Re: Radius Testing - Practical Experiments.
Posted: Sat Nov 10, 2018 5:50 pm
Knuckles I've been thinking why my 782 is happy going round much sharper curves than I designed. I think it
proves what Will L says on this page:
viewtopic.php?f=96&t=5030
You'll find useful and helpful stuff there. Particularly this conclusion
"This goes along with my experience that suggests that most of the problems people have getting locos round corners are much more to do with insufficient clearance between the wheels and the bodywork than any issue gauge widening. Having a test curve of your minimum radius on the work bench and building so that your locos go round it should see you home and clear."
And
"This is telling us that with 0.5mm end float on its middle axle our Black 5 is in only need of Gauge Widening on curves below 850mm (2’9”), and only if we are run monsters like a J19* should we to need to worry about gauge widening."
I didn't factor into my calculations on any of my loco builds either the Running Clearance or slop of 0.28mm nor the gauge widening given by the triangular tool. So he's right, P4 slop plus 0.5 sideplay on middle axle is going to get most locos round most likely modellers curves. The issue is much more to do with bogie and pony wheel (or Cartazzi truck) clearance from the chassis/bodywork.
Whether articulated frames and widened cylinders are needed you will have to find out but I would have thought they would add to the difficulties...no means of knowing except practical experience.
And by the way, yes regarding Check Rail gauged from the crossing. The 2ft test track incorporates the crossings of points (i.e. dummy points) to prove the point . The running reliability of switches of turnouts on 34" radius I would have thought could be more problematic.
PS obviously this was part of a discussion about gauge widening, and how much is needed. I think we're all agreed that the triangular tool works just fine.
proves what Will L says on this page:
viewtopic.php?f=96&t=5030
You'll find useful and helpful stuff there. Particularly this conclusion
"This goes along with my experience that suggests that most of the problems people have getting locos round corners are much more to do with insufficient clearance between the wheels and the bodywork than any issue gauge widening. Having a test curve of your minimum radius on the work bench and building so that your locos go round it should see you home and clear."
And
"This is telling us that with 0.5mm end float on its middle axle our Black 5 is in only need of Gauge Widening on curves below 850mm (2’9”), and only if we are run monsters like a J19* should we to need to worry about gauge widening."
I didn't factor into my calculations on any of my loco builds either the Running Clearance or slop of 0.28mm nor the gauge widening given by the triangular tool. So he's right, P4 slop plus 0.5 sideplay on middle axle is going to get most locos round most likely modellers curves. The issue is much more to do with bogie and pony wheel (or Cartazzi truck) clearance from the chassis/bodywork.
Whether articulated frames and widened cylinders are needed you will have to find out but I would have thought they would add to the difficulties...no means of knowing except practical experience.
And by the way, yes regarding Check Rail gauged from the crossing. The 2ft test track incorporates the crossings of points (i.e. dummy points) to prove the point . The running reliability of switches of turnouts on 34" radius I would have thought could be more problematic.
PS obviously this was part of a discussion about gauge widening, and how much is needed. I think we're all agreed that the triangular tool works just fine.