Oh dear, another K's..a Kirtley kit.....

[bertiedog]

The flanges looked bigger in the photos, but are the same overall, so I got the Scale link tender wheels with axles to suit inside bearings. There a small inner chassis made in 1.5mm thick brass sheet to fit into the tender, the exact height of the valance edge can be adjusted with packing, which can't be done with outside bearings. Gears here as well, 50:1 to suit a 2mm motor shaft, so using the 5 pole skewed slot motor from Ebay.

 

Most of the new fine detail parts made now, so a session soldering it all on with low melt solder over the weekend. Some clack valves and piping to make as well, and a new sprung drawbar to the tender to be made, and a brand power pickup plate for the loco to be made.

 

Stephen.

[bertiedog]

Measured up the new Markits wheels, and the are not truly exact RP-25 specs, the tyre width is too wide and the root curve between the tyre and the flange is too small, but they just about squeeze into the suggested max specification figures.

 

The slightly wider tyre actually helps in 00 16.5, as the outside edge helps the wheel not to fall into the frog on a point, as when it crosses the frog nose normally thin wheels tend to drop as nothing supports them in the gap.

 

EM can take a thinner wheel as the track standard is much tighter, but a wider wheel can still help, but you risk the total width of the entire wheel set becoming more than scale, and causing trouble behind splashers, which have to be set outwards a bit to allow for this, (plus side play).

 

Still awaiting the arrival of a selection of the 5 pole 2mm shaft skewed slot motors from China, I have one for testing and fitting to another loco, but I need one for the Kirtley now.

 

However it is a simple motor mount and position, and I don't expect any issues, as the motor fits the frames width, and with version with the longer shaft, it gives more options on exact position.

 

It would just be possible to drive the middle axle, but the rear axle could be driven at the expense of the gear set showing on the cab floor, (but with a cover). To use front axle will need a gear box transmission, a floating gearbox on the axle, and a drive shaft from the motor, with a universal joint in the bottom of the boiler.

 

The front driven axle would give a better chance of fitting a decent flywheel as well. The motor would fit the firebox better without showing, so in the end the front axle drive sounds the best option. The Markits 50:1 gear set is small enough to fit a brass gearbox, with bronze bearings for the axle and the 2mm silver steel worm shaft.

 

 The drive shaft universal can be a simple double ball joint, made with 3.5 / 4 mm brass balls, cross pinned, fitting into slotted cups, one fitted to the gearbox shaft, and one to the motor shaft end.

 

There should be space for two slim 2mm bore flywheels one at each end of the motor. The shaft drive should be just above the bottom level of the boiler, so invisible. There is a cross member between the foot plates, a cast part, that K's intended as a chassis mount, but that will be cut away, and a brass one fitted, cranked in the middle to get the mounting nut into position to take the bolt up through the chassis to secure it.

 

I have the chassis assembled, but now need the coupling rods made. The chassis is in a jig with dummy axles fitted that have scribing points on them, that can also be struck to centre pop the nickel silver blanks for the rods. I have nickel sheet that is thick enough for the rods, but not the bosses, so they will be soldered on, after the rods are drilled with pilot holes, using the pilot hole to fit them. The holes can then be drilled and reamed to the crankpin size, which is a collar on a 14ba bolt, 2mm in diameter, with a washer under the outer nut. I am using the Markit flycranks as the basis of the outside cranks.

 

As the quartering is not automatic with the extended axles, one side will be assembled with Loctite, then the other side fitted, by relying on the rods accuracy to get the quartering, which can be tweaked a bit as it is assembled. Then it can be tested as running correctly, and then each flycrank can be loctited in place permanently, and retested to ensure smooth running.

 

There's no need to add any traction weight as the body is heavy enough, and there is space for DCC if needed later on. For power pickup one side is earthed so it just needs three wire spring pickups mounted under the chassis. The outer frames cover the view so they will not show. the tender has ABS centred wheels, so any extra pickups would have to be fitted to both sides, fitted to the top of the tender chassis to be invisible. A small twin lead and RC plug could take the power to the loco.

 

No brakes will be fitted as they barely show with the outside frames.

 

Back to finishing the body detailing next,

 

Stephen.

[John_Miles]

It would just be possible to drive the middle axle, but the rear axle could be driven at the expense of the gear set showing on the cab floor,

 

If you look at High Level they do various gear boxes which you can poke under the cab floor without having to have any protruding gears. They are also excellent quality.

[bertiedog]

Even the High Level final gear would foul the footplate level, and it adds extra gears, also extra cost. I have proceeded with the front axle gear box, a stubby universal, and the motor pushed to the firebox end, all completely invisible to normal viewing. The Gear box is made from 1.5mm brass, very solid, with a full cover over the gears. I have tested it with a spare motor, but I am waiting for more 5 pole motors to turn up in the post before finalising the chassis. It will need a test run and fit a flywheel, final space permitting.

 

I have the main dimensions of the motor, but it is a can type with flats, and I do not yet know the distance from flat to flat, to be able to cut the boiler bottom behind the middle springs, so that it can slide into place. K's Mk1 and 2 were very slim motors, the armature was the widest part, as the poles were upright.

 

Stephen

[bertiedog]

If you look at High Level they do various gear boxes which you can poke under the cab floor without having to have any protruding gears. They are also excellent quality.

The High Level site does not make some basic clear, are the gears all metal?, and do the gears float on fixed shafts in the gearbox frame, or is the shaft in the intermediate gears fixed to the gear, with outer bearings in the gearbox shell?

I already have a 50:1 gearset to hand, all steel and brass.

Just curious as the materials and principles they use, as similar units in kits have failed to satisfy good smooth running, and took the patience of a Saint to assemble accurately.

Stephen.

[Nile]

In a high level gearbox the intermediate idler gears are plastic (nylon?)  and float on the 2mm shafts that are fixed to the frame.

[John_Hughes]

In a high level gearbox the intermediate idler gears are plastic (nylon?)  and float on the 2mm shafts that are fixed to the frame.

 

Not all the excellent gearboxes that High Level make are shown on their website - I've had some 'specials' that are really intended for groups like the TT people.

 

Can I suggest you give them a call? They are very helpful indeed if you just lay out the problem.

[bertiedog]

There's no problem, the 50:1 set fits perfectly under the front of the boiler, I have to solder on a cover and it is done, with a short coupling to the 2mm motor shaft.

There is no need for a universal joint as the axle is rigid.

 

I am sure high level work just fine, but I don't like floating gears on stub axles, and dislike plastic gears generally, if brass is available. Using the front axle gives a floor to the cab, albeit small due to 00 back to back, plus K's whitemetal thickness.

 

I found in professional engineering that floating gears on stubs increases the play, as the maker has to ensure the gear runs on the stub, as you can't ream out plastic in small amounts to get a running fit.

 

The better way is to put the gears on the stub axle, and ream bronze bearings in the gearbox frame wall, both ends, to a 10th thou or tighter fit, or honing them with a peice of the axle till to get a perfect fit.

 

The high level can be done that way, but it leaves the plastic gears. Now in no way am I commenting on High Level, but other Plastic gears supplied in kits of a similar nature  have a straight cut tooth form, when it should be an involute form, which gives smoother drive and less noise. Several makers over the years have supplied straight cut, including K's!!!  It is a highly technical point, but valid.

 

Stephen.

Edited June 27, 2016 by bertiedog

[bertiedog]

In case you not into engineering, this is the involute form, that should be used, and if it is not, then the gears tend to "purr" as they rotate. Brass wears and as they get older straight cut do get quieter, but very loose clearances develop. Many good commercial locos have been made with straight teeth, the Chinese were the main offenders, but are better now.

The "purr" can even spread to the pull on stock, and amplify the sounds, even rattling the couplings, making the whole train growl under loads.

 

[bertiedog]

I must add again, this information has nothing to do with High Level Gears as I have not examined one. They are known to work well, and are a quality product by repute.

Stephen

[Nile]

Interesting stuff Stephen. Any photos of your gearbox or is it too late?

I've had a closer look at the High Level gears and they all appear to be involute.

click for embiggenment.

[bertiedog]

It is in the loco, but I am doing another for the Crampton Loco and will take a shot or two, thanks for checking the gears

[bertiedog]

Project under way again, as the Chinese selection of motors have all turned up at once, so lots of choices to sort through, I expect the largest 5 pole will be the motor chosen, due to the weight of the castings. A couple of sets of gears are due as well, 40 and 50:1 worm sets.

So a motor cradle will be made to fit with flywheel.

Stephen.

[vember55]

Here's my wife's great grandfather on his 12" to the foot Kirtley. Hope it helps with completion.

[bertiedog]

Slight clean up?

 

[vember55]

Slight clean up?

 

k's.jpg

Very good - William Dean - on footplate - nods in approval.

[Poor Old Bruce]

Stumbled across this thread while looking for something else. What is the current state of play please? I've got a couple 'waiting' in part built state.

[cctransuk]

I must add again, this information has nothing to do with High Level Gears as I have not examined one. They are known to work well, and are a quality product by repute.

Stephen

 

I have just received the following e-mail from a customer who will not, I am sure, object to it's anonymous quotation :-

 

I have just completed an RT Models chassis for a J94 with a High Level 54:1 Roadrunner gearbox and your Mitsumi motor.

 

I would say it is the smoothest running loco I have ever built and it doesn't have a flywheel.

 

Without doubt all of this is due to the combination of three excellent products.

 

Although I did have to reverse fold the gearbox mount to suit the diagonal fixing holes in the Mitsumi motor which are opposite to the Mashima for which it is designed - but no problem.

 

Thank you for supplying such a good quality and economical motor.

 

I think that no further comment on the quality of High Level gearboxes is required, and the sentiments accord entirely with my own.

 

Regards,

John Isherwood,

Cambridge Custom Transfers (and Motors).

https://www.cctrans.org.uk/

[cctransuk]

Even the High Level final gear would foul the footplate level, and it adds extra gears, also extra cost.

 

 

Now I know that this isn't a K's Kirtley, but it does illustrate that High Level gearboxes can be set up to invisibly power virtually any loco.

 

Scratchbuilt, solid brass gearboxes with custom-made UJs are all very well for those with an engineering background, but for us lesser mortals, High Level products are the answer to our prayers.

 

I have just built three of these to fit in Airfix 4Fs and they run like Swiss watches. The same design has been fitted to three 3Fs, and a version is scheduled for three Airfix 2Ps.

 

 

 

Regards,

John Isherwood.

[hayfield]

For me the High Level gearboxes and motor bogies are the transmission of choice. They seem to work straight out of the box and come in many different formats

Edited January 27, 2019 by hayfield