-A restorations and hearing of peoples frustrations trying to replace lead tubing with rubber under the drawer, I decided to try something different. I designed and made a set of fanning strips which arrange the rubber tubing into two neat interleaved layers. The exact number of tubes in each of 4 areas was mapped and the space constraints determined. The Autocad layout proved everything would fit in the available space, so I proceeded to make the fanning strips out of 1/8" thick aluminum sheet. The photos illustrate what an astounding success this was. The main advantage is the ability to remove and replace a single tube if one should ever become obstructed or punctured during the useful life of the restoration.
At one point, I was looking into finding exact replacements for the equalizer springs. My search was unsuccessful and thanks to Noxon-7 metal polish, the original parts will now be usable.
Next, I will restore the take-up spool and do some actual spooling and alignment using a test pump.
Another trip to Keystone is penciled in sometime before Xmas.
Advertisement
