Martin Finney 7mm A3

P A D

Western Thunderer
Thanks to all for the positive comments.

Been working on the radius rods and expansion links. Here's the right hand unit partly constructed. The central laminated part of the expansion link with the slot, is now captive in the laminated radius rod by a length of 1.0mm NS rod. At the top and bottom are two lengths of 0.5mm NS rod which line up the the four parts of the expansion link, and represent the fixing bolts when trimmed and filed.
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Here are the pair completed. The expansion link and radius rod laminate were all done with 145 solder. However, for the fork joint laminate at the front, I used a higher temperature solder, and will revert to 145 for soldering the pin that will attach it to the combination lever. Hopefully the fork won't fall apart.
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The expansion link is then slotted into the valve gear support by springing the sides. The pivots are short lengths of 1.8mm rod, which are produced by soldering a length of rod through the holes, then cutting with the piercing saw and filing to length.
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Here's the right hand side. I think I'm going to have to do it the other way round and solder the pivots to the expansion link, then slot them through holes in the motion bracket, with washers either side to centre it, for it to work. The radius rod slides up and down nicely in the expansion link though.
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And the other side.
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Cheers,
Peter
 

P A D

Western Thunderer
Many thanks Paul.

The pivots were too short and needed re-doing. However after much faffing around and still not getting it right, I decided to do it the other way round, and solder the pivots to the expansion link, then slot them through holes in the motion bracket. After adding the pivots to the expansion link, I separated the motion bracket from the cylinders to make it easier to fit them. Here's one added. It needed a couple of washers on the outer side and I used 12 BA washers drilled out to fit. I soldered them to some waste etch so I could hold them while drilling.
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And both links in place and the motion bracket soldered back onto the cylinder assembly. I found it worked best with 2 washers on the outside with the inner pivot longer.
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And with the lifting links fitted.
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And from the other side.
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Here it is after the eccentric rod was added. The washer at the big end is to give clearance for the turned and thinned down 12 BA bolt head to rotate under the bearing cover yet to be fitted. The rod is spaced from the return crank with a washer, and after tightening the bolt to give a running clearance, it was soldered, snipped and filed smooth. Here it is in mid gear.
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Forward.
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And reverse.
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The rods slide up and down nicely in the expansion links without being sloppy, so I'm quite pleased with it.

I don't know if if will need something added to keep it in the set gear when running. I've got and idea how I can put a simple clip and spring on the reversing shaft if necessary.

Cheers,
Peter
 

P A D

Western Thunderer
Aren’t you going to put in a servo to change direction for forward and reverse?....

Tim

Hi Tim,
Would you by any chance be the Tim Watson who wrote the article on the Finney A4 some years ago in MRJ?

When I was building an A4 from the Dave Ennis designed kit, I hunted down both copies of the article as a very useful reference work. I remember well the reversible gear with servo. In theory the Ennis design accommdates making the gear reversible, but it was more complex to do it, so I just settled for having it in forward gear. To be honest I see it as a bit of a novelty and would have been happy if the design just allowed for easy setting in forward, reverse or mid gear, so no I have no intention of putting in a Servo. That said, I had to make it work, at least
manually using the big finger from the sky.

JB, I believe you have a servo for both the reversing and brake gear on one of your models, but those sorts of additions are just not my thing.

Here's the Ennis A4. When it's in motion all the valve gear parts including the 2:1 levers and the lubricator linkages move as they should. I don't think the lack of reversibilty of the valve gear detracts from the result. Each to their own though.
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Cheers,
Peter
 

Tim Watson

Western Thunderer
The comment was tongue-in-cheek, Peter. I too like to see valve gear fully moving, rather than twiddling in mid-gear. My Finney A4 is very much a showcase queen. Considerably easier with DCC to make these things work - and more besides - as shown by Steve Baldock’s wonderful models.

Tim
 

P A D

Western Thunderer
Hi Tim,
No problem, tongue in cheek or otherwise. It's a valid question when the gear is already reversible, and when you, JB and others have made it work. It's just not my cup of tea, although I applaud the skill and dexterity with which it is done.

Nice work on the K2 JB. At Kettering, Mickoo showed me the moving brake gear he has put on the Finney 7 W1 test built. It was tough enough on my patience adding all the link pins to the gear on the A3 to improve the appearance, but doing that with individual links and getting it all to work is incredible. You guys are lunatics! :)

Having said all that, on my A4 I had to scratch build the whistle valve, as if I recall correctly the supplied white metal casting left a lot to be desired. Nothing special there, but then I found out the operating cable ran from the valve along the inside of the injector pipe, between it and the casing back to the cab. Then I, the avowed " I can't see it and I know it's NOT there" modeler went and put it on. If you look , you can just see the top of the operating lever peeping above the injector pipe, and the 0.45 mm brass wire representing the cable. Too thick really, but the smallest I had. I don't think it brings much to the party but sometimes I can't help myself. At least the moving valve gear and brakes can be seen.
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Cheers,
Peter
 

mickoo

Western Thunderer
Peter, if anything the W1 brake gear is easier to do than valve gear, for the simple reason that it doesn't have to work at the end of the day. If one of the joints is tight or overly loose then it can remain so.

You already drilled and pinned the cookie cut valve gear on this A3 to add the pins to improve the appearance, on the W1 it's the same, but with pre drilled holes for you and instead of one large flat etch, it's just several smaller bits.

Having made your reversing lever work on the A3, I really think you'd walk through the W1 or B1 brake gear, as will anyone else who can make and model working valve gear on any kit :thumbs:
 

P A D

Western Thunderer
Hi Mick,
I forgot that the holes were pre-drilled on the W1 brake gear. Yes, that would certainly make it easier and less time consuming. Pre-drilled or not it is still an impressive piece of work.
Cheers,
Peter
 

Silverystreaks

Western Thunderer
Peter
Having completed a MF A4, A3 and V2 I don't recall having to do anything specific to maintain set gear running. You will have a better idea once the front end of the radius rod is secured to the rest of the valve gear and fore and aft movement into the rear of the valve guide is observed.

Personally I think Martins approach for the Expansion link and radius rod construction was one of his greatest ever kit design features . My expansion link experiences with his A4 A3 and V2 kits also benefited a couple of DJH Pacifics that followed

"Great work by the way"

Bob
 
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P A D

Western Thunderer
Hi Bob,
Many thanks.

It's good to know that the gear will need no additional work to keep it set when running.

One thing that has struck me though, is that once the connection between the lifting link and the reversing rod is made, the gear will be fixed, unless the reversing rod can slide. How did you tackle that?

I suppose I could just fix the reversing rod in the forward gear position, but not connect it to the arm on the lifting link??? Be good to hear how you did it on your 3 builds . I've been reading through Mickoo's thread on the W1 and I think he set it in forward gear.

I agree with your comments on the design of the expansion link by Martin Finney, but it's clear that in some areas Mick has taken things to another level. Whilst I personally like the MF slide bar design, I think Mick's design switching from vertical to horizontal laminations, is an improvement and certainly speeds up the construction. Most importantly it guarantees a perfectly smooth top surface which takes a lot more effort with Martin's approach.

Cheers,
Peter
 

mickoo

Western Thunderer
Peter, yes, Martins slide bar assembly is tried and tested and works very well, the only down side I found was trying to file the cusp inside where the cross head slides. By flipping the lamination's 90° the cusp is on the outer edges and much easier to clean up and leaves the working surfaces already perfectly smooth.

On the W1 the reversing lever crank can be moved to which ever position you choose, mine has just dropped to full forward due to all the handling.

In reality the engines had a clutch mounted on the cross shaft which locks the shaft in place or reduces the risk of it adjusting the cut off on the move.

The pins for the expansion link are always going to be hard which ever way you decide to develop the etches, on the W1 I went for pins in the expansion link (much like you have) and then made the motion bracket double lamination's to thicken up the boss area and reduce the need to add washers on the inside.

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I think the reversing rod is fixed on the A3 kits, you'd need to remove the half etch footplate bracket for starters and fabricate a new one attached to the footplate. The tail end where it goes inside the firebox wrapper should be long enough to support that end and as long as the front end is pinned to the reversing lever crank it should all work.

Where it falls down on the A3 (and W1 I have to admit) is when you try and take the body off. Right now I cannot think of a way round that for both kits, or any LNER pacific truth be told.

MD
 

P A D

Western Thunderer
Hi Mick,
Yes, your slide bar design is a definite improvement, particularly in producing smooth working surfaces. Much easier to file and smooth the outside faces of the laminate, as opposed to working on the horizontal ones in the cross head slot.

You've given some food for though on the reversing rod. Thanks for that.

Been working my way slowly through the W1 thread. Up to now I'd only read bits and pieces but after seeing it in the flesh at Kettering, it was about time I found out how you did it. What an amazing piece of design work and a fantastic build.

Cheers,
Peter
 

mickoo

Western Thunderer
Peter, cheers, though it has to be said, designs evolve all the time.

Lessons learnt in the W1 went into the B1, which has then since evolved and those lessons will be fed back to the final W1 model.

The W1 was a sponsor model for a handful of dedicated modellers but with their thanks was brought into the Finney7 brand, doing so requires the design spec to change from a detailed aid to scratch building to a full blown production kit, the differences and concepts between the two are marked.

We hope to raise the level of fidelity but not necessarily the level of complexity or skill set required by say current models. A lot of people have said "I couldn't build that", to which I counter, "you could, if you had the belief that you could". Having said that, I wouldn't point people to the W1 or B1 as their first etch kit.

Once the castings arrive back I'll be doing a final ground up web build so that people can see exactly what we have in the box. Those photos will also figure in the instructions and the two should come together nicely toward the end of the year. It has been a long gestation period (we basically lost the first two years changing from a small group build to a production run) but the lessons learnt will help us improve and streamline future projects.

MD
 

Silverystreaks

Western Thunderer
Quite simple Peter I cheated. Whereby with the MF A4 the reversing/reach rod was a working part of the valvegear, on the MF A3 the reach rod is permanently fixed to the body as on the prototype it runs under then through the running plate and into the firebox wrapper

At the front end of the reach rod I soldered a mock return crank arm which when the body is slipped over the chassis it sits nicely on top of the weight shaft rod and between both lifting links giving the impression that its all attached

You can then manually set the valve gear to mimic forward mid or reverse gear The V2 had the same treatment. After modifying the lost wax expansion links provided in the DJH Pacifics kits I applied the same procedure .

One problem though is when it comes to running remember to set the model in the correct gear. The V2 ran over an open day weekend set in reverse gear I only noticed when we were packing up.... no attendees noticed, if they did no one mentioned it.

So there you have it .......I cheated
Regards
Bob
 

P A D

Western Thunderer
Hi Bob,
Many thanks.

Any chance you could post some photos of the A3 arrangement please?

Cheers,
Peter
 

Silverystreaks

Western Thunderer
Peter

Hopefully the attached will be helpful. As per my previous post the reversing rod is fixed to the running plate a dummy link pinned to the front of the rod the base of which is fashioned so when the body is lowered on to the chassis it fits nicely on to the top of weight shaft rod and in between both lifting arms. giving the impression its all connected

You don't realize how dusty ones locos have become until you start taking close up images
Regards
Bob
 

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