60525
Member
Returnee to the hobby.
Posts: 8 
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Post by 60525 on Feb 8, 2020 18:21:55 GMT
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Post by Deleted on Feb 8, 2020 19:49:47 GMT
Hi 60525
Not easy trying to work out 'what's what' from afar but I do have an idea, it just depends on space..Your V4 being 3 1/2 gauge won't need as large a dia cross shaft as 4472's 5/32 so this may work but only you will be able to tell how much space you have. I note that the cylinders are inclined and thus the gap under the cylinder increases towards the front. I also note that the pony truck stay has 5 mounting bolts each side. If it was my model and if there's room for the shaft I would remove the stay and drill a hole in both frames between the 2nd and 3rd mounting holes from the front, this is for the shaft to fit, the stay will need modifying for the shaft to pass through. If there's not a big enough area below the cylinder for these holes the other more involved way could be to machine a rounded groove with a ball nose cutter half way through the stay in the same position between holes 2 and 3. You'd then file the other half of the holes in the frames. Basically that shaft passes halway through the stay's thickness of 1/8 as shown on the drawing with the filed matching semi-circle holes in the frames to complete the bearing. Whereas 4472 has a droparm in the centre, you'd need the arm to be above the shaft with the stay modified accordingly. Last job is two drop arms, one either side below the cylinders positioned so that they are inline with the draincocks...thinking about it, there must be enough space for the shaft as the drawing being 2D can only show the bottom of the cylinder and not the curve of the cylinder thus keaving much more room where it bolts to the frames. Sorry for the long post, I've been writing it as the idea has formed in my mind...
Pete
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60525
Member
Returnee to the hobby.
Posts: 8
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Post by 60525 on Feb 8, 2020 20:48:51 GMT
Pete I think you are onto something there........ I think I can create a route through above the pony truck rubbing plate/stay. Being a 2 cylinder design, as long as I avoid the steam and exhaust pipes, the only other item running through here is the actuating rod for the mechanical lubricator that sits behind the front buffer beam and is driven from a leading axle eccentric. I think I can feed a rod through above the plate to exit below the mating face of each cylinder block and fashion a crank type arrangement between the cylinder block and frame.......    Dad had a mate with access to an early CNC metal stamping machine and welding gear so welded the frame. I should be able to bore through the weld to give sufficient clearance for a small diameter rod? |
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Post by Deleted on Feb 8, 2020 21:06:01 GMT
Sounds like a plan sir...good luck, I'm sure it will work out fine.
Pete
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Post by andyhigham on Feb 8, 2020 21:26:57 GMT
Just an outside the box thought. If you are using a bowden cable system. why not run 2 cables from the lever to the drain cocks and omit the cross shaft?
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mbrown
Elder Statesman
Posts: 1,724
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Post by mbrown on Feb 8, 2020 23:00:41 GMT
I am not sure how the cocks were operated on the full size V4s, but some Gresley designs (the Hunts, and Sandringhams if I remember correctly, and maybe others) had a cross shaft in front of the cylinder and quite high up, connecting to a bell crank on the front cock with the usual link going from there to the rear cock. It looks as if you could put a cross shaft in front if the steam chest with an arm outside the frame on each side, and then replace the arm on the front cock with a bell crank so that it can be operated by a link from the cross shaft arm and connect with another link to the rear cock. Your Bowden cables would be between the frames and would have to negotiate the steam pipes, but that should be feasible. It would be easier to sketch it than describe it.
Just another way to skin this cat, maybe...
Malcolm
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60525
Member
Returnee to the hobby.
Posts: 8
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Post by 60525 on Feb 8, 2020 23:09:50 GMT
Pete...... I will draw it up in more detail to check clearance etc...... Thanks for your input......
Malcolm...... A second option. I think I prefer between the cylinder and frame option but may revisit this when I come to do the job...... Thanks
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Post by Deleted on Feb 8, 2020 23:14:18 GMT
I guess there's always the options of steam or auto draincocks...I believe that Flying Scotsman today has steam operated draincocks.
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Post by manofkent on Feb 9, 2020 21:23:04 GMT
My Bantam cock has slide valves and no drain clocks. I run it backwards for about 10 metres when cold, then it is OK and the cylinders are warmed up. Slide valves will lift to let the condensed water out.
A nice to have but not essential if it is really difficult to fix.
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Post by osiris09 on Feb 10, 2020 3:43:30 GMT
 Does this help in anyway? its a 3.5" pamela with control cable for the drain cocks. Its a tad disassembled at the moment but might give you an idea of layout. Image here --> ibb.co/G0zVM1z |
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Post by runner42 on Feb 10, 2020 5:00:09 GMT
Mounting the actuating shaft on the bogie bolster is the way to go. The above solution is an example but because the shaft is mounted midway it requires cut-outs to be made in the mainframes to accommodate the shaft. A simpler solution is to mount the shaft at the front of the bogie bolster so it doesn't require modification to the mainframes. Something like this.  cylinder drain cocks by Brian Leach, on Flickr Brian |
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60525
Member
Returnee to the hobby.
Posts: 8
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Post by 60525 on Feb 14, 2020 19:27:44 GMT
My Bantam cock has slide valves and no drain clocks. I run it backwards for about 10 metres when cold, then it is OK and the cylinders are warmed up. Slide valves will lift to let the condensed water out. A nice to have but not essential if it is really difficult to fix. The cylinders have the drains already fitted though I could blank these off I suppose. Unfortunately one of the valves has gone missing in the transfer from my Dad's workshop to mine so I'm faced with finding a replacement. |
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60525
Member
Returnee to the hobby.
Posts: 8
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Post by 60525 on Feb 14, 2020 19:31:01 GMT
Does this help in anyway? its a 3.5" pamela with control cable for the drain cocks. Its a tad disassembled at the moment but might give you an idea of layout. Image here --> ibb.co/G0zVM1zOsiris.... Thank you for taking the trouble to post your picture. It gives me a good idea of how I might fit the cross-shaft. It looks like it is operated using a push rod, am I seeing straight? |
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60525
Member
Returnee to the hobby.
Posts: 8
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Post by 60525 on Feb 14, 2020 19:33:17 GMT
Mounting the actuating shaft on the bogie bolster is the way to go. The above solution is an example but because the shaft is mounted midway it requires cut-outs to be made in the mainframes to accommodate the shaft. A simpler solution is to mount the shaft at the front of the bogie bolster so it doesn't require modification to the mainframes. Something like this. cylinder drain cocks by Brian Leach, on Flickr Brian I'm not sure that would work in my case the bolster acts as a rubbing plate for the pony truck. I think a cross shaft will fit as shown by the red blob:-  I can rod to the drains from here. Just scratching my head to work out how I terminate the Bowden cables within the frames when it is so close to the rubbing plate. |
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Post by osiris09 on Feb 14, 2020 20:20:32 GMT
Osiris.... Thank you for taking the trouble to post your picture. It gives me a good idea of how I might fit the cross-shaft. It looks like it is operated using a push rod, am I seeing straight? It’s not a great pic but there is a copper tube that runs the length of the chassis and inside there is a stiff wire that appears to have been silver soldered to the end clevis. At the drivers end it is held in place by a pinch bolt. The copper tube is out of alignment in the pic as I’ve taken the wheels off to make new axles. Let me know if you would like more pics of anything as I’m guessing they would be quite similar in size to yours. |
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