Small Metro builds 2023

[melmerby]

5 hours ago, Andy Keane said:

Yes that seems to be it - there is figure 6.6 on page 62 of Rice's chassis book that shows this and helped make it clear to me. What I next need to know is what stops the compensation beams moving sideways along the axles. Maybe the top hats are put in from the outside of the frames and soldered to the beams trapping the frame between them?

The figures also makes it clear that if you don't use the correct wheel sizes you will need to move the pivot point up or down to keep the frames level. I think they have to be 14 and 20 to work with the pre-etched holes.

It's a bit crude IMHO

With a 4 wheel set up I wont use compensation for the drivers, I will for the leading wheels but just using sprung wire and oval holes, as I am doing on my U1 chassis build.

[Siberian Snooper]

Yes, that's how they work, the best way is to mount the beams on a suitable piece of tube, the length of which is fractionally less than the width inside the frames.

 

I made a start on erecting the frames this morning, with a lot of swearing, trying to get all the spacers in place, I  managed to tack the ash pan and the motion bracket in place, before I had to come in for lunch. I'm building it rigid. I also need to order the wheel sets.

 

 

[Siberian Snooper]

Help needed, please. I can't find my loco bible and it's not mentioned in the destructions, what are the wheel sizes, both driver and "pony".

 

Thanks.

 

 

[Neal Ball]

26 minutes ago, Siberian Snooper said:

Help needed, please. I can't find my loco bible and it's not mentioned in the destructions, what are the wheel sizes, both driver and "pony".

 

Thanks.

 

 

 

Does this help?

 

[Andy Keane]

12 minutes ago, Neal Ball said:

 

Does this help?

 

It does except as far as I can tell the finecast chassis is not designed for those size wheels! They seem to assume 14mm and 20mm as the etch centres are 3mm apart in height. When you buy wheels with the chassis that is what you get though they have the wrong spoke count as well!

[Andy Keane]

2 hours ago, Siberian Snooper said:

Yes, that's how they work, the best way is to mount the beams on a suitable piece of tube, the length of which is fractionally less than the width inside the frames.

 

I made a start on erecting the frames this morning, with a lot of swearing, trying to get all the spacers in place, I  managed to tack the ash pan and the motion bracket in place, before I had to come in for lunch. I'm building it rigid. I also need to order the wheel sets.

 

 

In the Finecast kit they assume the compensation beams are hinged on 0.5mm wire for which holes are etched in the frames and beams! Not sure if they imagine short wires subs each side or a wire right across. I may try pins where the heads are inside the beams and tie each beam to its side frame. And of course the two compensation beams have to move independently of each other.

Andy

Edited January 30, 2023 by Andy Keane

[Siberian Snooper]

Many years ago, I  built a perseverance chassis for the Airfix 14xx and a piece of tube was supplied for the compensation beams, if you wanted to you could cut the tube through the centre, to give independent rocking on each beam. Either way, you will need to retain the rocking beams from moving on the axle(s).

 

Many thanks for the wheel sizes,  I will check the axle centres tomorrow.

 

 

[Andy Keane]

37 minutes ago, Siberian Snooper said:

Many years ago, I  built a perseverance chassis for the Airfix 14xx and a piece of tube was supplied for the compensation beams, if you wanted to you could cut the tube through the centre, to give independent rocking on each beam. Either way, you will need to retain the rocking beams from moving on the axle(s).

 

Many thanks for the wheel sizes,  I will check the axle centres tomorrow.

 

 

Not quite sure what you mean by "moving on the axles" - as I understand it the axles go through the holes at each end of the rocking beams and in fact hold the axle bearings?

[melmerby]

2 hours ago, Andy Keane said:

In the Finecast kit they assume the compensation beams are hinged on 0.5mm wire for which holes are etched in the frames and beams! Not sure if they imagine short wires subs each side or a wire right across. I may try pins where the heads are inside the beams and tie each beam to its side frame. And of course the two compensation beams have to move independently of each other.

Andy

I assumed a wire right across acting as a torsion bar between the beams.

[Andy Keane]

21 minutes ago, melmerby said:

I assumed a wire right across acting as a torsion bar between the beams.

anybody’s guess I suppose as no explanation is provided. In my case it will depend on the motor location as well. And if we pool our various approaches it will be nice to see what we can all come up with.

Edited January 30, 2023 by Andy Keane

[melmerby]

RE: wheel sizes, I bought Markits wheels, which I assume are scale diameter and therefore bigger than the 20mm allowed for by SEF.

In fact I've just measured them, they are 20.66mm 18 spoke, between spoke crank pin, which I think is as prototype.

[Andy Keane]

8 hours ago, melmerby said:

RE: wheel sizes, I bought Markits wheels, which I assume are scale diameter and therefore bigger than the 20mm allowed for by SEF.

In fact I've just measured them, they are 20.66mm 18 spoke, between spoke crank pin, which I think is as prototype.

All the photos I have are 16 spoke with crank pin in line with a spoke.

[melmerby]

1 hour ago, Andy Keane said:

All the photos I have are 16 spoke with crank pin in line with a spoke.

I can't count, mine are 16 spoke, but the crank pin can be either, depending on the loco, Nos 1499 & 1500 definitely between spokes when new, several others look like they were but photos not quite clear enough.

[Siberian Snooper]

19 hours ago, Andy Keane said:

Not quite sure what you mean by "moving on the axles" - as I understand it the axles go through the holes at each end of the rocking beams and in fact hold the axle bearings?

 

If you use a stub axle for the rocking beams, there is nothing to stop the beams from moving along any or all the axles, be it the driving wheel axles or the rocking beam axle. With a full length axle and the rocking beams soldered to a tube,  the rocking beams remain "in gauge " , even if you cut the tube in half.

 

HTH.

 

 

[melmerby]

20 minutes ago, Siberian Snooper said:

If you use a stub axle for the rocking beams, there is nothing to stop the beams from moving along any or all the axles

Stub axle?

I can't see how that would ever work.

The beams themselves will stay apart if they are soldered to the wire but the wire not soldered to the frame, they could be inside or outside the frames, neither seem like a particularly elegant solution to compensation.

[Andy Keane]

2 hours ago, melmerby said:

Stub axle?

I can't see how that would ever work.

The beams themselves will stay apart if they are soldered to the wire but the wire not soldered to the frame, they could be inside or outside the frames, neither seem like a particularly elegant solution to compensation.

This was the idea of a needlework pin. The pin head lies on the inside of the beam, is a sliding fit on the beam and is soldered to the frame. The beam is thus held against the frame but is free to rotate around the pin itself. The beam then has the top hat bearings in its ends and these carry the axles. If the top hats are not too long this allows differential movement of the axles.

So in this sketch the frame is black, the beam is blue the axles are green, the pin is red and the bearings are yellow, all seen from above for one half of the chassis.

[Barclay]

I don't know if this helps but on this chassis, which is an 0-4-2T, the twin beams on the drivers are each on their own piece of tube, which allows independent movement (essential), and stops them sliding up and down the shaft. The trailing axle is allowed to pivot. Please excuse this shoddy chassis but it's a rebuild of an old rigid fold up 00 chassis into compensated form in EM. Despite appearances, it works well !

 

[Andy Keane]

17 minutes ago, Barclay said:

I don't know if this helps but on this chassis, which is an 0-4-2T, the twin beams on the drivers are each on their own piece of tube, which allows independent movement (essential), and stops them sliding up and down the shaft. The trailing axle is allowed to pivot. Please excuse this shoddy chassis but it's a rebuild of an old rigid fold up 00 chassis into compensated form in EM. Despite appearances, it works well !

 

That helps a lot. But I guess the wire your tubes are threaded on is bigger than 0.5mm diameter?  And you are using horn blocks rather than beams that actually carry the main bearings. Also on the Finecast kit the front pivot is just a bit of flat etch with a hole in it for the axle and no bearing. Yours seems to have a proper bearing capable of rotation on the longitudinal axis.

Edited February 1, 2023 by Andy Keane

[Barclay]

Yes, I must admit if I have a kit that is different to this basic spec I would just alter it to conform, because I know this works, and don't like change! I am sure the bearings in the beam method works because I have a High Level kit that gives this as an option and he doesn't do any rubbish. Nevertheless I will still build it my way.

 

The trailing one is a 2mm hornblock bearing soldered to a piece of tube that rotates on a brass rod. 

[Siberian Snooper]

3 hours ago, Barclay said:

I don't know if this helps but on this chassis, which is an 0-4-2T, the twin beams on the drivers are each on their own piece of tube, which allows independent movement (essential), and stops them sliding up and down the shaft. The trailing axle is allowed to pivot. Please excuse this shoddy chassis but it's a rebuild of an old rigid fold up 00 chassis into compensated form in EM. Despite appearances, it works well !

 

 

 

That's pretty much what I have been trying to explain in my last few posts, but using the bearings supplied in the rocking arms.

 

 

[longchap]

 

I found this splendid looking example on the Great Western Study Group’s stand at an exhibition last weekend, but the chap behind the desk was in serious discussion with someone, so here’s a picture in lieu of further kit details, although I know the prototype's from the 1899 batch of locos numbered 3581–3600 .

 

I’ve just returned my completed questionnaire / enrolment form to Missenden, advising them of my desire for a working Metro chassis with appropriate compensation and admitting to my sad attempts to successfully folding up High Level Kits’ etched hornblocks, so need help in mastering the technique! I’ve read that the HL hornblocks are easy and reliable in use, so is it just me, or is there a trick with these little critters?

 

Hopefully all will soon become clear.

 

 

 

 

[Neal Ball]

By way of contrast, my Metro tank (no 615) has come out it’s Bath of brake fluid.

 

The smokebox door glue finally gave and left me with a very small space to consider which speaker and decoder are going to go inside….

 

The kit was supplied with two smokebox doors, 615 had the door on the left, but it’s tempting to use the later door on the right.

 

[darthmh]

I've got the Dean Sidings Resin Metro kit in my to do box.  Would be my first loco build, Following this thread has gotten me to get it out the box and have a go. 

[longchap]

6 minutes ago, Neal Ball said:

By way of contrast, my Metro tank (no 615) has come out it’s Bath of brake fluid.

 

The smokebox door glue finally gave and left me with a very small space to consider which speaker and decoder are going to go inside….

 

The kit was supplied with two smokebox doors, 615 had the door on the left, but it’s tempting to use the later door on the right.

 

 

Well that worked well Neal, although you now have some gap filling to do.  I've still got to decide on a prototype to model, which will depend on available photos, so I have some interesting reseach to do. Do you have a later prototype to model?

 

 

 

[Neal Ball]

14 minutes ago, longchap said:

 

Well that worked well Neal, although you now have some gap filling to do.  I've still got to decide on a prototype to model, which will depend on available photos, so I have some interesting reseach to do. Do you have a later prototype to model?

 

 

 

Strangely 615 had the older style dishes door, with 616 having the more normal shaped door.

 

Both locos worked the line in the 1920’s and early 30’s.

 

However the issue with 616 is that the coal bunker curve is different at the footplate 🤔