The Home Machinist!

What you should take away from this is that it is NOT a tolerance issue. It is an engineering issue, one of not choosing a size that will provide the necessary clearance to compensate for the undulation of the engine as it moves along a not so perfect track. H Which is exactly what I intended to co...

I don't think this is the correct takeaway. It seems you are mixing up clearance with tolerance. They are not the same. I'm surprised others have not chimed in here, as this has been covered here on Chaski before. OK, I'm not sure what you think I don't understand here. Tolerance in my shop is the ...

Yes, that is what I have. Did not know where it came from though. This is for a smaller 7 1/2" gauge loke, cylinders and saddle are grey cast iron. Say larger than a Fitchburg but smaller than a standard Mogul. They'll be silver soldered together. The port areas I have in the drawings now proportion...

Good advice. I learned this from my first mentor, the chief inspector for an aerospace tool & die works. He built his first locomotive to "plant" tolerances and it wouldn't run. As soon a one end of a part heated up and the other end of it didn't, things locked up solid. Relieving almost every slid...

I've been reading the RRSC "engineering manual" and also some old steam engine design books based on full scale practice. RRSC manual states ports should be at least .4 * diameter of cylinder long, then backs into width. The .4 factor is based on making cores that will stay during a pour. Writer end...

Looks like there is a little bit of pipe proud of the female part. Hacksaw blade to top of threads, take a punch and collapse the pipe. If you can get it started collapsing, you've got it.

What a beautiful place for a RR.

One thing I considered after looking at Liveaboard's post at the top - that red hot block is going to transfer quite a bit of heat into the shaft. The block is then going to shrink, with the shaft being the last to cool. I think it's quite possible the shaft will be "shrunk" by this, leading to less...

These folks bought out American Model Engineering, which made imperial sized miniature fasteners. http://www.godshallscustommachining.com/american-model-engineering-supply.html Here's the catalogue from the original website. http://www.americanmodeleng.com/id14.html Here's a place with metric and im...

used moulding sand. A core that the foundry was too lazy to remove after the casting was poured? Possibly, but this casting had a steel plate bolted onto the bottom that was the whole size of the saddle, and the sand was packed around the steam/exhaust pipes. The sand was tight against the steel pl...

Going back to college physics, we were all a bit surprised to learn that the area of contact was not a factor in the equation for friction. Friction is calculated simply Frictional force = force normal to the plane x coefficient of friction. Axle loading is a real good reason to have more axles thou...

In 12" = 1'-0" scale, we had a little Porter 0-4-0T at the museum - I mean TINY for standard gauge. That area was packed full of what I now believe was used moulding sand. It was really hard to dig out. The smokebox was open to the cavity for the steam & exhaust piping, so the sand was probably the ...