How do you drill out a headlight casting?

Model Railroader Layouts and layout building
1

I have a Penn Line I1sa model whose previous owner upgraded the detail with brass detail castings including including a headlight casting. The headlight had a crystal and silvered backing in it, which I removed when I removed the headlight from the model.

I want to drill out the brass casting to install a working headlight, but I haven’t had much luck drilling though the brass and I don’t want to damage the casting. Does anyone know anything about drilling out brass headlight castings?

S&S

2

Brass is a soft metal so you could probably drill it out by hand with a pin vise and bit. And I would do it in several incrimental steps rather than with just one drill bit. Also, if possible, I would place the casting in some sort of vise so that you have better control with your pin vise and bit.

Tom

3

Hi, S&S

I just performed this task a few weeks ago on a B&O Q4b I’m getting ready to paint. Brass is really nasty to drill because your drill is either too sharp and wants to grab or the brass work-hardens and you can drill forever and not make any progress. Those castings are notoriously thick where you have to drill, too.

You could find some that are already hollowed out for number boards from cal-Scale and others. On some brass engines I have used plastic moldings to avoid any chance of shorting the LED.

I used a smaller cordless hand drill and at slow speed drilled a #70 or so pilot hole. Once I had that I went progressively larger until I got to about #50 (.082) where I wanted to be.

The tender back-up light popped off when the drill grabbed but didn’t damage the headlight. I found that I could chuck the headlight in one of the larger pin vices I have, lens side out, and use the same process to drill it. I then used epoxy to recement the light to the tender body.

Hope this helps you out, Ed

4

The biggest problem with drilling brass castings is that if the drill bit bites in too hard the casting will spin in the jaws of your pliers and likely destroy all of the outside detail. However, sometimes it seems like the drill won’t bite in at all, which is usually caused by a deposit of brass on the tip of the drill bit.

When I am having those problems I resort to my Dremel tool with a round tip burr (or reamer if that is a more accurate term). It won’t bite in too aggressively, although you shouldn’t underestimate its ability to remove material quickly. I always brace my hand against the vise or workbench to control the movement of the grinder, and I use a very gentle touch. If my hand starts to shake I take a break. (I get lots of breaks it seems these days[swg][(-D]).

The hole doesn’t have to be perfect. You can use a round file to clean it up. If you don’t have a set of hobby files then I recommend making the small investment for a set like this:

http://www.walthers.com/exec/productinfo/271-55608

To protect the casting I wrap masking tape around the jaws of the pliers to cushion the grip. I put the tape on sticky side out to give more grip. You have to be careful because too much pressure will squash the casting. Been there - done that more than once[banghead]

Dave

5

You can minimize the size of the hole needed by using a tiny SMD LED. Doesn’t eliminate the difficulty, but cuts it down to an easier to handle size.

6

I agree with Tom (pin vise, gradual steps). Drilling the first hole is always the most difficult. Take your time. But you will need good quality bits. There was a recent thread about this. I also use a bit of oil to facilitate the process. Good luck!

7

Thank you all for your help!

Unfortunately I may not get to drilling the casting soon, since I just found a bind in the side rods that is occupying my time right now.

The brass casting has definitely hardened over time, and I have not been able to make any progress with a drill. I will try the pin vice technique first, and if that doesn’t work I think I will try using a burr.

S&S

8

Try using a Dental burr.

You can find some on E-Bay for a small investment.

Or talk to your denist. Most do not use the burr more than once so they just throw them away.

Here is just a sampleof what is out there. http://www.ebay.com/itm/Carbide-Burs-10-pcs-FG-57-Midwest-/331041980371?pt=LH_DefaultDomain_0&hash=item4d13a3bfd3

9

Woodone

Will the dental burrs fit into a standard Dremel tool?

Thanks

Dave

10

My Dremel came with three different size chuck inserts, so yes, it should. They fit in mine.

11

I have the same problem - those Dremels are big and heavy! I find that mounting the Dremel in a Dremel drill press and then having the part in a clamp that I slide around on the base of the drill press allows for a much greater degree of precision then trying to move the Dremel. The drilling depth limiter is another nice feature for machining because it keeps you from having a small “oops” and grinding away half your part [:-^].

S&S

12

S&S:

Good idea! I will investigate getting a Dremel drill press.

Thanks

Dave

13

S&S:

I just read through some reviews of the Dremel drill stand and not everyone is totally pleased with its performance. The major complaint seems to be that the Dremel tool is not mounted securely so the bit tends to wander around when drilling into some materials.

Any comments on that from anyone on the forum?

Dave

EDIT: I’m going to make this a separate topic so the question will be seen by more people.

Dave

14

The flexible extension Dremel offers might be a better way to go if you find the Dremel a chore to hold. That way you’re holding and moving less weight. It’s also easy to hang these near your workbench so it’s out of the way, but easily available.