Use of roller gauge

[martin_wynne]

As for wheel drop from the knuckle to the V nose, I seem to remember a thread on this site where it was stated that unless you build to P4 (or was it S4)standards then there will be an amount of wheel drop anyway, in EM & 00 because of the looser tolerances used in these gauges.

Hi John,

 

This isn't true.

 

There is far too much misinformation spread on these subjects -- let's not add to it.

 

There is NO wheel drop in 00-SF, DOGA-Fine, and EM, provided wheels are at least 2.3mm wide, which in practice means virtually all wheels on the market intended for 00 and EM. If you are getting wheel-drop in these gauges, there is something wrong with your 1.0mm flangeway gaps.

 

There is NO wheel drop in 00-BF, provided wheels are at least 2.8mm wide. Unfortunately there are many wheels on the market, sold for "00 Gauge", which are narrower than 2.8mm and these do therefore drop in the crossings on 00-BF. For this reason the impression has gained currency that wheel-drop is inevitable in 00. It isn't -- all that is required to prevent it is that the wheel width complies with the relevant standard.

 

Given that most modellers are stuck with the wheels currently available, the solution is to use 00-SF or DOGA-Fine standards to get good running from them. Of those two, 00-SF has the massive advantage that it doesn't require any change to the wheel back-to-back spacing on the axle, and gives good running without wheel-drop for wheels as supplied.

 

regards,

 

Martin.

[Guest jonte]

Jonte

 

Well done in not giving up you seem to be progressing very well. I seem to have missed how the V is higher than the wing rails.

 

As for wheel drop from the knuckle to the V nose, I seem to remember a thread on this site where it was stated that unless you build to P4 (or was it S4)standards then there will be an amount of wheel drop anyway, in EM & 00 because of the looser tolerances used in these gauges.

 

 

Thanks for the encouragement, John; it's deeply appreciated.

 

With regard to the dropping wheel, I'm of course guessing tht the radius on the wingrail is the cause of the problem; in truth, I've absolutely no idea!!

 

However, I'm sure this isn't right and it concerns me. Perhaps my car feeler gauge isn't as accurate as it may seem? Food for thought.

 

Jonte.

[Guest jonte]

Well, I'm pleased to report that although it's been a long time coming, said point to OO-SF standards (in a fashion anyway) is finished:

 

 

Still to have some ply sleepers fabricated, it's otherwise complete.

 

Rather than use a piece of narrower PCB between the sleepers as a tie bar, I've opted for a moving sleeper. Frankly, I'm not sure I like it; future attempts will revert, therefore, to the former.

 

And does it work? Yes. Prior to wiring, a Bachmann van traversed both roads as though running on air. Result.

 

The Hornby M7 followed suit and I was rather pleased. It shuddered in one or two places at slow speeds, but the rail is second hand and despite a good clean with white spirit followed by a dry rub with denim material, it would benefit from a further polish. Perhaps the loco wheels could benefit from a 'shine' too.

 

Only one point of note: on the diverging road, the M7 makes a noticeable and sudden change in direction, which the van didn't.

 

Consequently, I'm not sure whether I'd class the exercise as an absolute success. When it comes to smooth running I'm extremely fussy.

 

So, will I build the layout to OO-SF instead of 'OO' gauge? Dunno, to be honest. The jury's out.

 

Best wishes,

 

Jonte

[craigwelsh]

Only one point of note: on the diverging road, the M7 makes a noticeable and sudden change in direction, which the van didn't.

 

Best wishes,

Jonte

Looking at the last photo it does look like the diverging route is formed of two straights with a sharp turn in between. Better to make a railway curve to the desired radii and compare what you have against that.

 

Sounds like you're 99% of the way there though!

[Guest jonte]

Looking at the last photo it does look like the diverging route is formed of two straights with a sharp turn in between. Better to make a railway curve to the desired radii and compare what you have against that.

 

Sounds like you're 99% of the way there though!

 

 

Thanks, Craig. You're most kind.

 

I was quite pleased with the curves of both stock and switch/closure rais - in the previous photos, the closure rail wasn't soldered down and followed the curve of the template nicely, as did the stock rail before it. However, when gauging against the vee, the smooth curvature of the stock rail is lost as it is when gauging off against the closure rail. I'd considered letting the gauge widen to keep the curvature, however, thought I'd better stick religiously to the dictat of the calipers. Why is none of this straightforward!!!!!

 

Jonte

[Guest jonte]

Thought I'd write this down before it goes out of my head.

 

Lying in bed earlier, thoughts returned to my recent build, especially the problem encountered with height differences between Vee and wing rails. Suddenly, the penny dropped, so thought I'd better write it down before it goes completely out of my head.

 

So then, what did I conclude? But before I do, please be lenient, folks; I'm no technician.

 

Well, the problem isn't with the rails as I see it, but the wheels, specifically the rims with which I'm sure most contributors on this forum will be familiar. Cone shaped ( which is the only way I can describe them) they spend the majority of the time riding on the surface of the rim that's nearest the wheel face i.e. the deepest part of the cone shape. So, here comes the technical bit: when it traverses the closure and lower part of the wing rail, it's riding on the deepest part of the rim as suggested. However, as it crosses the knuckle of the wing rail, the rail begins to diverge as the wheel approaches the gap between vee nose and diverging wing rail. Just prior to leaving the wing rail, by which time it's mainly over the gap, the rail is now in contact with the outside surface of the wheel rim i.e. the shallowest point of the cone, therefore, the wheel has descended by a height equal to the difference between the inside of the wheel rim and the outside rim (I think I gave it as 0.1 mm) so by the time it reaches the vee, the wheel has dropped by that distance and therefore smacks the nose of the vee head on. The reverse is the case when travelling in the opposite direction.

 

So, what is the solution then? Well, the only suggestion I can make is to narrow the gap between wing and crossing rail at that point i.e. flangeway distance, however, it is likely that the more random measurements of 'OO' gauge wheels are likely to cause them to become 'squeezed' in the tighter flangeway settings.

 

Conclusion? Perhaps finer tolerances are not for 'OO' gauge afterall and should be the sole preserve of matching wheel and track standards i.e. EM and P4.

 

Please feel free to give me six of the best for sacrilege before banning me from posting on here ever again

 

Best wishes,

 

Jonte

[blueeighties]

Hi. Youre going through the exact same thought processes I did. And it did my head in

The really critical thing seemed to be getting the wing rails perfectly placed. The one pre constructed common crossing I had worked perfectly, the next 4 I tried to build myself didn't.

I'm past the headaches and just don't think about it anymore

Best of luck!

Regards,

Lee.

[martin_wynne]

So, what is the solution then?

Hi Jonte,

 

The solution is to follow prototype practice in preparing the nose of the vee. More info on preparing vees here:

 

http://85a.co.uk/for...hp?post_id=8326

 

from which (posted for the umpteenth time in various topics and forums ) :

 

The final tasks are to blunt off the nose as shown, to a scale width of 3/4" (bullhead) or 5/8" (flat-bottom), and to re-instate the rail-head corner radius on the filed areas. A few strokes with a fine file and a final polish with abrasive paper will do that.

It's also a good idea to take a few thou off the top of the vee nose so that it dips down slightly below the level of the wing rails. This allows for the coning angle on the wheels as they run off the wing rail onto the nose, producing smoother running. You can see these features in the prototype here:

© Mick Nicholson with thanks

Showing the blunt nose of the crossing vee supported on a timber, with the actual gauge intersection located between the timbers. The top of the vee nose is taken down slightly below the level of the wing rails, and rounded off. Also a good illustration of the "slab & bracket" type of "A" chair.

 

Note that this works just the same in 00 as in EM or P4. All you need for good running in 00 is 1) a good quality set of gauge tools, 2) wheels of the correct width and profile to match, 3) wheels set to the proper BEF dimension (back-to-back).

 

Please don't perpetuate the misunderstanding that running in 00 gauge can't be just as good as in EM and P4.

 

regards,

 

Martin.

[craigwelsh]

So, what is the solution then? Well, the only suggestion I can make is to narrow the gap between wing and crossing rail at that point i.e. flangeway distance, however, it is likely that the more random measurements of 'OO' gauge wheels are likely to cause them to become 'squeezed' in the tighter flangeway settings.

 

Best wishes,

Jonte

Make the wing rail knuckle sharper than you currently have it and the tread will be supported higher up the cone for longer leading to less drop. Also when you round off the nose of the vee a little the wheelset doesn't bump up again the same.

 

Even with a little bit of a bump it should still be a lot better than Peco in looks and running.

 

Thinking about your earlier post i'd suggest a Hornby M7 is a bad choice for testing track as its got no side control on the bogie so isn't guided around curves properly. You'll see a change in direction being more dramatic with that particular loco. A plain 0-6-0/0-8-0 would probably be better.

[Guest jonte]

Hi. Youre going through the exact same thought processes I did. And it did my head in

The really critical thing seemed to be getting the wing rails perfectly placed. The one pre constructed common crossing I had worked perfectly, the next 4 I tried to build myself didn't.

I'm past the headaches and just don't think about it anymore

Best of luck!

Regards,

Lee.

 

Wise words indeed, Lee.

 

Now pass me the bottle...

 

Jon

[Guest jonte]

 

Please don't perpetuate the misunderstanding that running in 00 gauge can't be just as good as in EM and P4.

 

 

Sincerest apologies, Martin. Not trying to make your job harder, just thinking out loud - it's just the way my brain works I'm afraid. I think we're in pretty much of a safe environment here to do so. I shaln't repeat this any of this in open forum, I assure you.

 

All of this is now beginning to make sense, Martin, and I thank you for taking the trouble to compile your post for my benefit. I'm sure others will find it most helpful too.

 

Best wishes, Martin.

 

Jonte

[Guest jonte]

Make the wing rail knuckle sharper than you currently have it and the tread will be supported higher up the cone for longer leading to less drop. Also when you round off the nose of the vee a little the wheelset doesn't bump up again the same.

 

Even with a little bit of a bump it should still be a lot better than Peco in looks and running.

 

Thinking about your earlier post i'd suggest a Hornby M7 is a bad choice for testing track as its got no side control on the bogie so isn't guided around curves properly. You'll see a change in direction being more dramatic with that particular loco. A plain 0-6-0/0-8-0 would probably be better.

 

 

That really is most reassuring to know, Craig, thank you. To be frank, I think I'm right in saying that the choice of say a 1 : 8 vee would be less of a challenge for stock and more akin to the mainline, however, not sure whether they might be too long to accomodate on my 7' 6" baseboard? Does anybody know how long turnouts of this proportion are and where I could print off a template?

 

Best wishes,

 

Jonte

[craigwelsh]

1:8 is the crossing angle, total length of the arrangement would then depend on the switches chosen. You would normally have B switches with a 1:8 though you could model loose heel switches to give a shorter formation.

 

A B7 would probably be better on your short length of board. A B8 would probably still be restricted to something like 45mph in speed!

 

Martin or someone else should be able to help with length in 00 as you have to modify angles a bit.

[Guest jonte]

1:8 is the crossing angle, total length of the arrangement would then depend on the switches chosen. You would normally have B switches with a 1:8 though you could model loose heel switches to give a shorter formation.

 

A B7 would probably be better on your short length of board. A B8 would probably still be restricted to something like 45mph in speed!

 

Martin or someone else should be able to help with length in 00 as you have to modify angles a bit.

 

Thanks, Craig.

 

Jonte

[martin_wynne]

Does anybody know how long turnouts of this proportion are and where I could print off a template?

Hi Jonte,

 

Here attached is a printable PDF template from Templot. It's a B-7 in 00-SF. You should be able to print it easily from Adobe Reader or Foxit Reader. When printing make sure you set scaling to "none" -- the thin blue lines should be exactly 50mm apart both ways.

 

00_sf_b7.pdf

 

regards,

 

Martin.

[Guest jonte]

Hi Jonte,

 

Here attached is a printable PDF template from Templot. It's a B-7 in 00-SF. You should be able to print it easily from Adobe Reader or Foxit Reader. When printing make sure you set scaling to "none" -- the thin blue lines should be exactly 50mm apart both ways.

 

00_sf_b7.pdf

 

regards,

 

Martin.

 

Wow! That looks tremendous, Martin. Thank you. I think this is more along the lines of what I'm looking for.

 

Took a little more time to assimilate the contents of your earlier post; I look forward to trying out your method of vee forming - appears fail safe.

 

Thanks once again.

 

Best wishes,

 

Jonte.

[hayfield]

Wow! That looks tremendous, Martin. Thank you. I think this is more along the lines of what I'm looking for.

 

Took a little more time to assimilate the contents of your earlier post; I look forward to trying out your method of vee forming - appears fail safe.

 

Thanks once again.

 

Best wishes,

 

Jonte.

 

Jonte

 

I am a Templot user and I find it much easier building from these templates rather than C&L plans, as the latter is not as clear and well defined as Templot. Also I can print them off in what ever size, radii and configerations I require, but that a different story.

 

Good luck with the build and thanks to all who have contributed to this interesting thread

[Guest jonte]

Jonte

 

I am a Templot user and I find it much easier building from these templates rather than C&L plans, as the latter is not as clear and well defined as Templot. Also I can print them off in what ever size, radii and configerations I require, but that a different story.

 

Good luck with the build and thanks to all who have contributed to this interesting thread

 

 

Thanks, Hayfield.

 

Yes, it has been interesting - in my case novel - and I'm truly grateful to those who've generously shared their indepth knowledge of the subject.

 

Jonte

[Donw]

From my data I can tell you that a SR B8 would have a lead (the distance from the points of the blades to the crossing nose of 65ft1.25ins and an effective radius of 612ft. If you simply scale these by 4mm to 1ft you would not get it correct because the gauge is not at 4mm:1ft for 16.5 mm these dimension should be at 3.5mm:1ft. Other dimensions are the switch rail having a planned length of 7ft 4in at an angle of 1/32. The beauty of templot is that is does all of this for you and allows you to curve both legs and knit together a number of turnouts. Comercial printed template are so restrictive.

 

Interestingly the SR C8 turnout has a lead of 73ft5.5ins but an effective radius of 563ft. Showing the C switch giving a slower transistion to the curve which is then tighter. I would suggest that b6's in the yard and b7 or b8 for the mainline turnouts would be suitable unless you are really compressed when A5.5 and B6 have worked well for me in 0 gauge.

Don

[Guest jonte]

From my data I can tell you that a SR B8 would have a lead (the distance from the points of the blades to the crossing nose of 65ft1.25ins and an effective radius of 612ft. If you simply scale these by 4mm to 1ft you would not get it correct because the gauge is not at 4mm:1ft for 16.5 mm these dimension should be at 3.5mm:1ft. Other dimensions are the switch rail having a planned length of 7ft 4in at an angle of 1/32. The beauty of templot is that is does all of this for you and allows you to curve both legs and knit together a number of turnouts. Comercial printed template are so restrictive.

 

Interestingly the SR C8 turnout has a lead of 73ft5.5ins but an effective radius of 563ft. Showing the C switch giving a slower transistion to the curve which is then tighter. I would suggest that b6's in the yard and b7 or b8 for the mainline turnouts would be suitable unless you are really compressed when A5.5 and B6 have worked well for me in 0 gauge.

Don

 

 

I shaln't argue with any of that, Don. Thank you. It's easy to overlook that we're scaling things out for 'HO' here and not 4mm scale.

 

Incidentally, I was thinking of B6 in the yard and B7 on the main so thanks for the confirmation. Mind you, let's see how I fare with my next one before I get too carried away

 

Best wishes, Don.

 

Jonte

[martin_wynne]

I was thinking of B6 in the yard and B7 on the main

Hi Jonte,

 

B-6 is a popular model size, but not very common on the prototype. The B-switch is a bit too long for a 1:6 V-crossing. In a yard (but not a running line) an A-6 is more likely.

 

However, for the largest radius in the shortest turnout, you might prefer to use loose-heel geometry rather than the REA switches. By changing to a 12ft switch instead of the B switch, you can get a shorter turnout while actually increasing the radius:

 

templates from Templot

 

A 12ft switch has the same 1:32 planing angle as a B switch, so you can use the same point blades for both.

 

regards,

 

Martin.

[trisonic]

Martin,

Is there a difference between "loose heeled switches" and "pivot heeled"?

 

Best, Pete.

[craigwelsh]

Martin,

Is there a difference between "loose heeled switches" and "pivot heeled"?

Best, Pete.

If pivot heel is an American term for a loose tightened fishplate and a chair not holding the rail firmly in place then no difference.

edit: There are some British industrial pics referred to as pivot but they look to be basically the same idea of pivoting at the fishplate.

 

Worth noting in model form people don't always bother to make it a proper loose heel and flex the rail as before..

[Guest jonte]

Hi Jonte,

 

B-6 is a popular size, but not very common on the prototype. The B-switch is a bit too long for a 1:6 V-crossing. In a yard (but not a running line) an A-6 is more likely.

 

However, for the largest radius in the shortest turnout, you might prefer to use loose-heel geometry rather than the REA switches. By changing to a 12ft switch instead of the B switch, you can get a shorter turnout while actually increasing the radius:

 

templates from Templot

 

A 12ft switch has the same 1:32 planing angle as a B switch, so you can use the same point blades for both.

 

regards,

 

Martin.

 

Gosh, Martin, there seem plenty of permutations. Please forgive my ignorance but could I use the diagrams posted as templates?

 

Best wishes and thanks again.

 

Jonte

[craigwelsh]

Gosh, Martin, there seem plenty of permutations. Please forgive my ignorance but could I use the diagrams posted as templates?

 

Best wishes and thanks again.

Jonte

You'll have fun trying to scale them correctly and they'd be a bit blurred too as they aren't high resolution.

 

I'd suggest building the B7 Martin provided in the pdf which is a scaled Template.