Taff Vale S class Hudswell Clarke for P4 and a small layout

Taff Vale S class Hudswell Clarke for P4 and a small layout

Postby Bertiedog » Fri Jun 05, 2009 9:58 am

A new job for the workshop, a Taff Vale "S"class Ex K's Kit 040 Locomotive in P4.

Many thanks to those who identified it in the Queries forum section.

The plan is to produce a P4 Light Railway Locomotive, with springing and compensation, and home produced wheels in stainless steel, with brass centres. The chassis will be milled brass, with springing and a swing axle compensation, brass cylinders, and nickel silver rods and crossheads. from the photos posted, I think I can sort out the chassis details, and the brake gear arrangements.

The cast whitemetal body was built up a long time ago, all soldered with low melt, I cannot quite remember when! and the locomotive body was stored undecorated, so it has been paint stripped, but she needs tiding up further, and a selection of fine details added. The handrails ave already been replaced with my own ones, but there are struts for the cab, bunker tops, and shunting pole supports to add, along with crew etc in the cab. Some brass window frames are on the list as well.

I will get some of the Dart casting Monty figures for the cab, a Driver and a "boy" for the fireman, as there is not much space on the footplate!

The buffer heads need replacements, difficult to spring, as the bufferbeam is oddly arranged on such a small locomotive, with the beam back higher than the footplate, so nowhere to hide the springs. it is even difficult to add springs to the coupling hooks, so they may be fixed in place, with new home made screw link couplings.

IMGP0019rz.jpg
Side view
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The motor is a Far Eastern 5 pole skewed armature 12 volt motor, tested to ensure good running, chosen so as to be able to fit a gearbox and and take a small flywheel on the opposite end.

IMGP0023.JPG
Loco body and motor to suit
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I am considering using one of the new Exactoscale gearboxes, the bronze cased type, although I am going to look into making one as well. I have not got a gear cutting machine, and it's a lot of work on the milling machine on a rotary table!

Making a start on the new wheels today, with the buffer heads, and laying out the chassis ready for milling from solid brass. The bronze hornblocks will be fitted into milled slots, with coil springs etc., the back axle will be restricted in movement and the front allowed more swing to allow smoother running.

The wheels will be rim insulated, as it has outside cylinders. I did consider split frames, but felt it would be easier to do pickups.

Off to the workshop for a while,

Stephen
Last edited by Bertiedog on Mon Aug 31, 2009 10:41 pm, edited 5 times in total.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby gr.king » Fri Jun 05, 2009 10:22 pm

Would it help to spur you on (though I doubt if you need to be spurred on) if I were to say something silly such as "it can't be done". That kind of remark usually does the trick for me. I just have to prove that it CAN be done :thup
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Steam on Shed » Sun Jun 07, 2009 8:35 am

Hows the chassis coming along Stephen?, I'm looking forward to seeing your handiwork & springing arrangement.

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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Sun Jun 07, 2009 2:04 pm

Working on the S class 040 chassis details this afternoon, the wheels are on hold a while, as they are a bit of a problem as at 11mm they are very small indeed. I have some brass castings for 16 spoke wheels, but Hudswell Clark are only 10 spokes.

Alan Gibson wheels list the correct types, but they are quite costly and not made in Nickel Silver or Stainless Steel, only Mild steel tyres, which I do not like to risk in case of rust, especially on such a small light locomotive.

Romford are to large, even turning down a slightly larger wheel, and the mazak centre cannot be soldered to the new P4 tyre rim.

Normally I used slitting saws, mounted in pairs, to make the wheel centres spokes, but I have no suitable matched pairs of blades to work with, and again purchase cost is high, so looking at direct milling of the spokes, with four blanks at once, on a rotary table.

The small size of the Hudswell Clarke wheels also raises problems with a commercial gearbox, as the overall size of the casing would be so small, so I may make a double geared one with the worm set above a spur gear drive, as a one stage 30;1 might be too low a ratio.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Mon Jun 08, 2009 10:13 am

A small, well small chassis, but bigger bit of work done yesterday evening on the new Chassis, solid brass block, I happened to have a block the right width for the frames, .7mm less than Back to back for P4, just right. The milling is done on a Prazimat mill with 2.5 solid carbide mill inserts.

The basic shape is milled out, with the profile on the top and bottom. A recess was done top and bottom to leave 1mm thick sideframe edges,leaving the centre as a long frame spacer block, and then space milled out for the motor and gearbox. The elongated holes allow for the cast box attachment bolts.

The motor mount pad is estimated for the possible max gear size, (smaller than the 11mm wheels, minus thickness of casing of the gearbox), and it will need more machining after the gears are sourced, or made.

I am looking into gears next. They may have to be made in the workshop. It's still open as to whether it should be a single stage worm, or a worm and spur tower unit to raise the motor up. There is not much space to play with in the very small body on the S class Taff Vale.

The hornblock will be tubes, split around the gearbox, and 2mm axles to save a bit of space. The springs can be simple phosphor bronze wires supported in holes in the end block, with a retaining brass frame on the underside of the milled chassis to keep the axle box tubes in place. About .75mm suspension movement will be allowed. There may just be space for compensation bars inside the frame as well.

The cut outs at the front of the frames top are for the cylinder support bar, and the area between the wheels on the outside will take the slidebar support frames. I have some home match brass brake shoes to suit aside already.

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More soon,
Stephen
Last edited by Bertiedog on Mon Jun 08, 2009 10:55 am, edited 1 time in total.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Pudley Wonderer » Mon Jun 08, 2009 10:52 am

Bertiedog wrote:The handrails ave already been replaced with my own ones......
Dont forget to add the sand gear operating rods that ran through the handrails :wink:
I will get some of the Dart casting Monty figures for the cab, a Driver and a "boy" for the fireman, as there is not much space on the footplate!
I cant remember the exact figures I used on mine, but they did come from the Montys range. As you say, there's little space for them in the cab, so I fitted mine before attaching the rear cab section, after painting, though I know this wont be so easy for you to do.
.....it is even difficult to add springs to the coupling hooks, so they may be fixed in place, with new home made screw link couplings.
I wouldn't even attempt to make the coupling hooks sprung, as it's impossible! I had to take out a fair bit of whitemetal from the rear buffer beam, so as the coupling hook could then be bent around into the recess created, and still allow for it to then be fitted to the rear of the footplate! The front coupling hook was thinned down a fair bit, and then attached in place using epoxy on the underside of the footplate.
Puds.................I Know What I Like (On My Workbench)

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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Mon Jun 08, 2009 2:08 pm

Bit more done this morning, the buffers replaced with lathe turned stainless steel bufferheads, non sprung, there is little or no space for a spring, even an internal one.

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The body needs quite an extensive clean up, it was painted for years and so a lot of it is a bit stubborn in coming off, I will soak in thinners to soften it. On with the chassis in the meantime, looking for a gear set to save making one.

The sandboxes are not correct way round, might have been the original Keyser instructions at fault. The Nu-cast version has two handrail knobs etc, and the K's three. I replace the plastic ones that they did with brass lather turned ones, made by myself The original had pretty awful wheels, right type, but somewhat over sized, and steel tyres that rusted easily. It also had the infamous D profile axles, and the worm and motor to match the eccentric design, all binned at the time as completely unusable.

Stephen
Last edited by Bertiedog on Wed Jun 10, 2009 2:03 pm, edited 1 time in total.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Mon Jun 08, 2009 10:22 pm

Chassis hornways done, ready to take round bearings floating on springs. The body is a bit cleaner, still a bit of paint to clear so soaking again. I found one of the original connecting rods, but I am doing new Nickel Silver ones, a bit thicker than the etched K's rather skeletal ones. The original cross heads are one sided whitemetal castings, again they need replacing with more solid ones in steel or nickel.

Imgp0040rm.jpg
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Stephen,
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Tue Jun 09, 2009 7:37 pm

A bit of a problem has arisen with the gearbox, because of the small diameter of the wheels, traditional pitch worm sets are not small enough, it would require a very small pitched gear to work, and they are difficult to make without a gear hobbing machine.
Most commercial ones are just too big, or too costly in the forms available. I am looking into an alternative , the 14:1 Tenshodo gears available from Nigel Lawton. They are brass and steel and accurate , but the ratio is far too low for a shunter, but he markets belt drives to use with his narrow gauge locomotives.

Although pulleys are made for specific sixes and pitch centres I think I may just get some belts and machine up from scratch the best fit pulleys for the small space available. A quick measurement shows that about 3:1 would be achievable, giving a much better overall ratio of 42:1.

I am also going to change over to one of his new small 12 volt coreless motors, they are inexpensive and good quality, I have one too hand and testing it shows it to be powerful enough and almost silent. being even smaller it throws more space free for the gear box and allows higher up mounting of the motor out of the way of the frames.

In the meantime I am starting on the wheels, brass centre with stainless steel rims and tyres. This is not a quick process. four blank disc are made to just over thickness, and soldered into a stack, and then the spokes are machined with micro sized end mills. The centres are then separated and cleaned up, machined to the wheel centre form and then the rims added and the whole thing turned to a finished set of wheels, plenty of steps to go wrong !!! The rims will have to be insulated, with the outside rods and cylinders.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Tue Jun 09, 2009 10:18 pm

It turns out that the 14:1 Tenshodo gearsets are brass and plastic, but Nigel Lawton Models does 15:1 gears in steel and brass, so opting for these instead, for the S class. The Tenshodo gears can be used in an 016.5 loco, Pendon.

With an estimated 4:1 belt drive, possible theoretically from the pitch diameters possible with a 12mm belt , this should give an approx ratio of 60:1 overall, much better for a small shunting locomotive like this one.

I have also ordered one of the new 12mm diameter 12 volt Coreless motors that he does as well. I previously had one of these motors, and they are top quality, very smooth and near silent.

The whole motor gearbox combination will float as one unit on the suspension springing. Quite a bit to make for the gearbox casing, and a carrier frame to make for the motor as well, all in brass sheet and brass bar stock on the milling machine.

More on the wheels soon.

Stephen
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Adam » Wed Jun 10, 2009 8:56 am

Some very impressive engineering, but I'm slightly baffled as to why the obvious commercial solution for a low ratio gearbox - something from the High Level range - doesn't appear to have crossed your radar? This isn't a criticism, I'd just be interested in your reasoning.

Best

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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Wed Jun 10, 2009 9:58 am

Adam wrote:Some very impressive engineering, but I'm slightly baffled as to why the obvious commercial solution for a low ratio gearbox - something from the High Level range - doesn't appear to have crossed your radar? This isn't a criticism, I'd just be interested in your reasoning.

Best

Adam

Cost, apart from anything else, the Nigel Lawton gear sets are quite inexpensive, saving me making the gears myself. The coreless micro motor is about as good as made in the size and the space is very cramped in here. With the High Level system it would really need the matching Mashima as well, adding up to about ?30. The combination of a 15:1 final ratio and 4:1 belt drive gives a potentially silent drive system as well, and still allows a small flywheel as well.
Stephen.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Wed Jun 10, 2009 12:02 pm

Layout for the gearbox, not exact scale, in solid milled brass, with drive belt on the front.

gearbox S class.jpg
Taff Vale S Class Gearbox layout
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Working on Wheels next.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Miss Prism » Wed Jun 10, 2009 1:41 pm

Snap!

axle-hung36(rotated).jpg
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(pic by permission of CLAG)
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Wed Jun 10, 2009 3:19 pm

Modified design to allow for simpler machining of the brass block, allowing use of 12 BA screws to attach side cover, and addition of a ballrace to the main shaft, and a split mount to allow adjustment of belt. I do not want to add side pressure from the belt drive to the main motor shaft so ball race is needed, also it will help if a small flywheel is added to the motor shaft.

I had a look at the CLAG Site, the design comes out very near to the type featured there, but this one is in more solid milled brass.

gearbox S class modified.jpg
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Stephen
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Wed Jun 10, 2009 7:12 pm

A small development, I have found an old 1950's/60 Lindsay Kemtron gearbox, which contains a couple of 14:1 gears, nice steel worms, and phosphor bronze gears.

Imgp0041rm.jpg
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These are good quality, and correct gear form tooth shape, and with test wires, and a dial gauge, test as extremely accurate. They need a new shaft, and bearings, and a good clean, but are the way to go to get the best from this set up. I will check out the Nigel Lawton gears as well when they arrive, but I think these old ones will be very hard to beat.

Imgp0043rm.jpg
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I am going ahead with the brass gearbox casing based upon these Kemtron gears, and careful re-calculation of the belt drive pulley sizes, and the cord centre of the belt, gives about 67:1 as the available final ratio for the box, totally acceptable for a small loco for shunting and light goods duties.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Miss Prism » Thu Jun 11, 2009 1:14 pm

Those Kemtrons look well tasty - much better than the Tenshodos!
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Thu Jun 11, 2009 1:54 pm

I have got the Nigel Lawton micro motor, and the drive belts, in by post as well, along with the gear sets, and yes, the Kemtron 14:1 are better machined than the plastic ones , but the 16:1 set is fine as well, although the tooth form height has a bit of a taper on them, but the root form is correct. I will test out both sets to see which is better. I think NWSL may still make the gears in the USA for the Lindsay gearbox.

Imgp0045rm.jpg
Components with gearbox blank
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The coreless 12volt motor is fine, tiny though!, as are the drive belts. The short length of the motor shaft may stop the use of an extra ball race, but the motor appears to have a sound main bearing. Shot shows the basic drive componants, working on fitting the motor, and making the pulleys next, with 5p for scale as well as rule

Imgp0046rm.jpg
Lawton 16:1 gearset in steel and brass
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More soon, back to workshop........
Stephen.
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Re: Taff Vale S class Hudswell Clarke for P4 layout

Postby Bertiedog » Thu Jun 11, 2009 9:59 pm

This evenings shots of the new brass gearbox frame and the motor mount, almost small enough to go in a 2mm scale loco........the mount is drilled to take the extensions with the axle bearings, which act as hornblocks, and the motor will be held by a clip on the wired end, the other end fit into a recess in the mounting plate. The axle box extension plates, the covers on the sides, will have to be drilled in situ , after checking the gear mesh, which will slightly adjustable with oversized holes in the coverplates.

Imgp0025rm.jpg
Gearbox mainframe
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The drive gearbox fits into the firebox area, just!..and there is plenty of space in front of the motor for a DCC chip.

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The hornblocks will be in phosphor bronze.

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As I found out today that the current Alan Gibson wheels have not got undercut rims, and therefore the tyre comes off, I am considering ordering these wheels, as they do the correct Hudswell Clarke 10 spoke pattern, 11mm is diameter. I can turn new P4 profile tyres in Stainless Steel to fit myself. I will phone and check that they are available at the moment.

Stephen.
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Re: Taff Vale S class Hudswell Clarke for P4

Postby Bertiedog » Fri Jun 12, 2009 10:01 pm

The new S class gearbox is nearer completion, with the sides fitted temporarily with Loctite, to allow the outline shape to be filed exactly to the gearbox frame.

The sides and the extensions are made in Aluminium bronze, and now await drilling and reaming for the 2mm axles, as does the other front axle bearing, which is made in nickel bronze. The bearings are still over length at the moment, they will be machined to suit the back to back of the wheels. If the Kemtron gears are used then the bearings will be 3/32 rather than 2mm, with the wheels bushed to suit. Other than that the gear could be bushed as easily to allow 2mm........

Imgp0028rm.jpg
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The hornways have been machined square bottomed to get accurate seating for the bearings, and the gearbox. I am allowing for about 1.25mm suspension movement maximum.

Imgp0029rm.jpg
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The holes for the 14 BA bolts to retain the sides, and the bearings, of the gearbox casing will have to be spotted through from each side, one side at a time, after the plates are removed with a spot of heat to destroy the Loctite bond. Once marked and drilled they should allow disassembly and remain accurate for location.

Imgp0030rm.jpg
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The suspension springing wires will have plenty of space along the top of the bearings, easy to adjust etc., and there is lots of space for pickups etc., on the underside, with a brass retaining plate along with brake gear etc., attached to it. With the motor so small there is lots of space for a DCC decoder in the saddle tank.

Off to Chatham tomorrow, bits to be bought, small drills etc., at the MRC show at the Historic Dockyard.

Stephen.
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Re: Taff Vale S class Hudswell Clarke for P4

Postby Bertiedog » Sun Jun 14, 2009 10:59 am

Wheels supply for the Taff Vale is solved, care of a 1950's HO locomotive, a Japanese Brass loco awaiting a re-build, which has the correct pattern 10 spoke wheels, just need the counterweight patterns altered to the Hudswell Clarke style. The rims are brass plated and removable, and can be changed to stainless steel P4 profile. The Japanese loco can have a new set of Alan Gibson wheels fitted later on.

The wheels fit 3/32 inch shouldered 1/8 inch axles, and can be drilled, reamed, and bushed to fit 3/32 to suit the Kemtron gears if needed. The centres are Mazak, no deterioration at 50 years old. They can be chemically blacked, rather than painting. The existing couplings rod screws can be use, with the the heads reduced in size to fit the recessed bores in the bosses in the new rods.

I am making some custom collets to fit the lathe to hold the centres accurately for machining. The rims are insulated, and will need new epoxied paper insulation added before the final machining. The tyres will be the P4 profile, done to max width, with minimum outside edge relief, as the wheels are so small. This helps a touch with preventing any wheel drop on the frog, which should not happen anyway with P4 standards, but it's best to take precautions............... Photos coming.
Last edited by Bertiedog on Sun Jun 14, 2009 5:41 pm, edited 1 time in total.
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Re: Taff Vale S class Hudswell Clarke for P4

Postby blackwoodvalleyrailway » Sun Jun 14, 2009 11:03 am

I have been watching this topic since the start, and its fasinating! Its a lovely little loco. It must be really really tiny!
Peter-John
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Re: Taff Vale S class Hudswell Clarke for P4

Postby Knottyjohn » Sun Jun 14, 2009 1:02 pm

Just caught up with this project and have been reading up and taking in the photos. An interesting project this, look foward to reading more about it. John
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Re: Taff Vale S class Hudswell Clarke for P4

Postby Bertiedog » Sun Jun 14, 2009 4:30 pm

This is the form tool profile, for the published P4 standards, for the 2mm tyre width, which is the maximum based on the prototype.

The area at the back of the flange, marked Y on the drawing, is important, some commercial wheels have a flat below the level of the tyre, affecting the effective flange thickness. The radius on the other side of the flange is shown as .21mm but can be .17mm, it is never in contact with anything, except on the very tightest curves, when the smaller radius helps. It rounds the lowest point of the flange slightly, widening the shape, otherwise the flange thickness is wrong, affecting the back to back etc. In my opinion the 0.21mm radius for the root radius is a bit small for practical model use on wagons etc, and I do it at .30 mm for stock, and only .21mm for locos. In theory, a nearer to flat tyre could be modelled as the shape portrays an un-worn wheel.

Some experience with NMRA RP-25 wheel profiles shows that no root radius increases haulage on locomotives, but I would not apply it to P4 standards, where the correct prototype profile of the rail head is specified in the published standards.

14062009_123135.jpg
P4 PROFILE.
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I check the tool form, and resulting turned shapes, with a calibrated micro magnifier, it is marked in thousandths of an inch so needs conversion, 0.25 of a thou can be measured, and radiuses to 1 thou., shown on a glass graticule scale optical target.
.001 Inch equals 0.0254mm
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Re: Taff Vale S class Hudswell Clarke for P4

Postby Bertiedog » Sun Jun 14, 2009 7:13 pm

TAFF VALE WHEEL.jpg
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The wheels I have are 12.5 mm at the moments over the tyre, so with the new tyres can be machined to the required 11mm over the tyre tread.
Imgp0002 RM.jpg
Imgp0002 RM.jpg (112.6 KiB) Viewed 1086 times


The original HO tyres are brass plated, so are not re-usable for P4, so they will need stainless steel rims. The mazak centres are in 100% un-corroded condition.
Imgp0004 RM.jpg
Imgp0004 RM.jpg (112.57 KiB) Viewed 1084 times


Back to machining the new rims, new washers and spacers, and silver steel axles to fit the Kemtron gears.
Bertiedog
.... “Sir, Sunday morning, although recurring at regular and well foreseen intervals, always seems to take this railway by surprise.”
W.S. Gilbert
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Bertiedog
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