Hunslet 50550 Mercian kit

[k22009]

While I await the lining transfers for the Crimson Claughton I've been considering what to tackle next.

 

Some time ago I picked up what I thought was a Mercian J94 kit from an Ebay auction.

 

 

When it arrived there were no instructions so a quick email to Trevor Cousens at Mercian promptly had a pdf copy by return. Excellent service. I never really had a good look at it apart from seeing that everything major appeared to be there. I never closely inspected all of the etches until this afternoon. It seems I have a chassis etch for a J94 and the balance appears to be for a 50550 with square cab windows front and back and deeper buffers. So it looks like my hand has been turned into constructing this instead.

 

On inspection of a drawing for this however, it's obvious that the frames will need to be made from scratch as they have a deep profile from buffer beam to buffer beam. So my first job was to cut 2 lengths of 14mm nickel silver strip to length and transpose the positions of the hornblock cut outs, rear axle holes and brake hanger positions.

 

 

 

The J94 frames are above the pair soldered together with masking tape on the top. I've checked with my High Level gearbox planner and a Loadhauler + 80:1 will fit driving the rear axle so I can compensate the front 2 axles. I'll cut these out and drill as necessary hopefully tomorrow.

 

Dave

[doilum]

11 hours ago, k22009 said:

While I await the lining transfers for the Crimson Claughton I've been considering what to tackle next.

 

Some time ago I picked up what I thought was a Mercian J94 kit from an Ebay auction.

 

 

When it arrived there were no instructions so a quick email to Trevor Cousens at Mercian promptly had a pdf copy by return. Excellent service. I never really had a good look at it apart from seeing that everything major appeared to be there. I never closely inspected all of the etches until this afternoon. It seems I have a chassis etch for a J94 and the balance appears to be for a 50550 with square cab windows front and back and deeper buffers. So it looks like my hand has been turned into constructing this instead.

 

On inspection of a drawing for this however, it's obvious that the frames will need to be made from scratch as they have a deep profile from buffer beam to buffer beam. So my first job was to cut 2 lengths of 14mm nickel silver strip to length and transpose the positions of the hornblock cut outs, rear axle holes and brake hanger positions.

 

 

 

The J94 frames are above the pair soldered together with masking tape on the top. I've checked with my High Level gearbox planner and a Loadhauler + 80:1 will fit driving the rear axle so I can compensate the front 2 axles. I'll cut these out and drill as necessary hopefully tomorrow.

 

Dave

For the record the 7mm version is correct. I did however have to reverse engineer my frames for S112. Having cut off the leading corner(don't ask, it's another story), I cut and soldered bits of scrap etch to restore the full depth to the front of the frames.

S112 had a normal rear buffer to clear the mechanical stoker and the frames were cut to match. I understand that the current owner has restored the full depth of the frames welding in new sections of steel.

[k22009]

Just an hour at the workbench today but managed to get the frames, spacers and compensation pivot beam cut out ready for soldering up. I'll do the coupling rods next, once they're done I can get the high level hornblocks and guides positioned.

 

 

 

Dave

[doilum]

2 hours ago, k22009 said:

Just an hour at the workbench today but managed to get the frames, spacers and compensation pivot beam cut out ready for soldering up. I'll do the coupling rods next, once they're done I can get the high level hornblocks and guides positioned.

 

 

 

Dave

Why not start with the coupling rods? They can then be used to get the frames correct. Better still, start with a template made from scrap etch with 1mm pilot holes.

Does the use of hornblocks influence the decision?

[k22009]

19 hours ago, doilum said:

Why not start with the coupling rods? They can then be used to get the frames correct. Better still, start with a template made from scrap etch with 1mm pilot holes.

Does the use of hornblocks influence the decision?

 

The second photo of the topic shows the template I made, under the marked out (on masking tape) area are 2 off 14mm nickel silver strips tacked together and ready for drilling. I use 0.5mm drills to pilot hole everything.

 

As i'm compensating the chassis, there is only one pair of axles, the driven ones in brass bearings that need to be positioned accurately to start with, the other 2 axles have cut outs for the hornblock guides which when you offer up the 2 assemblies on an alignment axle, the spring keeps them in place and by using the coupling rods now it automatically positions them exactly. Do this for both axles and solder the guides to the frames and you have a smooth running chassis.

 

 

With the pivot beam in position (this can be done after).

 

 

Dave

[doilum]

1 hour ago, k22009 said:

 

The second photo of the topic shows the template I made, under the marked out (on masking tape) area are 2 off 14mm nickel silver strips tacked together and ready for drilling. I use 0.5mm drills to pilot hole everything.

 

As i'm compensating the chassis, there is only one pair of axles, the driven ones in brass bearings that need to be positioned accurately to start with, the other 2 axles have cut outs for the hornblock guides which when you offer up the 2 assemblies on an alignment axle, the spring keeps them in place and by using the coupling rods now it automatically positions them exactly. Do this for both axles and solder the guides to the frames and you have a smooth running chassis.

 

 

With the pivot beam in position (this can be done after).

 

 

Dave

Ah I see! Everyday a learning day. I have yet to have a go at a scratch build with horn blocks. Maybe if lockdown lasts into autumn I will be looking at a set of ancient Slater's 4'3'' 14 spoke non quartered wheels. Austerity # 4?

[k22009]

A few chassis details added, sandboxes and pipes and brake gear although i'll add the pull rods later.

 

  

Made a start on the footplate, the valences were not very straight from the etch sheet so I used some brass flat instead. Buffer beams are double laminations and had the rivets punched out prior to sweating together. I've also added the footplate supports underneath, buffer beam stiffeners, grab rails and sand box fillers too. I matched up the chassis to the footplate and drilled the spacers to suit the positions of the footplate holes before soldering nuts to the top. 

 

 

 

On with the saddle tank, firebox assembly next.

 

Dave

[doilum]

Looking good. 

[k22009]

The saddle tank and lower boiler section come pre rolled however they both needed re shaping to suit the profiles.

 

 

The rolled saddle tank lower edges needed curving to the shape of the formers, this is a half etched area and it says to lap over the top of the lower section which must also be shaped to suit the lower curves.

 

 

Before the 2 halves where soldered together, the formers were attached to the lower section. the upper saddle was then sprung over the bottom, soldered up and filed to a smoothish transition. Handrail knobs and the recessed safety valve/whistle support were also added mainly from soldering inside but the smokebox front knobs I couldn't reach. The smoke box sides need a little trimming and the stiffener flap at the top of it above the rivets had to be removed as it was fouling the handrail underneath. It all fitted well otherwise.

 

 

Cab next up.

 

Dave

[doilum]

Keep the tank, cab and footplate as separate units until you have trial fitted them on a motorised chassis. It is a long time since I built an austerity in 4mm ( Bristol models chassis and Kitmaster body) but even in 7 mm it is a squeeze to get the motor vertically into the firebox and much use is made of the Dremel.

[k22009]

23 hours ago, doilum said:

Keep the tank, cab and footplate as separate units until you have trial fitted them on a motorised chassis. It is a long time since I built an austerity in 4mm ( Bristol models chassis and Kitmaster body) but even in 7 mm it is a squeeze to get the motor vertically into the firebox and much use is made of the Dremel.

 

Thanks for the tip I will. 

 

The cab went together well I used the beading supplied for both the doors and the bunker top, however no cab front window frames were supplied (they're not mentioned in the J94 instructions i'm using either). There is a half etched rebate around them to the outer face so I added some 0.3mm dia wire forming and soldering it around bit by bit. The main parts are all fitted just the cab handrails and interior to detail.

 

 

 

As Doilum suggested though before I go any further i'll get the gearbox made up and fitted with a motor to see how it all goes together, or not.

 

Dave

 

[doilum]

37 minutes ago, k22009 said:

 

Thanks for the tip I will. 

 

The cab went together well I used the beading supplied for both the doors and the bunker top, however no cab front window frames were supplied (they're not mentioned in the J94 instructions i'm using either). There is a half etched rebate around them to the outer face so I added some 0.3mm dia wire forming and soldering it around bit by bit. The main parts are all fitted just the cab handrails and interior to detail.

 

 

 

As Doilum suggested though before I go any further i'll get the gearbox made up and fitted with a motor to see how it all goes together, or not.

 

Dave

 

For anyone new to this artform, the kit manufacturer has thoughtfully provided some etched liines in the cab front. This area can be removed to allow the gearbox or motor to steal a a little precious space. It is worth almost cutting this with the Dremel in case you need the space later.

In 7mm it can be worth ditching the cast firebox backhead and fabricating a new one with an extra couple of millimeters. Noone will be the wiser once the roof is on!

These lessons were learned the hard way!

[k22009]

Been drilling my Gibson wheels for the crankpins so I though i'd add a few photos of a small jig that can be altered depending on the crankpin throw which helps to ensure the wheel is drilled perpendicular while it lies perfectly flat, if like me you don't possess a pillar drill. Apologies it could be a neater jig, but it does me ok.

 

The main part is 2 tubes (ideally these should be square section) which are a good sliding fit. The outside tube I've added some 3mm channel to raise the assembly above the wheel. At one end there is a 8ba nut and the tube is drilled so this will act as a clamp. At the other end I have soldered on a short section of 1'8" axle which I reduced in size slightly so that it fits the Gibson axle hole without any effort. The inner tube then has a hole drilled right through, this must be through the main axis. It could be improved by adding a guide either side of the drill bit ( a bit of brass flat or a rod would be fine) soldered to the main outer tube, this then ensures the drill is at 90 degrees to the wheel.

 

 

 

In use add the Gibson wheel to onto the stud, hold a drill bit through both holes of the inner tube so that it lines up with the dimple or predrilled hole of the wheel, clamp the inner tube by the 8ba screw and drill gently through.

 

 

All wheels should then be drilled to the same throw and you only need to line the drilling position up when offering the wheel onto the stud.

 

 

Dave

[doilum]

1 hour ago, k22009 said:

Been drilling my Gibson wheels for the crankpins so I though i'd add a few photos of a small jig that can be altered depending on the crankpin throw which helps to ensure the wheel is drilled perpendicular while it lies perfectly flat, if like me you don't possess a pillar drill. Apologies it could be a neater jig, but it does me ok.

 

The main part is 2 tubes (ideally these should be square section) which are a good sliding fit. The outside tube I've added some 3mm channel to raise the assembly above the wheel. At one end there is a 8ba nut and the tube is drilled so this will act as a clamp. At the other end I have soldered on a short section of 1'8" axle which I reduced in size slightly so that it fits the Gibson axle hole without any effort. The inner tube then has a hole drilled right through, this must be through the main axis. It could be improved by adding a guide either side of the drill bit ( a bit of brass flat or a rod would be fine) soldered to the main outer tube, this then ensures the drill is at 90 degrees to the wheel.

 

 

 

In use add the Gibson wheel to onto the stud, hold a drill bit through both holes of the inner tube so that it lines up with the dimple or predrilled hole of the wheel, clamp the inner tube by the 8ba screw and drill gently through.

 

 

All wheels should then be drilled to the same throw and you only need to line the drilling position up when offering the wheel onto the stud.

 

 

Dave

I vow to never say anything rude about Slater's wheels again!

[k22009]

Chassis has been primed and painted the last  couple of days. I only wanted to fit the Gibson wheels once or twice at the most so with fingers crossed pressed them onto the axles. I used a Comet gearbox for the rear driver in the end as it positioned the small Mitsumi motor perfectly sitting up into the firebox with plenty of room all around. Coupling rods fitted and after a test with some trailing leads and a trim of the brake hangers which the coupling rods were just catching it all works very smoothly.

 

 

I'll add some pickups next and make a final check before I progress and add some weight to the boiler/saddle tank assembly and in the bunker and fit it to the footplate.

 

Dave

[k22009]

I've now added the saddle tank assembly to the cab/footplate, added steps and gave it a test on the track. Apologies for the poor phone video.

 

 

All of the small details to be added next.

 

Dave

 

[doilum]

Excellent movement. I would be happy with that in 7mm using an ABC transmission. I hope you remembered handrail knobs under the tank sides. My first austerity Diana lacks them. By the time I noticed them on the drawing it was too late. The remaining fine detail will depend on the example chosen and date.

[k22009]

I added most of the details, handrails, fittings etc i also made up a new backhead with manifold, pipes and gauges but they are difficult to see in the cab. 

 

It's gone together pretty well, parts fitted well and with the Comet gearbox and £1 chinese motor it runs fine. This is my first Mercian 4mm kit and apart from having the wrong frames in the kit i've no complaints.

 

 

 

 

Thanks for looking in. Whats next?

 

Dave

[doilum]

If you are willing to risk a Hunslet addiction, there are 15&16" versions available from Judith Edge. 

[Michael Edge]

We have the 14" as well in 4mm scale - others also in 7 and 3mm scales.