Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => AmpTools/Tech Tips => Topic started by: terminalgs on December 19, 2014, 06:11:15 pm
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For years I've always hated drilling the two small fastener holes for socket retainers. I finally made this and it makes quick work of it. I drill the pilot for the large hole, then use a spare drill bit to position this template. once the first hole is drilled, I use another spare bit to hold it in position while the third hole is drilled. Then, I unibit out the center hole to fit the socket or unibit and then knockout if its an octal or large noval. If you use a knockout, drill the center hole out with a unibit a step at a time until the knockout arbor barely passes,, this helps ensure the center hole stays centered.
(http://i.imgur.com/dVQTQ30.jpg)
I'd like to make another one with a longer brass bar to make clamping it easier. I did this with scrap. since the brass bar is square, I can use a t-square to line it up right.
what do other folks do?
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I like it!
If you are constantly making similar "tube lineups" you could get a long piece of flat stock and make a template that you line up once, clamp down, and drill all your holes without any re-positioning. Maybe clamp it down, drill two of the mounting holes at opposite ends and use those holes to screw the template down and remove the clamps so the clamps don't slip on you.
Normally, I make-up a template in a CAD program and tape that to the chassis, center-punch and then drill. Still never seems to come out perfect though.
Drilling the chassis is my least-favorite part of the build at this point. Used to be twisting heaters but I don't twist the wires anymore, so that's easy now.