Back to Back Gauge for Hornby wheels?

[darren01]

Back to back gauge.

I want to sort out the back to backs on all my Locos.

 

All my loco are Bachmann and Hornby and my track is code 75, I have been having a look and their a lot of different types around.

 

What is the best one to use to do this ? , also how do you pull the wheels out on a loco to set it to the right gauge?

 

All the best

 

Darren

 

[34theletterbetweenB&D]

A 6" steel rule with 0.5mm graduations and a good light is all the b-t-b gauge I have ever required for OO. (Mixture of code 100 and code 75.) The problem with OO, (particularly if you have items over 30 years old still operating, but still applicable to modern production) is that a b-t-b gauge does not inevitably lead to the right setting. Setting b-t-b is actually a proxy for the wheel back (at rail top) to flange root dimension, and for it to work reliably a standard flange width and profile is required. And although RTR OO wheels are now generally much superior to what we had in the past, examples of 'deviant' flange thickness and profile do still occur. Everything you need to know here, courtesy of the NMRA http://www.nmra.org/...rp/consist.html

 

Adjusting RTR wheel settings.

 

Undriven wheels and driven wheels on modern traction can generally be eased in and out by hand.

 

Driven wheels on steam types (and any modern traction with outside rods), are best adjusted by a tap on the axle end to open them out, or a squeeze of the wheel boss in vice jaws (ideally soft faced, in an engineering vice) to close up. This minimises the risk of disturbing perpendicularity to the axle and crank quartering.

 

Major exception among current product, Bachmann and Hornby split chassis wheelsets, as on your Ivatt 2MTT and some Hornby modern traction. Hand adjustment, insertion of washers, use of high grade adhesives like 24hr Araldite.

[2ManySpams]

darren, you'll find the worst offenders of your stock will be the Hornby WC / BoBs produced 5-7 years ago. For some reason these came out with the b2bs set 0.5mm too narrow. I've used a wheel puller on most of mine but be carefull as they can pull the wheel out of true. I don't recall where mine came from but could have been Eileens Emporium or East Kent Models.

[bike2steam]

I have come up against some new Hornby Stanier 2-6-4T's with, just slightly, undersized back to backs. I use a brass block b2b gauge (along with code 75 brass track roller gauges) from SMP bought many years ago, now part of Marcway I believe ?

The driving wheels were reset by gently prising out with small jewellers screw drivers,put two in behind the wheel ( both same size screw drivers), each side of the axle, and gently lever each one at a time to suit. the pony wheels are done by gently pulling, and twisting between thumb, and first finger of each hand. Checking each time with the b2b gauge on at least 4 points at approx 90 degrees on the circumference on each wheel.

[Simon G]

I use a digital caliper to check my B-t-B's - easily purchased for less than a tenner. As I have a variety of locos dating from the 1960s through to recent purchases, the required B-t-Bs vary according to how coarse the wheels are. The older Triang wheels, with their thick flanges, work best with a B-t-B of about 13.5mm, while newer thinner flanges I set to about 14.2mm

 

I generally agree with bike2steam below on how to adjust the B-t-B's on steam locos, but will occasionally use the two screwdrivers simultaneously to ease out the wheels - I find that this helps keep them square on the axles. I recent had to adjust some very obstinate 1960s wheels that I couldnt move in-situ and had to remove the wheels. I then placed the wheel into a slotted piece of metal sheet, so that the wheel itself rests on the metal, with the axles in the slot. The axles can then be lightly tapped to ease them off the wheel. I have added a simple drawing to show this (the yellow bit is the slotted metal sheet).

 

I also agree that the use of a vice is best to move the wheels closer - it keeps them square on, and if used carefully with frequent measurement checks, a vice will give a very accurate result.

[Il Grifone]

The 'correct' B-B setting depends on the track. It has to be such that, when the back of one flange is against the check rail, the front of the other misses the crossing nose. Conversely, the B-B has to be greater than the span of the check rail/wing rails.

 

The B-B thus varies with the wheels and unless one profile only of wheel is used a one size fits all B-B gauge does not exist, though 14.5mm suits most. For this reason, I set my wheels with vernier caliper (currently under £5 in 'Wilkinsons') or you can use a digital caliper if you prefer.

 

The NMRA site explains it all better than I can. The check gauge (B-B + flange thickness) is typically in the range 15.0 - 15.4mm. The wheels that the track will accept then depend on the width of the flangeway - the wider the flangeway the thicker the flanges can be , but if the wheels are too narrow they will drop into the crossing gap (overall width of wheel should be slightly greater than twice the flangeway).

 

I would have thought 13.5mm a bit tight for Tri-ang wheels, though this will depend on the track. The flanges are roughly about 1mm thick (they vary) suggesting a B-B of about 14mm, though their flanges are on the deep side and require code 100 rail at least. Later Tri-ang Hornby wheels are similar to the Dublo standard which specified B-B of 14.2mm. The latest wheels are finer and require a wider B-B. Peco code 100 is quite tolerant, but I undestand the code 75 is less so.

[darren01]

Hi

 

Yes it is the new West Country that I have just got, keeps jumping off the double slip, when going backwards.

 

I did see a back to back gauge being sold for Hornby and Bachmann on the net, but can not find it again!

 

All the best

 

Darren

[naugytrax]

the Hornby WC / BoBs produced 5-7 years ago. For some reason these came out with the b2bs set 0.5mm too narrow.

 

I found the same was true of the Hornby rebuilt MN ("Clan Line") which I purchased in August, 2000. I was able to correct the gauge using the tap-on-the-axle-ends method, but then I couldn't fit the brake rods because these go outside the wheels and the wheels are too fat! Perhaps the undergauging of the Bulleid Pacific models was necessitated by the thick wheels. Anyway, my "Clan Line" is running with no brakes until I get round to fitting slimmer drivers.

[2ManySpams]

Darren

 

Just come across a photo of a wheel puller on Kenton's blogg here http://www.rmweb.co.uk/community/index.php/blog/53/entry-532-the-basic-frames/.

[Ben Alder]

Darren

 

Just come across a photo of a wheel puller on Kenton's blogg here http://www.rmweb.co.uk/community/index.php/blog/53/entry-532-the-basic-frames/.

 

I have one that, like a lot of these things, is very useful at certain times. IIR. it was got from GW Models- who are mentioned elsewhere just now with regard to contact details. HTH

Richard