A middle cylinder with most of the top plates in place
After the final pieces of the exhaust passage tops were fitted a piece of plate was prepared for bending up to make the smokebox saddles, seen here on the milling table after machining the sides and ends
Here is the set up for bending the plate. Another good reason for having a thick walled smokebox. As can be seen the plate is laid on the top of the vice with the smokebox on top and a steel bar passed through it. The screwed rod goes through the bare at each end and passes through another bar underneath , and by tightening the screwed rods, the plates bend to the radius of the smokebox, so theory has it.
The bending progresses
The bending progresses continued
The bending progresses continued
The bending progresses continued
The bending progresses continued
The bending progresses continued
The bending progresses continued
Here the bent plate is seen sat on the frames before it is cut into two pieces
After cutting the bent plate is attached to the smokebox, now mounted on the rotary table in the milling machine
The holes for the saddle bolts are drilled using the rotary table to locate them
Each hole is counterbored before tapping .
Tapping in progress
All the bolts fitted
Whilst the smokebox is mounted on the rotary table, the opportunity was taken to make some of the openings in it. Here the hole for the snifting valve has been drilled and the first stage of the hole for the chimney is in progress
Next the boring head is employed to open out the hole to its correct dimension
Next the boring head is emp1oyed to open out the hole to its correct dimension continued
Next the boring head is emp1oyed to open out the hole to its correct dimension continued
During WW2 most LNER loco smokeboxes lost their countersunk rivets round the back at the boiler connection and round the front at the smokebox door ring in favour of roundheads which require less labour, as there is no need for them to be flushed off. By the late fifties many engines had regained the countersunk rivets at the front , but the round head were still used at the back. This applied to 61962 and I decided to put in dummy rivets (the boiler connection being a simplified version more appropriate for the model). This required drilling around 90 1/32" diameter holes through the 9/32" thick steel, and here it is in progress
This was, much to my surprise accomplished with just one 1/32" drill, seen here in close up
The large opening over the inside cylinder was also machine during this set up on the rotary table. First a slot was machined right through the saddle plate and the smokebox
This was then extended to the full width of the opening
And then extended to the full extent of the opening
The Final break through
Next the outside of the saddle was machined to size.
Other holes for the handrail stanchions and the bake ejector exhaust wer also drilled at this time
At last the saddle plate could be fitted to the inside cylinder with more temporary 10 BA screws.
The holes above the exhaust ducts in the side plates were plugged.
And the little gusset plates made and fitted to the front and back of the saddle.
The Inside cylinder main steam pipe flange was turned up and carefully fitted as it needs to be vertical.
After masking the areas that would not benefit from the application of silver solder the cylinder was fluxed ready for what will be the final soldering operation.
The cylinder is ready for final soldering.
The cylinder is ready for final soldering continued
The cylinder is ready for final soldering continued
Two inside cylinders after soldering.
The inside cylinder assembly mounted on the rotary table for machining the side flanges. By using the rotary table some certainty can be give to the alignment of the middle cylinder by making finishing cute on the same tool settings each side.
The initial cuts brought the ends of the exhaust ducts flush with the flanges
The right hand flange finished
And the left
Checking the width of the cylinder with a 6" micrometer.
With the cylinder rotated 90 degrees the top of the slide bar support could be machine d accurately parallel with the cylinder centre line.
The outside cylinders were also set up on the rotary table for the slide bar bracket initial facing. The cutter can only reach a part of the face because the machined surface extends under the end of the valve chest.
The cylinder is then mounted vertically on the milling table to complete the machining of the bracket. The internal corners are unable to be machined and needed finishing using a very sharp chisel and swiss files.
With the outside cylinders now mounted on an angle plate on the milling table the footplate angle support could be machined.
And the main steam inlet bored with a bull nose cutter.
Likewise for the inside cylinder the steam pipe bore is finished and the inlet and exhaust flanges faced off.
Mounted the other way up the draincock flanges are faced and the holes drilled.
As the side faces of the middle cylinder were faced with the block parallel to the cylinder there is a triangle under the saddle that needs machining. The cylinder was set up on the milling table with the saddle parallel to the boiler centre line and a ball nosed milling cutter used to finish the flange and put a radius between the saddle and the flange.
As the side faces of the middle cylinder were faced with the block parallel to the cylinder there is a triangle under the saddle that needs machining. The cylinder was set up on the milling table with the saddle parallel to the boiler centre line and a ball nosed milling cutter used to finish the flange and put a radius between the saddle and the flange.
Back on to the rotary table now to machine the bottoms of the transverse supports, which because of the inclination of the cylinder are all different. The cylinder set up viewed from the side shows the angles marked on for the machining operation.
After machining this end view shows the shape of the underside of the cylinder to which the lagging will be attached.
The next operation reverted to the lathe, with the cylinders mounted on the vertical slide for accurate finishing of the steam chest bores with a between centres boring bar.
A completed steam chest bore almost ready for the liner.
A similar method was used for the inside cylinder.
The valve liners were the next step towards completion of the locos. Twelve lengths of cast iron were prepared and bored for the liners.
A mandrel had been made that fitted in the 2 Morse taper of the lathe which was also centred at the outer end for support with the back centre. The valve liner blacks were fitted in pairs between spacer blocks for machining.
All the roughed out blanks were remounted on the mandrel, again in pairs, and and machined to the correct diameter, leaving a flange at one end.
Mounted in the four jaw chuck the liners were accurately centred with a dti.
And through bored to the required diameter.
A chamfer was machined in to both ends to help with getting the ringed valve heads in to the liners. Those on the inner end help to get the heads through from the front to the back valve passages.
Back to the rotary table and a milling cutter was used to start forming the ports.
Showing the initial holes all drilled and a 1/16" cutter mounted ready to square off the ports.
Two liners with the ports almost complete.
An outside cylinder with a liner entered ready to be pressed home.
An inside cylinder with a length of screwed rod in place ready to press the liners in.
Checking to see the liners are all the way home with a 6" micrometer.
- A view through the valve chest with the liners in place.