Finding the centre of a boiler?

Model Railroader General Discussion (Model Railroader)
1

Hello everyone,

I need a bit of help sorting out a problem. I need to drill a small hole in the top of a boiler so that a bell can be inserted and glued in place. After I finish work that needs to be done around that area, I’ll have to find the centre of the boiler so that the bell is installed in the correct place.

How would I do this and after, drill the hole?

Thanks in advance.

2

Let me see if I understand your question. I think what you are trying to find is the CENTER LINE along the top of the boiler. Unless the boiler if off-centered, that would probably be the HIGHEST point of the boiler at that particular cross section. If the other parts of the locomotive- walkways, etc are located equally on each side of the boiler, that CENTER LINE should also be at the center line of the entire locomotive.

If your boiler ON the locomotive-- and the loco standing on its wheels where you can easily see the highest point, or measure with an offset height gauge? If the boiler is NOT on the loco, does its had a firebox that makes it easy to determine which side is up and down.

3

Here’s how to make a center/centre finder: http://www.instructables.com/id/Make-a-Center-Finder/

Step 9 shows how to use.

However, this may be more in line with what you need to do: http://www.wttool.com/product-exec/product_id/17753/nm/Round_Bar_Center_Finder_PEC_Tools_

This is essentially the same thing, just illustrated photographically. http://www.hartvilletool.com/product/10831

Hope this helps.

Andre

4

Suppose you wrap a piece of scotch tape from one hand rail to the other, across the boiler. Mark where the hand rails are and remove the tape. Lay the tape flat and find/mark the center between the two hand-rail lines. Then reinstall the tape and prick through it with an x-axcto knife at the center point. Remove the tape and drill the hole.

As far as drilling the hole, I recommend a drill press as the best way to do it. Lacking that, I’d go to a twist drill in a pin vise, because it is slow enough that you can eyeball your work and make little adjustments to your angle.

5

To find the center line of the top of the boiler on my scratchbuilt steam projects, I start by setting the boiler on a flat surface right side up. The boiler sitting on the fire box will keep it level as long as there are no appliances or piping in the way. Now grab your scale ruler and hold it perpendicular and level to the top of the boiler and using the edge of the ruler drag it back and forth on the boiler top. It will scribe a mark in the exact center of the boiler. If the boiler won’t sit level on your work bench due to piping or appliances hanging down, you can do the same thing with the boiler attached to the chassis. Just make sure the loco stands level and doesn’t lean to one side.

John.

6

Thanks to all who provided advice. As it turned out, there was a small hole on the top of the boiler where I wanted to put the bell from something that I had removed earlier. It was just a matter of driling a larger hole in the same place. I’ll try my best to post some pictures of the engine if i have some time.