Sunday 24 April 2016

Dreaming of Reaming.....

We achieved good progress during the last week - largely focused on reaming the bolt holes for the new LH Driving Hornblock. This involves using an expanding reamer - a hand tool that gradually increases the diameter of a hole by shaving material away a few thousands of an inch at a time. The holes in the horn block casting and their partners in the frames have to align perfectly and have to be exactly the same diameter. (This is so that the fitted bolts that clamp the horn block to the frames have a proper chance to prevent any relative movement between the parts.) It's quite hard work and carries the continual risk of getting needle-like shards of steel embedded in the operator's hands. It took four full working days to get 18 of the 22 holes to an acceptable condition. The remaining four holes are being used by the temporary bolts that are holding the horn block in position on the frames. They'll be reamed once the horn block is permanently in place. During week commencing 25/04 the horn block will be transferred to the machine shop so that we can machine a true landing surface on the back of the casting and give the correct seating for the fitted bolt nuts.

Thanks to Brian Thomson we now have the new castings for the hornclips (or tie-bars) that provide the essential closure to the open end of the horns underneath the axleboxes. Brian collected these from Blantyre Castings and brought them up to Aviemore a few days ago. They will be measured up and machined to a good fit on their respective sides of the loco.

During the week we had three additional Volunteers working on the loco - grateful thanks therefore to Martin McLeod, Nick Thomson and Dave Butler. 

Away from hornblocks we made some progress with trying to true up the eccentric sheaves. As a result of kind cooperation by the SRPS at Bo'ness Brian Thomson produced the basis of a mandrel for mounting the sheaves in our big lathe. Brian finished manufacture of the tool at Aviemore and it was duly mounted in the lathe. The first set of sheaves was clamped around it and the lathe given a spin at low speed . Unfortunately it was immediately obvious that Mr MacIntosh's eccentrics need a bigger lathe than we possess. There was an audible clunk from the lathe gearbox / headstock assembly at every revolution and the operation was suspended. There are a couple of options - we know that the RPSI at Whitehead in Northern Ireland have suitable capacity for handling this job. They have been asked to give us a price and delivery proposal. The alternative is to dress the sheaves by hand at Aviemore and machine the eccentric straps to fit the sheaves in their worn condition. More on this next week. In the meantime Alan French has come up with an excellent proposal for ensuring a good bond between the cast iron of the eccentric straps and the white metal lining.

Still on the subject of eccentric straps Calum Titley has carried out a very impressive controlled temperature weld repair to a crack in one of the straps. Taking infinite pains he has very slowly built up the damaged casting using a procedure that ensures that the parent metal temperature never increases above a required maximum temperature. This ensures that the cast iron grain structure is unaltered and the repair should have the required integrity.

The new hornclip castings with a boot to give an idea of scale..

Different view of the new castings; same boot.

Martin McLeod demonstrates the use of an adjustable expanding reamer (and sensibly wears gloves to avoid a handful of steel skelfs)

The reamer, driven by Martin, makes it way slowly out of the frames..the steel shavings can be seen in the adjacent holes.
Brian Thomson grinds the embryonic eccentric mandrel; Nathan keeps things steady.

Brian machine the newly manufactured mandrel to a precise 8" diameter. 828's crankaxle lurks in the background..

Nathan and the arm of Nick Thomson getting close to giving the LH eccentric set a spin in the lathe..

Nick Thomson steadies things in the big lathe..

Slight concern about the welfare of the lathe....Mr MacIntosh didn't skimp on the size of his eccentric sheaves (or pulleys, as the Caley called them.)

Dave Butler took on the task of stripping the gauge glass fittings for overhaul and here he is with one of the water-side fittings.

After stripping all the fittings Dave then started cleaning them up. They should be bright and shiny but their working environment tends not to help this...
Calum Titley working on his controlled temperature weld repair to one of the eccentric strap halves..

A pause for the camera..

CR828 draws admirers from far afield - she had a visit from this young couple who are Volunteers on the West Somerset Railway and were very impressed with a blue locomotive - a change from Brunswick Green and copper capped chimneys ...

Monday 18 April 2016

It's Hornblock Time Again....

After going slightly astray on its travels between Dudley and Aviemore we found the newly machined LH Driving Hornblock when an Inverness courier phoned Keith Holyland on 12th April and asked if this large pallet-load addressed to the Strathspey Railway Company was urgent.....!

Having got the necessary confirmation it arrived at Aviemore Shed a couple of hours later and there were the old and new hornblocks. So here we go again with a tale of lifting, marking, drilling (and reaming yet to come)....

Arrival at last...Keith Holyland admires the newly arrived hornblock package. Forklift driven by Nathan Lightowler.

With CR828 looking on with interest Dave Green steadies the newly machined hornblock and checks out the excellent finish achieved by Harco Engineering

Shunting by JCB.....Colin Vaughan and Dave Green get the old girl out of the shed in readiness for the first trial fit of the new hornblock. Absence of buffers and any loco brake makes this a somewhat delicate operation - but no problem - the scotches are safely in  position.

A study in wheels.....

Lifting the hornblock under the loco. Forklifts and pallets are wonderful inventions...

Using the pallet as a working platform Dave Green steadies the precisely-cut wooden block that gives the forklift enough height to lift the casting into the correct position..

After a bit of filing on the frame horns the hornblock lifted nicely into position and we clamped it against the frames to allow marking out of the initial four holes for the temporary bolts that would then allow all 22 holes to be marked out..

In the machine shop on the big radial arm drill the hornblock complete with four holes scribed into the marking paint waits on Nathan getting to work..

Nathan clamping the hornblock to the drilling machine table...

The scene a few hours later after refitting the hornblock to the loco with the four temporary bolts and marking out all the bolt holes. Nathan has generated a huge pile of swarf and the casting has its bolt holes...

With the loco back in the shed the hornblock is firmly jacked and bolted into position and all the bolt holes have been job is to commence reaming the holes truly circular and parallel. This is the view from inside the frames. Once we have reamed all of the holes the hornblock will be taken off again to allow the inner face to be skimmed to provide a true seating for the nuts. We also have to fit the new hornclip to the bottom of the hornblock and check the fit of the axlebox...

The view from outside the frames. Three of the four temporary bolts can be seen

A lovely picture of CR828 during her visit to the Severn Valley Railway a few years ago. She was seen by many people as the star attraction of the 2011 Autumn Gala (Notwithstanding the presence of "Tornado"). The perfect condition of the loco is a great credit to the Strathspey Railway Company "Minders" who stayed with her and made sure the loco was properly looked after and operated correctly. Picture by Mr David Wilcock.

Monday 11 April 2016

Blue Fingers......

Progress on CR 828 at Aviemore in the last week has been mainly focused on scraping of big end bearings resulting in a set of fingers deeply ingrained with engineers blue...interspersed with some blood when the sharpness of one of the scrapers was proved. ...

Off site Harco Engineering Ltd made great progress with machining the new Hornblock casting and it is due back at Aviemore around April 11th.

Dr HJC (Campbell) Cornwell, former SRC Chairman and former Chairman of the SLPTF (owners of CR 828) and the leading authority on CR locos from the 1880s until the Grouping in 1923 kindly provided copies of the drawings for the eccentrics and straps. This will be very useful when Nathan machines the components and Alan French relines the straps with white metal.

On the table at Harco Engineering - the new LH Driving Hornblock receives the attention of the CNC milling machine

A close shave....

Beautiful will be a shame to get it dirty...!

The Neilson Reid drawing of the 812 Class Eccentrics and Straps supplied by Campbell Cornwell. The Caley built 812 - 828 themselves at St Rollox and contracted Neilson Reid to build 829 - 848 at the Hyde Park Works in Springburn. The St Rollox drawings may not have survived but fortunately those developed by Neilson Reid have...!

Back half of the LH Big End patch was very reluctant to come into contact...and the horridly sharp triangular scraper is hoping for another chance...!

The LH Big End bearing in the "secret" 828 cupboard in Aviemore Shed

A place of greater safety....original and new safety valves stand alongside each other dreaming of high pressure steam...
The old girl in the 1990s in her light blue Caley livery. Charging out of Kinchurdy Cutting in the days of ash ballast and wooden sleepers...long since upgraded to stone ballast and concrete sleepers.

Just for fun - a rare double header on the Strathspey Railway. In September 2011we had some Friday evening fun with a special working for Members and Friends. Here we are at Croftnahaven with Outdoor Superintendent G McNair giving directions to the late (and much missed) Driver Graham Elkin on CR 828. Driver John Greig on 46512 EV Cooper Engineer waits patiently with his loco in mid gear.....the photographers take it all in...! Something we could do with repeating....??

The scene we want to see again soon.....CR 828 rolls into Boat of Garten (strangely deserted) on a June day in 2010.

Sunday 3 April 2016

Scraping Through....

Activity on CR828 in the last few days has included a lot of scraping of white metal (thanks Nathan Lightowler and Benny McInnes) ; removal of brake rigging from the tender (thanks Dave Green); blanking off of the boiler safety valves (thanks again Dave Green) and some reflection on the process of white metalling the eccentric straps (thanks to Alan French). The front buffers have been removed to allow renewal of the wooden packing plates that lie beneath them. The C&W Dept is helping with the production of the new plates.

Further afield Harco Engineering have set up the new LH Hornblock casting on their appropriately sized milling / boring machine. They will turn the job round pretty quickly and we should have the component back at Aviemore in a week or so. Then we'll have the fun of fitting it to the frames..!

The new LH Hornblock casting on the table at Harco Engineering. On our machine at Aviemore it looked huge; here it looks a bit diminished...

The wonders of CNC machining.....! Punch in the code and go and have a cup of tea....??

Front buffers removed to allow renewal of wooden packing plates (one of the old ones is on the front buffer beam). But why did the Caley fit packing plates..? Because the dimensions of couplings were altered after 828 was built and the new standard required the buffers to protrude further.

Old friends reunited. Mr Graham King, the man who returned 828 to operation in the early 90s after she had slumbered for 30 years stands beside his former charge. A combined age of 197 years and both still capable of a hard day's work...!
Following some final electrical work on 30/03 by Paul Blount the lathe was returned to operation. Nathan Lightowler machines the bore of the RH Big End bearing (and catches the valuable white metal swarf in a strategically positioned bucket.
Scrapers at the ready to tackle the LH Big End

Scraping underway. It takes a while because of the generous radii at the end of the crankpin. The bearing has to be bedded onto the radii before it comes into contact with the parallel portion of the pin.

The RH Big End fully fitted to its crankpin and temporarily held together by a special clamping tool. Great work by Nathan and Bennie in getting the fit achieved.

The tender minus its brake rigging thanks to Dave Green. Also in the picture is the horrid spring that forms part of the drawbar between loco and tender. A very bad joke perpetuated by JF MacIntosh on the CR fitting staff. If anyone wants to find out why you are welcome to come along and refit it when the tender is recouped to the loco...

Not 828 but a very nice picture from 30/03 by Dave Green showing 46512 doing what we expect 828 to be doing in a couple of months.....