BR Standard class 6 No. 72010 'Hengist' and Clan Discussion Thread

Aye that EGM in a Portacabin at Barrow hill' What have i joined here ? sprung to mind. The team will still dig the tunnel with a spoon if thats what it takes but fortunately have some better tools to hand nowadays....

The fact that even with the thick frame plates and two lines if horizontal bracing the frames still sag a little under their own weight ( even if its only a few thou.) demonstrates the amount of flex available when a loco is working

 

Looking at the last photo, it's amazing to see the frames on the machine looking like a Hornby model... Also amazing is the fact that a complete set of assembled frames can be manoeuvred and manipulated as a whole to be machined in this way. Fascinating stuff, as is the news section of the 72010 website.!

Richard.

 

It seems like a very complicated and slow method to construct the horn guides especially all the milling work. How was it done back in BR days?

 

At swindon pretty much the same way but with the frames horizontally on a dedicated machine. At Crewe who knows - couple of apprentices with big files...?

 

Not so. Even in Webb's, or possibly even Ramsbottom's, days Crewe had a machine which ground all twelve horn faces simultaneously.

 

Is that the origin of the 'Sacred' wheel spacing...!?
the big files perhaps i was thinking if Doncaster (exit stage left at some speed)

 

I don't think so. I have seen a photo of a set of DX frames with the rig attached, dragged outside on to the traverser, so I imagine the spacing was adjustable.

Realistically, the 'Sacred' wheel spacing was Derby: 8. 0" + 8' 6".

Edit: Found it!

 

I was always under the impression that, in the Victorian era, Crewe was about as efficient as it got in loco construction. Seem to recall reading that in the mid-Victorian era they could build an 0-6-0 for £500; even assuming that that didn't include a tender, that was far below other workshops and must have only been possible if the workshop had been arranged with a very high degree of efficiency.

Tom

 

Excellent example of railway engineering, though it does not look that the centres were adjustable. Perhaps they had a series of these for the most prolific of the engine types?

 

I recall a photo taken inside the Swindon erecting shop, showing a rig utilising beams of light, directed by mirrors and prisms for acurate frame alignment. Can't remember the date though.

 

I would suggest that it is adjustable, if you can see the top location bar, that will be a dedicated location bar for this loco's wheel centres, any other loco centres will also have its own location bar. The central drive pulley will be a two groove, with the drive for each individual side taken from each groove, therefore each loco will also have dedicated drive belts as well as the location bar, so the three cutting heads and drive, are able to be assembled for each individual loco.

 

If you can get hold of "Swindon Steam 1921 - 1951" by Kenneth J Cook it's shown in the photos (along with the 'horn grinding machine') AND is all discussed in chapter 10 "Locomotive Repairing Circuit; Optical Methods for Frame Setting, New Machinery."


Sent from my iPad using Tapatalk

 

Crewe's workshop practice was always up there with the best.
WAS was astonished to find the Crewe foundry producing castings that Swindon would not even attempt

 

What really impressed me about Crewe, albeit from the Stanier Era, after Bowen-Cooke & Lemon had modernised the place, was their ability to drill all the stay holes in the inner and outer fireboxes of the Coronation Pacifics (and presumably many other classes also), before the plates were bent to shape. I believe that Swindon were also impressed by this.

Richard.

 

If I’m not mistaken the optical alignment equipment went to Bridgnorth.

 

Presumably first used for Box Hill tunnel....

I did wonder about the way the Clan horguides were being done. I haven't seen any others being done - I have seen pics of the GCR4-4-0 having the hornguides individually machined from castings, but no idea if that is the final action. It *seems* excessive the way the Clan is being done, but presumably the kit that CT Seal have makes it easy as once it's got the frames located and datum set, it can move and track accordingly.

The alternative has to be very careful marking out and individually working on each in-situ
There's something in Working With LMS Steam where the hornguide marking out is done in different ways by the LMS and the GWR with one being disparaged by the other (I think the ex-LNW method comes off worst)

 

Provided you know about it, the LNWR system works fine, the problem was that the GWR shed the did the hot box on the Super D didn't know, which is why it all went pear shaped.

2968's hornguides being machined at Bridgnorth, 29 June 2019.

 

Thanks for that suggestion but I cannot make that out, must be my eyesight needing testing. Though I think the central pulley must be 3 grooves, driving belt + 2 driven belts?

Basically, the machining problems we have today existed way back and we have just answered them in different ways according to our technology and needs. Re-inventing the wheel comes to mind, but at least it was a different wheel each time. As I see, each Company had it's own way and would wear theirs was the best way. Just like today!!

 

Maybe something to do with them being welded into the frames... so they cant be offered up and taken off and machined until almost spot on, all has to be done in situ.

 

Yes sorry missed that out, the drive as I explained is common to all wheel centres, the explanation was aimed at which part of the dedicated kit was for each loco wheel centres which remain the same, 2 belts and one location bar.