Jump to content

Driving wheel spoke number


Recommended Posts

This is somewhat esoteric, but as we move further away from the steam era, a lot of knowledge fades. 

I was wondering if anybody knew where the number of spokes in locomotive driving wheels originated: I'm aware that different locomotive designers and the companies for they worked used their own design of wheel latterly based on whatever master they had in their casting shop or in line with company policy. However, was there a ratio of, for example, number of spokes: wheel diameter or number of spokes: wheel circumference? 

Cliff

 

Link to post
Share on other sites

Ask the 82045 Fund! They acquired a wheelset from a Standard Class 3 tender engine for their new build. It turned out that one type had sixteen spokes and the other seventeen (I can't remember which way around). Both were BR Standards with 5' 3" coupled wheels, but they weren't the same.

  • Like 1
  • Interesting/Thought-provoking 1
Link to post
Share on other sites

Just now, LMS2968 said:

Ask the 82045 Fund! They acquired a wheelset from a Standard Class 3 tender engine for their new build. It turned out that one type had sixteen spokes and the other seventeen (I can't remember which way around). Both were BR Standards with 5' 3" coupled wheels, but they weren't the same.

Was that on the same axle? Did both have the triangular rim? 

Link to post
Share on other sites

6 minutes ago, LMS2968 said:

Ask the 82045 Fund! They acquired a wheelset from a Standard Class 3 tender engine for their new build. It turned out that one type had sixteen spokes and the other seventeen (I can't remember which way around). Both were BR Standards with 5' 3" coupled wheels, but they weren't the same.

 

I thought the wheels came from the 4MT 2-6-0 that was scrapped at Barry - 76080.

 

https://www.flickr.com/photos/[email protected]/49990979201/in/photolist-RUTZbF-2i5mZpY-2jawQsv-SPmzsq-Sfujhe-RaqDd4-28jrWVZ-aS3t3a-Tu95oT-qokNG-RAWLSK-Sfuj7z-SDC7we-jQuJs-TqHY1u-Sfujd6-R7C4ps-SU9K6b-SfuiYt-Sn6ANw-pyi7C4-Dy8Ls-RH2tun-2hPNyJc-2e7aNUp-ScDk3J-RCVjV7-R7xbSN-Q7d1i4-SQ2MkW-RFP62Z-21SUKgq-RDb3gn-RaqDjX-qGqP5A-Qs3YY8-RFP61X-RkSynp-RFP61r-9USLiu-asPLnG-asPKxb-asPJMU-asPJqy-asPMkL-asPM3Y-asPKYw-asM7KV-2btA3f2-asM9kK

 

 

Jason

Link to post
Share on other sites

Although I'm a member of the Fund, it isn't my biggest concern and all this happened quite a few years ago. The wheelset was, I think, a display somewhere and might well be the one you're thinking of, SS. Sorry, Penrith Beacon, I don't know which axle it was, but I ASSUME the rim was the same. I remember they were a bit miffed about it: they had persuaded the owner to part with it and then found it wouldn't do, so they'd have to make three new coupled wheelsets rather than two. I remember talking to Chris Proudfoot about it at the time.

 

I've heard of rivet counting, but I suppose spoke counting would be even easier. 

 

I've now had a look at the website:

 

http://www.82045.org.uk/news/82045_news_no5.html

http://www.82045.org.uk/news/82045_news-mar13.html

 

The tender engine used sixteen spokes as in No. 5 above, while the pattern for the tankie's seventeen spokes is shown in March 2013. An appeal for sponsors in October 2012 specified six driving wheels: 

Pattern £3,560 x 1

Driving wheels £9,500 x 6

Axles £2,540 x 3

Axle boxes £625 x 6

Axle box under keeps £350 x 6

Springs £800 x 6

Spring hanger castings x £712 12

Crank pins £750 x 6

Tyres £1,798 x 6

 

It just goes to show: just how non-standard were the Standards?

 

  • Interesting/Thought-provoking 3
Link to post
Share on other sites

The story I had heard was someone was down there taking photos when they started cutting it.

 

Apparently they asked them to save the wheels and some spare parts. If you look at this photo what I assume is the tender wheels are also still intact.

 

https://www.flickr.com/photos/[email protected]/6473516889/

 

Maybe different works had their own foibles. However I've always assumed that BR Standards had spoked tender wheels. :scratchhead:

 

No wonder Mike Sharman got obsessed with wheels.

 

 

 

Jason

Link to post
Share on other sites

3 hours ago, LMS2968 said:

Although I'm a member of the Fund, it isn't my biggest concern and all this happened quite a few years ago. The wheelset was, I think, a display somewhere and might well be the one you're thinking of, SS. Sorry, Penrith Beacon, I don't know which axle it was, but I ASSUME the rim was the same. I remember they were a bit miffed about it: they had persuaded the owner to part with it and then found it wouldn't do, so they'd have to make three new coupled wheelsets rather than two. I remember talking to Chris Proudfoot about it at the time.

 

I've heard of rivet counting, but I suppose spoke counting would be even easier. 

 

I've now had a look at the website:

 

http://www.82045.org.uk/news/82045_news_no5.html

http://www.82045.org.uk/news/82045_news-mar13.html

 

The tender engine used sixteen spokes as in No. 5 above, while the pattern for the tankie's seventeen spokes is shown in March 2013. An appeal for sponsors in October 2012 specified six driving wheels: 

Pattern £3,560 x 1

Driving wheels £9,500 x 6

Axles £2,540 x 3

Axle boxes £625 x 6

Axle box under keeps £350 x 6

Springs £800 x 6

Spring hanger castings x £712 12

Crank pins £750 x 6

Tyres £1,798 x 6

 

It just goes to show: just how non-standard were the Standards?

 

Many years ago on National Preservation I got into a disagreement concerning the number of spokes that the BR3 engines had. Now I understand why.

I assumed that the tank and tender engines had the same wheels; not so. I counted the spokes on the tender engine because they were easier to see, hence I was wrong for the new build tank engine. 

This is weird. Why did Swindon design two wheels with all the expense involved when one must surely have served? Crackers!

Link to post
Share on other sites

I have no idea, but it is possible that the reason might be found in the axle load difference between the 3MT tank and the mogul.  The tank is heavier in working order than the mogul, so it makes some sense that the wheels needed to be stronger, while the mogul was specifically designed for the lightest axle loading possible, so a wheel with less spokes may have been a way of shaving weight from the loco.

 

Of course, if the 77xxx had more spokes than the 82xxx, all this is clearly nonsense!

Link to post
Share on other sites

4 hours ago, Compound2632 said:

Wasn't it roughly one spoke per foot run?

Yes and our old friend Pi has a lot to do with it.

 

An easy example, a loco with 7ft drivers (Midland Compound, 2P) had 22 Spokes. Now I wonder how the Midland worked that one out?

Often for smaller size wheels, i.e. 3ft 6in (common on carrying axles/tenders) which should be 11 spokes, then they picked the next number of spokes to a round number, which is 12.

 

Mike Sharman produced a book with this information (apparently with a small number of errors).

  • Like 1
Link to post
Share on other sites

I've been counting spokes a lot for the locomotive drawings I do for my publications. There was clearly no consensus for a given size, but they were rarely very far apart. There doesn't seem to have been any objection to odd numbers of spokes, nor for numbers that aren't spaced at whole numbers of degrees. It's never occurred to me to explore whether they were round numbers of radians, if indeed that's possible. 

I suppose one thing to consider with the BR standards is that it seems to me they must have been visualising building hundreds of each class, so standardising components between classes wouldn't have been seen as that important. 

  • Like 2
Link to post
Share on other sites

16 minutes ago, JimC said:

It's never occurred to me to explore whether they were round numbers of radians, if indeed that's possible. 

 

It's not, since the number of radians in a full circle is an irrational number, 2pi.

 

For, say, 17 or 21 spokes, I do wonder how the pattern shop people marked out the pattern.

Edited by Compound2632
  • Like 2
Link to post
Share on other sites

6 minutes ago, Compound2632 said:

 

It's not, since the number of radians in a full circle is an irrational number, 2pi.

 

For, say, 17 or 21 spokes, I do wonder how the pattern shop people marked out the pattern.

In a similar way to how I would work out a design for a flight of stairs. But the other way round so to speak as you would usually be given the angle and the rise and you would then have to calculate and mark out the number of treads. CAD did make such tasks much easier.

 

Going back to driving wheels. Is the requirement different for a flat rim as opposed to a beveled  type of rim?

Bernard

Link to post
Share on other sites

3 minutes ago, Bernard Lamb said:

In a similar way to how I would work out a design for a flight of stairs. But the other way round so to speak as you would usually be given the angle and the rise and you would then have to calculate and mark out the number of treads. CAD did make such tasks much easier.

 

I'm afraid I don't follow. For, say, 16 spokes it's straightforward as one can readily bisect the angles. It's a bit harder for 12, 18, or 24 spokes,  as sin 30 = 1/2 comes to one's aid. Nine spokes can be done by marking out 18 and rubbing out every other one! No doubt the pattern shop had a large wooden protractor to hand anyway. But for prime numbers or for numbers such as 21, where the angle between spokes is an irrational number of degrees, I suppose it was simply a case of being near enough...

Link to post
Share on other sites

21 minutes ago, Compound2632 said:

 

I'm afraid I don't follow. For, say, 16 spokes it's straightforward as one can readily bisect the angles.

After thinking about it for a bit, I wonder if the drawing office calculated the size of an segment of the circles representing hub and rim, and then gave the pattern shop a spacing between the spokes at each end. But I've just had a look through some GWR drawings and there's no sign of such a dimension - indeed nothing to give any guide as to how radially spaced items were laid out. Perhaps this was too commonplace to need instruction?

  • Interesting/Thought-provoking 1
Link to post
Share on other sites

12 hours ago, Steamport Southport said:

....... If you look at this photo what I assume is the tender wheels are also still intact.

 

https://www.flickr.com/photos/[email protected]/6473516889/ ......

Wagon wheels, I'm afraid - plain journals not rollers !  Chances are the tender ( chassis ) had already gone to the steelworks as a slab carrier. 

Link to post
Share on other sites

20 hours ago, Peppercorn said:

This is somewhat esoteric, but as we move further away from the steam era, a lot of knowledge fades. 

I was wondering if anybody knew where the number of spokes in locomotive driving wheels originated: I'm aware that different locomotive designers and the companies for they worked used their own design of wheel latterly based on whatever master they had in their casting shop or in line with company policy. However, was there a ratio of, for example, number of spokes: wheel diameter or number of spokes: wheel circumference? 

Cliff

 

The techniques probably go back to the days of making wheels for horse drawn vehicles, and from what I have seen from modern practitioners of the wheelwright's trade, probably made use of circumferential measurement rather than angular ones.

 

  • Interesting/Thought-provoking 1
Link to post
Share on other sites

3 hours ago, Bernard Lamb said:

Going back to driving wheels. Is the requirement different for a flat rim as opposed to a beveled  type of rim?

Yes. The distance between the spokes at the rim is related to the stiffness of the rim and the load that has to be carried.

 

  • Like 1
  • Thanks 1
Link to post
Share on other sites

6 hours ago, Compound2632 said:

 

I'm afraid I don't follow. For, say, 16 spokes it's straightforward as one can readily bisect the angles. It's a bit harder for 12, 18, or 24 spokes,  as sin 30 = 1/2 comes to one's aid. Nine spokes can be done by marking out 18 and rubbing out every other one! No doubt the pattern shop had a large wooden protractor to hand anyway. But for prime numbers or for numbers such as 21, where the angle between spokes is an irrational number of degrees, I suppose it was simply a case of being near enough...

No. I thought I was replying to a point about 17 and 21 spokes so why introduce other numbers?

It was pride in your work on getting it exactly right and any skilled metal worker would not take kindly to "help" from the drawing office.

 

Bernard

Link to post
Share on other sites

2 minutes ago, Bernard Lamb said:

No. I thought I was replying to a point about 17 and 21 spokes so why introduce other numbers?

 

To clarify why I saw 17 and 21 as examples of challenging numbers.

 

3 minutes ago, Bernard Lamb said:

and any skilled metal worker

 

Were these not wooden master patterns made by the foundry pattern makers?

 

4 minutes ago, Bernard Lamb said:

would not take kindly to "help" from the drawing office.

 

What evidence can you produce to show that this was the case in 19th and first-half-of-the-20th-century railway foundries? 

Link to post
Share on other sites

4 hours ago, jim.snowdon said:

...probably made use of circumferential measurement rather than angular ones.

 

That seems logical to me. I was wondering whether, in a simpler age, they just took a pair of dividers and adjusted the spread until they could walk them round the rim and have the last point land on the first mark. In that case there's be no need for the drawing office to provide anything but the diameter of hub and tyre and the number of spokes - which is exactly what's on the GWR drawing I looked at.

  • Agree 1
  • Interesting/Thought-provoking 1
Link to post
Share on other sites

Regarding the number of spokes in a wheel, I recall from a Railway Bylines article on GER 0-6-0Ts that the number of spokes related to the material of the wheel centre, cast iron for goods and shunting versions had more spokes than steel wheel centres for the westinghouse fitted locos (iirc of course).

  • Interesting/Thought-provoking 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...