London Power 3 channels amplifier project

[makinrose]

Well, ran into a small issue, will delay the project a bit ahah

Turns out that the Hammond's Steel chassis is one hell of a bitch to drill, everything was going well until I had to ream the tubes holes. I've got a step bit that I've used in past project and a Mastercraft (cheap) press drill that I'm using for the first time. Well, since the holes has to be big enough for the tubes to pass through the chassis (as opposed to my previous projects where just the socket would pop out) and that the chassis is much stronger than the aluminium ones I've used in the past, I can't do a clean job. The power tubes holes has to be as big as my step bit's biggest size and the drill keep on jamming (did I mention that I'm using a cheap press drill).

So I'll either have to find someone locally who can save the chassis I'm using or I'm ordering an aluminium one so I can at least get something done. Unless someone has some ingenious way to deal with that issue

I would encourage you to persist with the  Hammond steel chassis or get a non-hammond Aluminium chassis.  I've found the Hammond Aluminum chassis to be rather flimsy at only .04" thick.  With your drill press you may need to change the speed, use a newer step bit, and use metal cutting oil to ease getting through the larger holes.  I've used many Hammond Steel chassis and generally with a good bit and the proper speed you'll get though it just fine.  To clean up the burs I'll use a grinding stone on a hand drill for large holes and countersink bit on smaller holes. For the hard to reach spots on the panels I use a drill bit holding extension arm (what are they really called?) with the grinding stone.  You'll clean em' right up! 

If you prefer to go Aluminium I'd suggest that the chassis be .07" to .09" thick.  There's seller on Reverb that can make them custom sizes and make bottom plates if you need one. 


I hope that helps!