Tyneside Society of Model & Experimental Engineers
November 2019 – News Letter
Preamble
I’d planned to have something out in October, a respectable three months on from the previous issue, but life has an irritating habit of getting in the way of things. As Edmund Blackadder so eloquently put it – “The path of my life is strewn with cowpats from the Devil’s own Satanic herd”. Be assured, however, that I’ve swept up and what follows is wholly fragrant ….
Around and About the Club
Big things
have been happening out on the grass of late as work has progressed steadily with
building the new Carriage Shed for the raised-track riding trucks. Many cubic
metres of soil have been excavated to prepare the ground for the floor-slab (6m
long by 2m wide by 10cm deep) which sits several centimetres below the
surrounding ground level. Four courses of blockwork are raised on this to
roof-eaves level. A door-frame and sill have been fabricated in steel which
occupy the full width of the track-ward end. Provision is made in the floor to
bring in mains electricity.
Whilst the
ground works for the carriage shed were underway, the area in front of the
locomotive shed was also prepared to accommodate the new dual-gauge traverser
and the slab for this was poured at the same time.
Work also
continues with improvements to the track signalling and point control systems.
Receiving attention now are the points between the station loop and main line
so that these cannot be operated whilst a train is in transit. Additional
train-detectors have been installed in the track and associated cables laid-in
back to the Signal Box where a new cabinet houses the extra circuitry required.
Creosote Day,
Saturday 7th September, witnessed a good turnout of willing helpers
to get this annual maintenance job done. Both ground-level and raised tracks
were thoroughly treated using a combination of spray-guns and brushes.
If you’ve
visited the TSMEE website recently, you’ll have noticed a quite radical change
in appearance and content. John Rowley has taken over the job of webmaster and
is keen to stress that it is, presently, very much “work in progress”. User
feedback and constructive comments are welcomed.
Events …
Open Weekend 27/28th
July
This annual
two-day event was not blessed with particularly good weather. It rained
on-and-off on the Saturday and Sunday was dry but overcast. Nevertheless, there
was a respectable turnout of both TSMEE members and visitors, the latter hailing
from as far afield as Scotland, Cumbria, York and Leeds.
Visiting
locomotives were :– in 3-1/2” gauge BR
“Britannia” 4-6-2, Great Central O4 2-8-0, Freelance 4-8-2 – in 5” gauge “Chub” 0-4-0 Tank, BR Standard 4 2-6-4 Tank,
NER Q6 0-8-0, NER B2 4-6-0 – and in 7-1/4” gauge GWR 14XX 0-4-2 Tank .
Saturday lunch
was Fish ‘n Chips and on Sunday our Catering Stalwarts laid on their usual
splendid buffet.
Trip
down the Tyne 31st August 2019
Six
members joined our party on the “Fortuna” for a cruise down to Tynemouth from
the Quayside in Newcastle. The weather was reasonable, even allowing for the
blustery wind, and we all enjoyed the trip.
There is a full and very informative commentary on the way to Tynemouth. I have made the trip a couple of times over the years and I am amazed by the way that Tyneside industrial heritage has disappeared in a comparatively short time. It used to be the remains of ship yards, dry docks and associated industries all the way to Tynemouth. Now much of the bank-side is wooded and under modern housing. It all looks very different.
The remaining working areas are impressive and Tyne Dock is massive. The Fish Quay and Tynemouth with the Harbour Lights, like much else of the riverside, are becoming tourist attractions. That’s progress, so we all went to the bar and drank to the past. Malcolm Phillips
Trip
to see the G5 at Shildon and the P2 under construction at Darlington, 7th October 2019.
Another
enjoyable day out, perhaps more related to model engineering. Volunteers at
both sites were very helpful and thanks are due to Phil Work who kindly
arranged tea and biscuits at Shildon.
The
G5 is not quite an engine yet, but most of the parts are ready to go together.
The frames, boiler, cab and plate-work just need finishing touches. The bogie
for the 0-4-4 and one set of driving wheels have been finished but the crank
axle has yet to arrive, as manufacture of parts and machining is all done
outside. The group has been working to original plans and has had to make many
patterns, some of which are placed beside the finished castings.
From
Shildon we proceeded to Darlington. The P2, to be named “Prince of Wales”, is a
truly impressive machine. Like the G5 it has yet to go onto its wheels, all of
which have had their tyres polished to a mirror finish. Cab and smokebox are on the frames and the
boiler cladding is set up on frames beside the locomotive as the boiler is yet
to come from Meiningen.
We were told about some of the technical problems – the wheel flanges have been computer designed to ease passage round curves on Heritage Railways and steam distribution will be by poppet valves.
The original Gresley design was not too successful so the designers have used the designs evolved in America after the war which were better. Boiler design has been modified by experience with Tornado and their boilers are interchangeable.
I
do not know what will become of the polished wheels – one of the volunteers
told me that the painters were upset because on its first trip to York of thirty
miles, their beautiful paint finish was spoiled by excess grease and oil coming
out of the axle boxes!
The
NELPG shops were closed so we completed the trip with a visit to the Head of
Steam Museum across the way from the Hopetown works. This is a nice museum with
exhibits of Stockton and Darlington and NER origin. Hackworth’s “Derwent” and
“Locomotion” are well displayed and there are some interesting small exhibits. Malcolm
Phillips
For your diary …
Public Running
Day – Santa Special – Sunday 1st December
Christmas Tea
– Sunday 22nd December
Something a bit different now – Gordon
Bullard has very kindly submitted the following rather interesting article…
An Automatic
Cylinder Drain-cock
Back in the 1980’s over a pie and a pint in a local hostelry, a friend and I were discussing the pros and cons of cylinder drain cocks and associated linkage to the cab of a miniature steam locomotive.
The locomotive he was building had two sets of Stephenson’s valve gear and an axle pump between the frames, together with lubricator linkage which left little room for direct drain- cock rodding. We discussed the possibility of automatic drain cocks and I suggested that a small inverted safety valve type of arrangement might be possible.
A set of small valves was made and fitted, each consisting of a stainless ball which was held on its seat by a small bronze spring. The valves performed well but they looked like upside-down safety valves, which is, of course, exactly what they were.
Clearly, a horizontal arrangement was required which would be more prototypical of full sized practice. So, another set of valves was made in a tee configuration with basically the same internal arrangement but in a horizontal orientation.
These valves worked reasonably well. They certainly cleared the cylinder condensate very efficiently but for some reason when the locomotive was running slight puffs of steam were occasionally noticeable.
Closer observation showed that one of the valves seemed to be working well with no visible leakage whilst the loco was running. With the expectation that the poor sealing of the three sub standard valves was probable due to poor workmanship on my part, all of the valves were disassembled for examination.
I was amazed to find that I had forgotten to put a
spring in the valve that worked perfectly.
The valves were quickly reassembled without springs and found to all
work perfectly. Since then I have fitted
this type of valve onto three of my locomotives with no failures. The last loco was to LBSC’s “Maisie” design
and has run on the club track on numerous occasions. The attached drawing shows the design of the
valve which is made of bar material with a silver-soldered joint.
It took a while to work out how the valve worked without a spring. When the locomotive is stationary any condensation in the cylinder drains down into the valve where the ball is resting on the bottom of the chamber so any water can drain away via the front hole.
When the regulator is opened a combination of condensate and steam enters the valve where the ball is unable to seat properly due to the turbulence in the chamber. A combination of water and steam exits the valve due to this turbulence until all of the water is displaced, which leaves the chamber full of steam which in turn forces the ball onto its seat. It’s as simple as that.
You may well ask what the reduced diameter on the rear
of the valve is for. It is purely there
to improve the fitting visually, disguising the fact that it is just a piece of
simple bar material. For members who
follow full size practice and require drain piping to the locomotive’s buffer
beam, the front of the valve seat could
have a small ME thread machined onto it to take a nut, nipple and associated
pipe.
In conclusion, this simple valve is easy to produce, is fully automatic in operation and requires no linkage to the cab. It would be easy to say that I had a light bulb type of moment concerning this valve’s conception but in reality it came about more by accident than design.
Drain-cocks fitted to 3-1/2″ “Maisie”
Postamble
As I remarked in the previous issue, a
Newsletter requires News, and this one would have been a rather thin affair but
for the contributions of Malcolm Phillips and Gordon Bullard. My thanks to them
both.
Membership Subscriptions will be due for renewal at the end of the year. The cost remains at £35 Single and £45 Family. Our Treasurer Ian Spencer will take payment in cash or cheques (payable to “TSMEE Ltd”).
Now that the valve liners were made and fitted it was necessary to finish machining the ends of the steam chest ready to take the valve spindle crosshead guides. These were mounted on the mandrel on which the valve liners were machined, using the No 2 Morse taper in the rotary table set up on the milling machine.
The cylinders were located by carefully setting the back plate on 0 degrees using a dial gauge
An end mill is used to finish the flange to the correct diameter, concentric with the valve centre
and to face the flange so the face is flat, square to the valve centre line and correctly positioned in relation to the cylinder
A recess is formed to ensure the valve spindle guide is accurately positioned concentric with the bore
Once all twelve ends were machined the holes for the holding down studs were drilled tapping size for 8BA.
each accurately placed thanks to use of the rotary table.
Next the cylinders were set up on the cylinder centre line to drill the cover stud holes
The small dial gauge was used to check the bore was concentric with the established centreline. It was found necessary to introduce a jacking bolt to ensure the cylinder stayed vertical when drilling loads were applied.
After spotting the holes with a centre drill the holes were drilled tapping size for 7 BA.
Moving to the middle cylinder, again mounted on the rotary table with the bore vertical, the dial gauge is being used to align the cylinder with the table circle graduations.
Here is a centre cylinder being checked for concentricity. The jacking bolt is fully evident in the photograph.
A view of the front of a centre cylinder after drilling the stud holes
The cylinders were then reversed to drill the stud holes for the piston rod gland housing cover.
Like all straightforward turning jobs the inside cylinder rear valve cover and spindle guide starts as a bit of bar, actually mild steel grade EN1A, in the lathe chuck. In this case the four jaw chuck, as concentricity is important when the half turned job needs to be reversed to turn the other end.
After turning down to size a spigot is machined to a close sliding fit in the steam chest end and bored and reamed for the valve spindle guide bush.
The inside is bored to a depth in line with the flange face with radius corners which will form the projections that help prevent the valve liners from moving should they come loose, as will be seen later.
After parting off the guide is reversed and reduced to the outer flange dimension.
This is then further reduced with a radius tool to make the tapered body.
Next the cover is mounted on the rotary table to drill the fixing holes in the flange and machine the flat on the side where the main frame intersects, finally producing the finished article shown here with the guide bushes (the long ones). The small bush is for a valve guide and cover shown later. The small hole in the outer flange face is the pressure relief passage that prevents hydraulic pressure build up in the end cap when the valve spindle moves back.
The cover is seen in place here and the opening in the top for the guide oiler that discharges oil to the spindle from an annular groove in the outside of the guide bush.
The other steam chest end covers are also the valve crosshead guides and the valve spindle gland housings. These start in the same way as the inside steam chest cover but end up with a flush face which after fitting the gland housing will become the seat for the crosshead guides as seen in this where one is temporarily fitted to the back of an outside cylinder to check the fit.
Several lengths of steel bar were machined in the milling machine to make the sections that will become the valve crosshead guides.
.... finally looking like this
Also I discovered the process could be speeded up if I drilled longitudinal holes to reduce the amount of material being removed by my arguably lightweight milling machine thus saving some time in producing the twenty lengths needed for the two locomotives.
Here are some in various states of machining.
The gland housings were machined and the lozenge shape was also formed with the part mounted on the rotary table
The gland covers were machined as "top hats" and the lozenge shape formed on the rotary table. The obvious way would have been to fit them to the valve guides and machine the lozenge as the valve guide was done. but for some reason Doncaster drawing office decided they should be smaller than the housing
Also the gland housings were machined and the lozenge shape was also formed with the part mounted on the rotary table
Also the gland housings were machined and the lozenge shape was also formed with the part mounted on the rotary table
A setting block was made to mount the guides and gland housing during silver soldering.
and these were clamped with purpose made buttons in the fixing holes to accurately position them.
Once clamped with the setting block and a toolmakers clamp the buttons were removed and the flux applied
and silver soldered.
After pickling the assemblies they could be mounted on the cylinders for photographic purposes. The front of the cylinder block showing partly finished valve crosshead guides in position
The parts were then mounted on an angle plate on the rotary table for machining the tapers on the guides. Note the setting block being used to help support the guides during machining.
Once the top and bottom tapers were done on all the guides the sides were machined on a similar set up. It is to be noted that each engine has five guides. The Outside cylinder guides are of two lengths, and the inside is of a different length to the outsides and the K3 inner is shorter than the H4 inner. Thus there are no less than twelve different machine settings to form the tapers on the guides. The final operation was to machine out the recesses for the oil pots, Holding them on the angle plate on the rotary table as before.
Also - Once the top and bottom tapers were done on all the guides the sides were machined on a similar set up. It is to be noted that each engine has five guides. The Outside cylinder guides are of two lengths, and the inside is of a different length to the outsides and the K3 inner is shorter than the H4 inner. Thus there are no less than twelve different machine settings to form the tapers on the guides. The final operation was to machine out the recesses for the oil pots, Holding them on the angle plate on the rotary table as before.
With a small amount of file work to radius the ends of the guides and blend them in to the flanges, they could be temporarily fitted to the steam chests.
A length of steel bar was machined for the oil pots here seen having the rounded ends machined with a corner rounding cutter.
Mounted in the lathe these could be drilled and parted off ready for silver soldering to the guides.
Finishing the oil pots to height.
The guides were now returned to the lathe for finishing the inside face and spigot, here being clocked true in the four jaw chuck.
Facing the flange.
On the same setting the guide was drilled to depth and reamed (using a D-bit) for the bronze guide bush and gland.
The guides were then transferred to the milling machine to form the lugs for preventing movement of the valve liners.
A finished valve guide.
At this stage I began to think I should check the cylinder alignment. Although the cylinder back plates were drilled to the same dimensions as the pilot holes in the frames, many machine operations had been done and it was conceivable the alignment would now need some adjustment, before finally fixing the cylinders. A dummy axle had been made to help with the axle box alignment and this was now accurately drilled transversely through the centre 3/8" diameter. With the driving axle boxes blocked at the running position a ground steel bar was fitted through the cylinders using previously made plugs for position and the hole in the dummy axle, and the primary holes for the cylinder bolts were checked for alignment and drilled through. For the record there was no indication of any positional errors.
Also - At this stage I began to think I should check the cylinder alignment. Although the cylinder back plates were drilled to the same dimensions as the pilot holes in the frames, many machine operations had been done and it was conceivable the alignment would now need some adjustment, before finally fixing the cylinders. A dummy axle had been made to help with the axle box alignment and this was now accurately drilled transversely through the centre 3/8" diameter. With the driving axle boxes blocked at the running position a ground steel bar was fitted through the cylinders using previously made plugs for position and the hole in the dummy axle, and the primary holes for the cylinder bolts were checked for alignment and drilled through. For the record there was no indication of any positional errors.
Also - At this stage I began to think I should check the cylinder alignment. Although the cylinder back plates were drilled to the same dimensions as the pilot holes in the frames, many machine operations had been done and it was conceivable the alignment would now need some adjustment, before finally fixing the cylinders. A dummy axle had been made to help with the axle box alignment and this was now accurately drilled transversely through the centre 3/8" diameter. With the driving axle boxes blocked at the running position a ground steel bar was fitted through the cylinders using previously made plugs for position and the hole in the dummy axle, and the primary holes for the cylinder bolts were checked for alignment and drilled through. For the record there was no indication of any positional errors.
Also - At this stage I began to think I should check the cylinder alignment. Although the cylinder back plates were drilled to the same dimensions as the pilot holes in the frames, many machine operations had been done and it was conceivable the alignment would now need some adjustment, before finally fixing the cylinders. A dummy axle had been made to help with the axle box alignment and this was now accurately drilled transversely through the centre 3/8" diameter. With the driving axle boxes blocked at the running position a ground steel bar was fitted through the cylinders using previously made plugs for position and the hole in the dummy axle, and the primary holes for the cylinder bolts were checked for alignment and drilled through. For the record there was no indication of any positional errors.
The valve spindle crossheads were the next parts to be tackled and these were made in cast iron. I had been given a number of discarded tensile test specimens which were effectively cylindrical.
These were machined to a rectangular section, and then reduced to fit in the crosshead guides which made them a cruciform shape.
I chose to use a similar design of crosshead to that employed on his P1 loco by Geoff Moore. Geoff kindly gave me his drawings and I was able to adapt them for my locos. This design offers almost infinite adjustment of the valves rather than the half turn of a 40 tpi screw often used in model locos. The cast iron bar was cut into the required lengths and at one end a short piece was machined out to half thickness and a matching piece was made to fill the gap.
A countersunk hole was formed at each side for fixing screws to hold the two parts together.
Countersunk screws in place.
Each crosshead was drilled and reamed as required for the valve gear pin, vertically for the front and horizontally for the back.
Set up in the four jaw chuck for drilling the valve spindle hole.
Counter boring with a D bit to an exact depth for the valve adjusting nut using a toolmakers clamp as a depth gauge.
The tool used for cutting the internal groove at the bottom of the counter bore.
A front crosshead's components showing the adjusting nut.
Here is the inside valve crosshead which is not adjustable, valve setting being achieved from the outside front crossheads, so there is an opening in the middle of the crosshead for a slotted nut to lock the crosshead on to the valve spindle.(
I began to think the frames should be painted, not only to ensure access, but as a bit of a morale booster. The build program became focused on getting all the non-removable parts made and fitted to the frames. Items such as the motion brackets, footplate supports and angles, weigh shaft bearing supports, brake hanger supports and other minor supports and brackets. The cylinders also needed to be fitted before the frames could be painted, which meant an awful lot of bolts would be needed. The first of these were the mountings for the 2 to 1 gear. On the H4 this is a small bracket mounted on top of the swing link stretcher with six bolts. On the original engines these had a tendency to work loose and cause the bracket to move, allowing the middle valve to over travel to the extent the valve spindle crosshead would strike the gland housing particularly at high speed. Here the bracket is being fabricated from mild steel and ready to be silver soldered.
The bracket is shown after soldering and machining, awaiting final finishing.
The 2 to 1 lever middle support in bolted position on a shoe which is fixed to the swing link pony truck frame stretcher.
One of a number of corrective measures taken to rectify the over travel problem of 1921, the design of the 2 to 1 lever support was modified, and became a substantial frame stretcher, still bolted to the swing link support. Here the fabrication for the K3 is at an advanced stage and is seen set up in the mill for boring the bushes tor the centre bearing.
A through bush has been soldered in position and is in the mill for final machining.
A woodruff cutter is being used to cut out the material between the bushes.
The completed stretcher with the bottom hole tapped to receive the fulcrum pin. This is a departure from scale as in full size it is possible to access the bottom of the pin to fit a nut and a spanner to tighten it. Not an option in 5" gauge.
Moving on to the frame attachments here's a length of steel strip having a grove machined along the centre for the back and top of a footplate support bracket.
The three main components are together for silver soldering.
First machining operation to the back and top surfaces complete.
The outer end of a bracket being rebated to clear the footplate angle.
Thickening piece added to the underside at the outer edge.
Spotting the fixing bolt holes.
Trial mounting of a couple of brackets.
Brackets mounted with round head bolts to simulate rivets. Note the holes in the right hand brackets for the vacuum brake train pipe.
An early stage in the fabrication of the weigh shaft bearing supports.
The simple cylindrical tube and flange had been turned on the lathe and fixed inside the frames opposite handed to spot through the bolt holes. The curved cut out in the flange was machined with the boring head on the mill after a careful set up and the flat for the top edge was machined in the milling vise.
Returned to the lathe, the barrel was turned with a very shallow taper, and the half round bead at the end was fashioned.
Now set up on the rotary table three groves were cut to locate the gusset plates.
These were silver soldered in place with a ring around to hold them in place.
They were then put back in the lathe to machine the gussets.
After pressing in the bronze weigh shaft bearing at the outer end, small threaded bush was fitted for the prominent brass oil pot.
The fabrication of the outside combined motion plate and expansion link brackets were started not long before the 2017 Doncaster exhibition. The diary for 2016 ends here so the description of these complex fabrications can be undivided, but as usual the format here is a photograph of the two subjects on display at NM&MEE 2017 with some excellent companions.
