Dave Holt Posted September 24, 2017 Share Posted September 24, 2017 The rocker arms were not horizontal, sloping down from outside to inside, as shown on this drawing extract. Dave. Link to comment Share on other sites More sharing options...
PAD Posted September 24, 2017 Author Share Posted September 24, 2017 Hi Richard, Many thanks. That is most helpful. I will use that and the prototype photos posted by Petebe to hopefully get something close. Here's one of Pete's photos. I believe your cylinders/valve gear are de-mountable, so do you need to withdraw both the bolt on the valve rod as well as at the rocker pivot, to remove them? Dave, Thanks for the drawing extract. I did not realise the rocker arm sloped but I think for the purpose of the model, I will make it horizontal as Richard's appears to be. Cheers, Peter 1 Link to comment Share on other sites More sharing options...
dikitriki Posted September 29, 2017 Share Posted September 29, 2017 Hi Richard, Many thanks. That is most helpful. I will use that and the prototype photos posted by Petebe to hopefully get something close. Here's one of Pete's photos. post-32071-0-37707000-1505212375_thumb.jpg I believe your cylinders/valve gear are de-mountable, so do you need to withdraw both the bolt on the valve rod as well as at the rocker pivot, to remove them? Dave, Thanks for the drawing extract. I did not realise the rocker arm sloped but I think for the purpose of the model, I will make it horizontal as Richard's appears to be. Cheers, Peter Hi Peter, Yes, both bolts each side need to be withdrawn, and it's still a PITA to get the rocker and valve rod out. I must admit I didn't know the rocker arm was inclined, and given the etches, it would be tricky to duplicate it. I'll settle for it working properly! Richard Link to comment Share on other sites More sharing options...
Dave Holt Posted September 29, 2017 Share Posted September 29, 2017 I can't see any particular problem with making the rocker horizontal, but the slope on the real thing may explain why the pivot mounting appears a bit low compared with the outside valve spindle, as commented by someone earlier in the thread. Dave. Link to comment Share on other sites More sharing options...
PAD Posted September 29, 2017 Author Share Posted September 29, 2017 Hi Richard, Thanks, you have confirmed what I thought would be the case, and that it is a PITA to get the rocker and valve out. I'm not a "you can't see it but I know it's there" modeller, so think I may go for a cosmetic modification only, and not connect the rocker arm to the pivot on the frame. That way removal of the gear will be much easier. If it looks the part when running then I'll be happy. Dave, What you say about the slope also makes sense in relation to pivot mounting position. Cheers, Peter Link to comment Share on other sites More sharing options...
PAD Posted October 9, 2017 Author Share Posted October 9, 2017 I have now modified the valve rod and completed the left hand valve gear as well as making a start on the right hand side. I've not gone for the full Monty as Dikitriki had with his Finney 7 build, opting for an improved appearance over full functionality. It looks the part when moving and it's easy to remove. Here's the return crank and bearing cover. And the right hand side. Here's a broadside of the complete left hand motion. Cheers, Peter 4 Link to comment Share on other sites More sharing options...
JeffP Posted October 10, 2017 Share Posted October 10, 2017 How are you keeping the wheels so corrosion-free? Link to comment Share on other sites More sharing options...
Black Country Mon Posted October 10, 2017 Share Posted October 10, 2017 Hi Peter, The valve gear is looking fantastic and the tips you've given us all regarding laminating the spare etches is invaluable. I have an assembly question if i may. How have you attached the return crank to the crankpin? I presume the eccentric rod is pinned from the rear to the crank and the bearing cover soldered onto the front. Cheers Dave Link to comment Share on other sites More sharing options...
PAD Posted October 10, 2017 Author Share Posted October 10, 2017 Hi Dave, I'll draw a diagram and post some pics later to answer your questions. Jeff, I find it's impossible to keep the wheels free of corrosion when soldering parts to the chassis with the wheels in. I just clean them periodically with a circular wire brush in the mini drill. It's quicker and easier than taking the rods and wheels on and off, and in any case you need them in when aligning the brake gear. Just don't leave them for the whole build to clean at the end, and the same goes for cleaning the brass. Do it as you go along (ideally after each soldering session). Cheers, Peter Link to comment Share on other sites More sharing options...
Petebe Posted October 10, 2017 Share Posted October 10, 2017 Hi Peter Yeah Dave. That's the bit I've been waiting for!!!!! The crank pin. I think I've made a school boy error, The rocker arm mount on yours looks right but mine is too low. The cylinders when rechecking are too high and not fitting correctly, so a refit me thinks. Dam. Still doing my oil boxes. Looking very good there Peter Pete Link to comment Share on other sites More sharing options...
Horsetan Posted October 11, 2017 Share Posted October 11, 2017 The valve gear is looking fantastic and the tips you've given us all regarding laminating the spare etches is invaluable. The close-up photos really help, too. Link to comment Share on other sites More sharing options...
PAD Posted October 11, 2017 Author Share Posted October 11, 2017 (edited) OK here's a diagram of the center crank pin and return crank/eccentric arrangement. It's a bit crude but I hope it makes sense. First up I replaced the 12 BA bolt for the crank pin with a 10 BA after enlarging the hole in the wheel boss to to take it. As mentioned earlier by "Petebe", the rods are very close to the wheel centers, so I added a steel washer (to the front and rear cranks also), before adding the brass top hat bush, drilled out to clear the 10 BA bolt. Then the coupling rod is added. To space the connecting rod away from the coupling rod, I made a spacing washer from 4 X 8 BA brass washers soldered together with the hole opened to clear the Slater's top hat bush, then the connecting rod is added. Finally, another Slater's top hat bush tapped 10 BA is screwed on (flange to the outside) to secure it all. Both bushes need to be filed to reduce slop but leaving get a working clearance. The return crank hole where it fits to the crank pin was also tapped 10 BA, and then a cocktail stick is "screwed into the bush and then into the return crank. The excess length of the cocktail stick being pushed into a suitable hole in some suitable flat wood to hold the pieces firmly together, before soldering. The outer laminates are then lined up with the inner one and clamped in a vice while they are soldered together to prevent and movement of the bush to the inner crank. The completed return crank, coupling rod, spacer and connecting rod are then screwed onto the center driver ( which is off the axle). The position of the return crank is then adjusted from the rear by turning the 10 BA bolt with a screwdriver, to be "leaning forward" when the crank is at the bottom of the stroke. This can be secured with a blob of epoxy or other methods if necessary. For the eccentric rod to return crank joint, I used a C/S brass 12 BA bolt as the pivot. The hole in the end of the crank is therefore tapped 12 BA. As a spacer between the rod and crank, I soldered a brass washer to the rear to the eccentric, drilled to clear the 12 BA bolt. The hole on the outside was then countersunk and the diameter of the bolt head reduced by filing whilst spinning it in the mini drill. this is to give clearance inside the etched bearing cover. And from the inside. Here you can see the mods. made to the valve rod. The rod and crank are then screwed together tight enough to give a running clearance without slop, and the end of the bolt is then soldered on the inside of the return crank. The excess bolt is then snipped off and dressed back with a file. The etched bearing cover posses a problem as the clearance provided is insufficient to clear the head of the 12 BA C/S bolt. To increase the clearance, I soldered a suitable sized brass washer to the inside face of the etching. Here's a spare etching on the left, with the modified one on the right. The black colour it from a felt marker used to prevent solder running into the recess in the etch. The dental burr was then used to further increase the clearancein the cover. Here you can see the difference it makes comparing an original and a modified cover. I didn't dare risk soldering the cover to the eccentric rod and risking a melt down, so I opted to glue it using a gel type super glue, spotted around the perimeter with a pin. And the cover added to the rod. The lifting link and the rest of the motion has also been added to the right hand side. i just need to add the valve rod cross head guide casting to complete it. So far it all runs silky smooth. . Here's a couple of shots from below. This is my simplified take on the valve rocker levers. They are not connected to the frame pivots as they should be, and only move in a forward to backwards motion, not in an arc as they should, but with the body in place, they look the part from normal viewing angles. I'm quite pleased with how it's turned out so here's a few gratuitous shots to finish the post. Cheers, Peter Edited October 12, 2017 by PAD 1 Link to comment Share on other sites More sharing options...
JeffP Posted October 12, 2017 Share Posted October 12, 2017 That should be bookmarked. Excellent idea, excellent write-up and superb modelling. Thanks. Link to comment Share on other sites More sharing options...
Black Country Mon Posted October 12, 2017 Share Posted October 12, 2017 Peter thanks very much for taking time out to take additional photos and putting that all down onto paper. Brilliant. Dave Link to comment Share on other sites More sharing options...
PAD Posted October 12, 2017 Author Share Posted October 12, 2017 (edited) Thanks Dave. Did it all make sense? Cheers Peter Edited October 12, 2017 by PAD Link to comment Share on other sites More sharing options...
Black Country Mon Posted October 12, 2017 Share Posted October 12, 2017 Thanks Dave. Did it all make sense? Cheers Peter Peter yes it does. A drawing shows what a photo and descriptions sometimes have difficulty conveying in plain and simple terminology. That's another reason why i find Mitchell and Finney kits in particular a cut above as they not only provide good detailed descriptions of how they designed and envisaged an item fitting but they show the builder too with good detailed drawings. Replicating it is a different matter entirely however. Dave Link to comment Share on other sites More sharing options...
Pete Harvey Posted October 12, 2017 Share Posted October 12, 2017 OK here's a diagram of the center crank pin and return crank/eccentric arrangement. It's a bit crude but I hope it makes sense. 20171010_222012.jpg First up I replaced the 12 BA bolt for the crank pin with a 10 BA after enlarging the hole in the wheel boss to to take it. As mentioned earlier by "Petebe", the rods are very close to the wheel centers, so I added a steel washer (to the front and rear cranks also), before adding the brass top hat bush, drilled out to clear the 10 BA bolt. Then the coupling rod is added. To space the connecting rod away from the coupling rod, I made a spacing washer from 4 X 8 BA brass washers soldered together with the hole opened to clear the Slater's top hat bush, then the connecting rod is added. Finally, another Slater's top hat bush tapped 10 BA is screwed on (flange to the outside) to secure it all. Both bushes need to be filed to reduce slop but leaving get a working clearance. The return crank hole where it fits to the crank pin was also tapped 10 BA, and then a cocktail stick is "screwed into the bush and then into the return crank. The excess length of the cocktail stick being pushed into a suitable hole in some suitable flat wood to hold the pieces firmly together, before soldering. The outer laminates are then lined up with the inner one and clamped in a vice while they are soldered together to prevent and movement of the bush to the inner crank. The completed return crank, coupling rod, spacer and connecting rod are then screwed onto the center driver ( which is off the axle). The position of the return crank is then adjusted from the rear by turning the 10 BA bolt with a screwdriver, to be "leaning forward" when the crank is at the bottom of the stroke. This can be secured with a blob of epoxy or other methods if necessary. 20171010_162304.jpg For the eccentric rod to return crank joint, I used a C/S brass 12 BA bolt as the pivot. The hole in the end of the crank is therefore tapped 12 BA. As a spacer between the rod and crank, I soldered a brass washer to the rear to the eccentric, drilled to clear the 12 BA bolt. The hole on the outside was then countersunk and the diameter of the bolt head reduced by filing whilst spinning it in the mini drill. this is to give clearance inside the etched bearing cover. 20171010_162408.jpg And from the inside. 20171010_162438.jpg Here you can see the mods. made to the valve rod. 20171010_162503.jpg 20171010_162537.jpg The rod and crank are then screwed together tight enough to give a running clearance without slop, and the end of the bolt is then soldered on the inside of the return crank. The excess bolt is then snipped off and dressed back with a file. The etched bearing cover posses a problem as the clearance provided is insufficient to clear the head of the 12 BA C/S bolt. To increase the clearance, I soldered a suitable sized brass washer to the inside face of the etching. Here's a spare etching on the left, with the modified one on the right. The black colour it from a felt marker used to prevent solder running into the recess in the etch. The dental burr was then used to further increase the clearancein the cover. 20171010_223033.jpg Here you can see the difference it makes comparing an original and a modified cover. 20171010_223056.jpg I didn't dare risk soldering the cover to the eccentric rod and risking a melt down, so I opted to glue it using a gel type super glue, spotted around the perimeter with a pin. 20171010_223010.jpg And the cover added to the rod. The lifting link and the rest of the motion has also been added to the right hand side. i just need to add the valve rod cross head guide casting to complete it. So far it all runs silky smooth. 20171010_222842.jpg. Here's a couple of shots from below. 20171010_162616.jpg 20171010_162645.jpg This is my simplified take on the valve rocker levers. They are not connected to the frame pivots as they should be, and only move in a forward to backwards motion, not in an arc as they should, but with the body in place, they look the part from normal viewing angles. 20171010_222619.jpg I'm quite pleased with how it's turned out so here's a few gratuitous shots to finish the post. 20171010_222120.jpg 20171010_222143.jpg 20171010_222500.jpg 20171010_222533.jpg Cheers, Peter Peter How do you stop it undoing but still have it removable for maintenance? Link to comment Share on other sites More sharing options...
Petebe Posted October 12, 2017 Share Posted October 12, 2017 Hiya Outstanding that man. I think it all makes sense, quite alot to get ones head around. What did you do with the rocker? Pete H makes a good point. Loctite, cyano, nail varnish? I met a guy at the Bristol Model engineering ex called Roger Melton, he has a site called Just the ticket engineering supplies. Worth a look. Anyway he said he could get left handed BA nuts and bolts. I was trying to think though the crank pin and left handed sounded good for one side and right the other. Maybe I was over thinking it!!!!. Good stuff Peter Pete Link to comment Share on other sites More sharing options...
Horsetan Posted October 12, 2017 Share Posted October 12, 2017 ....Roger Melton, he has a site called Just the ticket engineering supplies. Worth a look. ..... Here Link to comment Share on other sites More sharing options...
PAD Posted October 12, 2017 Author Share Posted October 12, 2017 Hi Pete, Definitely not cyano. On the Duchess the cranks tighten up pretty well but can still be unscrewed easily. If there is a tendancy to work loose I will add a smear of dilute PVA to the bolt threads, let it dry, and then refit the cranks. Left and right hand thread won't help as the cranks can still work loose depending on which direction the loco is running. It might be easier to explain the mods to the rocker lever with a diagram. I'll do that later. By the way, there is only one rocking lever on the etchings so you cannot build as per the instructions. Cheers, Peter Link to comment Share on other sites More sharing options...
Rob Pulham Posted October 12, 2017 Share Posted October 12, 2017 Hi Peter, Is there any reason that you don't blacken the wheels to stop them rusting? One of the first jobs that I do on a loco build is to blacken the wheels and then smear a light covering of oil on them. although the oil gradually wears of with handling they don't go rusty. - I use Birchwood Casey Gun Blue for Steel. Link to comment Share on other sites More sharing options...
PAD Posted October 12, 2017 Author Share Posted October 12, 2017 (edited) Hi Rob, No logical reason springs to mind. I just prefer to do it the way I do. Pete, Have a look at the diagram of the mods. I made to the valve rod guide and see if it makes sense. At the top you see a view of the right hand side looking from front. To the right is the frame with the cast pivot bracket. I added scratch built parts made from waste etch to represent the plates above and below the valve guide, and also the forked end of the rocking lever. These additional parts and the 0.8mm NS rod are soldered on as they don't need to move as on the real thing. The etched rocking lever was cut back as per the middle diagram and soldered to a piece of waste etch to beef it up. This is then soldered to the bent in ends of the fork joint. If you want to be able to remove the cylinders and valve gear easily, you need to make sure the inner end of the shortened rocking lever clears the bracket on the frames. Lower down you see the view from the top looking down on the left hand side. I have marked where you need to file the valve guide cross head to give sufficient clearance for the movement of the combination lever. Without doing this it won't run smooth. It might be OK with the gear in neutral, but not set in forward gear. Have a look at the prototype pics you posted and the ones Dikitriki added of his Finney 7 build. Richard's actually work the rocking lever and inside valve rod, but my solution is purely a cosmetic approximation. It's much easier to do than describe so perhaps I'll be more forgiving of the author of the next set of poorly written instructions I have to contend with.(no criticism of the Gladiator instructions intended) Finally, to reduce the slop of the valve rod in the cast cover, I added a suitable length of brass tube into the hole in the casting. This runs the length of the cylinder and keeps the valve rod parallel when moving. I hope that helps but if you have any other questions just let me know. Cheers, Peter Edited October 12, 2017 by PAD 2 Link to comment Share on other sites More sharing options...
Petebe Posted October 13, 2017 Share Posted October 13, 2017 Hi Peter Firstly thank you for your time drawing and sharing your most inner secrets. I now understand. There are two rocker assemblies in the kit, the other one is made of brass. I thought the same as you, so I contacted Dave Hill and as per norm he sent me a replacement. I then found the one in the kit, it had got mixed up with the unused bits from the tender. So I have three, two unused brass. If you are listening in Dave, sorry. Just add the cost onto my next purchase While I'm on here, a question. I got my water scoop to work on the tender. Does anyone know where it was operated from. I've asked a lot of people and all I've got back was a lot of chin stroking. Pete Link to comment Share on other sites More sharing options...
Horsetan Posted October 13, 2017 Share Posted October 13, 2017 (edited) ....I got my water scoop to work on the tender. P1020162.JPG DSC_0582.JPG Does anyone know where it was operated from. I've asked a lot of people and all I've got back was a lot of chin stroking. The operating handle was on the leading bulkhead of the tender, but I can't remember whether it was on the left or the right of the coal chute / shovel plate opening..... Are you making yours actually raise and lower? Edited October 13, 2017 by Horsetan Link to comment Share on other sites More sharing options...
PAD Posted October 13, 2017 Author Share Posted October 13, 2017 Hi Pete, I'm glad it helped. Here are some more shots of the right hand side (cruel close ups) before I added the final casting to complete it. This shows the area that needs filling to give clearance for the movement of the combination lever. And a shot of the cylinders and valve gear removed from the frames. And back together again. There's more detail to be added (an oil box on the top slide bar, some oil feed pipes etc) but I'll come back to that later. I have looked in the box and at the pictures of the etchings at the beginning of the thread, and I cannot find the brass rocker arms. Maybe I can't see the wood for the trees, or perhaps it was a small supplementary etch that I have lost??? Either way I don't need it. The water scoop is lowered and raised by the handle on the left hand front tender bulkhead. This is CoB's tender. Now that I've got the valve gear done, I might press on with the tender and see if I can catch you up. Cheers, Peter Link to comment Share on other sites More sharing options...
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