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The Oily Rag

The Dirranbandi & Toowoomba Light Railway

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Undoubtedly some of you will know something of what I get up to. I scratch build everything I can including live steam locomotives, battery electric locos,  stock, buildings and infrastructure but use commercial track. Everything I do is geared to FUN (capital letters) and my preferred scale is always 7/8ths inches to 1 foot (1:13.7) running on 45mm gauge track. clearly all based on 2 foot narrow gauge. All of my modelling is geared towards Colonial and Industrial practice giving me complete freedom to freelance my designs (all done in house) and scratch build whatever appeals to my eclectic tastes.

 

The DTLR used to have a portable track which went to a few exhibitions. However a number of unfortunate circumstances came together forcing a house move upon us which made me dismantle the whole garden railway and the portable track. I still have the track, most of the stock and locos, and of course "Gill's Cafe" named after my long suffering wife. The move was a downsizing as well which meant a rehash of the workshop facilities (one of the REALLY important things in life) and I had to sell of a lot of tooling and the bigger machines and flypress. A re-equip with smaller items, a complete rebuild into a smaller space and we are beginning again. The land has been cleared, made-up (although a small pond has yet to be drained and filled in) and hopefully this year will see a start on the "civils".

 

I have attached a few pics for perusal by anyone interested. Finishing off the railcar is the priority currently, its been around too long.

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Really great to see you back up and running O.R. I see you are still as skilled as you ever were ! Here's to seeing more postings this year and the DTLR rebuilt and running again, i have someone to chat to that i actually know on here again!  :yahoo:

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Thanks Bob. Its good to be in harness again as they say. But I bet no one has spotted the deliberate mistake when I built number 4 the green one) of the workhorses. My mate Ivan Bentmettle in the photos with the wrecking bar at it again. :onthequiet:

Edited by The Oily Rag

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 But I bet no one has spotted the deliberate mistake when I built number 4 the green one) of the workhorses. 

...is it left hand drive?  :jester:   :D

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:senile: No mate. A senior moment when wielding the 5 minute epoxy glue. The Rads have 20 components each and trying to be clever stuck the top tank on the wrong way round. :blind:

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.............if you had'nt of said owt i'd never have known :pardon:

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:lol: It comes to us all mate. The trouble is at a number of shows there has always been someone pick that up, so I stick my hand up to it. Its a bit like the guy who comes along (having never built anything for himself)  who says "they are not prototypical or to scale Huh!"

 

 My reply? "Unfortunately Sir, they are. They were designed in house in the DTLR drawing office to do a specific job (at which they excel) and even the slots in the screws are lined up to the issued works drawings."

 

I never mind admitting my mistakes (and how I overcame them) as you know. That way the knowledge gets spread around and hopefully stops some one else making the same mistakes.

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A bit of progress on the railcar. The bogie for the semi trailer is now complete along with its chassis and I have the drive unit chassis erected. A good bit of the gearboxes components have been made so I will illustrate them as a complete kit when finished.

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Armchair experts taking their fun seriously! ;)

Looks lovely and I'm looking forward to more :)

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Question: Were those figures made by you, and if so what did you use and how did you make them? They look splendid!

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The figure were actually "kit" figures in 7/8ths from Steve Warrington at Back2Bay6 when Steve was still around. I believe they were Carlo De Spirito (?) figures originally that Steve had permission to re-master. All the parts were plain resin castings glued together with epoxy. Some make up had to be done with Milliput. Painting (a job I find to be tedious on anything) is all Humbrol matt enamel with the exception of the flesh colour which is Precision Paints.

 

I have 3 or 4 left to build up as time allows. However whilst I know I am not good at figures really I am going to try and have a go myself as evening work, "table top" stuff. I read a really good article in "Model Boat" mag.about figures on balsa armatures. Trouble is its as expensive in epoxy putty as buying some figures particularly in this scale. I have a supply of DAS and that might work if the paint is kept in good order. Hence making them a bit cheaper. The other option is to make moulds and cast my own parts in resin as I make a lot of mechanical bits in whitemetal and resin. Then with a variety of components I could mix and match.

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Yes. Simon does some nice stuff as well i agree. They are not so "wooden" as the Carlo figures giving a better atmosphere of animation.

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There has been some progress on the rail car drive trains. All the parts are now made for both motor gearboxes. As such I attached a picture of all the parts needed. The plastic gears come from a handful of these things that I had left over and which had been skulling around the bits box for quite a time. They are from these very inexpensive "GEARTECH" kits which are around. You will note the heavy mods to the large final drive gear to all the use of of the brass driving hub of home manufacture. The motors are again very cheap (they were 50p each in a bag full of Mabuchi 6v/12v from a well known supplier at a show). If all this works then I have just one left for another project. Ho Hum.

 

The little alloy parts in the centre of the two sets are "solder buttons" counterbored to enable the layshaft and final drive shaft bearings to be clamped in place whilst the soldering is carried out to fix them squarely into the side plates.

 

Finally a couple of pics to show where it all happens these days. Now I am down to 9ft 6 inches by 7ft 4". Spring and summer job as time allows will be to start insulating the place. Everything is a bit tight now but is just about manageable. Mind you I have to wait for fine dry weather to cut timber outside. The days of cutting up in the dining room or kitchen have had to be consigned to history. :nono: :jester:

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There is a saying about the best laid plans and mice and men........, well this weather has blown the DTLR schedule out of the window. I think the next few days are going to be spent "on the drawing board" and searching for some good insulation for the workshop. The 2KW heater is not even keeping pace at the moment. The planned pond drainage has to be held as there is currently a layer of ice over 2 inches thick on it and the pumps are seized with the cold. Any attempt to thrust a spade into the ground or even a fork has it bouncing back transmitting those horrible vibrations back up the arms.

 

OR------ I could just sit back and dream of lazy sunny days with the rattle of wheels over rail joints in the background. :sungum:

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Never mind O.R. You have my sympathies, as i tried running my battery loco's yesterday, and although i had fun, it was very short lived and too flaming cold! Best to stay in and get other stuff done and finished off, just like i am today.....and probably for the rest of the next week as well.  ;)

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 Glad I've found your thread. Love your clean tidy workshop ,never can keep mine looking like that. How big is that shed? Do you machine your own wheels? phil

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Thanks Phil. I am now so tight for space that I have to keep things tidy. The shed nominally is 10 feet by 8 feet but they don't quite work out that way and my working space is as I said 9 feet 6 inches by 7 feet 4 inches. Having sold all my big machines for the house move I now manage with bench top machines, but for all my stuff now they are adequate if a little slower. In answer to your question, yes indeed I do make my own wheels. In a previous internet life I did a write up on how I do it using just conventional machinery and standard of the shelf tooling, just using normal machinery geometry and generating the profiles. I had a well tooled Colchester Bantam then but even this bench lathe will do the job with care. Owd Bob knows the one i mean. I could regenerate that here if there is any interest in my babblings :laugh:

 

For the new rakes of wagons I really would like curly spokes so I am considering laying out a brass pattern very carefully and then making moulds to cast polyurethane resin or similar wheels. Andel Models used to do this. The sacrifice is of course weight low down, something you get as a bonus with turned steel wheels.

 

regards

Ian

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Yes please ,would like to see how you made the rail bus wheels. I have a Toyo mini lathe and milling head and an old myford but not a lot of tooling with it .

Anytime you want to share your machining techniques id be interested phil

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I apologise for the delay Phil in getting the wheels article together. The photos are not a problem I have them all lined up. I went over to the previous forum (now with Tapatalk) and it seems all of the technical type material has been removed. I don't have (or truthfully can't find) a copy of my text on my system so I will have to rewrite it to interlace with the pictures. It will be a hefty post as the sequence shows some 20pictures with explanations.

Regards

Ian

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Well lets try and start on the wheels. Please remember I had bigger equipment at the time but all CAN be done on the bench top faclities I have now.

Firstly making my own wheels started because I wanted a specific size wheel for a project which "too small" for any of the professionals to be bothered with really unless at an astronomical price. I did fear the prospect of making my own. Whilst in the past I had got by with USA Trains (the best you can get) and Accucraft wheelsets, neither made the size and in any case they are really small in width for 7/8ths, the standard being 8mm (nominally 5/16"). For those fortunate (and wealthy) enough to have sophisticated CNC (computer numerical control) machinery and tooling, read no further. I am not in that bracket and rely on a lifetime of experience in engineering and design to work things up from basics to achieve my goals.

There are two basic methods, using conventional machines. One is to have a tool profiled exactly to the tyre/tread profile, the other is to use the lathe's own inherent capabilities to actually generate the profile. To a great extent, the diameter is irrelevant as tread and flange profile is pretty much standard. Most of the time having a disc type wheel is not a problem either because it cannot be seen when running up the garden.

 

Wheels 01 picture.

 

The tool on the left is a homemade holder with a homemade tool bit from high carbon steel hardened and tempered in the workshop, (heat cherry red, soak at this heat, oil quench and then temper to straw colour, polish up, hone on oilstone). This method will work but the lathe has to run at its slowest, in my case 36RPM. Even then one out of every three wheels will be scrap or not very good. Chatter is the problem and there just has to be suds (water soluble oil 20:1) in good supply.

The tool on the right is a professional tool with the ISO coding (hence formal geometry of tip) MCRNR2020K12. Angled in compromise it will profile pretty close to requirements. The tip is replaceable, indexable and is from very hard sintered carbide usually. These are negative rake (i.e. the tip leans forwards towards the work) and they need very high speeds to give a good finish with suds everywhere. Brilliant if you have rigid powerful CNC machines with really beefy workholding and toolholding. My lathe is 51 years old (Colchester Bantam 1965 vintage) with a maximum speed of 810RPM on single phase and its not enough for this job despite the bed weighing close to half a ton (1020lbs). Hence I am still looking for an easier route to the one I have to take which is to generate the profile each time. Not as bad as it sounds------ Honest!
 

Wheels 02 picture

 

This picture shows the actual tools I now use and have done for a while purchased in 1995 and of Toolmex manufacture. These are again totally standard ISO tools (geometry fixed). The left hand tool in the picture is a standard CSBPR bar turning tool (SPUN 1103 square tip) which has the tip left hand cutting edge at 15deg to the tool axis. The centre tool is a straight right hand CTGPR 90deg turning tool and the other tool is a straight CTFPR facing tool. The tips for both of these tools are triangular TPUN 1103. The corner radius on each and every corner is 0.3MM. Each, in operation is fitted into a quick change holder. Please don't hold me to the ISO specifications as I looked at the standard for this text and our wonderful bureaucrats seem to change things on a whim so it all becomes a new learning curve but these are the designations when I purchased them from Toolmex.

 

I am having some problem inserting the pictures at the appropriate points in the text so I think it best to have a series of posts with just a couple of pics attached.

Edited by The Oily Rag
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The top or compound slide is set parallel the lathe axis and then the QC toolpost is set dead square to the top slide. I am using a quick change post, its a luxury. Plus I made stops and an index plate for it to lock onto, so setting is quick. By the way that gizmo at the back of it is the capstan attachment I use a lot in place of the standard tailstock.

 

Wheels 03 picture

 

Not easy to see but the whole topslide assembly is then rotated 5deg anti clockwise which has two purposes. Firstly the flank angle of the wheel flange can be formed/generated by the bar turning tool, its approach angle being reduced to the requisite 10 deg something which I have found to be more critical than the angle of the tread cone and the 5 deg, offset of the compound slide will generate the coning on the tread with a straight turning tool as above. Hence no resetting of the machine and only two dial readings to be watched. I know the critics will say that the cone should be 3 degrees, yes but in real life its makes almost no difference in our sizes, do the trigonometry, its less than a few thousands.

 

Wheels 04 picture

 

Just a pretty poor picture to show the offset is actually there.

 

Wheels 05 picture

Edited by The Oily Rag
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To complete the set up and profile the first set of four wheels. There are two further ops to do to finish them but first of all a little information. These wheels are for a project requiring scale 18 1/2" diameter wheelsets which means a diameter at the railhead of fractionally under 34mm, using good running geometry means a flange outside diameter of 38mm or 1 1/2". Despite the world glut of steel at rock bottom prices this is becoming somewhat difficult to get in bright mild steel and even worse the price is going up not down. However I found a metre length of black 40mm diameter bar at a really sensible price from an internet stockholder.

These larger wheels give me a problem as I like to work off the bar stock anyway but even my lathe headstock spindle will only take a maximum of 1" diameter through its hollow centre. Hence I fit up my biggest chuck and I can cut off lengths of bar 130mm long which will fit into the chuck leaving a sensible amount out of the jaws when bottomed out for the very first wheel of the day. Then as each is profiled and cut off it can be moved out. There will be a small offcut at the end which comes in for other things on another day.

So based on previous paragraphs, put the facing tool into the post and face the sawn end square.

 

Wheels 06 picture

 

Set up some form of depth gauge so that on the next wheels the bar over hang after facing is exactly the same as when we started on this first wheel.

 

Wheels 07 picture

 

 

Remove facing tool and fit the 15 deg. bar turning tool into the post. Set the dial on the Top Slide to comfortable zero on the slide and KEEP this setting, monitor it throughout the job as you will have to return to it several times.  I set the cross slide feed dial to the amount required for the cuts before the zero point so that when the OD is correct we have a zero on the dial. Turn the OD of the bar to the required OD of the flange for, in my case of 7/8ths wheels 8mm wide, some 16 to 17mm.

 

Wheels 08 picture

 

Set a stop at the length so that it can be returned to with some accuracy and some ease. There are any number of items on the market for this and are easily made at home. This is a picture of the 5 position stop set up I made from the sketches in the Colchester handbook spares pages as finding these now is like obtaining hens teeth.

 

Wheels 09 picture

 

Now using the same tool turn a parallel diameter to the major diameter of the coned tread setting a stop at the finish point which is the root radius of the flange, in my case this is a length of 10.5mm. You will note that the flank angle of the flange has been automatically generated by the tool as has the root radius, in my case 0.4mm (the radius on the tool tip). Now what could be anohter bone of contention, I always the 2x 2 rule for flange geometry, i.e. 2mm high by 2 mm wide at the the theoretical intersection of the cone angle and the flank angle of the flange. It works! It enables running on most if not all commercial 45mm gauge tracks with code 332 rail, USA Trains, LGB, Aristocraft, Hartland and so on.

 

 

 

 

 

Edited by The Oily Rag
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