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]

PUNCHES

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]

PRICES.

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]

FDEGROVE

$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]

D-SUB

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

 

[Burnedfingers]

The very simple step drill that pinkmouse mentioned is a very cheap way of getting the job done. They generally cost less than $30.00 if cost is an issue. In addition to cutting the hole they can also deburr the opposite side when you turn it over. I have punches I could use but I prefer to use the step drill for this operation.

Joe

 

[dhaen]

Just to give you another possibility:

I have recently cut some large ~70mm holes in 6mm aluminium.
I used a "fly cutter", at least that's the UK name.

You need a "pillar drill" (drill press). It must be run at the lowest speed.

It was necessary to bolt the workpiece to an MDF base, and to flip and cut from each side, (changing sides at half time)

The results are good, but I wouldn't recommend it for "normal" chassis work, just for thick material, or holes too large to punch.

 

[Ciscokid]

Hi,

I have had good luck with a circle cutter for big holes and unibits for the smaller holes.

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ck

 

[dhaen]

Nice.
How thick was the material.
Was it aluminium?

 

[Ciscokid]

Thanks,

Top plate was .090" brushed aluminum. Seemed to cut real easy. When finished, I hit with steel wool in same direction as brushed to blend in any scratches.

ck

 

[dhaen]

Hi ck,

What's your project?
Looks like a pair of monoblocks.

 

[Ciscokid]

Hi John,

I built a pair of JE Labs 300B's . This was my first DIY and am very pleased with the results.


Here is a link to my site with a few notes and pictures: Tube Stuff

Regards,
ck

 

[dhaen]

Hi ck,

Nice site. I rewcognise your pictures. Perhaps I've visited before.

Are you pleased at how it sounds?

Cheers,

 

[contaxchen]

Hi,
I just read the instruction manual from Greenlee for thier knockout punch set.
It says that you can punch through up to 3.5mm or 10GA aluminum by hands...
Well, I am currently involved with holemaking work, but I really don't think it's feasible.
Has anybody succeeded before?
Thanks.
Lhchen

 

[fdegrove]

Hi,

Has anybody succeeded before?

Sure enough...

Even through 3.5 mm steel if must be but it would kill the punches if you'd do that regularly.

Aluminium, however, is pretty soft and the Greenlees go through it like a knife through butter.

Cheers,