Kozo Shay Wheels – Have I stuffed up the blank?

[HobbsParticipant @edwardhobbs3]

Hi Folks,

I've just started building a kozo shay, and I'm currently on chapter 1 building the wheels. I've started with one so I can see how the process goes, but I think I might have got too keen and made the flanges smaller than they should be.

I've got to the point where the blank needs to be mounted on a fixture to turn the tapers for flanges and tread, but the plans are difficult to read and I think that I have misread the flange width.

Apologies for the scribbles on the plans but I thought I should probably blank out the non-relevant dimensions to avoid copyright issues.

I've turned the blank (without tapers) to 2.5mm thick on the flange, as I thought that was the finished dimension for the base of the flange, but i think looking at the plans it may actually be 2.5 at the top of the flange. Should this cause an issue? From what I can see the worst thing that will happen is the flange will be slightly thinner at the outside edge, but given where the wheel runs and the small angle that might be fine? Any advice would be massively appreciated.

Hopefully this makes sense, happy to draw more pictures to clarify what I mean.

[HobbsParticipant @edwardhobbs3]

[Jeff DaymanParticipant @jeffdayman43397]

I doubt that it will make any practical difference. If you want to calculate the difference of the 2.5 dim at the OD or at the base of the flange, you can find it by solving a right angle triangle of 10 deg and the adjacent side as (od-base dia/2). probably not a big number. In addition the Shay is not a high speed express locomotive so it will be unlikely to "hunt" on the track as a high speed loco might if the wheel gauge was a bit wide caused by thin flanges. The original Shays were specifically designed to operate on rough temporary track, sometimes badly laid, in areas being logged.

[duncan webster 1Participant @duncanwebster1]

It's a fairly poor drawing! I'd get a copy of the SMEE wheel standards and work to that. Even that is a bit iffy, measuring to the intercept between a cone and a radius. I did have a way of measuring it using a roller against the tread and flange, if you're interested send me a PM and I'll try to root it out. I't for 5"g, but I could work it out for 3.5 if that's what you've got

[old martParticipant @oldmart]

Full size wheels often had a "tyre" shrunk on them as the old profile wore down. You could do the same with yours if you are very concerned. As already mentioned, it will not be particularly noticable if practice.

I was very lucky to be of the right age to go on a school outing to the Eastly Locomotive Works near the end of the steam era and saw tyres being shrunk on to locomotive wheels and later turned to the original profile. There was a pacific hanging about 30 feet up in the air when we visited.

[HobbsParticipant @edwardhobbs3]

Sorry for the delay, thanks for all the responses – It sounds as though it shouldn't be the end of the world.

Given I still need to make at least 7 more I think I'll chalk this one up as a test part, finish it off to see how turning the tapers goes then proceed with the SMEE 3.5" standard wheels for the 8 that will actually end up on the loco.

[Another JohnSParticipant @anotherjohns]

Edward;

Just FYI, there is a gentleman over on modelenginemaker who did a fantastic writeup on making his "new Kozo" shay, using small machine tools.

Chris Rueby is his name; he's a prolific builder and always interesting and mentally positive to read his postings.

I'll try and put a link in here:

Chris Rueby Shay Build

You might need to register to see the photos, so if no photos present, it's worth it in my opinion to see how he works, and how to build on small non-industrial-sized machines.

You'll note that he made 9 wheels at once, 9 in case one did not turn out, and, well, one did not turn out!

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