Chassis – Mount Tube Sockets / Variable Caps

Yesterday the mounting hardware arrived.  I had ordered a number of different length 6-32 zinc-plated machine screws ranging from 3/16 in. up to 5/8 in. from McMaster Carr.   While BoltDepot was cheaper for the same machine screws, McMaster had narrow 6-32 zinc-plated nuts and 6-32 Black-Oxide truss head machine screws (for the front panel) that BoltDepot did not carry.   The narrow nuts (1/4 in O.D.) work better for mounting certain parts than standard 5/16 in. O.D. nuts.  After factoring in shipping, it was more economical to just get everything from McMaster.

The tube sockets were mounted using 1/2 in. 6-32 screws, #6 external tooth washers, flat washers, and standard 5/16 in. O.D. nuts.  The National SW-3 Continue reading …..

Chassis – Prep and Paint

As mentioned in Post #1, I found a nice Bud aluminum chassis (17x8x2) at a local hamfest.  I laid out and marked the positions of the tubes, transformers, RF coil sockets, crystal filter unit, etc.  However, there was not enough room to fit the 2A5/42 audio output tube (or it’s output transformer for that matter)!  I conceded to the idea that I would have to build the audio output circuit on a separate chassis.

But luck once again came to the rescue.  While visiting a local “junk” dealer to acquire some tubes and Hammarlund coil forms, I found a larger NOS Bud aluminum chassis (17x10x3) and an old receiver cabinet amongst the piles of vintage goods.  This new chassis would be more than sufficiently sized to accommodate the entire receiver circuit without resorting to an outboard audio amplifier.  It was also a perfect fit in the old cabinet.

I proceeded to lay out the parts and mark locations on the new chassis.  Once again, I was met with another obstacle.  Continue reading …..

Parts Acquisition

Over the last few weeks I’ve been acquiring parts to complete the 1934 superhet receiver.  As with many projects around here, it seems a bit of luck plays a hand in some finds.

Through some casual searching online, I found a source (oldradioparts.com) for many of the necessary parts, including some useful items for future transmitter projects.  National ceramic tube sockets (4, 5, and 6 pin), cloth wire, vintage mica and paper caps, high inductance RFCs, National SE / ST style variables, and National vernier dial lamps were amongst the goodies:

I decided to try and source the IF transformers and crystal filter by Continue reading …..