November 2019 - News Letter - Tyneside Society of Model & Experimental Engineers

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 7^th 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^/28^th 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 31^st 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 1^st December

Christmas Tea – Sunday 22^nd 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”).

Earlier I had machined the smoke boxes on Allan Bones' Harrison Lathe. At the time I didn't have the material for the smoke box front rings, but Allan came up with some suitable discs of mild steel from which they were machined. This view shows a disc on the rotary table with a quarter inch milling cutter being used to cut the hole through.

Once done the ring was mounted on the Super 7 for a rebate to be machined to fit it into the smoke box. My normal practice is to make the smoke box front a good fit into the smoke box so it can be removed reasonably easily for maintenance purposes. I usually put in a couple of concealed screws to make sure it doesn't work its way out.

Now reversed in the lathe to reduce the thickness of the flange and overall diameter such that the smoke box projects the scale thickness of the plate and the corner radius representing the flanging of the front gives a fair representation of a typical Doncaster locomotive smokebox front.

The front face shows the thickening of the plate where the door seals.

Later I decided to put in the packing groove that was introduced in the mid 30s to improve the sealing of the smoke box doors. Whilst not correct for the H4 I decided that since it was not wholly visible, this engine would also have the packing ring so as not to compromise its performance in relation to the K3. Other improvements to the K3s were also included in the H4, where this does not cause clear visual differences, e.g. valve gear,

As noted at the end of stage 10, the outside motion brackets are described in this stage to keep the description all together. This starts with a drawing.

I spent many hours studying the works GAs, photographs and looking at the V2 in the NRM and the K4 on the NYMR before I made the drawing. This view shows the bracket as applied to a K4 locomotive. This is a complex casting used on all Gresley's pony truck engines, each being particular to its class. The K£ was very like this.

The V2 had a much more robust design, and with the weigh shaft bearing support made integral with the motion bracket, much as in the later pacifics.

The first step was to make the back plates. Here they are set up in the milling machine for drilling the many bolt holes to match those in the frames.

Two backplates after drilling

The holes in the frames for the motion bracket fixings

a backplate mounted in the milling machine for machining the locating slots for the attached components

and on the rotary table for milling slots where the various connecting pieces will be silver soldered into place.

A curved slot being machined on the rotary table

A back plate with the finished slots.

Here the backplate and the front vertical plate are assembled. The opposite bracket is assembled at the other end of the top plate so the handed pair can be machined together.

The intermediate vertical plate set up for machining a curved slot.

A curved plate joins this with the back plate and the marks indicate the final shape of this part of the bracket, with a piece of square bar set in the corner of the joint as provision for the machining of an internal corner radius at the join.

After silver soldering this joint,

The assembly is cleaned and set up in the rotary table for machining an external corner radius on the outside edge. The set up is also used to machine the locating slots for the other parts of the assembly.

The internal radius being roughed out for the radius cutter

A ball nosed cutter sees the radius completed.

Here the parts are trial assembled before silver solder is applied. Missing is the angled piece that joins the top plate to the back plate over most of its length.

This is made from a separate piece of steel with the sides chamfered to the necessary angle seen here in the milling vice being machined.

shows the corner plates in position, waiting for a temporary fixing bolt to be fitted.

The plates have been fitted and secured with a single 8BA screw to each and then fluxed up for silver soldering.

One of the brackets after silver soldering and pickling. Some parts of the joints have been missed, but the next soldering operation will rectify them.

The brackets are now put in the milling machine to get the edges trued and the angle of the top machined. The angle is set using a digital protractor.

A pair of brackets after machining.

The front plate is marked out carefully for the slots and openings

The top plate is marked for removal of surplus material.

Milling the openings in the front plate.

A large section needs to be removed from the back, top and front to clear the leading coupled wheel. With the help of chain drilling

and slotting,

Out it comes. Final machining of the curved edge was done in the milling machine using the rotary table.

We are now back to May '17 and the previous stage has a photograph of the locos at Doncaster with the partly made motion brackets in place. Here's another view of both locos keeping good company.

The next part was the outside expansion link bearing support, here showing the four marked out for machining. Since the advent of DROs and CNC techniques, traditional marking out is much less used. I do, however, like to mark out complex parts before embarking on machining them so I can see whether I'm working in the right field. The marking out included locating the centres of the radii for the legs of the brackets, since the plan was to use the rotary table and DROs for all the work.

First stage was to mount all four plates in the machine vice and spot all the holes, both locating and internal corner radii..

and then drill through them with appropriate sizes

The plate was then moved to the rotary table using one of the guide holes for positioning and straight and curved slots machined.

With a larger cutter a curved slot was machined, not as deep as the plate to form a land..

After repositioning a further slot and land was formed.

After repositioning a further slot and land was formed..

The outer profile was then machined by slotting and two further set ups allowed for the rest of the profile to be formed.

Two outer trunnion support plates ready for bending and fitting to the motion bracket

At this point a plate was offered up to the motion bracket to check for fit.

Here is the wider view of the component set up, the dial gauge being used to correctly orientate the work piece on the rotary table.

The inner trunnion bearing support plate was machined in a similar manor

Next the bearing housings were machined. The H4 has a simple cylindrical housing produced off the lathe, but the K3 housings were for roller bearings and these had cover plates that have three through bolts to secure them which necessitated three half bosses on the housing. The cylindrical steel blank was mounted on the rotary table to machine the profile and was finished by careful filing.

After final machining and parting off in the lathe, the inner and outer bearing supports for both locomotives and the bearing cover plates for the K3.

At this point the outer bracket could be bent to shape in the vice using a piece of machined bar as a former.

The inner and outer supports were then mounted on the main bracket for silver soldering. Note the removable spacer between the bearing housings well coated with correction fluid.

The bracket after the final silver soldering operation

After soldering the bracket was carefully set up in the milling machine for machining, the seat for the slidebar support pad

The top is marked out for last machining operation on the fabrication which was to cut back the top..

The majority of the surplus material is removed by manually hacksawing before setting up in the milling vice.

The top plate is milled to finished sizes

and the rebate for the footplate edge angle is milled out.

once all the machining is done the bracket can be fitted to the main frames and is seen here front,

side

and back views.

The final operation is to drill and tap the holes for the dummy oil pots on the H4, which actually has ball bearings concealed by a brass bush so it looks like it has plain bearings as the prototype.

Now the motion brackets are temporarily in place the slide bars can made. An embryo slide bar clamped between the cylinder support and the motion bracket. The 7/16" test bar is set up between the front of the cylinder and the centre of the driving axle, and by measurement the distance between the test rod and the underside of the slide bar can be determined and the slide bar position checked for parallelism. Shims will be fitted at one or both ends to ensure the slide bars are parallel to the centreline of the piston rod.

The bottom slide bars for one engine after machining to shape. These will be separated with a hacksaw to produce the six needed, each to be finally machined on the milling machine.

A slide bar in the milling machine for final machining.

Six slide bars after machining.

A top slide bar having the oilways cut on the underside.

A full set of top and bottom slide bars ready for drilling of the fixing bolts and fitting of the brass spacer blocks.

The top of the top slide bar has now had the tapers machined on the top and the fixing holes drilled.

The assembly has the space between the slide bars machined out to for the con rod to clear. The angle was set using a digital angle gauge.

Three sets of slide bars for the H4 ready to be fitted.

A set of slide bars temporarily fitted to the K3. Note the dowels locating the motion bracket until the bolts are fitted.

73/74 11-69 At this point it became obvious that the motion brackets should be finally fixed to the frames. As on the prototype, where fitted bolts are used, turned to a drive fit in reamed holes. For the model a tight fit is needed and the bolts were therefore machined individually and driven home before tightening the nut on the inside of the frame. The bolts are made in S303 stainless steel, which is high tensile and free cutting. A few of the bolts are shown after turning and screwing 7 BA and are part of approximately 500 required for the two locomotives.