[COLOR="DarkGreen"]Use a flat surface and a 90-degree triangle or L-angle to align the new holes with the existing holes. Then measure the hole spacing off of the bottom edge to match the top edge.

Drill-press would work, but I cannot quite picture putting a shell on a press (I am a dinosaur).

Uni-Bits (stepped drill bits) are awesome for drilling shells because the holes never result in splintered or torn plys. if you are using a regular bit, just make sure it's nice and sharp.

In the absence of unibits, I usually drill the hole very small first (1/16" diameter or so) from outside-in and then drill the larger hole from inside- out.

ALWAYS BACK YOUR HOLES WITH A PIECE OF 1X OR 2X OR THE PLYS WILL TEAR; particularly old thin shells.

So the bottom edge is already shaped, eh ?[/COLOR]

Hello,

Thanks so much Jaye. Really appreciate your excellent advice. Hadn't thought about the triangle, that's probably the best way to go - thanks!

I had never even heard of uni-bits, I have since checked them out on-line.

I guess one would have to be careful not to drill too hard as to go through to the next "step" on the bit.

I don't know if I've got a drill that will be able to fit inside the 13", will have to see about that.

When you mention 1x and 2x, are you referring to just a regular scrap/block of wood?

What would you recommend to steady the tom? Just a regular clamp to a table?

The reason I mentioned a drill press was because I was worried about drilling the holes crooked by hand. But it sounds as though you've done this before with a hand drill.

By the bottom edge being shaped, do you mean flat?

I'm going to try and add some photos here.

Thanks for everything.

The bottom edge being a bearing edge and it looks like those shells have them. Even if you use a drill press you should back up the shell with a scrap piece of material. The shells are not that thick that you should worry about drilling a perfectly straight hole.

[COLOR="DarkRed"]What he said. Is the bottom bearing edge beveled and rounded already ? (it looks like it is, but hard to tell from pic).

Yes, just back the hole with solid pc. of wood.

You don't NEED a unibit....they just make things easier. They cut so clean that I have never come close to accidentally going to the next diameter.

I just hold the shell w/ my free hand. You can certainly clamp it.

Yes, you'd need a small enuff rig to get inside the 13. Mine can get inside a 12, but not a 10...so all my drilling on 10's or smaller is from outside.[/COLOR]

Thanks very much you guys, I appreciate all the info.

It's always a little nerve-wracking when you're about to attempt to do something you've never done or don't know how to go about it.

Thanks very much.

Take care.

I probably am going to sound like a dark cloud descending here, but...

I have to go on record for recommending against doing what you are proposing.

Here's why:

While I am not a fan of the old concert toms of that era, they are a style of drum that represented that era. I remember well when many drummers out there thought that the concert toms were THE shiz. Everybody wanted them. Anyone who had a string of them on their kits were cool. That's the way it was.

Nowadays, times have changed and most people smirk at the thought of concert toms.

But, trends change. because of this, I am fairly confident that the look will come back. I feel the sound will come back.

If your concert toms had looked chewed up or beaten up, then I would have probably not mentioned it -as the value would be in excellent examples. But your tom looks pretty much in really nice shape.

If you aren't familiar with such a job, this one may be a bit trickier than you might think. Any slight mis-measurement and your bottom head idea may not work. In fact, it might even sound worse! And then, not only is the project a loss, but it's the loss of a fairly nice example of a drum from "that time".

I advise you to leave them as-is and just get some two-headed Ludwig toms somewhere else.

I don't mean to be discouraging. Good luck in whatever you decide to do. They're your drums.Yes Sir

Although I am not a fan of concert toms either, I must agree with O-lugs. That tom looks to be in pretty good shape. How is the rest of the kit? Are you using these toms to match an existing kit? I did it on a Slingy tom that I got for real cheap but it needed a lot of work. If you decide on drilling, those being black shells, I would wrap blue painters tape around the shell where you are drilling the holes. Makes it easy to see your marks, less mistakes!

Good luck.

It's a good devils' advocate thought to have and a worthy consideration. BUT, they are just some old black cortex drums and they already appear to have bearing edges on their bottoms.

I'd get the drill, IMHO....

[COLOR="DarkRed"]Always possible that some day they will have a renaissance. But I just don't think they ever sound very good. If the shells were 6-ply no rings, then I think the argument becomes stronger to leave 'em. But the thin-ply ringed shells are just an animal made for a res head, in my opinion.[/COLOR]