Rhymney A & A1 Critique

[Penrhos1920]

I’ve drawn these locos with the intention of having them 3D printed. I would like anyone who is interested in the Rhymney to have a look at these drawings and review them for any errors. Items like safety valves, hand rails and other details that will be fitted have been left off. I have included the smokebox handle as it appears to be unique.

If there is interest in them I could either make the 3D print available or use it to make a master for resin casting.

RR A.jpg

RR A-A1.jpg

RR A1.jpg

The dome needs some attention, but a the moment it is reaching the limits of CAD abilities.

[Penrhos1920]

RR AA1 bunker.jpg

[Newport_rod]

This looks very impressive Richard. Not being expert in the Rhymney I can't comment on its accuracy but here are a couple of general thoughts
■ Might the smokebox door wheel be better etched?
■ Similarly might it be an idea to omit the buffer shanks to allow turned brass ones to be used
■ With the safety valve base I wonder if it would be easier to fit the base, valve casings and arm as one commercial casting rather than add them onto the printed/resin base.
■ In terms of the printing process would it be printed from the bottom up? If so there is a lot of way to be laid while the steps are being printed, it might be preferable to print these separately (the same consideration might apply to the buffer plank)
■ And MOST importantly would you consider creating a variation for the B&M 39 class?

[Penrhos1920]

This looks very impressive Richard. Not being expert in the Rhymney I can't comment on its accuracy but here are a couple of general thoughts
■ Might the smokebox door wheel be better etched?

Possibly. I'm going to try both. Have you seen this lost wax casting for something almost the same: CaleyJim's smoke box hand wheel. I'm tempted to do the same thing and make a separate casting.

■ Similarly might it be an idea to omit the buffer shanks to allow turned brass ones to be used

The buffers have a hole centre for the buffer ram and spring and a smaller hole in the buffer beam. I expect that these might become separate items.

RR Buffer.jpg

■ With the safety valve base I wonder if it would be easier to fit the base, valve casings and arm as one commercial casting rather than add them onto the printed/resin base.

The safety valves are coming from Markits; their Ross Pop Tall turnings. There was no arm on the Rhymney safety valves. Did you see Bill Bedford's S&DJR 1F at Scalefour North? Bill has 3D printed the boiler and firebox with dome in place and the thinness of the dome base was impressive.

■ In terms of the printing process would it be printed from the bottom up? If so there is a lot of way to be laid while the steps are being printed, it might be preferable to print these separately (the same consideration might apply to the buffer plank)

I don't know which way it will be printed. I am going to split it into two main sections of (footplate, cab and bunker) and (smokebox, boiler and firebox). Plus a few odd bits like sand box and splasher. I have thought about etching the steps.

■ And MOST importantly would you consider creating a variation for the B&M 39 class?

What are the differences?

[Newport_rod]

■ And MOST importantly would you consider creating a variation for the B&M 39 class?

What are the differences?

Richard
A fair question! I think that these are the major differences

• No top feed of the B&M engine
  Different shape sandboxes
  All the B&M engines have round-top fireboxes
  Circular cab windows (front and back)
  Balance pipe under the cab door is circular in section on the B&M
  Safety valves
  On the B&M engine the front steps are the same width (lower step is wider on the RR A)
  Leading axle spring is underslung on B&M

[Penrhos1920]

■ And MOST importantly would you consider creating a variation for the B&M 39 class?

What are the differences?

Richard
A fair question! I think that these are the major differences

• No top feed of the B&M engine
  Different shape sandboxes
  All the B&M engines have round-top fireboxes
  Circular cab windows (front and back)
  Balance pipe under the cab door is circular in section on the B&M
  Safety valves
  On the B&M engine the front steps are the same width (lower step is wider on the RR A)
  Leading axle spring is underslung on B&M

Russell says the the B&M 36 class was based on the Rhymney R class, not A class. Is he wrong?

Sandboxes, balance pipe, springs and steps will be separate parts if its goes into production as a resin cast.

Do you have a drawing giving the location and size of the cab windows?

[Newport_rod]

Russell says the the B&M 36 class was based on the Rhymney R class, not A class. Is he wrong?

Do you have a drawing giving the location and size of the cab windows?

I don't think he is wrong, Richard, I obviously need to swat up on my RR 0-6-2Ts! I think that I've got a drawing somewhere of the B&M 36 class to compare with the A in the Rhymney drawings book.

[Penrhos1920]

I've had the drawing printed by Shapeways using their Frosted Ultra Detail. This is as it has arrived. It needs cleaning, painting and the large surfaces gently sanded before it can be assembled.

IMGP2030s.jpg

IMGP2031s.jpg

IMGP2032s.jpg

The footplate has got bent in the post. I'm hoping it will straighten out or else it's speak to Shapeways about it.

[andrewnummelin]

Well done!

[Newport_rod]

Excellent work Richard. The way that you've created the various fittings separately should allow for variations to be accommodated more easily - good thinking.
Looking forward to the next step!