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Re: GWR Steam Railmotor Chassis

Posted: Mon Sep 11, 2017 2:24 pm
by dal-t

Thanks for the 'encouragement', I might at least take another look at the actual etch - although, if Jeremy isn't too pissed of with us for hijacking his thread, I'd still be very interested should an updated supplement became available (I understand the 7mm version has been greatly 'improved'). Meanwhile, any time you're ready to reveal your cunning plan for tackling the glitches I'll be watching out for it. As for the finish, I agree Peter G's looks very nice, but having just made a right pig's ear of a David Geen 50' full brake (22 panels per side, plus doors and duckets!) I'm going 'back to basics' with a couple of 6-wheelers before I attempt anything as challenging as the Railmotor.


Re: GWR Steam Railmotor Chassis

Posted: Fri Sep 29, 2017 9:12 am
by GWMark
Jeremy, having spoken to you at Scaleforum and seeing your test build I'm really impressed by what you have been doing here. I would certainly be in the market for two or three of the motor bogie etches and the diagram Q rail motor as well. I've now tried three different ways to build rail motors, the Mallard ones are a little crude, but nothing on the NuCast, although the NuCast is the only one that runs for me at the moment, albeit with a mix of NuCast and Mallard motion. The NuCast 70 foot rail motor suffers from being a white metal vehicle that makes it incredibly heavy and not the best looking beast - it works well as a way to make sure track work is well bedded down!

Impressive stuff

Re: GWR Steam Railmotor Chassis

Posted: Fri Sep 29, 2017 3:36 pm
by kelham
I'm another who would be in the market for a 'proper' railmotor chassis etch as there's a couple of Mallards in my "things to do if I manage to retire before I go gaga/blind/etc" pile.


Re: GWR Steam Railmotor Chassis

Posted: Sun Oct 22, 2017 8:28 am
by Jeremy Suter
Hi David
Sorry no plans for an LNWR one at the moment .

Thanks to every one for showing an interest in having a chassis kit. I am slowly trying to get things right.

With Scaleforum and a holiday over its back to work on the Railmotor Chassis.

My 3rd test etch was received just before Scaleforum but have not started it yet.
I added the OO and EM spacers along with the Gearbox which uses High Level gears on a 54:1 ratio. The brakes have been simplified, as although nice when made up they are so small that I thought 4 pieces in 3mm was a bit much for one brake.


I have not been idle while waiting for the etches to arrive and have now made the masters for the castings on the chassis which include 4 Sand Boxes, 2 Cylinder tops and 2 Boiler inserts.


In this photo I have double sided taped them to the chassis.
The body underframe is in the background with the some more patterns for the tanks and vacuum cylinders on, and on the left are a couple of buffers started. I still need to make springs and axlebox patterns for the 8' Fishbelly bogie which the Gloucester built Railmotors had.


And a distant view of my work room with the project on the bench.


Re: GWR Steam Railmotor Chassis

Posted: Mon Oct 23, 2017 8:49 pm
by Le Corbusier

Could I ask who does your etching.

Re: GWR Steam Railmotor Chassis

Posted: Tue Oct 24, 2017 6:44 pm
by Jeremy Suter
Hi Tim
I use PPD to do all my test etching. The production etches I have are with Photo etch consultants

Re: GWR Steam Railmotor Chassis

Posted: Thu Feb 01, 2018 7:37 pm
by Jeremy Suter
It seems like ages since I have done any modelling for my self but have finally had some time to play.

The 3rd chassis test etch with wider gap between the wheels and slide bars has been put together and all seems well. The wheels go round with the connecting rods on and the cross head in place. although I have still put the bearings on the wrong way round to keep coupling rods close to the wheels and away from the slide bars so as not foul the crosshead as they go round. Actually the crosshead is behind the crankpin.

I have also used the slightly smaller 3'11" Gibson wheels with a shorter crank throw and the correct number of spokes and there smaller size is not noticeable. Although I have painted the chassis there are none of the castings fitted as I have not had them cast yet.


On this side I have fitted the Union Crank and Combination Lever then attached to the Valve Gland box which needs to move back and forth but the Radius Rod which makes the pivot I got the wrong length on the 1st Valve Gear test etch is not attached.
As you can see on the picture below that the distance between the Reverse Lift Lever hole and the Expansion Link hole is much bigger than it should be .This picture is one of David Brandreths who is also working on my test etches for a second opinion. It shows all the cranks fitted together and the valve gland which is made from a fold up box which should slide in and out along the valve rod. I have tried the full valve gear and it does work but keeping the Gland Box level is not working very well. I have just sent a new Valve Gear test etch to the etchers with a few variations on it to see how I can keep it level by fitting the Radius Rod to the Value Rod.

valve gear_2815[1].jpg

This next Picture shows the MK 2 and the Mk 3 versions together from above to show the different distances between Wheels and Slide bars. You can also see the Valve Gland box between the cylinders and the slide bar bracket. I have also fitted all the valves rods on the opposite side but not fitted the eccentric crank yet as I still want to take it apart to put a motor gearbox in which has been done but needs slight alteration to the configuration to get the gears out of the way of the Brake Roding. Also fitted are a couple of Copper Clad strips for he pick ups.


Re: GWR Steam Railmotor Chassis

Posted: Thu Feb 01, 2018 7:42 pm
by JackBlack
I would very much like one of these kits when you make them available.

Thanks, Nick

Re: GWR Steam Railmotor Chassis

Posted: Sun Feb 04, 2018 8:18 pm
by Jeremy Suter
While waiting for the new Valve Gear etch to arrive. I have been putting together the second test etch for the Diagram Q Underframe. On the whole every thing has gone together well, there are just a few minor tweaks to put right. Like re spacing the under beams as the steps cross one of them, which as far as I can see they should not. I need too look at the Queen posts as the tie bar is flat not round I have used .6mm rod and this will have to be an etched strip. The steps need to be altered as I have still to add the hand rail for the doors.



This next view shows the underframe sitting on top of the chassis. Tomorrow I will make the first set of mounts to mount the chassis to the body. Also seen in this view are the underframe castings. The gas tanks have no straps on as they are on the etch and have not been used yet. I also have not drawn the levers for the brake rigging yet.


Close up of the steps checking photographs I think all I need to do is add an extension with a hole in to represent a hand rail knob



Re: GWR Steam Railmotor Chassis

Posted: Thu Feb 08, 2018 5:37 pm
by Jeremy Suter
Now the Mounts are made.

Firstly the outer solebar bracket was cut from 40thou/1mm brass sheet on the Pantograph milling machine. A plasticard pattern was made at 3 times the size and glued down on another sheet. I use a 3:1 Ratio as working at 12mm :foot scale so that 1mm represents 1 inch which makes an easy conversion from Imperial to Metric.

Being Cut.

Cut Out.

Once all cut out I have drilled one end with a .6mm drill so I can fit a .6mm nickel silver rod through it as a mount.

I could, but have not drilled to fit a mounting spigot to go through the hole in the solebar. They fitted the solebar perfectly so I soldered them straight on.

Now with the posts mounted on the solebar. I made the Under Beams in the same way on the Pantograph Milling Machine from 60thou /1.5mm Brass sheet. These need to be shaped in 2 plains. So once I got the profile they need to be cut along the top and bottom.

Mounted in the tool post of my Boley lathe and the cutter in the collett they can be machined.


After first cut.

Once shaped they need to be drilled and a .7mm drill on the outer and 1mm on the inner holes so that the 14ba bolts fit through and then mounted through the .6mm rods on the body.


Now the beams can be fitted to the chassis and height adjusted with the position of the nut on the bolt and a spot of paint to stop them coming undone.



The chassis can be fixed to the body with either a little bend in the outer pins or by a 16 ba nut.

My intention is to machine the body mounts and have the Under Beams lost wax cast.

Re: GWR Steam Railmotor Chassis

Posted: Thu Feb 08, 2018 7:04 pm
by Phil O
Fantastic modelling, Jeremy. Those Dean style suspension and mounting parts are a work of art.


Re: GWR Steam Railmotor Chassis

Posted: Thu Feb 08, 2018 7:45 pm
by Alan Woodard
Outstanding work Jeremy.

Looking forward to it's completion. ( and the kit. :-) )



Re: GWR Steam Railmotor Chassis

Posted: Sat Feb 10, 2018 4:39 pm
by andrewnummelin
Fantastic indeed!
Any idea what the minimum radius curve for such a set-up will be? I’ve a long term plan to build 0-4-4ST that had this type of suspension.

Re: GWR Steam Railmotor Chassis

Posted: Sun Feb 11, 2018 7:52 pm
by Jeremy Suter
Any idea what the minimum radius curve for such a set-up will be? I’ve a long term plan to build 0-4-4ST that had this type of suspension.

Thanks Andrew
Very good question. Something I had not yet thought too much about.
placing the underframe and chassis on the only turnout I have to hand, I think it will just go through, but it will not go to any tighter radius and will probably jam at this if I had powered it.

To increase the swivel on the chassis there are a few variables to think of. I have used 14BA nuts and bolts which are a bit thicker than they should be to attach the suspension to the chassis 16 BA or lace pins would be better this would allow them to rock further forward and back.
The Under Beams could be slimmer to allow further movement as the rear one almost touches the brakes when straight. Even the position of the solebar mounts could be a fraction closer to each other. and of coarse increase the size of hole in the under beams to allow further swing.

Its really about how much swing I can get on the inner suspension hangers.

Re: GWR Steam Railmotor Chassis

Posted: Sun Feb 11, 2018 9:35 pm
by essdee
That is simply superb, Jeremy.

I can empathise heartily, as I am still wrestling with a Falcon Brass MR Railmotor and trailer; started 2012, shelved 2014 and only recently pushed towards completion.

'You are a braver man than I, Gunga Suter'! Although my MkII motor bogie uses the Falcon sideframes, with modified Mallard valve gear (the Falcon version appeared not to be practicable after shooting down from 7mm to 4mm scale), and has had CSB retro-fitted, I baulked at the vertical motor option, and also at the prototypical bogie suspension. I was actually quite happy with the fabricated (and amputated at the base) bogie suspension bracket that I devised - until I saw what a fantastic job you have made of the prototype arrangement.........

Time pressures now preclude me going back to the drawing board on my build; but what a splendidly high bar you are setting!

In total admiration,


Re: GWR Steam Railmotor Chassis

Posted: Mon Feb 12, 2018 12:03 am
by DavidM

Just brilliant Jeremy, superb engineering.
For me, this is what our side of the hobby is all about!


Re: GWR Steam Railmotor Chassis

Posted: Tue Mar 06, 2018 12:24 pm
by Jeremy Suter
The Rear Bogie test etch arrived on Monday morning and I put it together in about 2 hours.


Looking at it you should see that it is one piece which makes up the two sides and ends by a series of folds. As is usual all folds are inwards.

Its just knowing what order to do it.

I am very pleased as it has gone together very well first go, every thing fits in the right place.

At the moment the only error I have made is the fold out for the suspension between the centre bolster and the axle is too low but the spring wire fits all the other positions perfectly. Actually I now think it is too close to the axle. So it will be removed completely from the next version.

All folded up with the Axle box keeper plates added these had to be cut off and reversed as the fold was the wrong way round.

Brakes now added and here I have made a big mistake. The holes for the mounts are in the wrong place and the length of the hangers is two short, I think I used the spring mount hole which is to be removed to set hangers by accident when drawing the original brake. The good news is that the brake rigging seems to be all correct length.

Now with wheels added. It runs and springs well but only without the brakes

Added to the underframe.

The next Job is to go back to the driving end as the second valve gear test etch is ready to be done and I have a few new ideas about getting the bogie to rotate further.

Re: GWR Steam Railmotor Chassis

Posted: Tue Mar 06, 2018 9:47 pm
by John Lewis

Any news on your railmotor chassis (and the Iron mink), please?

John Lewis

Re: GWR Steam Railmotor Chassis

Posted: Wed Mar 07, 2018 5:55 pm
by Jeremy Suter
Any news on your railmotor chassis (and the Iron mink), please?

Hi John Thanks for the question.

The Rail Motor chassis etch is all done now. The valve gear etch I hope will need very little change when I test it next week. Then the only thing holding up the kit are the castings. Chassis and Underframe casting patterns are all done, just working on the patterns for the Bogie Springs and Axlebox. 4 sets needed so that one spin equals one kit. I also need a lost wax caster for the suspension beams.

As for Iron Mink kits they have been available since Scaleforum last year at £30 each they are not on the stores list but available from me I've Just ordered another 20 kits from the etchers and should be here by Scalefour north.

Re: GWR Steam Railmotor Chassis

Posted: Wed Mar 21, 2018 1:21 pm
by Jeremy Suter
Now back to the Chassis Valve gear.

The second test etch is done.

I have cut one sides valve gear out and laid in line. You will see I am using David Brandreth method for the rivets with a piece of .5mm Nickel rod soldered into the inner section and the links then sandwiching the next part together trapping them all in line. A 16BA screw soldered into the back of the crosshead so it can be screwed together as the drop link is in the way to be able to slot in.

All lined up. There is a extra piece on the top. This is the expansion link which has a fold round to slot onto the valve gland rod so that it will hold it level and the small box Valve gland this should fit Round/Over it.
Now all fitted together in line. the only rivet I used is connecting the eccentric rod to the crank. with a sandwich joint on the expansion link end.

Now all fitted to the chassis
I had to remove the top section of the combination lever as the movement back and forth was being obstructed by the Valve gland box. I don't notice there is no movement in the valve gland now. I could of coarse mounted the combination lever to the top hole only and through the valve gland box.
The Eccentric rod fold area had to be slightly filed back to fit the valve gland box over it

Re: GWR Steam Railmotor Chassis

Posted: Thu Mar 22, 2018 3:57 pm
by Phil O
Hi Jeremy,

The un-powered bogie looks like a fishbelly, will you be making them available as a seperate item? I had a pair pencilled in with Chris Parrish, who has sadly passed away.



Re: GWR Steam Railmotor Chassis

Posted: Fri Mar 23, 2018 3:20 pm
by Jeremy Suter
Hi Phil
The un-powered bogie looks like a fishbelly, will you be making them available as a seperate item? I had a pair pencilled in with Chris Parrish, who has sadly passed away.

Yes it is a Fish Bell Bogie. Although it is only an 8' version rather than the 9' which are more common. These 8' units were special to the Gloucester Built Railmotors. If you would like, I can redraw it to a 9' unit, as I do have the drawing.

Re: GWR Steam Railmotor Chassis

Posted: Fri Mar 23, 2018 7:06 pm
by Phil O

That would be great. I'm sure I could find a use for 2 or 3 pairs.



Re: GWR Steam Railmotor Chassis

Posted: Wed Mar 28, 2018 10:00 pm
by Horsetan
Looks very promising. Hopefully not too far away from production version... :thumb

Re: GWR Steam Railmotor Chassis

Posted: Tue Apr 03, 2018 5:23 pm
by CornCrake
Hi Jeremy,
Thoroughly enjoying your progress!

With regards to the solebars:-

Do they have separate overlays?
If so what thickness do you use for the overlays?
Is the river detail etched or punched from behind?
If punched from behind may I ask what tool do you use to get such consistency?