adrian
Flying Squad
I got a set earlier in the week - unfortunately I'm away for the weekend so won't be able to post anything about them until Monday - if you can wait that long.
Stanier 8F in S7
- Thread starter DavidinAus
- Start date
I got a set earlier in the week - unfortunately I'm away for the weekend so won't be able to post anything about them until Monday - if you can wait that long.
DavidinAus
Western Thunderer
Fairly clearly, I have a set.
In the set are all the items which connect between the two frames, including the beams at either end of the frames (buffer beam and under the cab).
The motion bracket has also been altered and new etches provided. I am at work now, but will post all the part numbers from the instructions tonight.
They seem to fit extremely well, as you might expect from MOK, it seems. The cylinders, slide bars and motion bracket are assembled in a way which allows them to be taken on and off easily after assembly, which is really good. I haven't put the wheels in yet (I am going to wait and get the S7 Group wheels when they come out), but looking at the cylinders, slide bars, and a set of S7 driving wheels from another loco., the clearances seem like they will work well, also.
David
In the set are all the items which connect between the two frames, including the beams at either end of the frames (buffer beam and under the cab).
The motion bracket has also been altered and new etches provided. I am at work now, but will post all the part numbers from the instructions tonight.
They seem to fit extremely well, as you might expect from MOK, it seems. The cylinders, slide bars and motion bracket are assembled in a way which allows them to be taken on and off easily after assembly, which is really good. I haven't put the wheels in yet (I am going to wait and get the S7 Group wheels when they come out), but looking at the cylinders, slide bars, and a set of S7 driving wheels from another loco., the clearances seem like they will work well, also.
David
Thank you Adrian and thank you David both answers would be helpful. I have already built an MOK 8f a couple of years back but in finescale so I'm fairly familiar with the construction. I have two more that I have had stored away and had planned to make these to S7 after becoming a S7 member earlier this year so thank you for your efforts with the widening kit David. I'm building the first of the 8F's from the top down so I didn't want to fit things like buffer beams if the kit included new wider ones.
Regards
Mark J
Regards
Mark J
DavidinAus
Western Thunderer
OK. Home now.
Parts on the S7 etch are:
102, 103, 104, 105, 106, 107, 111, 124, 137, 138, 141, 142, 154, 163, 167/8, 170, 172, 173, 180, 186, 187, 188, 189, 191, 192, 193, 194,
I have had the kit on my shelf for so long that my instructions are probably dated about 1998 (!), and I have had some discrepancies between the numbers on the etch and the numbers in my instructions.
Someone out there might be able to help me as I make the valve gear. The top end of the combination lever appears very tight in the valve piston crosshead, and this tiny crosshead doesn't seem to allow sufficient room for the combination lever to move forwards and backwards as the main crosshead is moved by the connecting rod. How much freedom to give it is difficult to gauge: it depends on how much the main crosshead moves forward and back (I think I've worked this one out actually: 14" throw x2 = 16.3mm in 7mm scale), and also how much the radius arm moves the top end of the combination lever (I'm going to try and put the valve gear in a position as though set for forwards power). So can anyone tell me how close to the cylinder end the crosshead comes, and how close to the other end of the slidebars (at the motion bracket). Also can anyone tell me how much movement to allow for at the other end of the combination lever, and does it move in-phase or out-of-phase with the main crosshead?
All help gratefully received ....
David
Parts on the S7 etch are:
102, 103, 104, 105, 106, 107, 111, 124, 137, 138, 141, 142, 154, 163, 167/8, 170, 172, 173, 180, 186, 187, 188, 189, 191, 192, 193, 194,
I have had the kit on my shelf for so long that my instructions are probably dated about 1998 (!), and I have had some discrepancies between the numbers on the etch and the numbers in my instructions.
Someone out there might be able to help me as I make the valve gear. The top end of the combination lever appears very tight in the valve piston crosshead, and this tiny crosshead doesn't seem to allow sufficient room for the combination lever to move forwards and backwards as the main crosshead is moved by the connecting rod. How much freedom to give it is difficult to gauge: it depends on how much the main crosshead moves forward and back (I think I've worked this one out actually: 14" throw x2 = 16.3mm in 7mm scale), and also how much the radius arm moves the top end of the combination lever (I'm going to try and put the valve gear in a position as though set for forwards power). So can anyone tell me how close to the cylinder end the crosshead comes, and how close to the other end of the slidebars (at the motion bracket). Also can anyone tell me how much movement to allow for at the other end of the combination lever, and does it move in-phase or out-of-phase with the main crosshead?
All help gratefully received ....
David
Hello David,
Thank you for the help with the part numbers I can now get a bit further with my kit.
I don't think the instructions have been changed since 1998 the kits that I brought around 2 years ago refer to things in the instructions that you no longer need to do on the kit so I guess it's evolved without some stuff being updated.
On the clearance problem front it could be that you have an old etch that's been updated now. I have old etches in my original kit as I kept hold of the spare bits in my spares box. Check the dates on your etches and I will compare it to my more recent kits the all have a date and issue number ok the edge of the sheets.
I don't remember having to fiddle and fettle my original kit valve gear but it was about 4-5 years ago when I built it.
Thank you again for the part numbers
Regards
Mark J
Thank you for the help with the part numbers I can now get a bit further with my kit.
I don't think the instructions have been changed since 1998 the kits that I brought around 2 years ago refer to things in the instructions that you no longer need to do on the kit so I guess it's evolved without some stuff being updated.
On the clearance problem front it could be that you have an old etch that's been updated now. I have old etches in my original kit as I kept hold of the spare bits in my spares box. Check the dates on your etches and I will compare it to my more recent kits the all have a date and issue number ok the edge of the sheets.
I don't remember having to fiddle and fettle my original kit valve gear but it was about 4-5 years ago when I built it.
Thank you again for the part numbers
Regards
Mark J
DavidinAus
Western Thunderer
I thought it conceivable that others might be interested in my progress with the 8F in S7. So here we go. Although I have now used most of the special parts from the S7 etch, and am very happy with them, I guess we still cannot be certain that it will work.
From what I see so far, though, there is going to be enough clearance between the front end of the coupling rod (plus the fixing nut on the front driving wheel) and the back of the main cylinder crosshead. This was the major difficulty when I built the Garratt in S7 (see my avatar!), so I am a little nervous about this particular dimension!
I am going to wait for the Scale Seven Group wheels for the 8F, so will not be able to try this out in reality until they are produced and I obtain a set.
I’ve been working slowly on the “motion bracket” and the slidebars and crosshead assembly, toghether with some of the valve gear.
Here are some pictures of the progress so far:
These are the radius bar and union link, made with bifurcated ends.
Here is the expansion link with the radius arm fitted.
In most models (I think) the radius arm is left in a neutral position, through the centre of the expansion link. This is convenient, as the centre of the expansion link is the pivot about which it moves forward and back, but for the radius arm to be there is to have the model always in neutral gear. So instead I have decided to make my model in a forward gear, with the radius rod just below the central expansion link. I was inspired into doing this because MOK seem to have made the construction of the expansion link with this possibility in mind: the inner parts of the laminated link have holes below the central pivot and above it. These allow the radius arm to be mounted to the expansion link on a separated pivot from the main one. Thus the radius arm is either below the centre of the expansion link (forward power) or above it (reverse gear).
I have successfully done this. The radius arm will move forwards and back a very small amount as a consequence, but the construction should be able to be done reasonably easily (I think).
This show the radius arm/expansion link in position, in the motion bracket. It is possible to see (if you look carefully!) that the radius arm is just a small amount below the pin around which the expansion link moves.
This is the motion bracket in position on the frames.
The whole construction is made to come off the frames for ease of maintenance and building.
It isn't complete, of course.
More later, perhaps.
David
From what I see so far, though, there is going to be enough clearance between the front end of the coupling rod (plus the fixing nut on the front driving wheel) and the back of the main cylinder crosshead. This was the major difficulty when I built the Garratt in S7 (see my avatar!), so I am a little nervous about this particular dimension!
I am going to wait for the Scale Seven Group wheels for the 8F, so will not be able to try this out in reality until they are produced and I obtain a set.
I’ve been working slowly on the “motion bracket” and the slidebars and crosshead assembly, toghether with some of the valve gear.
Here are some pictures of the progress so far:
These are the radius bar and union link, made with bifurcated ends.
Here is the expansion link with the radius arm fitted.
In most models (I think) the radius arm is left in a neutral position, through the centre of the expansion link. This is convenient, as the centre of the expansion link is the pivot about which it moves forward and back, but for the radius arm to be there is to have the model always in neutral gear. So instead I have decided to make my model in a forward gear, with the radius rod just below the central expansion link. I was inspired into doing this because MOK seem to have made the construction of the expansion link with this possibility in mind: the inner parts of the laminated link have holes below the central pivot and above it. These allow the radius arm to be mounted to the expansion link on a separated pivot from the main one. Thus the radius arm is either below the centre of the expansion link (forward power) or above it (reverse gear).
I have successfully done this. The radius arm will move forwards and back a very small amount as a consequence, but the construction should be able to be done reasonably easily (I think).
This show the radius arm/expansion link in position, in the motion bracket. It is possible to see (if you look carefully!) that the radius arm is just a small amount below the pin around which the expansion link moves.
This is the motion bracket in position on the frames.
The whole construction is made to come off the frames for ease of maintenance and building.
It isn't complete, of course.
More later, perhaps.
David
The S7 wheels for the 8F are on order from Slater's but we have no date for completion yet. I was speaking with David White yesterday (Sunday) and asked him where we were with these and he said he had done the tyre drawing but wouldn't be drawn on anything beyond that except to say they were in the pipeline.
Regards
Rob
Regards
Rob
DavidinAus
Western Thunderer
A brief update: construction is still going well, with no problems from the conversion to S7. It's going slowly, though, due to other things in my life.
I always have the problem as I construct connecting and coupling rods, valve gear, etc: just how free does the mechanism need to be, in the non-lubricated state? The answer always is the same - as free as possible - but how long does one keep trying to get that little bit less resistance?
As I put together the bits named above (picture repeated below) it became clear that there was resistance to the crosshead going forwards. It seemed to be only after I had attached the union link/combination lever/radius arm, but whcih joint was causing the trouble?
Fortunately I could ask Richard Davidson, when I went down to Melbourne on a day trip (!) to see his railway and run some S7 trains. As an aside, does he hold the world record for the longest continuous loop of S7 track? His garden railway has a continuous loop of about 60 metres length!
Anyway, Richard was able to identify the joint producing the problem, and I don't think that I would have ever suspected it myself: the joint between the bottom of the combination lever and the union link was stiff (the lever caught in the bifurcated end of the union link). This made the combination lever move upwards as the crosshead advanced in the slidebars, causing the piston-valve spindle to rub on the upper surface of the hole into which it moves. Just this minor proble caused the extra resistance. I freed the relevant joint, and the crosshead moved much more freely.
It all goes to show: 1. make all valve gear joint as free as you possibly can; 2. ask for experienced help if you are stuck!
David
I always have the problem as I construct connecting and coupling rods, valve gear, etc: just how free does the mechanism need to be, in the non-lubricated state? The answer always is the same - as free as possible - but how long does one keep trying to get that little bit less resistance?
As I put together the bits named above (picture repeated below) it became clear that there was resistance to the crosshead going forwards. It seemed to be only after I had attached the union link/combination lever/radius arm, but whcih joint was causing the trouble?
Fortunately I could ask Richard Davidson, when I went down to Melbourne on a day trip (!) to see his railway and run some S7 trains. As an aside, does he hold the world record for the longest continuous loop of S7 track? His garden railway has a continuous loop of about 60 metres length!
Anyway, Richard was able to identify the joint producing the problem, and I don't think that I would have ever suspected it myself: the joint between the bottom of the combination lever and the union link was stiff (the lever caught in the bifurcated end of the union link). This made the combination lever move upwards as the crosshead advanced in the slidebars, causing the piston-valve spindle to rub on the upper surface of the hole into which it moves. Just this minor proble caused the extra resistance. I freed the relevant joint, and the crosshead moved much more freely.
It all goes to show: 1. make all valve gear joint as free as you possibly can; 2. ask for experienced help if you are stuck!
David
Overseer
Western Thunderer
Looking good David. Next time you are coming to Melbourne we should organise a South East Australia S7 Area Group meeting. Last time I tried to get people together when I exhibited my layout at Caulfield in 2012 everyone was away overseas, or half way across the Nullabor in Richards case. Although I should also make an effort to get to VicGOG meetings to catch up with people.
DavidinAus
Western Thunderer
I have been contructing parts of the valve gear, as shown.
I am a little puzzled, and slightly worried, that little mention of this difficulty has been made by others who have built this kit: it would be the same in Finescale as it is in S7. I cannot think that it is to do with me wanting the valve gear to be in a position of forward-power, because I have only set the radius rod slightly below neutral position (so little that I don't think it is realistic, actually!). So here we go ....
The detail of this kit is such that the combination lever, with a complex shape at its top, if faithfully reproduced. Unfortunately this means that the where the lever goes through the crosshead of the piston valve it is such a tight fit that there is not enough movement in the model form.
These are pictures of the piston valve shaft and crosshead (all one moulding) and the combination lever, unmodified as yet.
Combination lever – unmodified
Piston valve shaft and crosshead – all one piece of “lost wax” casting.
They both have to be carefully filed back to allow the combi. lever to move through an angle of about 25 degree either side of verticle in the crosshead.
So with some careful filing I have achieved enough clearance, but was there a better way around?
So this is where I am up to so far ....
I will have to move onto something else now, I think, until the S7 wheels become available. I will try to find something else to do with this kit first.
Incidentally, I have previously used dummy axles to set the driving wheels at the correct distance apart for the coupling rods, but this kit comes to be made in such a way that the axle positions seem fixed in advance, and the coupling rods are also of a fixed distance between crankpins. Will this work out OK, or is there some other trick that I should know about? At least the coupling rod is correctly articulated.
David
I am a little puzzled, and slightly worried, that little mention of this difficulty has been made by others who have built this kit: it would be the same in Finescale as it is in S7. I cannot think that it is to do with me wanting the valve gear to be in a position of forward-power, because I have only set the radius rod slightly below neutral position (so little that I don't think it is realistic, actually!). So here we go ....
The detail of this kit is such that the combination lever, with a complex shape at its top, if faithfully reproduced. Unfortunately this means that the where the lever goes through the crosshead of the piston valve it is such a tight fit that there is not enough movement in the model form.
These are pictures of the piston valve shaft and crosshead (all one moulding) and the combination lever, unmodified as yet.
Combination lever – unmodified
Piston valve shaft and crosshead – all one piece of “lost wax” casting.
They both have to be carefully filed back to allow the combi. lever to move through an angle of about 25 degree either side of verticle in the crosshead.
So with some careful filing I have achieved enough clearance, but was there a better way around?
So this is where I am up to so far ....
I will have to move onto something else now, I think, until the S7 wheels become available. I will try to find something else to do with this kit first.
Incidentally, I have previously used dummy axles to set the driving wheels at the correct distance apart for the coupling rods, but this kit comes to be made in such a way that the axle positions seem fixed in advance, and the coupling rods are also of a fixed distance between crankpins. Will this work out OK, or is there some other trick that I should know about? At least the coupling rod is correctly articulated.
David
adrian
Flying Squad
I don't have any drawing or photographic evidence to hand to confirm it but I think the back of the piston valve guide should be completely cut away. So that the guide is just a U shape rather than a box shape. That's how I did it on my Ivatt 2 and 4MT.
DavidinAus
Western Thunderer
Good. It is great to get all the information about the combination lever/piston valve crosshead. I must remember to ask for help earlier in the process, though: I have made up the assembly without removing the back of the crosshead. This probably made it unnecessarily difficult, but I have now managed to do it, and to pull it all apart now and re-do it seems ridiculous. So it is going to stay as it is!
Now onto the next bit. Whilst I wait for the S7 wheels to become available (see separate thread), I will try to progress with other parts of the engine. The next bit in the instruction which I have is the pony truck. So I have started on this.
This is clearly going to be a project effectively build by you all, just with me doing the soldering, etc., whilst you give me advice/instructions!
Here is the basic construction.
As can be seen, there is no compensation on the pony truck. I doubt that this is necessary, because there will be a little bit of lateral sway of the mechanism once in place, and so with only one axle surely compensation will not be required? However I lack experience to say that this is so with confidence.
Should I add weight to the box-like centre of the pony truck?
Comments, anyone?
Incidentally, I have a works diagram of the engine, and the frames of the pony truck are the correct distance apart (±0.5 mm, which is good enough for me). So, Scale Seven bretheren, we can relax about this!
David
Now onto the next bit. Whilst I wait for the S7 wheels to become available (see separate thread), I will try to progress with other parts of the engine. The next bit in the instruction which I have is the pony truck. So I have started on this.
This is clearly going to be a project effectively build by you all, just with me doing the soldering, etc., whilst you give me advice/instructions!
Here is the basic construction.
As can be seen, there is no compensation on the pony truck. I doubt that this is necessary, because there will be a little bit of lateral sway of the mechanism once in place, and so with only one axle surely compensation will not be required? However I lack experience to say that this is so with confidence.
Should I add weight to the box-like centre of the pony truck?
Comments, anyone?
Incidentally, I have a works diagram of the engine, and the frames of the pony truck are the correct distance apart (±0.5 mm, which is good enough for me). So, Scale Seven bretheren, we can relax about this!
David
Scale7JB
Western Thunderer
Hi David, all looking good..
Just a couple of things, are your wheels going to have enough clearance behaind the sidebars and cross heads of the valve gear? Is the kit set for S7? In the past with outside valve gear locos, when I've had to widen the frames, it means narrowing down the cylinders, just thought I would check before you go too much farther..
Also, with my K2's and L1 with a leading pony truck I have had to spring the axle, and also provide downward force from underneath the front of the runnin plate. You may want to see how you go as if the pony truck frame is already soldered up, it's no biggie to give it a go, an adjust later, but with the fine S7 flanges it's something to think about for the future..
JB.
Just a couple of things, are your wheels going to have enough clearance behaind the sidebars and cross heads of the valve gear? Is the kit set for S7? In the past with outside valve gear locos, when I've had to widen the frames, it means narrowing down the cylinders, just thought I would check before you go too much farther..
Also, with my K2's and L1 with a leading pony truck I have had to spring the axle, and also provide downward force from underneath the front of the runnin plate. You may want to see how you go as if the pony truck frame is already soldered up, it's no biggie to give it a go, an adjust later, but with the fine S7 flanges it's something to think about for the future..
JB.
DavidinAus
Western Thunderer
It has been a while since my last post on this thread, and progress is slow, because I do other things.
It hasn't stopped altogether, however. I've made as much as I can easily do of the chassis without the wheels, and am waiting now for the Slaters S7 wheels to become available. In the meantime I have constructed the pony truck, the rear steps, and am now doing the front footplate sub-assembly. This is a great example of how the parts can be put together "dry" - no solder - because of the excellent tab-and-slot construction. In making this sub-assembly, I have come across a minor problem. Probably only minor, but before I make irrevocable cuts into the footplate, could I ask if anyone out there sees a better solution?
See the attached images.
As can be seen, the problem is that the upright frame for the motor mount has a width of 29mm, whilst the distance between the edges of the footplate is 26.5mm.
It's not a major problem, I guess, and probably the answer is simply to make a couple of small cut-outs in the footplate - 1.25 mm each side is only a small amount, I guess. Before I do this, however, I thought that I should ask if there is an alternative solution which anyone can see. Making cuts in the footplate is all very well, but what the effect on the later construction and the overall end-appearance I cannot yet tell.
The reason that Dave Sharp wanted to "upgrade" this kit is largely about the instructions, I gather, and for me this IS a minor problem, because it's difficult for me to see sometimes what the relationship between parts is, unless they are visible on pictures of the real engines.
I can easily cut a little out of the footplate and make it fit, but it would be mice to be able to predict what the final effect will be!
David
It hasn't stopped altogether, however. I've made as much as I can easily do of the chassis without the wheels, and am waiting now for the Slaters S7 wheels to become available. In the meantime I have constructed the pony truck, the rear steps, and am now doing the front footplate sub-assembly. This is a great example of how the parts can be put together "dry" - no solder - because of the excellent tab-and-slot construction. In making this sub-assembly, I have come across a minor problem. Probably only minor, but before I make irrevocable cuts into the footplate, could I ask if anyone out there sees a better solution?
See the attached images.
As can be seen, the problem is that the upright frame for the motor mount has a width of 29mm, whilst the distance between the edges of the footplate is 26.5mm.
It's not a major problem, I guess, and probably the answer is simply to make a couple of small cut-outs in the footplate - 1.25 mm each side is only a small amount, I guess. Before I do this, however, I thought that I should ask if there is an alternative solution which anyone can see. Making cuts in the footplate is all very well, but what the effect on the later construction and the overall end-appearance I cannot yet tell.
The reason that Dave Sharp wanted to "upgrade" this kit is largely about the instructions, I gather, and for me this IS a minor problem, because it's difficult for me to see sometimes what the relationship between parts is, unless they are visible on pictures of the real engines.
I can easily cut a little out of the footplate and make it fit, but it would be mice to be able to predict what the final effect will be!
David
Attachments
mickoo
Western Thunderer
Is it possible to narrow the mount?, the mount sides look to be a part of the main frames and support the transverse plate that the motor attaches too, I fear if you remove the sides to let the footplate drop down then the vertical transverse motor plate may not have enough strength to hold the motor. If you do remove the sides then it might pay to strengthen the joint with L (blue) channel soldered to the inside of the frames and to the motor mount; an alternative would be some 20 thou scrap etch bent to form a larger bracket shown green, but again on the inside of the frames.
Richard has a point about the white metal firebox, it's going to be very thin in that area to cover the mount and not appear overly wide on the footplate, on the real loco the frames pass up through the footplate by several inches, if you cut the footplate then you may have to start cutting other parts later on. I'm going to guess that the MoK kit has some etched extension pieces that are soldered to the footplate to represent this.
I think I'd go with Ozzys option but add the reinforcing straps to retain strength in the motor mount, they will be inside the frames so should minimise further problems.
Its looking good so far and coming together really well
Dog Star
Western Thunderer
Please excuse this Swindonite intruding into a Crewe/Derby/Bow/Horwich etc. discussion... if the motor mount comes from the S7-specific etches then one can believe that:-
a) MOK would have considered the fit of the new S7 etches into the existing etch parts;
b) the S7 etch parts would be supplied with notes to identify where, if at all, the original etch parts need modification to accomodate the new S7 parts.
How about asking the kit designer what is intended? There is always the possibility that the conflict that you encountered has not been seen by MOK as yet.
regards, Graham
a) MOK would have considered the fit of the new S7 etches into the existing etch parts;
b) the S7 etch parts would be supplied with notes to identify where, if at all, the original etch parts need modification to accomodate the new S7 parts.
How about asking the kit designer what is intended? There is always the possibility that the conflict that you encountered has not been seen by MOK as yet.
regards, Graham
adrian
Flying Squad
I presume the problem is that the footplate is still a "finescale" item so the 26.5mm between inside edges is so that they meet the finescale chassis. I think the problem will be that the footplate will now overhang your wider frames and look unusual.
This is one of the main reasons I switched to Scale7 to avoid over width footplates and fireboxes sitting on top to the footplate. It depends how confident you are in scratch building items, for my 8F I'd contemplate making some new footplates of the correct width so they just meet the frames. I've not looked in great detail but you could use the originals as a template and then cut the new ones slightly narrower.