Cone angle for railway wheels?

If we were to make our own wheels, how important would it be for the cone angle to be 3 degrees, and for the flange angle to be 10 degrees?

Could we have, say, 4 degrees and 11 degrees? (Because peering at some old N gauge wheelsets here, they look (without measuring) to be much steeper)

The reason I ask is the realisation that the indexable tipped tools by Glanze and sold by Chronos have an angle of 105 degrees on the bigger of the two angles making up the diamond shape, and this would make for a much simpler tool set-up, accompanied by a single parallel cut from the crossslide.

Yes - we'd be cutting on both faces of the tip, but only for the short distances represented by (in my case) 16mm ng wheels.

Reply to
gareth
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Depends on the track/rail standards. As you've found, some older N wheels have much steeper angles, where almost anything will run through chunky code-80 N track.

My concern would be whether the tipped tools hold enough of a point at the

105 degree angle to get into the corner, but not too much as there needs to be a radius transition from tread to flange. And you'll still need to do the rear of the flange.

For the handful of wheels I make, I use a single point tool, set angles on top-slide, etc.. I finish the fine curves with a hand graver (very basic watchmaking tool).

If the wheels are for electrical pickup, surface finish is more important than angles; near polished is ideal.

- Nigel

Reply to
Nigel Cliffe

The debate between the cone treaders, and the flat treaders has been raging for nearly a century! Hardly matters, as the radius between tread and flange does the job quite well on models of any gauge up to 7 1/4" - 7 1/2".

That's my opinion anyway!

Steve R.

Reply to
Steve R.

Coning of treads serves two functions:

- centering the wheelsets on the track with no friction from the flanges.

- it provides a "differential" effect because on curves the largest diameter is on the outside rail and the smallest diameter (wheel) is on the inside rail of the curve. The 3 degrees/1:20 angle is the same as on most prototypes but we tend to run much sharper curves for which we don't make any allowance.

IOWs it's an angle found to work well on the prototype and logically a much greater angle would probably work better on our models. The flange angle is there to push the wheel against the outer rail for "steering". The closer the flange face comes to being parallel to the rail, the greater the friction/the less wheels a locomotive will pull. Note that the effective angle of the flangle is a straight horizontal cross section at rail-top height, not the angle we cut on the lathe. Note that our model flanges interact with the rail at a much greater angle than does the prototype because of our sharper curves. (your longest rigid wheelbase describes a chord across your sharpest radius. Basic geometry will give you the angle that your flange intersects at.

Last point: the fillet between the tread and flange does most of the guiding, the remainder of the flange deals with worst case rail misalignment and rail gaps. (neither of which should exist anyway ;-) The curved surfaces at the tip of the flange, both inside and out, project the flange beyond it's actual extent, so those are also important.

Greg.P. NZ

Reply to
Greg Procter

Thanks for a most enlightening reply, the gist of which I take to be, "Just go ahead with it!"

I liked your term, "angle of the flangle" :-)

Reply to
gareth

Hi Gareth,

long long ago when I bought my first lathe I decided I couldn't live any longer with Maerkln and 3 rail/stud contact. I trimed the HO wheels to NMRA RP25 dimensions overall and isolated the relevant bits. While the wheels were in the lathe I used a fine file to round the various bits until they looked like the RP25 profile. I might have tossed out a wagon wheel or two out of a couple of hundred attempted, but all the loco wheels worked.

I did learn the importance of the fillets and curves and that the dimension from the front of one flange to the back of the opposite wheel is THE important dimension. Total wheel width or tread width is important in relation to frog gap width. (if it falls in it won't work 100%)

Give it a go - if you get it wrong you can make a new wheel!

Greg.P.

gareth wrote:

Reply to
Greg Procter

That's what I keep trying to tell people, but they insist on measuring back-to-back and using the same gauges regardless of the wheel manufacturer.

MBQ

Reply to
manatbandq

On Oct 5, 2:24=A0am, Greg Procter wrote: SNIP

SNIP

Greg

You are correct with your first observation. The coning of the wheels is there to centre the wheelset within gauge and to limit "hunting" (ie where the wheelset bounces back anf forth against alternate flanges).

However, the assumption that it provides adequate differential on curves is a myth and has been disproved many times in Model Magazines

- as well as in publications on full-sized rail vehicles. Simple maths using prototypical rail curves, tread widths and tread coning easily shows that the differential circumference due to coning is nowhere near the differential path lengths on the rails.

Andy

Reply to
houstonceng

Generally its easier to check back-to-back distance B but you have to check flange thickness T also. Check gauge K = B + T. When measuring flange thickness T remember to measure at the right distance P from the thread as shown in RP-25.

Reply to
Erik Olsen

The importance of check gauge is poorly understood. In another group, I had an confusing with a poster who thought that RP-25 should have a flange thickness standard, not realising that the check gauge (which is specified) automatically gave him that.

wolf k.

Reply to
Wolf K

That should read "...the check gauge in conjunction with back-to-back (which are specified) gave him [flange thickness.]"

cheers, wolf k.

Reply to
Wolf K

Either you're not trying hard enough or ... Years ago I produced a range of B2B guages on the NZ market for individual wheel manufacturers so anything could be operated on the purchasers layout - surprise surprise, they didn't sell, but the ones labeled RP25, Brit standard, NEM and Marklin B2B sold like hot cakes until I got bored making them.

Greg.P.

Reply to
Greg Procter

I bow to your superior knowledge!

Greg.P.

Reply to
Greg Procter

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