mickoo
Western Thunderer
Yeah but now you have to add all the authentic stays and inside motion
Building the Martin Finney A3
- Thread starter oldravendale
- Start date
Peter Cross
Western Thunderer
Must be one for Nick to do. He seems to like a challenge.
mickoo
Western Thunderer
Brian, as discussed elsewhere, that looks like another type of frame I'd not found before, the rear end is original with an oval hole blanked off and the next hole forward looks like a round hole and open right through, yet there are no other holes. By rights a new front end frame with a hole at it's rear (just ahead of the rear driver and indicating a 1930-33 Lot 317 frame) should have holes all along.
After 1933 (Lot 331) the frames have one hole right at the front.
I've found a very nice broadside view of 500 (nee 2747) in works grey (1944) and it has one round hole at the rear of the new frames and one fully blanked off oval hole on the original rear frames. This matches 60051 above and 60103 in another image. By rights these engines should have round holes all along the new section. RCTS does list 2565 as having all round holes in the new frame section and a patch with two round holes, so I suspect they must have had some evidence to write that. A lot of the class are not detailed or even mentioned in the frame change section, suggesting evidence isn't as concise as we'd like nearly 60 years later.
I'm beginning to suspect (and evidence from photos recently acquired) that there are a batch of machines out there with one rear round hole on the new front section, these being slightly modified Lot 317 frames with only one hole at the rear.
I feel a little pictorial set of diagrams are needed to show original builds and modified; then I can cross check all my photos (where the lighting allows) and then list engines under each diagram.
MD
oldravendale
Western Thunderer
Hi Mick.
Just amazing info which I'll now collate. Above everything else, 60066 will be a credible loco, and at this distance in time and from my perspective that'll do me!
Thanks for huge help.
Brian
Just amazing info which I'll now collate. Above everything else, 60066 will be a credible loco, and at this distance in time and from my perspective that'll do me!
Thanks for huge help.
Brian
oldravendale
Western Thunderer
Hi Mick.
In the occasional hour I have available at the moment I'm pressing ahead with building up the F7 hornblocks - even that's a very satisfying exercise as everything fits. In fact, once the cusps are filed away I found the best means of assembly is to locate the guides and put the assembly in my bench vice. As it tightens there's a satisfying "click" as the guides lock in to place. Soldering is then a doddle, and the bearings are a perfect fit.
Anyway, the reason for this message, Mick. I'm about to start work on the frames proper and I'd like clarification about your comment above. I read this as meaning that there are no visible rivets on the frames including the hornguides. However, on reconsideration it may mean that the rear hornguides should have visible rivets on the outside of the frames and that all the rivets should be pressed through between the rear hornguides and the rear end of the frames, but that the hornguides for the first two axles at the front are plain. My photo of the frames shows where the rivet locations are marked.
I've tried to see clues in the photo of 60066 but it's not clear enough for me to be certain.
Clarification will be gratefully received.
I've also had the firebox on the bench. I don't think the conversion from type 94 to 107 is beyond the wit of man, although that washout plug on the lower front corner will be a bit of a pig to fit now. I've asked F7 stores for a set of mudhole door clamps - whilst it may be possible for me to remove them it's more than likely that I'll melt those already fitted during the removal and reinstating process. I'd not yet fitted the washout plugs so it's just a question of checking their proper position for the 107 firebox.
Brian
mickoo
Western Thunderer
Brian,
Frame rivets are as big a conundrum as the frames themselves. As far as I understand it, Doncaster used counter sunk or smooth rivets but North British didn't or in some cases, vice versa. The new front frames were all fitted at Doncaster and generally are flush riveted, there are parts of some engines where snap head rivets have been used, for example the repair or replacement of a J hanger or a snapped off one on the motion bracket which has been replaced by a snap head.
These two photos are tight crops of copyright images so shown for indication only.
60110 late in her life, we can see very few rivets forward on the new front frame extension, the intermediate driver brake hanger is fixed exactly on the joint between the two frame sections. There are the few odd snap head rivet here and there and both sets of frames appear to have countersunk for the hornguides. However, the rear section has a lot of rivets around the rear frame stay, this is where the rear extension is bolted on.
At this point it is important to understand the real machine and how it was built.
An excerpt from the GA for the first batch of engines in 1925, all others followed the same principle.
The main frames coloured blue do not kick outside the Cartazzi as they do in the model, they kick inside and taper toward the rear drag beam. The outside Cartazzi extension is bolted on the outside and fits up and over the rear brake hanger casting. To strengthen this joint a doubler plate in green is fitted inside.
We can tell this is an original drawing because there is no patch plate (orange oval) where the joint between the old and new frames would be, the orange line indicates where the frames were cut in later life on oval hole machines.
I tried to replicate some of this on one of my first 7mm models.
The right side frame is as it would be laid out on Doncaster shop floor with the rear end kicking in and tapering toward the drag beam, the extension part is lying beside it. The left hand frame above has the extension fitted.
Inside we can see I didn't add the doubler plate, I don't know why I didn't do that, possibly because I was slowly realising at this point that no matter how much I threw into the model it'd never achieve what I wanted.
Anyway, we can see the frame extension patch plate I added inside where the two frames join, it only has one hole up front as that matched my engine (can't remember which one now) yours should have two round holes to match #66
So, going back to your engine and the image of #110 it's fairly common to have snap head rivets in the area of the doubler plate, which on the Finney7 kit are marked by the red box.
I would not punch out any of the hornguide ones and the others are at your whim. Photos of any engine that show all the rivet detail are very rare so you cannot be wrong, we can only add what we can see and be sure of, the rest is a best guess. As I said the other day, I've not yet gone through all of my data, so there may be a nice photo of #66 that shows more detail.....I just haven't found it.
Another crop of #74
Clearly countersunk rivets all over and this would be a new front frame on and oval hole rear, but, note the two replacement snap head rivets on the front J hanger/brake trunnion bracket.
Finally, if you're considering removable brake gear with small screws then you will need some sort of bracket, I don't think the kit comes with one and the thin frame sheet material won't support a 14BA thread very well.
So get yourself down to the Finney7 stores and grab some of these.
It's a small detail set for Gresley Pacific engines and brake gear, those parts that are common to all.
On the left are the four brake hanger castings, the feed acts as a securing pin into the frames via a 1.0 mm hole you have to drill. There's an indent in the end to guide the 14BA drill which goes right through the castings and into the frames; this makes a very good strong and solid fixing for the brake hanger.
The gap between Slaters wheels and these brackets is very very close, you can smooth the side of the brackets, but I found I also had to skim a little off the wheel rim to be sure (0.1-0.2 mm), more so as one of the tyres was slightly oval on one of my wheels.
There is no trailing driver brake hanger bracket on the A3/A4/W1 it's part of the rear stay that supports the firebox toe.
On the right of the sprue are a couple of slack adjusters and two brake cylinder shafts with clevis joint on the end. The brake shafts and trunnions differ on the A3 and A4 to the W1, so I'd trot off to Ragstone and look at their castings, check out their engine springs and hangers.
You need E63 springs, 11 plates at 3'-6" centres, not the more common E69 which are 16 plates at 4'-0" centres (I do plan to do some of those when I get to the A4 project).
E63 fits the W1, A3 and D49.....plus others I've not researched yet I suspect.
E69 fits all the other Pacifics, Gresley, Thompson and Peppercorn (maybe others), except the A2/2 which uses an odd spring I've not yet found the code for.
Finney7 do some E63 springs (no hangers or retention pins) but the keep plate is correctly off set to allow for the wider base on the hornguide, where the adjustment slipper goes. Not sure if your hornguides have that feature, in which case the keep plate might not centre correctly and look odd, I can post photos later but other chores call.
I also think I've got a spare set of brake hanger etches for the A3, these fit the cast hangers noted above and are designed to take the Finney7 insulated brake shoes, so you can get your shoes real close to the tyre and not short out.
Frame rivets are as big a conundrum as the frames themselves. As far as I understand it, Doncaster used counter sunk or smooth rivets but North British didn't or in some cases, vice versa. The new front frames were all fitted at Doncaster and generally are flush riveted, there are parts of some engines where snap head rivets have been used, for example the repair or replacement of a J hanger or a snapped off one on the motion bracket which has been replaced by a snap head.
These two photos are tight crops of copyright images so shown for indication only.
60110 late in her life, we can see very few rivets forward on the new front frame extension, the intermediate driver brake hanger is fixed exactly on the joint between the two frame sections. There are the few odd snap head rivet here and there and both sets of frames appear to have countersunk for the hornguides. However, the rear section has a lot of rivets around the rear frame stay, this is where the rear extension is bolted on.
At this point it is important to understand the real machine and how it was built.
An excerpt from the GA for the first batch of engines in 1925, all others followed the same principle.
The main frames coloured blue do not kick outside the Cartazzi as they do in the model, they kick inside and taper toward the rear drag beam. The outside Cartazzi extension is bolted on the outside and fits up and over the rear brake hanger casting. To strengthen this joint a doubler plate in green is fitted inside.
We can tell this is an original drawing because there is no patch plate (orange oval) where the joint between the old and new frames would be, the orange line indicates where the frames were cut in later life on oval hole machines.
I tried to replicate some of this on one of my first 7mm models.
The right side frame is as it would be laid out on Doncaster shop floor with the rear end kicking in and tapering toward the drag beam, the extension part is lying beside it. The left hand frame above has the extension fitted.
Inside we can see I didn't add the doubler plate, I don't know why I didn't do that, possibly because I was slowly realising at this point that no matter how much I threw into the model it'd never achieve what I wanted.
Anyway, we can see the frame extension patch plate I added inside where the two frames join, it only has one hole up front as that matched my engine (can't remember which one now) yours should have two round holes to match #66
So, going back to your engine and the image of #110 it's fairly common to have snap head rivets in the area of the doubler plate, which on the Finney7 kit are marked by the red box.
I would not punch out any of the hornguide ones and the others are at your whim. Photos of any engine that show all the rivet detail are very rare so you cannot be wrong, we can only add what we can see and be sure of, the rest is a best guess. As I said the other day, I've not yet gone through all of my data, so there may be a nice photo of #66 that shows more detail.....I just haven't found it.
Another crop of #74
Clearly countersunk rivets all over and this would be a new front frame on and oval hole rear, but, note the two replacement snap head rivets on the front J hanger/brake trunnion bracket.
Finally, if you're considering removable brake gear with small screws then you will need some sort of bracket, I don't think the kit comes with one and the thin frame sheet material won't support a 14BA thread very well.
So get yourself down to the Finney7 stores and grab some of these.
It's a small detail set for Gresley Pacific engines and brake gear, those parts that are common to all.
On the left are the four brake hanger castings, the feed acts as a securing pin into the frames via a 1.0 mm hole you have to drill. There's an indent in the end to guide the 14BA drill which goes right through the castings and into the frames; this makes a very good strong and solid fixing for the brake hanger.
The gap between Slaters wheels and these brackets is very very close, you can smooth the side of the brackets, but I found I also had to skim a little off the wheel rim to be sure (0.1-0.2 mm), more so as one of the tyres was slightly oval on one of my wheels.
There is no trailing driver brake hanger bracket on the A3/A4/W1 it's part of the rear stay that supports the firebox toe.
On the right of the sprue are a couple of slack adjusters and two brake cylinder shafts with clevis joint on the end. The brake shafts and trunnions differ on the A3 and A4 to the W1, so I'd trot off to Ragstone and look at their castings, check out their engine springs and hangers.
You need E63 springs, 11 plates at 3'-6" centres, not the more common E69 which are 16 plates at 4'-0" centres (I do plan to do some of those when I get to the A4 project).
E63 fits the W1, A3 and D49.....plus others I've not researched yet I suspect.
E69 fits all the other Pacifics, Gresley, Thompson and Peppercorn (maybe others), except the A2/2 which uses an odd spring I've not yet found the code for.
Finney7 do some E63 springs (no hangers or retention pins) but the keep plate is correctly off set to allow for the wider base on the hornguide, where the adjustment slipper goes. Not sure if your hornguides have that feature, in which case the keep plate might not centre correctly and look odd, I can post photos later but other chores call.
I also think I've got a spare set of brake hanger etches for the A3, these fit the cast hangers noted above and are designed to take the Finney7 insulated brake shoes, so you can get your shoes real close to the tyre and not short out.
Steph Dale
Western Thunderer
Mick,
This photo is very interesting - it shows something I've not noticed before. Those rivets have been double-struck. So they've been made normally and ground flush. At some point they've then had a further 'bash' at them which has depressed the centre of the rivet head.
Did the A3s have a reputation for working their rivets loose? That would be the typical reason to re-strike a rivet head. Alternatively it might be part of a testing regime to see if the rivets are loose.
Steph
This photo is very interesting - it shows something I've not noticed before. Those rivets have been double-struck. So they've been made normally and ground flush. At some point they've then had a further 'bash' at them which has depressed the centre of the rivet head.
Did the A3s have a reputation for working their rivets loose? That would be the typical reason to re-strike a rivet head. Alternatively it might be part of a testing regime to see if the rivets are loose.
Steph
oldravendale
Western Thunderer
Dunno really what to say, Mick. "Thank you" doesn't seem to be enough.
I've put my supplementary order in to F7 for the parts you've mentioned. I'll also check the castings provided in the kit and see what supplements are needed from Ragstone - mind you, that's a big catalogue!
As for the rivet detail, I'm now thinking that I'll use that shot of 60051 frames as my guide for rivets - taking due care to make the lightening holes in the frames as you've described. It is certainly my intention to use the Mickoo method of screw and tube for the brake hanger fixings.
While I collect together the additional parts I need I may just start something else!
Many thanks again, Mick. Your input will make this a far higher fidelity build than it otherwise would be.
Brian
I've put my supplementary order in to F7 for the parts you've mentioned. I'll also check the castings provided in the kit and see what supplements are needed from Ragstone - mind you, that's a big catalogue!
As for the rivet detail, I'm now thinking that I'll use that shot of 60051 frames as my guide for rivets - taking due care to make the lightening holes in the frames as you've described. It is certainly my intention to use the Mickoo method of screw and tube for the brake hanger fixings.
While I collect together the additional parts I need I may just start something else!
Many thanks again, Mick. Your input will make this a far higher fidelity build than it otherwise would be.
Brian
mickoo
Western Thunderer
I feel I should clarify the previous statement.
"possibly because I was slowly realising at this point that no matter how much I threw into the model it'd never achieve what I wanted."
The model wasn't the Finney7 kit, it was the David Andrews kit, even so, this is not a reflection on the kit or any other A3 kit in reality.
It's was my own desire to walk a different path with 7mm models.
MD
"possibly because I was slowly realising at this point that no matter how much I threw into the model it'd never achieve what I wanted."
The model wasn't the Finney7 kit, it was the David Andrews kit, even so, this is not a reflection on the kit or any other A3 kit in reality.
It's was my own desire to walk a different path with 7mm models.
MD
mickoo
Western Thunderer
Steph, yes, of sorts, though I've not seen it written specifically for the frames, the A3 were prone to shearing smokebox saddle bolts and middle cylinder flange bolts, the reason cited is uneven stresses caused by the 3:1 linkage wear and lack of maintenance, especially during WWII.
Even later in their lives you there were prone to smokebox saddle bolt shearing, Gateshead engines were the most prone and I've seen photos with the odd bolt here and there missing, can't lay my hands on the evidence right now, fairly sure it's in the Townend book (written) and one of the others (pictorial).
oldravendale
Western Thunderer
Grabbed another few hours yesterday.
Here are the frames with the lightening holes and compensation beam holes opened out together with the made up hornblocks, one of the strengthening plates complete and the second blank ready to go. I drilled the holes out with a 5mm drill (pretty tough going on my Proxxon) and then filed to the approximate size before finishing with a 9/32" hand reamer which happened to be exactly the right size for the required hole. This was included in a bulk buy of hand reamers from ebay some years ago and of a size I thought I'd never use, but the hole lot were less than a fiver and included 3/16" and other sizes which I've found useful. In fact it was brand new and still in its hard wax protective sheath.
The oval hole had to be finished by hand with files as I couldn't find an oval drill anywhere(!)
The strengthening plates were cut from spare etch, marked up with reference to the frame holes, approximately centre punched, drilled out to 3mm and then the holes were opened out with increasing sizes of hand reamer, finally centring the holes with files and finally opening to full sizes with the 9/32" reamer. Decent quality sharp reamers made this much quicker than it sounds.
The top picture is of one of the plates as it will be fitted, on the inside of the frame, and the following one is the view through the frame. There is a half etched section along the inside top of the frame, and I'm uncertain what this is for. I'm assuming, however, that it has some function later in the build so the strengthening plates do not cover this. I'll drill the holes for the compensation beams once the plates are fixed using the existing holes in the frames as guides.
More next week.
Brian
Here are the frames with the lightening holes and compensation beam holes opened out together with the made up hornblocks, one of the strengthening plates complete and the second blank ready to go. I drilled the holes out with a 5mm drill (pretty tough going on my Proxxon) and then filed to the approximate size before finishing with a 9/32" hand reamer which happened to be exactly the right size for the required hole. This was included in a bulk buy of hand reamers from ebay some years ago and of a size I thought I'd never use, but the hole lot were less than a fiver and included 3/16" and other sizes which I've found useful. In fact it was brand new and still in its hard wax protective sheath.
The oval hole had to be finished by hand with files as I couldn't find an oval drill anywhere(!)
The strengthening plates were cut from spare etch, marked up with reference to the frame holes, approximately centre punched, drilled out to 3mm and then the holes were opened out with increasing sizes of hand reamer, finally centring the holes with files and finally opening to full sizes with the 9/32" reamer. Decent quality sharp reamers made this much quicker than it sounds.
The top picture is of one of the plates as it will be fitted, on the inside of the frame, and the following one is the view through the frame. There is a half etched section along the inside top of the frame, and I'm uncertain what this is for. I'm assuming, however, that it has some function later in the build so the strengthening plates do not cover this. I'll drill the holes for the compensation beams once the plates are fixed using the existing holes in the frames as guides.
More next week.
Brian
daifly
Western Thunderer
Unintentional I'm sure but very droll!
Dave
oldravendale
Western Thunderer
Totally deliberate, Dave, I assure you.
Bloody smellchucker.....
B
Bloody smellchucker.....
B
Dikitriki
Flying Squad
I'm sorry I'm late coming to the party on this, but I have had my camera out today, so I took some photos of the rear end.
I found both on the A3 and the Radial, that the single wire that provides both side control and downward pressure does not work, even on 6 ft radius curves, with the inner wheel tending to lift. The answer, IMO, is to have 2 separate wires.
This shows the screwed in shaped strip. The only function is to stop the radial truck dropping out.
These 2 (sorry about the quality) pics show the 2 lengths of nickel silver wire springs. They are attached to the underside of the frame spacer, where the wire is looped round to give a greater bonding area, and bear on the flat top of the radial truck. There is no sideways control in this example - I didn't want any as the bogie was more of a problem than the radial truck with clearances. You could add side control by attaching angled stops to the top of the radial truck that engage with the springs.
Richard
oldravendale
Western Thunderer
Thanks Richard. I think I may use this technique just to ensure that I don't have problems.
In fact, with the radial I lashed up a side control and have had no problems with wheels lifting, but this is rather more elegant!
Brian
In fact, with the radial I lashed up a side control and have had no problems with wheels lifting, but this is rather more elegant!
Brian