Pebbles

John Edgson's J21 drawing shows this as 3ft 4 1/8 inches.

Very fortunately I only worked a stones throw away. My most memorable memory was seeing the plasticard Q1 featured in a early 1960s RM. Was this on the Charford layout?

This is an interesting photo as it would appear to contradict when the front buffer beams were modified.

Tragic!

Bath of Caustic Soda.

My understanding, that I received from very good authority, as to why the Sharman range hasn't been continued relates to the wide range of varying tyres that Mike used. Even when wheels were of similar diameter the tyres could be different. This lack of standardisation, requiring custom production of tyres, simply didn't fit with automated production.

This may not help but, I think the worm is basically a 1/4 inch Whitworth thread pitch at 26 tpi. This is much the same as the old Romford 40:1 gear and indeed the old K's 35:1 gears . As I previously said the Hornby gear is two start which means that the gear wheel will have twice the number of teeth for a given ratio.

T Cut is a mild abrasive not a lubricant, you will degrade the bearings. K's motors suffer from many problems, perhaps the main ones being their glued construction and narrow pole pieces. It is possible to break the glue bond, carefully realign, reglue then remagnetise. The narrow pole pieces can be widened by gluing shaped pieces of iron/steel to the pole pieces. However, one other possible issue is a misalignment of the commutator and armature. Despite their shortcomings, the late Mike Sharman used some heavily modified K's motors in many of his weird locos, that said at that time there was no alternative!

As far as I recall the original 20:1 ratio gear was a two start.

Whilst it may not be the cheapest, the simplest and safest way forward is to re-magnetise and return to its original specification.

It is just possible that the problem is a result of replacing the armature and not taking the appropriate measures to protect the magnet during the armature replacement.

Just change the direction of rotation.

Just a suggestion. Cut a piece of 6mm brass bar to about 10mm long. In a vertical drill, using the size drill required to open up the axle box journals, drill though the 10mm length. With a cutting disc cut two drills to half the required length. Do I need to go on?

From memory previously Richard Jones raised this point some time ago. Either whoever soldered the kit used to high a temperature, effectively also melting the white metal, or over time there is some chemical interaction taking place that effectively raises the melting point of the low melt solder. Whatever the cause I have repeatedly encountered similar problems when attempting to desolder white metal kits.

Many thanks geoff, you have it correct. The company still does rewinds etc, unfortunately the gentleman who did the "replacement motors", that is new thicker profiled pole pieces, is apparently no longer with us.

Can anyone recall the name of the company, located on the south coast, that made replacements for Hornby Dublo Ringfield motors utilising either Triang/Hornby XO3/4 3 pole armatures or MRRC 5 pole armatures?

I have been told that Arthur has been admitted to hospital. I have no further details, but for the present it would be best not to bother him.

K's original motors - that is those with two magnets - had 5 poles, to a small degree this addressed the cogging issue, but not entirely. Many years ago, at the Nottingham show, the late Mike Sharman showed me a motor using the K's armature and magnets married to machined pole pieces of the same width as the originals but with a very small airgap. Apparently the result was rubbish, it failed to start smoothly and displayed excessive cogging. Fast forward to some time later. There was a small outfit on the south coast who produced replacement motors for Hornby Dublo Ring Field motors. These would use either the MRRC armature or Margate Hornby three pole armatures. Now the magic! the inner radius of the pole pieces was 30% greater than the radius of the armature but with a very small airgap. I have tried this and it works, although making the pole pieces was a bit of a bind. OK, where the magnet has lost its magnetism possibly re-magnification will help. However, often the motor will be so old that the bearings will be worn and all that restoring the magnetism will do is produce excessive cogging and, as been mentioned, require a higher starting current resulting in jack rabbit starts. Finally, the rear bearing on an XO3/4 is rather flimsy and more of a stabiliser, the front bearing being the main one. Packing the rear bearing with grease can help, but once worn it really needs replacing.

It is possible that Mike's was inspired by Dave Bradwell using one of his J26/27 on his N9 build. Mike has clearly replaced a number of castings in seeking to achieve the level of detail he wants and now a new chassis. As there are dimensional similarities between the N8/9 and the N10 could not a more cost effective route be Arthur's N10 with a larger scratch built splasher married to the chassis of of his forthcoming J21?

Having watched the evolution of the N8, and the parts that have been incorporated from Arthur's range, I'm wondering whether it was worth buying the LRM kit in the first place?

Many years ago there was an article in MRN about soldering Mazak, from memory I think it was about converting a GWR loco body. Resulting from this, around about 1977, I obtain a sample of suitable flux from Fry's and can confirm that it worked. As generally the Mazak is a casting, with a substantial heat sink, a prime prerequisite is a high wattage iron and a substantial bit.

Sorry, but I have to question whether you actually have a Bachmann C1 Chassis. Looking at photos, taken at the time the model was released, it would appear that the Bachmann C1 drives off the rear axle, also photos taken from below show the wheel flanges within a whisker of each other.

I have an old second hand guilotine, that I aquired as part of a job lot. It has an edge so the cuts remain square relative to the previous cut. Despite having a metric scale on its right hand side I have found it impossible to accurately cut to a specific size. That said, it's fine for chassis spacers providing you use the single cut for all the spacers on a chassis. On the other hand screwkers can produce fairly accurate first time cuts. However, if thicker metal is being cut the depth of the cut will produce a "v" shape and this will need to be taken into account. Finally my screwker is made from an old heavy duty hacksaw blade ground to the required shape.

The motor you describe would appear to be the last iteration of the K's type that originally had two magnets. You don't have to remove the pole pieces re-magnetise, and if you possessed a re-magnetiser it could be done. That said, other than preserving that original model you may not find the expense and effort justified.

At one of the last expo-EMs one of the demonstrators was showing an Arthur's D20 chassis modified for split axle pickup on all axles. Split axle current collection have always cause issues, and this has set me wondering. The very old plastic Gibson horn boxes were always problematical because of the robustness of their bonding to metal. In some ways this was not helped by the flange having a rather small contact area, better design and better adhesives could solve this. Bogie and tender wheels could simply run in bearing quality push fit nylon bushes. I fully realise that K's tried this with motor bearings, but things have moved on and a high revving motor is a different kettle of fish to an axle. I will now duck!