RC Locomotive 'Diesel-Electric'

[CertifiedMike]

I have ‘Track’ , OK so its just 4ft of track! But i now have somewhere to park my loco, no going back now.

View attachment 269543

Congrats!!! I feel like I should say 'you're on the right track now!'...


Track is avail in 4' lengths? I never gave much thought to the track. Does it need any special bed to lie on top of?
I'd like to hear more about how you install the track!

Such a cool project!!!

 

[Roog]

Congrats!!! I feel like I should say 'you're on the right track now!'...


Track is avail in 4' lengths? I never gave much thought to the track. Does it need any special bed to lie on top of?
I'd like to hear more about how you install the track!

Such a cool project!!!

Thanks @CertifiedMike, I rang a track sales business and of the three different types they sell this looked the most like scale track. The track i ordered comes as a set of parts and you clip it together, the shortest length of rail is just over 8ft (2.5m) but I only needed a 4ft, short length on which to park my loco, so I bought one rail and asked them to cut it in half. I assembled the 2 halves with the 15 sleepers and 30 rail clips. The sleepers are actually designed to accept a third rail, so that you can run both 3 1/2" and 5" gauge trains on the same section of track.

The track in the picture is designed for permanent installation, I suspect this means its the least sturdy and won't tolerate being dismantled and moved each time you use it. I think you are supposed to lay it on gravel 'ballast' but because my short section is just to give me some where to park the loco I will probably screw the sleepers to a wooden scaffold plank. At the club track the larger gauge tracks, 5" and 7 1/4" are laid on ballast and the smaller gauges 5" and 3 1/2" are on a elevated supports, probably made from concrete beams on posts, I've not looked closely on site.

https://www.bristolmodelengineers.co.uk/

Just a note: The track in the picture is sitting on a stub wall made from oak landscaping 'railway sleepers' :0)

 

[CertifiedMike]

Thanks @CertifiedMike, I rang a track sales business and of the three different types they sell this looked the most like scale track. The track i ordered comes as a set of parts and you clip it together, the shortest length of rail is just over 8ft (2.5m) but I only needed a 4ft, short length on which to park my loco, so I bought one rail and asked them to cut it in half. I assembled the 2 halves with the 15 sleepers and 30 rail clips. The sleepers are actually designed to accept a third rail, so that you can run both 3 1/2" and 5" gauge trains on the same section of track.

View attachment 269551
The track in the picture is designed for permanent installation, I suspect this means its the least sturdy and won't tolerate being dismantled and moved each time you use it. I think you are supposed to lay it on gravel 'ballast' but because my short section is just to give me some where to park the loco I will probably screw the sleepers to a wooden scaffold plank. At the club track the larger gauge tracks, 5" and 7 1/4" are laid on ballast and the smaller gauges 5" and 3 1/2" are on a elevated supports, probably made from concrete beams on posts, I've not looked closely on site.

https://www.bristolmodelengineers.co.uk/

Just a note: The track in the picture is sitting on a stub wall made from oak landscaping 'railway sleepers' :0)

Thats a very cool site! I don't think I've seen a rideable train this size. Pretty cool how they raise the track up!
I see those 3 rail tracks too. Interesting.

I thought the 3rd rail would be like a subway and shoot voltage to the cars. 220v @150a should do it.

This is a great project!!! My uncle would LOVE this at his house! I wouldn't mind one either if we could find a snow blower car for winter.

 

[Roog]

Thats a very cool site! I don't think I've seen a rideable train this size. Pretty cool how they raise the track up!
I see those 3 rail tracks too. Interesting.

I thought the 3rd rail would be like a subway and shoot voltage to the cars. 220v @150a should do it.

This is a great project!!! My uncle would LOVE this at his house! I wouldn't mind one either if we could find a snow blower car for winter.

Fun fact, many locos in europe including the class 93 that i am building can operate from an overhead wire, the real ones are set at 25,000V DC, could be fun to build such a thing in model form but the HT wire might ‘tickle quite a bit’ on a ride on loco

Incidentally i have heard of snow blower cars being fitted to the front of locos in cold climates, i guess you could use a model jet engine pointing forwards

Sadly i have no plan to build a track to circuit my garden as yet, but i could be persuaded

 

[Roog]

Quick check that my axle width calcs are right, using an adjustable test shaft

 

[Roog]

On to cutting bar stock, first time I've used my cheap band saw in anger, it worked much better than I expected. Saving loads of time and tired arms.

 

[CertifiedMike]

On to cutting bar stock, first time I've used my cheap band saw in anger, it worked much better than I expected. Saving loads of time and tired arms.

Angry chopping???!!!

Have you tried this method? Also likely to give you sore arms but its much faster than a saw...

 

[Roog]

Ends to be faced off to length, and holes to be drilled then tapped with m4 threads. The whole thing is held together with loads of cap head screws

Bought some new carbide milling tools, they work very nicely need to figure out a way to tap holes quickly and safely can’t afford to break a tap

 

[Roog]

Today i have been drilling and tapping holes, the image shows the last hole in one of the bogie side frames being drilled. Ill try a ‘dry assembly’ of the first bogie frame later on.

 

[Roog]

I thought i would share my experience with tapping blind holes with M4 threads in mild steel. Despite being told by my local model engineering society that there are “no short cuts” do it by hand. i bought some branded fluted taps and over sized the tap hole by 0.1mm. I gingerly drove them into the work piece
using a low cost 12v drill. Our equivalent of Harbour freight , it is light, has a very low top speed and very modest torque seemed do the job well.

Of course one broken tap stuck in tje work piece and ill be back to doing it the hard way!

 

[Roog]

Here is the first bogie frame bolted up with one temporary axis and wheels in place. I’ll probably add ‘decoration’ in the form of fake suspension either fabricated and bolted on or i can try to get someone with a 3D printer to print proper detail

 

[Roog]

Now that the wheels are machined there isnt so much turning to be done, although my machine shop tutor would probably not class my work as ‘turning’ more like, man (big child) playing with toy machine tools. Never the less the second bogie frame is underway, side plates sized and bearing holes drilled. But I do have one thing I need to sort, that is a design for the buffers, something like this,

I’d like to make then sprung, mainly because there is a thing going around the club poking fun at those who don’t have working buffers, plus they do seem to serve a purpose for those clumsy ‘coupling ups’. I could buy some, but the loco I am building uses odd rectangular faces with one edge cut at an angle

Could turn from rectangular bar then machine the face to suit, bit wastefull but tough result, but a more economical way would be to make the face of the buffer from flat bar and join them to a simple piston made from much smaller round bar. The ones in the first picture are for a 7 1/4” gauge loco so are quite a bit bigger so I can see why they would have an incentive to join separate parts which it looks like they have done.

 

[WickedFog]

Now that the wheels are machined there isnt so much turning to be done, although my machine shop tutor would probably not class my work as ‘turning’ more like, man (big child) playing with toy machine tools. Never the less the second bogie frame is underway, side plates sized and bearing holes drilled. But I do have one thing I need to sort, that is a design for the buffers, something like this,

View attachment 270318

I’d like to make then sprung, mainly because there is a thing going around the club poking fun at those who don’t have working buffers, plus they do seem to serve a purpose for those clumsy ‘coupling ups’. I could buy some, but the loco I am building uses odd rectangular faces with one edge cut at an angle

View attachment 270319

Could turn from rectangular bar then machine the face to suit, bit wastefull but tough result, but a more economical way would be to make the face of the buffer from flat bar and join them to a simple piston made from much smaller round bar. The ones in the first picture are for a 7 1/4” gauge loco so are quite a bit bigger so I can see why they would have an incentive to join separate parts which it looks like they have done.

What size would those rectangles be? Turning rectangular stock round is likely going to cost you more in inserts than the extra process of turning round stock down then machining the plate rectangular. Machining interrupted cuts sucks, especially as deep as that would be, plus basically being a groove cut to boot.

Could you make a much smaller version and turn a smaller square flange on your round bar stock and just bolt that rectangular face on from behind? Forgive this crude drawing.

 

[Roog]

What size would those rectangles be? Turning rectangular stock round is likely going to cost you more in inserts than the extra process of turning round stock down then machining the plate rectangular. Machining interrupted cuts sucks, especially as deep as that would be, plus basically being a groove cut to boot.

Could you make a much smaller version and turn a smaller square flange on your round bar stock and just bolt that rectangular face on from behind? Forgive this crude drawing.View attachment 270323View attachment 270324

Hi @WickedFog everything you’ve said makes sense, I hadn’t considered the never ending ‘cluck clunk clunk’ that would be the turning of four buffers from rectangular bar, I think the face is 25mm x 40mm and I did workout that 2” round bar would be needed to cut the rectangle from, price wise the cost of the stock metal is very similar. Thanks for the tip.

I am tempted to make the ‘cylinder part’ from brass, hopefully this will help the two parts slide against each other, although big bars of brass are pricy.

 

[WickedFog]

Hi @WickedFog everything you’ve said makes sense, I hadn’t considered the never ending ‘cluck clunk clunk’ that would be the turning of four buffers from rectangular bar, I think the face is 25mm x 40mm and I did workout that 2” round bar would be needed to cut the rectangle from, price wise the cost of the stock metal is very similar. Thanks for the tip.

I am tempted to make the ‘cylinder part’ from brass, hopefully this will help the two parts slide against each other, although big bars of brass are pricy.

That's smaller than I thought. Yeah, I'd definitely do round bar. Rough OD, rough drill/bore ID, finish bore or ream, finish OD, finish back or rectangle, part off, finsh rectangle face. You have soft jaws for your Kurt vise? Only problem is clamping on thin wall stuff to finish the rectangle in the mill. Boring a set of aluminum soft jaws would be best to keep it from spinning when cutting the profile.

 

[Roog]

Cheers @WickedFog fussy little piece to machine, I will mill the square faces and probably finish the angled face by hand. A bigger issue will be keeping them level on the loco. Round ones don't have that issue!

 

[WickedFog]

Cheers @WickedFog fussy little piece to machine, I will mill the square faces and probably finish the angled face by hand. A bigger issue will be keeping them level on the loco. Round ones don't have that issue!

Key the shaft and press a dowel pin in the housing to keep the plates perfectly level, then tack weld the pin in there. Key it on the bottom so it's hidden

If you shoot me your dimensions, I could CAD it all up and get ya a blueprint pretty easily I believe. Never tried it in Fusion, but I am pretty sure it creates blueprints pretty easily.

Or you could thead the hole for the pin and simply turn down the end of a bolt and thread your pin in there, and only have to key the shaft part way so it is unable to slip out. That would keep the pads locked the same distance out. Just key them all the way to the front and put your key towards the front of the housing. That would stop the bumpers from going back too far unless the pin got sheared

 

[Roog]

Key the shaft and press a dowel pin in the housing to keep the plates perfectly level, then tack weld the pin in there. Key it on the bottom so it's hidden

View attachment 270505

If you shoot me your dimensions, I could CAD it all up and get ya a blueprint pretty easily I believe. Never tried it in Fusion, but I am pretty sure it creates blueprints pretty easily.

Or you could thead the hole for the pin and simply turn down the end of a bolt and thread your pin in there, and only have to key the shaft part way so it is unable to slip out. That would keep the pads locked the same distance out. Just key them all the way to the front and put your key towards the front of the housing. That would stop the bumpers from going back too far unless the pin got sheared

Great idea @WickedFog and the rectangular buffers can be used to orientate the piece for milling the grove, still resent that round buffers don’t need orientation !

 

[Roog]

Today the temperature in my shed has exceeded 10deg C (50F) almost comfortable with my 4 layers on!

Each bogie is located with a 12mm (1/2”) diameter pin but the chassis needs to be supported above the bogie on a round platform to give lateral support so that the body work doesn't lean left or right. Not sure if the drawing helps much but the upshot is that the platform needs to be fastened to the top of the bogie by three screws. I plan to use a waxy plastic like a ‘big washer’ as the running surface.

Drilling the holes is straight forward as the Digital readout (DRO) on my mill has a function to allow a circular array of holes about a point to be dialled in. You tell it the centre, the no. Of holes, the radius on which they sit, plus start and finish angles on the arc.

Pressing ‘go’ gives x/y coordinates for the first hole, the idea is to twiddle the hand wheels which position the mill table so that both x and y are zeroed. I do occasionally have to remind me that the last digit displays 5 thousands of a mm, a level of accuracy that is largely irrelevant for the models I am building. Consider that a ‘close’ clearance hole for a 4mm screw is 4.2mm!

Then drill the hole. Repeat for each of the three holes, and yes my bench is a mess!

In the image above i have already gone around once with a centre drill, the system is accurate enough that you can go round and round carrying out different procedures each time without position drift.

Next i opened up the centre hole to 12mm dia, to a depth of 3mm to accept the base of the 12mm pin, again returning the DRO back to absolute mode and moving the mill table so that the x/y axis are zero takes you directly to the centre. Then drill to depth of 3mm by monitoring the z axis

The DRO, a low cost unit with three linear scales from amazon, is probably the most useful accessory i have bought for my little mill and whilst it probably isn’t best practice it allows accurate machining and drilling operations to be carried out without first marking out the workpiece, just set off from two edges as x/y zero reference is usually enough. I guess the next step is CNC, which feels like cheating, but I know some people use a small CNC for making multiples of items.

 

[Roog]

I then went on to the job i was dreading the axles, made from ground silver steel rods, machining these seems to eat my tooling. I wish I could figure out a better way to make the reduced dia ends as the distance between the internal shoulders is quite sensitive as it sets the distance between the wheels.
I am currently machining the axle to its final length then cutting the reduced sections the correct length to set the shoulders the right distance apart. Any way heres a picture of two axles in a box of increasing pile of parts