TH&B 70 ton hopper 1231 in Kinnear Old South Yard. Photo by Gerry Schaefer
This page compiles the posts about TH&B 70 ton hoppers in one place for easier navigation.
Part 1 – Introduction
Part 2 – How the cars were used
Part 3 – Slime service
Part 4 – Removing and replacing cast-on details
Part 5 – Paint and decals
Part 6 – Stock trucks aren’t so nice
Part 7 – Intermountain wheel sets
Part 8 – Weathering the trucks
Part 9 – Weathering the finished car
Ontario in HO Scale 
Hi Hunter,
I was woundering, what do you use to ream a spot you will later drill? I have a number of holes to drill and would like to be accurate as possable. I’m a fan of your work!
Best, Scott
Hi Scott. I’m flattered that you’re a fan, but please don’t consider me an authority on model building. I still have plenty to learn.
To mark the spot where a hole will be drilled into plastic or resin, I use a couple of different approaches. I have an awl with a very precise tip that I use for marking. Or I sometimes use an x-acto blade. I carefully position the tip of the blade where the hole will be and spin the knife handle once to make a mark. For very small holes that will be drilled in a repeated pattern, I sometimes build a jig with the holes in the places where I’ll need them. The single most important tool that has helped me to build more precisely is my magnifying visor, followed by my digital caliper.
To drill for the grab irons on the corners of the 70 ton hoppers, I used the location of the cast-on rivet to mark were my hole will be. Using an x-acto chisel blade, I slice under the two rivets and chop downward to cut them free from the cast-on grab iron. This leaves behind two circles, which then drilled through to accommodate the wire grab. Once the holes were drilled, I went back and removed the cast-on grab irons. That’s not my invention. I think I read about that technique in MR thirty years ago.
Some of the people who regularly read my blog are true master model builders. Hopefully some of them will share their wisdom on marking and starting precisely located holes.