Lancaster Green Ayre - The Barn Owls have returned.

[jamie92208]

Thanks for that Lezz.  I've found a drawing in Midland Record 2 and it now gets clearer.  The big problem us that the Gibson frames are too narrow to accommidate 2 cranks and the 4 eccentrics. I have found a pack of castings to convert the normal kit into one forcs 4F.  What I think I'm going to do is to fit yhe eccentrics withba crank web each side on the centre axle then fit the slidebars and a set of dummy cylinders and build the actual valve gear working but without the con rods moving. At least most of it will be there and visible.  Lots to work out but that's the fun if modelling.  Thanks for the input.  It should look good with the push/pull rods working especially if I fix it at about 50% cut off.

 

Jamie

[lezz01]

I was thinking about this while I was cooking Jamie and came to the same conclusion. If you can see anything well of the 4Fs valve gear it's the eccentric straps, radius arms and the valve spindles and rockers. NOT the crossheads and con rods. All of the rest is hidden under the counterweights. You can't really see the cranks and excentrics at all. There are no rockers on either the 2F or 3Fs and the Kirtley's have 8 foot eccentric straps and the radius arms are in front of the motion bracket between the slidebars so they all have their motions on display much more. Most of the motion is hidden away behind other bits of the motion that don't move very much if at all on a 4F. It just so happens that from normal viewing angle of a model 4F you're looking straight down into the gap between the boiler and running plate so not having anything there sticks out like a sore thumb.    

Regards Lez.  

[Dave Hunt]

7 hours ago, lezz01 said:

I was thinking about this while I was cooking Jamie .........  

 

Are you roasting him Lezz? 

 

Dave

[jamie92208]

Good evening and thankfully I've not been roasted but a chicken was, and it was in a very good cause.  I have spent various bits of the day studying drawings of 4F's. I think I have just about sorted out how I think the valve gear works. I then spread all the parts from the valve gear kit together with the 4F add on.  I think I've sorted out most of it and will hopefully  put some pictures up tomorrow.  

 

After tea I headed for the shed and continued with the tender.  The detailing if the footplate area is almost finished and it's really looking nice.

 

Thanks for all the help and input.

 

Three other things,

a)  I found another 2 sets of Stephenson Link motion so that will be the two 2P's sorted.

b)  whilst looking through Laurie Griffins website he does a special valve gear set for a Compound. I happen to have one to build.

c).  Whilst researching valve gear I found mention in Summerson that 3877 had a Detroit Lubricator fitted experimentally.  Can anyone point me towards a decent photo of one.

 

Jamie

 

[lezz01]

Lots of pics on Google I don't know which is which use this search :

"Detroit hydrostatic lubricator". It brings many pics some good some not so good.

Regards Lez. 

[Dave Hunt]

Jamie,

 

No. 3877 was fitted with a Detroit lubricator when it was built (the only 4F so fitted) and still had it in February 1924 but by the end of the year had been fitted with what had become the standard arrangement of two Silvertown lubricators. I'm afraid that I don't have a photograph though.

 

Dave

[lezz01]

It looks like it's on the backhead Jamie.

Regards Lez.

[jamie92208]

So that means no lubricator on the running plate then.   Thanks for the info both of you.

 

Jamie

[jamie92208]

Morning again.  I've loaded the photo of the parts which is here.

The only parts I'm not sure about are 4 small links with an eye at each end. One of them is just below the S of small. The other below it and the other two below the bracket making 4 identical ones in all.   From studying the drawings they seem to run from the two supports on the top rear of the motion bracket (below the L of Links) down to the drive from the expansion link to what would normally be the valve spindle.  Presumably 2 for each drive rod.  I can't make my photo editor do arrows so can't be any more precise than that.   After various other things today I may start a proper CAD drawing of the valve gear to make sure that everything fits.   The way the cylinders are mounted I may well have to carve some space into the bottom of the Smokebox saddle to give clearance.  It's all quite fiddly but I think that it will fill the blank space rather nicely especially if I can get the valve spindles moving.

 

Jamie

 

Edited July 31, 2022 by jamie92208

[Dave Hunt]

The lifting links that join the ends of the counterbalanced arms on the transverse shaft attached to the reversing lever to the die blocks in the expansion links.

 

Dave

Edited April 20, 2020 by Dave Hunt

[lezz01]

You also need to check on when/if they changed the counterbalance weights and if the early locos had the later pattern retrofitted or kept the two round one you have there. They might have been an LMS improvement that never found there way onto the MR locos. Or might not. I can only go from the brassmaster 4mm kit as I only have Essery and Jenkinsons volume 4 for reference which shows twin round type on the GA. I have much more data for the 3F but that don't help. The brassmasters motion kit has the flat oblong type which might be a later addition. The MR round type make the back half of the motion more visible than the flat oblong type. Sorry mate that's all I have for 4Fs it isn't my favorite Midland loco. I've never even thought about building one until I saw the Brassmasters kit with inside motion. I'm toying with building a small Midland layout, to rekindle interest in the big home layout, and Tewksbury shed and quay branch in either EM or S4 is top of the list. I  just can't make my mind up, I prefer making P4 track but I don't have to spring the stock in EM just rewheel it. Plus I have still have a 1F in EM that needs stripping and repainting and a Johnson 0F dock tank to start me off. It all freight and loco movement but I could backdate it with exchangeable modules and run a Kirtley and some 4/6 wheel coaching stock into the "old station". It would be so easy to keep extending it right down to the quay in small manageable modules and there are some interesting track formations not least the loco shed tandem. 

Right now, however I have to put all that aside because wifey had a positive test for you know what and if she has it I have it! It's day 8 and if you get through day 10 intact your gonna stay intact.........mostly and neither of use are terribly unwell. She is having bad headaches, an altered sense of taste and her sats are a little low while I am a little more breathless than normal but my sats are fine and I've had some bad headaches and that's it. So God willing......we'll come through.        

Regards Lez.     

[jamie92208]

Hi Lez,  Thanks for all that but first of all, very sorry to hear the news about the Lurgi.   I can only pray that you will both be OK.  My thoughts and prayers will be with you both.   

 

I'm going with the round weights as the drawing of an MR loco in Volume 4 shows round ones.   I've had chance to have a play with CAD today in between other tasks and managed to do something that I've never done.  I scanned the drawing in Vol 4 Jenks and Essery to a pdf, imported it to my CAD program then was able to scale it up to exactly 7mm scale.   I've put the pdf in one layer and then in another layer am drawing over it to get he layout of the motion.  I was dreading the task but it seems to be going OK. I've got the axles and most of the shaft drawn in. When I've got the motion drawn I can hide the pdf and print out a drawing of just the motion that I should be able to post on here and be able to annotate which should make things easier.   I really do appreciate the inputs from You Dave and others.  However I'm glad that I'm working n 7mm.  The thought of inside motion in 4mm would drive me potty.

 

All the best to the two of you.

 

Jamie

[lezz01]

Hi Jamie. Thank you for your best wishes mate. I'm sure all will be well. Anyway we are in very good hands. Her boss is my doctor and my boss is her pharmacist. 

The Brass masters web site has some very good pictures of the motion kit in stages of construction. The kit itself uses eccentrics instead of actual cranks and could well be used for any midland loco with minor modification. I know it's nothing like the LG/shedmaster kits, being mostly etches but it shows construction in stages that are the logical way to build inside motion and gives a very good picture of how these things go together and a general idea of how they should look. I have the kit penciled in for a few midland types should I go back to finescale as I plan.

Regards Lez.

 

[jamie92208]

Thanks very much for that Lezz. I've looked at the  brassmasters website and the photos very much agree with what I had in my mind. Now that I've cracked the drawing I should be able to modify the Gibson frames to accommodate most of the gear.  I think I'll be able to fit the crossheads and slidebars but not the con rods so the big empty space should look fairly full.  How sure are you that the Detroit lubricator was fitted on the backhead.   

 

Thanks again.

 

Jamie

Edited April 20, 2020 by jamie92208

[Dave Hunt]

All 4Fs built up to 1928 had circular balance weights on the weighshaft whereas those built during Stanier's time, 4562 - 4606, had nearly oblong ones, which type was used whenever replacements were required on earlier engines. Hence you will need circular ones.

 

As with other types of displacement lubricators, the Detroit type was fitted in the cab. 

 

Dave

Edited April 20, 2020 by Dave Hunt

[lezz01]

I knew Dave would know Jamie. As for the lubricators all the photos of that type, where in situ, show them on the backhead so it would seem a safe bet. 

Regards Lez.  

[jamie92208]

Evening all.  A good deal of work was done in the shed. The tender is nearly finished and the tank has been fitted to the chassis.  The main job left to do is fitting the coal rails. I've started to assemble them but have fi ally sorted out how to fit the support brackets after consulting  Essery and Jenks vol 1. Hopefully  they will be fitted tomorrow along with the axleboxes.  I did substitue a lovely Laurie Griffin brass casting of the tender filler for a white metal one.  I also need to sort out tender pickups.   I have done some more work on the valve gear drawing and that's coming on a treat. With the contributions from Dave and Lezz things are heading in the right direction.

 

Jamie

[jamie92208]

Major success on the CAD front this morning.  I finished off the motion links and then had a go at the printing. This is the result.

 

The first job was to scan the drawing in Essery and Jenkinson Vol 4.   This came out as a pdf.   I then found that I could import it into my CAD programme.  The coupled wheelbase of course was 16' 6! so it was measured and turned out to be just over 4mm.  The scale command was then used to increase the whole picture by a factor of just over 24.   The pdf did pixelate a bit.   I then placed the pdf in a background layer.  Then in the main layer I drew over the features that I could identify such as axle centres and shaft ends.  This was all done in purple with the wheels and footplate in green so that I could see it. Then doing one area at a time I drew in the various links.  Everything seemed to drop into place.   The pdf layer was then 'hidden' and the rough drawings tidied up.  After just 4 sessions this is what the drawing layer looked like.

 

Not sure why it printed in black and white but I am very happy with the result.  The nice thing now is that I can measure off any dimension on screen and transfer it to the model.   I did check the scaling by measuring the axle centres and that pair came out at 55.95 which I felt was near enough.   I'm very pleased with the result. Now I just need to get it all built.  

 

Jamie

Edited July 31, 2022 by jamie92208

[innocentman]

I did a similar thing when designing an etch for an LMS Patriot chassis

 

I drew all the component parts and then thought I will double check the geometry against the drawing I had just to make sure I had not done something dumb!

 

 

Worked out well in the end

 

I also have a Brassmasters 4mm kit to build in EM with the inside motion. Enjoying the discussion on the 4F inside bits, its nudging me to get that box off the shelf for my next project!

 

Best regards

 

Andy

 

 

[jamie92208]

Glad you like it Andy.  There is a little rat nagging in the back of my brain that says, if I've got to remove two frame spacers to put the dummy cylinder block and motion bracket in, I might as well go the whole hog and do a crank axle.  There's a quote in a John Le Carre book somewhere about having to feed the rat now and again.  As I'm dealing with dratted Gibson frames I will have to do some careful measuring.  I also gave a part assembled Gibson 2P and another unstarted Gibson 2P so it may well be worth going through the pain now so that I have some idea what to do with the 2P's.

 

Jamie

[lezz01]

Might I suggest Jamie, that you use the motion bracket as one of the spacers. You can solder a piece of angle to each side of it and then tack into place. You can then either drill and tap the angle something like 12 or 14 BA and then bolt through the frames or just drill and use nuts instead of tapping. If you drill out the front spacer for the rods and valve spindles. Then you can build the motion on the bench and slide the whole thing in from the bottom and then bolt up the motion bracket. If you drill the rear cylinder plate at each corner you can bolt it to the rear of the front spacer. That way the only other point of contact is the pin through the counter balance weight/reversing crank pivot. Then you can be sure in the knowledge that you can remove the whole thing as one unit from the rear cylinder cover plate to the crank axle. This will be useful both for painting and maintenance. Not only that but should something nasty happen to the loco the motion will be recoverable. A small amount of extra work will bring huge benefits. The thing 7mm is that you can bolt things together rather than soldering which is never a disadvantage.

Regards Lez. 

[jamie92208]

That's some good advice Lezz. I like the idea of ut all being removable.  The motion bracket was going to be one of the spacers anyway. The cylinder and valve block is quite high.  I might leave a plate spacer in place and then make the whole motion plate /crosshead/ slidebar assembly as one bolt in unit then by releasing the crank axle the whole lot can come out.  I need to do some measuring up first once I've mended a light fitting.

 

 

Jamie

[Dave Hunt]

7 hours ago, lezz01 said:

 The thing 7mm is that you can bolt things together rather than soldering which is never a disadvantage.

 

 

Until the 16BA nut on the eccentric strap pings off into the workshop black hole...... (how do I know that?)

 

Dave 

[jamie92208]

Evening all.   Various things have been done today.   I finished the tender except for the pickups.   

Here it is paired up with the loco.

I'm quite happy with that.

Until I took this close up.  I need to do a lot of cleaning.    However I also took a picture of the loco roughly from the angle it will be see on a layout.

 

Look at all that empty space.

Decisions made.  After a lot of measuring up, I've worked out that I can increase the width of the frames by 2mm which will give me enough room to fit both sets of cranks.   This I can fit the con rods as well and make them work.   My thoughts are to make a complete sub assembly of the crank axle, valve gear and cylinders that bolts into the frames.   I can use the motion bracket at on spacer but will have to take about 1.3mm off each side of it. I can probably fit a flat spacer below the cylinders that the cylinder block bolts on to.  However this will be something like a 10BA not 16..   Happy days are hear again, and please Dave don't say it would be easier in Scale Seven.

 

Jamie

 

Edited July 31, 2022 by jamie92208

[Dave Hunt]

34 minutes ago, jamie92208 said:

Happy days are hear again, and please Dave don't say it would be easier in Scale Seven.

 OK, I won't

 

But I'm glad you are biting the bullet.

 

Dave