[R-390] 390A Drawings, was Engraved front panels

[Todd Bigelow - PS]

Don Reaves W5OR wrote:

>So what kind of machine was used to do engravings?  I'm 
>familiar with the badge engravers used at conventions and 
>'fests to engrave names in plastic.  Is that what Tom means 
>by 'rotary tool'?  How much set up time and expense would it 
>be to take a silk screened panel and engrave it?  Lets hear 
>from you machinists.
>
Looks like others have nailed this one pretty well, Don. I always 
wondered this myself, since doing one panel at a time would be awfully 
time-consuming. Along with the fact that you'd want repeatability 
through many examples. I have seen references to both stamped panels in 
some literature, and more recently engraving for the 
previously-mentioned mixing console (which is almost 4' across, so not 
easily engraved). The manual is dated late 40s/early 50s.

Here's an even more interesting thought though: the console panel has a 
wear mark around one lever switch used for opening and closing the main 
mic. The paint appears to be several layers thick, a good baked on 
paintjob. However - the actual engraving in the metal sits somewhat 
below the paint. Therefore it *appears* to me that these huge panels 
were painted, then baked, *then* engraved afterwards through the 
thickness of the paint. Nothing else  easily explains the crispness of 
the letter edges in the paint above the metal surface.

So, with one of these nifty machines and the knowledge to set it up and 
operate it, the world is your oyster! I'm sure many application used 
stamping instead or in addition to angraving, simply for the time 
involved and economy of large runs. I'm not prepared to say that panels 
for the R-390 or A were all stamped because I have no proof. Until 
recently I assumed so, based on what I knew. It certainly makes sense to 
me that large production runs would warrant this approach. No idea the 
time involved with a...Pantograph(?) in regards to how long it takes to 
set up or to complete a panel. If it's all automated, then probably not 
long. One other note worthy of mentioning is this: the console panel is 
shaped, not a standard flat panel. This may have some bearing on the 
method used. My guess is that the main panel was bent when it was made, 
certainly before painting or the paint would've cracked off.

As far as my radios, the Teledyne R-390A indeed has a stamped/engraved 
panel. I'm 99.9% certain that the Collins-tagged R-390 does too, but 
I'll check again to be sure. The #2 R-390A came with a silkscreened 
panel and a Motorola tag. John Watkins fixed me up with a nice 
replacement panel for it though, so the silkscreened version will be 
available if someone wants authenticity or something to experiment with. 
The paint is still in decent shape overall.

It sure would be nice to find a place that could properly engrave 
panels. Instead of trying to plug those 1/4" holes added by a previous 
owner, one could just get a new panel made. Probably wouldn't be cheap 
(the good stuff seldom is), but I bet it would look great.

de Todd/'Boomer'  KA1KAQ