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-   -   Reproduction Back for Admiral Models 19A1X & 17T1X (http://www.videokarma.org/showthread.php?t=255507)

Winky Dink 09-07-2012 03:16 AM

Reproduction Back for Admiral Models 19A1X & 17T1X
 
Phil Nelson's recent 19A12 restoration showed a superbly finished Bakelite cabinet, but the back was missing. Since I have an almost-identical back for a 17T12, I thought I'd try to do a reproduction that would fit Phil's set. The only difference between the two cabinets is the rectangular cutout for the 17T12's Rotoscope antenna.

https://lh4.googleusercontent.com/-o...ack%252003.jpg

All modesty aside, it turned out great. The tools were simple and the materials were cheap. All I used was a saber saw, electric drill, sanding block, ruler, paper, and patience. And a 35-year old Black and Decker Workmate.

https://lh6.googleusercontent.com/-Q...ack%252004.JPG

The original material was Masonite, a composite wood product first used in the 1920's. Home Depot calls it "temp board," and others refer to it as a variety of hardboard. One side is smooth and burnished; the other side has the imprint of a screen. A 2x4-footx1/8-inch piece cost about eight dollars.

https://lh5.googleusercontent.com/-_...ack%252007.jpg

To make it appear authentic, it has to look machine-cut. To be sure all the holes lined up perfectly, instead of tracing it directly on the Masonite, I made a paper template. Then I triangulated the hole circles to get each hole center placed perfectly. I used a small drill bit to mark the hole centers through the paper.

https://lh6.googleusercontent.com/-x...ack%252010.JPG

Tracing complete, holes marked, and ready to cut:

https://lh6.googleusercontent.com/-w...ack%252012.JPG

The next challenge was to get cleanly cut holes and edges. After some experimentation I rejected the sawblade and drill bit that I would usually use. For saw-cuts and drill holes without furry edges, I used a scroll blade and a "brad point" wood boring bit. The holes measured 11/32 inches, and I had to go to a woodworking store to find bits in 1/32-inch increments. That was another four bucks.

https://lh6.googleusercontent.com/-n...ack%252015.JPG

The brad point bit will cut a clean circle it's run at very low speed. I made the holes at about 100 rpm. If it ran much faster than that, it would tear the wood fibers on the surface and leave a fuzzy hole. Also, the point of the bit is excellent for accurately centering the hole.

https://lh4.googleusercontent.com/-V...ack%252020.JPG

Here's the finished product. Since I had the original power cord, I tried to make a metal interlock bracket. The result was only fair, so I temporarily positioned it for this photo.

https://lh3.googleusercontent.com/-8...ack%252050.JPG

This is a comparison of the original with the reproduction (I later drilled the one missing ventilation hole and the hole for the top middle screw so it would fit the 19A1 without a Rotoscope antenna).

https://lh3.googleusercontent.com/-C...ack%252060.jpg

Total cost was 12 dollars, but I still have plenty of Masonite to replace the damaged back on this Motorola 12T2 with 1,700 holes. And after that I'm going to climb Mount Everest in shorts, a T-shirt, and flip-flops.

https://lh4.googleusercontent.com/-k...ack%252090.JPG

If you know anyone who needs a back for an Admiral 17T1X or 19A1X, here are links are for a template in two parts. If the Flickr download in original size is used, it'll give you two JPEGS which, when printed on letter-size paper, will give right-side and left-side prints that can be joined to make a perfectly-sized paper template.

https://flic.kr/p/WEYyor

https://flic.kr/p/WP6rU7

-Winky

vts1134 09-07-2012 05:48 AM

That's looking good. Lots of patience lining up and drilling all of those holes :yes:.

bandersen 09-07-2012 11:17 AM

Outstanding work:thmbsp:
I need three of these backs and was gearing up to do the same experimenting you did including trying a variety of drill bits. You just saved me a lot of time and effort :yes:

Phil Nelson 09-07-2012 11:44 AM

Very nice job! I need to make a couple of backs, too, but I have been holding off because I didn't want to make something with fuzzy edges and vent holes.

Phil Nelson

Kevin Kuehn 09-07-2012 06:22 PM

Excellent job.

[edit] Was just thinking, since they likely didn't have CNC routers or laser cutters back in the day, I suppose the originals were made with a stamp and die set. I don't know how else they'd of mass produced these.

Reece 09-08-2012 11:20 AM

That's a beautiful job. The tough part of these is making them accurately, and you solved that by triangulation. I copied the layout picture for future reference. Thanks.


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