Why Would I Choose 00-SF ?

[AndyID]

It is that simple, a matter of looking what you are doing and measuring or gauging on the flanges. I have gauged hundreds of wheelsets including quite a lot with the sort of step you illustrate. Nothing says you should push the axle right into the slot in the gauge, or into the corner if its a L shape gauge. You look at the backs of the wheels and only insert the gauge to the depth of the flange in such cases. Its quite common where metal tyres are on plastic centres for the plastic to be proud on the back.

 

(my bold)

Hi Keith,

 

There is no step on these wheelsets. The backs are beveled at a shallow angle for a considerable depth. That's why it's not so simple.

 

Andy.

[martin_wynne]

The backs are beveled at a shallow angle

 

It is even drawn as such at 5 degrees on the EMGS 1976 profile, although I don't believe any actual kit wheels are like this:

 

 

The coning is shown at 2 degrees rather than he usual 3 degrees (1:20).

 

Martin.

[Armchair Modeller]

That taper makes next to no difference. Based on the EMGS diagram, the difference between BTB at the bottom and top of the taper is only .006 inches, or around 0.015mm (allowing for both wheels). If you take into account where the flange touches the rail, the difference would be even less. There should be no need to work to that level of precision when checking the BTB.

Edited September 9, 2015 by Armchair Modeller

[martin_wynne]

the difference between BTB at the bottom and top of the taper is only .006 inches, or around 0.015mm

 

.006 inches is 0.15mm, not 0.015mm.

 

The back-to-back range for RTR wheels in 00-SF is 0.1mm (14.3mm - 14.4mm). So 0.15mm is 50% greater than that.

 

The permissible range on the DOGA-Intermediate standards sheet is the same 0.1mm (14.35mm - 14.45mm).

 

If any wheels are like this (I don't believe they are), checking the back-to-back would require some care when measuring to the back of the flange.

 

Martin.

Edited September 9, 2015 by martin_wynne
DOGA note added

[Armchair Modeller]

Yes, apologies - my mental arithmetic let me down. However, the 0.006 inch is right down at the bottom of the flange (more or less). The point where the flange rubs against the railhead is very roughly 3/4 of the way up the taper. The difference in BTB between the wheel back and this point will only be 0.025-0.03mm, which really is quite small.

 

Using the wheels drawn in the diagram, measuring the BTB from the bottom of the taper will be less accurate than measuring the BTB using the wheel backs with a conventional BTB gauge.

[AndyID]

The 

 

It is even drawn as such at 5 degrees on the EMGS 1976 profile, although I don't believe any actual kit wheels are like this:

 

 

The coning is shown at 2 degrees rather than he usual 3 degrees (1:20).

 

Martin.

 

I can't see where it's specified, but It appears that the bevel starts at, or very close to, the same radius as the tread. If that is the case I don't think there would be any problem with measuring the b2b on the flat portion of the wheel backs.

 

The problem with the Hornby wheels is that the bevel starts at a much smaller radius than the tread radius. BTW, don't ask me what the angle actually is

[AndyID]

 

Where you are trying to set wheels of varying profiles/widths to run on track to a particular set standard, and when wheel run-out and tapered rear faces need to be allowed for, then a go/no-go gauge of the type already illustrated is really the only way of setting a usable running b-t-b measurement as far as I can see and will vary for each different profile.

 

Hi Izzy,

 

I think that's the best approach. We really don't need to know what the actual measurement is. We just need to know if we are likely to have running problems, and I think that's what most modelers would care about. Test gauges as you have described could be made very similar to the method Martin described above using thicker strips and adding two additional strips (of the same thickness) to support the wheel treads.

 

If we want to quantify the actual dimension, it would probably be best to use a series of these test gauges with some reasonable delta between the steps. I think 14.2, 14.3. 14.4 and 14.5 mm would be more than sufficient for my needs.

 

Cheers!

Andy

[martin_wynne]

I can't see where it's specified, but It appears that the bevel starts at, or very close to, the same radius as the tread. If that is the case I don't think there would be any problem with measuring the b2b on the flat portion of the wheel backs.

 

Hi Andy,

 

It's specified as tangential off the .006" bottom radius, which has defined centres, and is only .001" off the overall wheel width so the drawing is misleading. I posted it only to show that an angle is actually specified on some drawings. It's a bit academic, because I don't believe any actual wheels are like this.

 

I agree that measuring to the wheel back would be fine. The difficulty would be the need for differing measuring methods for different wheels.

 

regards,

 

Martin.

[AndyID]

Hi Andy,

 

It's specified as tangential off the .006" bottom radius, which has defined centres, and is only .001" off the overall wheel width so the drawing is misleading. I posted it only to show that an angle is actually specified on some drawings. It's a bit academic, because I don't believe any actual wheels are like this.

 

I agree that measuring to the wheel back would be fine. The difficulty would be the need for differing measuring methods for different wheels.

 

regards,

 

Martin.

 

Ah right!  "DO NOT SCALE PRINT"

 

(To get out of certain domestic responsibilities I might have to draw it to scale so we can see what it really looks like    )

[Ravenser]

Thanks to Andy for flagging this up. I must have noticed a circular mark on the wheelback in the past , without ever realising quite what it was and the implications.

 

Just to add another twist, the bevel appears to vary between wheel types with Hornby

 

I've found a 12.6mm plain disc wheel unused in one of my boxes, and as far as I can judge (measurements with a ruler are not going to be exact figures in this situation) the bevelled area is approx 1mm deep from the tip of the flange (but not significantly more than that). The 3 hole discs are in a sealed packet , and I don't really want to open it for fear of losing them - presumably they are similar??. 

 

But the bevel on Hornby 14mm coach wheels is much less - certainly no more than 0.5mm from the tip of the flange, possibly slightly less 

 

There's a very slight bevel on the tip of Bachmann spoked wagon wheels too - but it is a noticeably thinner ring than even on the Hornby coach wheels

 

I'm starting to wonder if this is why Hornby reduced their conventially measured B2B on rolling stock to 14.1-14.2mm a few years ago

 

This is a real can of worms

[Ravenser]

 

It's a bit academic, because I don't believe any actual wheels are like this.

 

It's becoming horribly obvious that quite a few RTR wheels actually are.....

[martin_wynne]

It's becoming horribly obvious that quite a few RTR wheels actually are.....

 

I meant any kit wheels claiming to be to the EMGS profile.

 

Martin.

[martin_wynne]

This is a real can of worms

 

I have suggested several times that there is a better way of setting wheel spacing than using a conventional back-to-back gauge. What's more it costs next to nothing to make if you are already building 00-SF or 00-BF track with the C&L 15.2mm check gauge. See:

 

 http://www.rmweb.co.uk/community/index.php?/topic/98904-oo-sf-back-to-back-dimension/&do=findComment&comment=1878333

 

It can be made small enough to be hand-held and used in the same way as a back-to-back gauge. Just one fixture is needed to provide the optimum setting for all wheels -- RTR, Markits, Ultrascale, etc., and for all 00-SF, 00-BF, DOGA Intermediate.

 

For those wondering where this topic is going, just to repeat -- most modern RTR models work fine on 00-SF as supplied. This discussion about setting wheels is for the small minority of them which don't.

 

Martin.

Edited September 9, 2015 by martin_wynne

[AndyID]

 

For those wondering where this topic is going, just to repeat -- most modern RTR models work fine on 00-SF as supplied. This discussion about setting wheels is for the small minority of them which don't.

 

 

Absolutely correct. There is nothing wrong with those Hornby wheels. I raised the point because I could see how people might try to adjust them when there was no need to touch them.

 

The reason I happen to be putting a lot of energy into this is because I happen to have a lot of 00 equipment from around 30 years ago a lot of which will need to be adjusted or re-wheeled. I need a very consistent and fast method of making sure it will operate properly, hence all the mucking about with gauges and stuff. The other reason is that I happen to enjoy mucking about with gauges and stuff.

 

It takes all kinds you know

[AndyID]

This is what the EM wheel profile should look like. As the bevel ends well below rail height (arrow) there should be no problem checking the b2b across the flat part of the the backs.

 

 

 

[hayfield]

Absolutely correct. There is nothing wrong with those Hornby wheels. I raised the point because I could see how people might try to adjust them when there was no need to touch them.

 

The reason I happen to be putting a lot of energy into this is because I happen to have a lot of 00 equipment from around 30 years ago a lot of which will need to be adjusted or re-wheeled. I need a very consistent and fast method of making sure it will operate properly, hence all the mucking about with gauges and stuff. The other reason is that I happen to enjoy mucking about with gauges and stuff.

 

It takes all kinds you know

 

Andy

 

I think simply because 00 standards have been in some terms so loose in the past (just think of the pizza cutter/steam roller  wheels of times gone by plus the tremendous variety of different wheels produced by several companies a certain amount of wheel adjustment/replacement will inevitability be required. By using standards similar to EM gauge (00-sf or DOGA fine) in that certain tolerances are maintained within defined limits then wheels that do not confirm to said standards will have to be adjusted/replaceed

[47137]

I am supposed to be building one of Martin's gauges but it's a fairly low priority because at the moment everything works and I don't honestly expect difficulties with future purchases of RTR locos from the last 20 years or so.

 

If you hunt around on market stalls there are quite small internal calipers out there which are really nice for checking (tho' not setting) wheels. The small tips are easy to wipe along the insides of flanges regardless of a step there. These ones (and the micrometer) are by Moore and Wright.

 

- Richard.

 

[martin_wynne]

Please don't use 00-SF,

 

unless:

 

1. you enjoy making handbuilt track, and

 

2. you are building a layout where running-line curves don't go much below about 36" radius (900mm), and

 

3. you want to mix rolling stock having kit wheels (Romford/Markits, Alan Gibson, Ultrascale, etc. wheels) with RTR models on the same track, and

 

4. you don't mind checking and if necessary adjusting RTR wheels (most modern RTR models will run on 00-SF as supplied, but a few may need attention), and

 

5. you like the visual improvement of the narrow 1.0mm flangeway gaps, and

 

6. you don't mind seeing endless discussion on RMweb about 00-SF, some of it bad-tempered, a lot of it misleading.

 

If none of the above apply, please don't use 00-SF. If you are making handbuilt track the other standards (00-BF and DOGA-Intermediate) work just as well for RTR models, with a bit more tolerance on wheel settings. If you don't like making handbuilt track, stick to Peco or similar.

 

If you are using only kit wheels, or don't mind adjusting every RTR wheel, the DOGA-Fine standard is an alternative to 00-SF. Wheels which have been adjusted for DOGA-Fine will not run on other 00 layouts, including 00-SF.

 

More about 00-SF is at: http://00-sf.org.uk

 

regards,

 

Martin.

Edited September 11, 2015 by martin_wynne
link added

[RichardS]

An excellent summary.

After points 1-5 Point 6 makes itself redundant.

[AndyID]

The wheels run on their treads rather than on their flanges. An alternative would be to mill slots in a solid piece to accommodate the flanges, but I don't have a means of doing that with sufficient accuracy, so I made it in two pieces instead.

 

 

[ianb3174]

I'm not sure that's clear enough. Can't you shroud it in a bit more mystery? What if I want my wheels to drop through the crossing? Can I get P4 in Setrack sizes if I use 00-SF?

[bgman]

On a lighter note .......

 

http://youtu.be/CjraY7L9Jig

 

Worth watching the real thing

[melmerby]

On a lighter note .......

 

http://youtu.be/CjraY7L9Jig

 

Worth watching the real thing

All those core boxes to cast all those chairs - so labour intensive. The whole process was!

My dad used to work for a firm which made the drying ovens for core boxes, don't know whether any railway works used them, the car factories definitely did.

He used to go on site to erect new ones or service old ones.

 

Keith

[Clive Mortimore]

Please don't use 00-SF,

 

unless:

 

1. you enjoy making handbuilt track, and

 

2. you are building a layout where running-line curves don't go much below about 36" radius (900mm), and

 

3. you want to mix rolling stock having kit wheels (Romford/Markits, Alan Gibson, Ultrascale, etc. wheels) with RTR models on the same track, and

 

4. you don't mind checking and if necessary adjusting RTR wheels (most modern RTR models will run on 00-SF as supplied, but a few may need attention), and

 

5. you like the visual improvement of the narrow 1.0mm flangeway gaps, and

 

6. you don't mind seeing endless discussion on RMweb about 00-SF, some of it bad-tempered, a lot of it misleading.

 

If none of the above apply, please don't use 00-SF. If you are making handbuilt track the other standards (00-BF and DOGA-Intermediate) work just as well for RTR models, with a bit more tolerance on wheel settings. If you don't like making handbuilt track, stick to Peco or similar.

 

If you are using only kit wheels, or don't mind adjusting every RTR wheel, the DOGA-Fine standard is an alternative to 00-SF. Wheels which have been adjusted for DOGA-Fine will not run on other 00 layouts, including 00-SF.

 

More about 00-SF is at: http://00-sf.org.uk

 

regards,

 

Martin.

Hi Martin

 

A lovely summary for us to think about why we should or not model using track built to 00-SF standards. Looking forward to seeing your layout built to 00-SF.

 

Yours

 

Clive

[AndyID]

Hi Martin,

 

Maybe you should add -

 

7. you don't mind people taking cheap shots at you.

 

Cheers!

Andy