|alan lloyd 3||14/06/2013 19:18:37|
141 forum posts
Hi, i have started to machine the engines wheels, there is not enough meat on my castings to obtain the 101mm dia for the tyres, the largest they have cleaned up to is 99.5 dia, not a great problem, but i wonder if anybody else has had this? I contacted Polly but because i've had the castings for over 2 years they don't want to know, i pointed out some people have sets of castings for years before they get round machining them, still they won't exchange them. if you have bought castings from any where do measure them to make sure theres enough meat on them, just a word of warning.
|John Alexander Stewart||15/06/2013 14:39:13|
|738 forum posts|
As I'm sure you know, full sized locomotives had tires (tyres?) that were turned on large lathes to reprofile them. I used to do a lot of full size stuff, but I'm forgetting the actual numbers, but a tire over here in Canada might have an extra inch of material available for removal before condemming.
So, 99.5mm might represent a locomotive that has had its tires turned, and as long as there's still something there (ie, you are not riding on the spokes) I'd be more than happy with that figure. And, it might look more prototypical than the 101mm.
How are you doing otherwise with the locomotive? I saw the preserved one early May for the first time, it was much more interesting than the 2 A4s beside it! (blasphemy, I know...)
|nick feast||23/07/2013 13:30:08|
75 forum posts
Just read this post, not been looking at the site lately.
As JohnS points out it is not unsurmountable but I am surprised. Measured 3 sets of machined wheels in the workshop and they are all close to 101.5 mm. However they were pre Polly doing the castings.
For the record the loco wheels on a Q1 were a nominal 5ft 1inch diameter. divide by 16 and metricate and you get about 97mm. I added a bit of diameter in the design, can't remember why now. Hopefully the detail of the wheel looks right.
4349 forum posts
Perhaps if they only had one wood pattern they used some castings as patterns so accumulated some shrinkage.
Edited By Bazyle on 23/07/2013 16:22:26
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