ModelWorks Foden
Builder's Diary

Please read disclaimer

Kit 13 - Cylinder Accessories

Kit 11 account

Foden Home

Kit 14 account

Events

Burrell

POP

9th November: It has been months since I touched the Foden. I understand that the cylinder accessory kit is in manufacturing and may be with us by the end of November.

Friday 23rd November: According to the ModelWorks website I should be getting the cylinder accessory kit by close of play today.

Saturday 1st December: November has come and gone and still no sign of kit 13 - is it jinxed? When I started the Foden build the planed completion date was December 2007. This was a comfortable schedule as, even allowing for last kit hiccups, the Foden would be finished for the start of the 2008 season. Today the most optimistic completion date is July 2009 though I wonder if I will have finished my Foden by Christmas 2008?

Monday 17th December: Kit 13 has finally arrived!

Contents of kit 13 - Cylinder Accessories

The bag labels now include a readable
name in addition to the part number

The 5" gauge boiler I am building (updated)

When I laid out the contents for checking and photography a worthwhile improvement was immediately apparent. The plastic bags containing the components now have an English name in addition to the part number.

The instructions advise that the cylinder accessories should not be permanently fitted to the cylinder block until the block is bolted to the boiler. I am not sure of the reason for this but it would be foolish not to comply. The instructions also warn that since the boiler needs to be lifted into the chassis it is advisable to delay fitting the cylinder unless heavy lifting equipment is available. The boiler cannot be fitted until 1) I have a boiler and 2) the hornplate kit is supplied so all that can be accomplished at this stage is trial assembly.

I do not plan to commence trial assembly for a few days as I am in the final stages of making a boiler for the 5" gauge Railmotor. I am nearly ready for the final brazing operations which I shall perform at my local club using oxy-propane. It has taken two months of hard graft during which time I have learnt a lot. Perhaps I will write this up one day though I think it would warrant a new domain name as the boiler on the right was definitely not supplied as part of a kit.

Friday 21 December: I had a successful session at my club and the bachhead and foundation ring are now silver soldered to the boiler. Yesterday I made ready for the final soldering session but will not be able to do this until the new year. With the decks cleared I have turn my attention to the Foden cylinder. As the first tasks are on the cylinder block I have described them here in the kit 11 account.

Piston assembly

The gouge is deeper than I thought
will steam escape?

It did not take long to prepare kit 11 for trial assembly of the accessories. The instructions ask that the piston rods be carefully deburred so that they fit through the piston glad. My rods would not fit through one of the glands and I found the problem to be the gland. As the piston rods were 7/16" and a suitable reamer was to hand the simplest solution was to run this trough the gland. Surprisingly a fair amount of metal was removed. The other gland of the pair did not need to be touched. Omitted from the kit were the studs to fit the gland to the cover. As a temporary measure I robbed M5 studs from the cylinder block.

I fitted the piston rings to one of the pistons to find how difficult it was to get them to enter the bore. To my surprise I found I could get them in relatively easily and I did not need to use a Jubilee clip or special jig.

When it came to fit the cylinder end covers I became more concerned at the depth of the gouges and the fact that they are only partially covered by the covers. This may allow steam to tunnel its way out. As I am not sure how to tackle this problem I shall contact ModelWorks in the New Year.

The instructions mention special bolts to secure the truck guides to the block and it took me a little while to twig the reason. The fixing studs are tight in the corners and there is not a lot of room for the nut. The give the best chance of fitting the special nuts have a one size smaller head ie 8mm AF instead of 10mm AF. The instructions state that it may be necessary to flatten this area with grinding stone using a mini drill. I found that a 4mm carbide bull nose burr did an excellent job. The advantage of the bull nose cutter being that I could form a nice rounded fillet where the guide leave the fixing flange.

Flattening the area around the truck guides
fixing stud using bull nose cutter in mini drill

Special slim nuts are used to secure the truck
guides as the studs are tight to the corners

Fixing the oval gland hole

Trial assembly complete

Saturday: Today I started by assembling the valves. I immediately hit problems when I found that the valve rod gland would not fit into its stuffing box. I had to remove the truck guides to give me clear access to diagnose the problem which turned out to be the hole in the cylinder block. Using my digital verniers I could sense that the stuffing box bore was oval. I was able to rectify this with a scraper. The problem only affected the top 1/8" of the bore and again judging by the marks could have been cause by careless handling.

I encountered no problems during the remaining assembly of the valves and regulator.

Having proved the assembly I will now dismantle the engine into suitable sub-assemblies for painting.

It is now obvious why final assembly has to wait unit the cylinder is bolted to the boiler. When it comes to fit the the fixing studs through the saddle the truck guides and exhaust manifold would get it in the way. Unfortunately I do not yet have my boiler despite being advised I would get it in October; it would seem my boiler was shipped elsewhere!

Sunday 30 December: I have not done much model engineering over the Christmas period but today I did get round to dismantling the block. As I had not done so previously I tried to fit the piston rings to the other piston. I found that they were an extremely tight fit in the groves such that they would not compress to enable the piston to be fitted into the cylinder bore. The hardest part came next, namely getting the tight rings off the piston. I wish I had checked that the piston rings were an easy fit in the groves before fitting (sliding it in to make a figure of eight). Once out, I diagnosed the problem as undersize groves in the piston. The first piston had a few thou clearance but with this piston the width on the piston ring was near enough the same as the grove. After the drama of getting the ring off the piston it did not seem to take long to set the piston to run true in a 4 jaw chuck and shave a sliver off the side of each grove.

Using a fly-cutter to re-machine the cylinder flange

Thursday 10th January: Steve suggested using JB weld to fill the gouges on the cylinder end flanges but I decided on more drastic action as once the cylinder is fitted to the boiler it will be extremely difficult to rework. Luckily the cylinder would fit under my mill and using a fly-cutter I removed about 25 thou from the face. I my need to compensate by machining 25 thou from the centre boss of the cylinder back covers.

The fixing holes in one of the end covers needed elongating so that they woulkd fit over the studs

Thursday 6 March: In readiness for mounting the cylinder on the boiler I decided it was about time I got round to painting the cylinder. Mike contacted me some time ago saying that his front cylinder covers did not fit. I though mine fitted but I decided to check them once again to make sure. Guess what mine did not fit either. The covers have a boss which is meant to go into the cylinder. My boss would not fit in the cylinder and I suspect I previously fitted them with the boss pointing outwards (as that was the only way they fitted!). I shaved a few thou off the diameter of the boss so that they would enter the cylinder and then checked alignment with the fixing holes as Mike warned me he had problems here. One cover would fit over the studs but some of the other cover's fixing holes were drilled up to 1mm out of position. This is strange as I would have thought CNC machining would have got these spot on. I reluctantly elongated the offending holes using a small round file so that I could fit the cover over the fixing studs.

The piston gland's boss was shortened by 3/16" to improve fit

Fitting the piston using a simple clamp to hold the piston ring flush

Friday 21 March: I have now fitted the cylinder to the boiler and am in a position to permanently fit the accessories to the cylinder.

When I packed the piston glands with the PTFE cord supplied I found that the gland's flange stood off too far from the cylinder cover to enable me to fit the nuts on the fixing studs. On my Burrell I have been forced to fit longer studs but I think it looks better if there is not a large gap between the flange and cylinder cover. I decided to shorted the boss on the piston gland by 3/16". I was nearly undone as when I subsequently tightened the bolts and the PTFE cord was compressed, the gland went in a little more than I would have expected. If I had my time over again I would only have removed 1/8".

With the cylinder fitted to the boiler I found it much more tricky to persuade the piston rings to enter the bore. After struggling for a while I made a simple clip from a strip of aluminium which enabled me to pinch the rings in place.

Rather than smear the end cover gaskets with Foliac I decided that a light smear of oil would be sufficient. I believe this is all that is necessary as I now have a good flat surface to bolt onto following my resurfacing of the cylinder end. MW have supplied longer 55mm studs and there was plenty of room for the nut after the truck guide was fitted. To match the special nuts I made small M6 washers by turning down a stack of standard M6 washers. I found this easier than trying to drill out M5 washers to M6. Fitting the nuts on the underside is fiddly. I might as well have left them off as the truck guide will need to be removed to fit the connecting rod to the cross head.

The exhaust manafold need quite a bit of metal removed and 1/2 nuts fitting on the cylinder to enable it to fit

Thursday 27 March: Finally recovered enough energy from the weekend's rally to continue assembling the cylinder. I expected to complete the job today but I spent all my spare time fitting the exhaust manifold. The plate that bolts against the cylinder fouls the cylinder mounting studs and there was no way it could be fitted without modification.

In order to increase the room available I replaced two of the nuts on the studs under the manifold with half nuts but this was not enough. I also had to remove metal from the bottom of the plate on the manifold. The final adjustment involved cutting out part of the 90 degree elbow to clear the stud. Had I known in advance I would have shortened the studs under the manifold to avoid having to do this.

The cylinder fully assembled with the valve covers off

From the front with the valve covers on

Friday: I got on a lot better today and just about completed the kit. I started with assembly of the side valves and valve rods. The gland boss was the right size and unlike the piston I had to make no adjustments. When it came to Loctite the valve guide bush into its truck guide support I ignored the pre-drilled oil hole. Its alignments was doubtful and there were so many other things to get right I decided to drill a new oil hole down through the oiler after the Loctite had gone off. To help prevent the Loctite sticking valve spindle I thinly coated this with 3 in 1 oil. I

Assemble of the regulator was also straight forward. To help seal the front valve gland I made a gasket from thin card which I coated with Foliac before it tight against the cylinder block.

On realising how many 5mm studs I needed to insert for the valve covers I temporally adjourned to the workshop to make a 5mm stud inserting adapter. With the adapter it took not time to insert all the studs I had but I was 4 short. Wanting to finish the kit today I returned to the workshop and quickly made four 5x25mm studs.