Roller track gauge for use with C&L and Exactoscale chairs

[hayfield]

A friend has offered to custom build a roller gauge for me to use with both C&L and Exactoscale track building parts. The problem is that as many of you know the chairs hold the rail at a 1 in 20 inclination as per prototype. The trouble is that the standard roller gauge has straight cut groves which hold the rail vertical not at an angle. So once the gauge is removed the chairs return from the vertical to the inclination, thus narrowing the gauge.

 

One option is to have the inside part of the gauge the full depth, one gauge I have has a depth of about 1mm and the outside 0.5mm, see the awful drawing below.

 

 

 

The idea is that the inside part of the roller gauge holds the rails in gauge, but the outside part of the roller gauge holds the rail without bending it to the vertical. I was hoping for a couple to EM gauge.

 

When it comes to curved track then I guess you could either do the same to a 3 point gauge, or as Exactoscale does, have 3 gauges +0.1, + 0.2 and + 0.3. ( I guess these are in mm ) The problem with these is they only have inside flanges

 

Thoughts please on the depth of both parts which hold the rail both in depth and width, also should the gap be slightly larger. I guess the same can be done with P4 if this method works.

[Debs.]

Why not simply have the gauge slot barely deep enough to sit on half (or perhaps three-quarters) the depth of just the head of the bullhead rail; thus permitting the whole rail to (effectively) 'pivot' beneath that and sit at the chair`s correct seat-angle.

 

IME, for it to reliably gauge in this way you`ll need to make the slotting tool a very accurate fit indeed for the brand of rail(head) you are using, as they do vary in section width/height........You may find that it`s more of a toolmaking-accuracy challenge, rather than simply a precision machining task.

[hayfield]

Debs

 

Thanks for the advice, I do have some slightly older gauges with shallower slots ( I think it came from the EM gauge society) and the depth is about the head of the rail, I have measured the set I have got from C&L and they have a depth of about 1mm which gives a nice form hold. The rail I use is C&L code 75 so that will determine the width of the slot, what I wonder is should it be slightly wider than the width of the rail head.

 

As code 75 rail is 1.9mm tall, 1mm I thought would be a decent depth on the inside of the rail for stability and 0.5mm on the outer part which is appx the size of the head of the rail.

[buffalo]

John,

 

I'm with Debs on this. No need for a different depth either side, all you need is a sufficiently shallow slot that does not engage on the foot of the rail. The rail head has rounded corners and will rotate within this and take up the position determined by the chairs. I've shown you a three-point gauge before that was milled down to a suitable depth to achieve this. I've a couple of roller gauges amongst my collection that are already a suitable depth, I think they came from Alan Gibson though memory may be wrong. These photos should illustrate the point. The first shows the gauge on C&L rail and the second shows the gauge rotated by a large angle, but with the inner rail face still in contact with the gauging face:

 

 

 

Track built with these gauges is consistently with 0.03mm of the intended gauge, usually much closer.

 

If your current gauges are too deep, I'd suggest getting your friend to turn them down so the the slot is just a little deeper than the height of the rail head.

 

Nick

[hayfield]

Nick

 

Thanks very much again for repeating your advice. I do have a roller gauge from the EM gauge society which has a depth much the same as you have shown. However if I can I would like to improve on it. Basically I like the feel of the gauges with a deeper slot which I use for constructing copperclad turnouts rather than the gauges with the thinner slot

 

Firstly I would prefer one without a check rail gauge fitted, but more importantly I believe it would be easier to use if the inside part of the gauge was a bit longer (as per your suggestion on the adaptation of the 3 point gauge)

 

I think one of the 2 options for gauge widening is the adaptation of the 3 point gauge which you suggested, sadly I do not have a milling machine but fingers crossed I now may well have a contact who has the both the skill and machinery to do this. Thank you for confirming the depth required

[Miss Prism]

Hayfield - I feel you perhaps should distinguish between a thing used to construct track and a thing used to check the constructed gauge. Owing to rail inclinations and slightly different widths of railhead, what's suitable for the former, e.g. a triangular 'claw' gauge or the JBS 'springy-bar' design, isn't always good for the latter, e.g. Exacto's '+0.1, +0.2' etc.

 

If you have access to modern turning, you might consider something like this construction roller for non-widened TG, which will allow rail inclination but will not be too fussy about railhead width. It won't suit all parts of turnouts though, which is why different forms of TG gauge exist.

 

 

[hayfield]

Miss Prisum

 

That looks very promising, certainly better than my initial thoughts. Thank you