What's the most painless way of enlarging the chassis tube socket holes?

[motzu]

Hello, I've built a Champ-style amp from a kit, and the chassis for it came with 1" tube socket holes (they're octal sockets, one for a 5Y3 rectifier tube and for the 6V6 power tube). I can fit all kinds of ceramic sockets in there, but I have to use a couple of washers to fit Belton Micalex octal sockets, which I strongly prefer (they're very tight and rattle-free).

Now, the washer solution works great, but I was thinking that maybe there's a painless way of enlarging the holes to fit the Beltons "properly". Please bear in mind that everything's already installed and working now, so I'd like to be able to enlarge the holes without removing the transformers, circuit board, etc. from the chassis. I also don't have a Dremel, or a step drill, or a punch drill, so if I'd have to buy something, and considering that this is probably the only time I'll ever have this problem, I'd like to be able to do it on the cheap. No point in throwing $200 at the problem and then forget the tools in some drawer (especially since I do have the option of doing nothing at all).

Thanks for reading.

[mooreamps]

I use a deburring tool to open up those holes. It takes a little bit of work..

-g

[JHow]

I would vote for step-drill. If you want cheap, go to harbor freight. You can use it anytime you drill a hole, so it will not be a one-time use of a tool. I would prefer drill over dremel, because drill will "follow" the orginal hole and the hole size will be uniform. You may still have to de-bur with dremel or de-burring tool. My second choice would be file, because dremel will remove a lot of material fast, which could get ugly.

[motzu]

Thank you for the replies. Unfortunately I can't go to Harbor Freight because I'm Romania, but there are a couple of HF-style alternatives here so I'll visit and see what the stock there.

[dai h.]

would a reamer work for that?

[motzu]

I've found a great solution. It's called a screw-hole punch - I've used one just like this one. The only other piece of equipment I've used was an ordinary wrench for turning the screw. Perfect holes, with the proper diameter out-of-the box.

It worked just fine for an approximately 2mm-thick steel chassis. There's also a more expensive version that uses a ball bearing between the screw and the metal cup that supposedly decreases the necessary applied force by 67%, but I was able to cut through with the regular version.

http://www.lmmpro.si/ruko/english_07...le_punches.pdf

Hope this helps.

[JHow]

Yup those are dandy, but I figured you didn't want a one-purpose-only tool. Here (USA) the punches are made by Greenlee, but also you can find old ones under the names Olson, Pioneer and Walsco.