How to cut holes for tubes

[woody]

I have a chassis out of 18 gage aluminum and need a good
way to cut a few holes for some octal chassis mount sockets.
I know a chassis punch would be preferred but wouldn't a 1.125'
punch be rather expensive? Oh! I need 8 holes if this has any
bearing on my best rout to follow.

Thanks in advance,

Woody AKA bob12345678

[Colt45]

holesaw, i guess.

[fdegrove]

Hi,

If you don't have to cut holes on a daily basis I can recommend these:

GREENLEE

Look at left "Holemaking".

They carry a range that makes for perfectly cut hole for all types of tube sockets as used in audio.

While I agree that these are not exactly cheap they last for ever.

Cheers,

[jackinnj]

the Greenlee chasis punches are always, always available on EBay (boy, could I use a subminiature D punch, however. You rarely see them, and new they are about $300.)

Before I purchased chasis punches I would mark the holes with a compass, drill 1/8" holes in the inside of the circle, place the chasis on a block of wood (like pine) and knock out the aluminum between the drill holes with a small chisel or screwdriver. Smooth the holes with a round rat-tail file. I used this technique for many, many ham radio transmitters.

[pinkmouse]

You could try a cone cutter on a pillar drill with a depth stop...

[fdegrove]

Hi,

You rarely see them, and new they are about $300

I paid mine about 30$/EA at a local hardware shop about 10 years ago.

In case anyone is interested I could make an enquiry about current pricing.

300$ seems awfully steep to me.

Cheers,

[Gabevee]

A hole saw is not the best idea. I tried that first a few years ago.

Here:

http://store.yahoo.com/triodeel/miscellany.html

you will find the best price for a set of punches for all the typical sized tube socket holes. A single Greenlee punch especially that size is about $50 USD. This kit Uncle Ned offers is $49 for five punches!!!

Nice clean professional looking holes.

Gabe

[jackinnj]

$30 for a subminiature, nine-pin "D" chasis punch ?
here's a link to the item at Allied Electronics http://www.alliedelec.com/catalog/pf.asp?FN=1016.pdf

[fdegrove]

Hi,

In that case..sure.
Anything that differs from round or regular rectangular shape is expensive.

No offense but I was referring to the standard tube socket diameters which are (thank God) a little more affordable.

Personally I only needed a sub-D punch once for a special automatic fuse.
Not worth the expenditure for a hobbyist I think.

Cheers,

[woody]

Thanks for all the fine feedback. I think that set over at triode
may be my best bet.

thanks again,

bob12345678