Gravity 'Go - NO GO' wheel back-to-back gauge

[Waterloo]

I was impressed with Tony Sissons article in the latest S4 News (issue 164, page 20) where he described how he designed and made a simple ‘go – no go’ wheel back-to-back gauge to improve the running on Charlotte Road.

I think that this would be an asset to all exhibitors and help to improve further the running quality of exhibition layouts.

Tony mentions that he is “tempted to make a gauge out of steel to improve the setting accuracy one more step up.”

Now, I certainly do not have the engineering skills of Tony to confidently make an accurate gauge myself so wondered if this could be an opportunity for some entrepreneur to consider producing said accurate gauge for us mortals. Fancy a production line Tony?

Steve

[modelmaker87]

I think that this would be an asset to all exhibitors and help to improve further the running quality of exhibition layouts.

Tony mentions that he is “tempted to make a gauge out of steel to improve the setting accuracy one more step up.”

Now, I certainly do not have the engineering skills of Tony to confidently make an accurate gauge myself so wondered if this could be an opportunity for some entrepreneur to consider producing said accurate gauge for us mortals. Fancy a production line Tony?

Steve

Steve,

I will take a very serious look at it next week. If the costs are sensible then it may be a goer.

Cheers, Tony

[Mike Garwood]

Tony

Count me in as well, very, very interested in the concept. Thought the article in snooze was excellent...but I have to ask - what is the mechanism by which the axles are held in the bogies/wagons, is there a common thread there as well?

regards

Mike

[Tim V]

Here is mine, I knocked it up in a few minutes
That's a Studiolith BB gauge.

IMG_2858.JPG (63.25 KiB) Viewed 3491 times

[modelmaker87]

Here is mine, I knocked it up in a few minutes
That's a Studiolith BB gauge.

Nice one Tim,

How do you find it works for you...?

Manufacturing update: Today I finalised the tool design that will permit grinding a taper on the gauge edge. I designed the tool with a capacity to surface grind 100 gauge plates at a time. This tooling and the component drawing has gone to costing. I'll return when the numbers are in.

Cheers, Tony

[modelmaker87]

Tony

Count me in as well, very, very interested in the concept. Thought the article in snooze was excellent...but I have to ask - what is the mechanism by which the axles are held in the bogies/wagons, is there a common thread there as well?

regards

Mike

Mike, my apologies, but I'm unsure exactly what you mean by "what is the mechanism by which the axles are held in the bogies/wagons, is there a common thread there as well?"

The axles are fitted into the wheel centres as has always been done, push fit. The axles are fitted into a wagon/bogies by their pin point bearings in the top hat bearing bushes, as has become our standard. The fitting of a correct B-B axle/wheel assembly is done after the wheels have been gauged. Thread, as in T.P.I. (threads per inch). Is this what you meant...?

By the way, does anyone reading this text know the correct metric term or acronym for T.P.I. Thought I'd ask.

Cheers, Tony

[Russ Elliott]

By the way, does anyone reading this text know the correct metric term or acronym for T.P.I. Thought I'd ask.

Pitch.

[Tim V]

Hi Tony

Great little tool, the wheels run down the slope, some stop on the gauge but some jump up and run off the end. Certainly works well though.

[modelmaker87]

Hi Tony

Great little tool, the wheels run down the slope, some stop on the gauge but some jump up and run off the end. Certainly works well though.

Tim, Sounds like it is working exactly like the two I made and wrote about. If your wheels jump off, what I do is reduce the angle of elevation so that they run down the slope slower.

Thanks for the feed back.

Cheers, Tony

[the fatadder]

Sounds a really good concept (will be getting an order sent to S4 stores in the morning!) Looking forward to getting it set up and finding out just how far off the back to back settings on a lot of my stock actually are.

Must say it was very handy being able to just click on the members index button at the top of the forum and dig out Tony's article from issue 164 as well, much easier than trying to dig out the issue from wherever in the modelling room it got put when I finished reading it!

[Flymo748]

Sounds a really good concept (will be getting an order sent to S4 stores in the morning!) Looking forward to getting it set up and finding out just how far off the back to back settings on a lot of my stock actually are.

If the anticipation of Tony's creation gets too much for you, the instructions are on-line already as a pdf download at:

http://www.scalefour.org/gravitygauge.pdf

Cheers
Flymo

[Russ Elliott]

What is the width of the large end of the plate?

[modelmaker87]

What is the width of the large end of the plate?

Russ,

18.06mm

Tony

[Rod Cameron]

Just got mine from Stores and made it up on Saturday - horrified when testing a random selection of wheelsets from the cupboard! This could well be one of those 'can't do without' pieces of kit, up there with the choc-block track gauge.

Have yet to try it with wheels already in vehicles, will do at DRAG tonight, but I feel that's going to be less convenient to do.

But well done from me Tony!

[Russ Elliott]

...horrified when testing a random selection of wheelsets from the cupboard

Rod - for the wheels that come to rest in the 'right area' of the gravity gauge, how do those wheels feel like in a conventional back-to-back gauge?

[modelmaker87]

Just got mine from Stores and made it up on Saturday - horrified when testing a random selection of wheelsets from the cupboard! This could well be one of those 'can't do without' pieces of kit, up there with the choc-block track gauge.

Have yet to try it with wheels already in vehicles, will do at DRAG tonight, but I feel that's going to be less convenient to do.

But well done from me Tony!

Rod, pleased you like it. The gauge is not designed to be used with finished stock. I know it can be used that way but you are back to feeler gauge style of interpretation of the BB spacing, a judgement feel.

Cheers, Tony

[Rod Cameron]

...horrified when testing a random selection of wheelsets from the cupboard

Rod - for the wheels that come to rest in the 'right area' of the gravity gauge, how do those wheels feel like in a conventional back-to-back gauge?

Hi Russ

This is going to vary with the exact dimension of the conventional gauge of course. With my Society L-shaped gauge (17.67-17.68 mm) I would call it a very light interference fit for a wheelset compliant with the gravity gauge. Not strong enough to hold the wheelset against gravity from the L-shaped gauge, but then again there is only a small part of the wheel rim in contact because all the wheelsets I have to hand (Gibson mainly) have a slightly proud plastic insert which precludes measuring against the entire back surface. With my Exactoscale gauge it's less than a light interference fit because that gauge is slightly under the lower mark at 17.65-17.66 mm.

As Tony's notes say it's also crucial to make sure the wheel moulding is clean - I can see that I will have to file the moulding pips down on most of them to allow them to run freely.

If anything the gravity gauge really focusses your attention on the wheel rim, which it should of course. I wonder how many gauge problems are really down to measuring across the whole of the inner face where it could be significantly undergauge because of the inserts.

[Rod Cameron]

The gauge is not designed to be used with finished stock. I know it can be used that way ...

Hi Tony

But this is quoted in your notes as being the second 'major advantage' and bulleted - I take your point though.

[Russ Elliott]

This is going to vary with the exact dimension of the conventional gauge of course.

Yes; I think I should have mentioned that aspect in my question. I have a couple of ancient Society L-shaped gauges, one of which is 17.65 to 17.77 if I remember correctly, and can be useful because of that spread, but I've never really liked the L-shaped design, preferring to use homemade rim roller types*, because of the potential interference by a plastic insert. How thick is the plate in Tony's gravity gauge?

* my favourite being turned for a 17.80 to 17.82 setting (and hence my query to Tony on what the maximum width of the plate was)

I wonder how many gauge problems are really down to measuring across the whole of the inner face where it could be significantly undergauge because of the inserts.

Incorrect use of an L-gauge with some Gibbo wheels will definitely result in a overwide BB, so I always measure and set only at the rim. (There was a previous thread discussing this problem.)

[modelmaker87]

This is going to vary with the exact dimension of the conventional gauge of course.

How thick is the plate in Tony's gravity gauge?

Russ,

I called for ground stock Max 0.047" (1.193mm) Min 0.044" (1.117mm) Steel supplier came up with alternative of 0.043" (1.092mm), which I accepted.

Tony

[Rod Cameron]

How thick is the plate in Tony's gravity gauge?

Russ,

I called for ground stock Max 0.047" (1.193mm) Min 0.044" (1.117mm) Steel supplier came up with alternative of 0.043" (1.092mm), which I accepted.

Tony

And I just measured mine (unscrewing at one end and swinging round!) at 1.09 mm

[Russ Elliott]

Thanks Tony. Nice choice.

[Bob Ellis]

The instructions recommend mounting the gauge on a piece of styrene or plasticard to provide smooth running and fixing this onto "a piece of stable and smooth timber". A simpler method, in my opinion, is to dispense with the styrene and wood and mount the gauge instead on a piece of tufnol carp of suitable dimensions, which can be bought on eBay at a reasonable cost if you don't have one to hand. Mine was 340mm x 60mm x 10mm and cost £4.30.

I deliberately bought a long piece so that I could use the gauge to check the back-to-back distances on wheelsets that were already mounted in stock, including bogie coaches. It might appear that only the outside wheelset of each bogie can be tested, but sliding suitable pieces of brass or plasticard strip either side of the jig enables you to raise the outside wheelset in order to check the back-to-back of the inside set.

[Flymo748]

[color=#0000BF]The instructions recommend mounting the gauge on a piece of styrene or plasticard to provide smooth running and fixing this onto "a piece of stable and smooth timber". A simpler method, in my opinion, is to dispense with the styrene and wood and mount the gauge instead on a piece of tufnol carp of suitable dimensions, which can be bought on eBay at a reasonable cost if you don't have one to hand. Mine was 340mm x 60mm x 10mm and cost £4.30.

Hi Bob,

I have to say, that's an excellent suggestion

As the person that wrote the instructions, based on Tony Sissons' pictures and my own experience of the Gauge, I had not even thought of Tufnol - it's not a material that I normally use.

The recommendation of plasticard then timber was to give a very smooth surface for the flanges of the wheels to run down, rather than getting stuck on any slight ridges or dips evident on even smooth-planed timber. The timber supporting it is to give rigidity, as even something like 2mm plasticard is still quite flexible, and wouldn't be sufficiently strong in its own right.

Could you share with us the name of your supplier? That would be very helpful. There is a lot Tufnol out there on Ebay!

You've also cracked exactly, and illustrated very well, what I was trying to do in suggesting that by mounting it on a longer base you can use it to check already-installed wheelsets on vehicles.

Thanks for a great post!
Cheers
Flymo

[Bob Ellis]

Thanks for your comments, Flymo. I am glad you like my suggestion. I chose carp grade tufnol because, like plasticard, it provides a smooth and even surface on which to run the wheel flanges and because it is unlikely to warp or distort.

I bought my tufnol at a buy-it-now price on eBay from a supplier who calls himself 'bunaday'. I have copied below the address and contact details he posted on the eBay listing for the tufnol I bought. It arrived in two days.

Davis Industrial Plastics Ltd
Ebay Sales
Dialog Unit 1
Fleming Way
Crawley
West Sussex
RH109NQ

Phone: 01293 552836
Email: gavin.davis@davis-plastics.co.uk