Rob Roy loco

[Dalboy]

Been a little busy lately so was not able to do much on the loco. Now the weekend is over and all my woodturning put away after a great weekend at a rally(No photos)

I have however managed to make the parts for the motion plate and bracket as I am waiting for some more steel to do the axles.
Anyway I made these over a couple of days while trying to catch up in the garden.

 

[CHJ]

Very neat and sharp edged profiles.

 

[Dalboy]

Thank you Chas

 

[CHJ]

I did my initial training as an instrument maker before moving to aviation electronics, my best pal Neville (& subsequently my best man & eldest's godfather) never managed to beat me in the end of year awards but took to modelling as a hobby with a 5-1/2" scale loco that was an order of clean finishing that I could only aspire to, this background has always influenced my appreciation of work seen at various model engineering shows and work in progress articles.

 

[Dalboy]

Well I managed to make a jig so that I could drill the offset holes in the eccentrics when I turned them well jig made eccentrics turned and holes also drilled. Just the holes for a grub screw to lock them to the axle.

I forgot to take a picture of the jig but will try tomorrow as I will also be using it to drill the grub screw holes



A test fit to a steel bar of the same diameter as the axle which will be silver steel.

 

[CHJ]

Those are very satisfying pictures, clean and consistent, the reality must be considerably more-so.

 

[NickM]

Those look good. When my dad was doing a lot of metal model making, I think he spent most of the time making tools and jigs for doing tasks like that.

 

[Dalboy]

Thank you Chas and Nick. I know what he meant Nick I make so many jigs even when I made my wooden models.

As promised todays work and an overview of the jig use.

This is the set up for doing the off centre hole and drilling and tapping the thread for the grub screw may not be how many would do it but it seemed to work for me.

The jig with a turned eccentric this was after I had drilled and reamed them just to show one in situ.



Again just set up for the photo as it would sit on parallels and be lined up with the end of the vice for repeatability. Note the slit so it could grip the eccentric from moving during this operation



second operation I had marked the eccentric so that I could line it up with the scribed mark on the little jig. Drilled and tapped






Needed to finish the tapping in a vice




Cleaned the inside of the bore where the thread came through using a small circular diamond burr to clean up the burrs

 

[Dalboy]

Set too and got the three axles cut and turned to length followed by turning down 1/2" at each end for a good fit so the wheels can be pressed on.

I also made a start on a fence locking handle for my axminster wood bandsaw as I was getting fed up of keep walking past it and saying "I must repair that sometime" you know what I mean a round tuit job. I could buy a new part but why do that if I have the machines to do the repair myself and it will not be made from plastic like the original that is why it broke in the first place(sorry no photos will take some when complete)

 

[CHJ]

Good luck with the 'Round To its' they are like hens teeth around here.

 

[Dalboy]

Spent today making up a jig/fixture to quarter the wheels I am trying to keep it simple. I cut two pieces of ali plate 10mm thick and squared it all around to 3.750" found the centre and drilled and tapped a hole through both at the same time this was tapped to 5mm as that is what I had in a screw for the purpose I needed it for. From that centre I marked and drilled the offset equal to the offset of the crank pins followed by reaming it to 1/4" the same as the pins.
Took a few photos to give an idea how the set up will work once complete.
Because I squared each plate by turning one 90deg will give the correct angle for quartering. The two screw threads will have a point machined to go into the centre of the axles by slackening them off a fraction at a time while pressing the assembly together should keep everything in line I will be doing this on a surface plate to keep the jig from twisting.

 

[NickM]

Looking good, and I can tell you're really enjoying making this!

 

[Dalboy]

Looking good, and I can tell you're really enjoying making this!

Thank you Nick. Yes enjoying every minute.

Not much done today so no photos just machining bits and pieces for jigs so I can finally assemble the axles and wheels as well as start the connecting rods

 

[Dalboy]

Getting ready to start the connecting rods and for some of the machining I need the use of my rotary table but to hold the plate which I machined flat so that I can mount a connecting rod to it I need to first make some T nuts as the ones on the milling machine are just way to big.
Got the T nuts shaped and rough cut to length with one end square I now need to machine them to the correct length that I have worked out I need as well as drill and tap a hole in the for these operations I need to make up a stop so I can do all the repeat operations and complete them.
A case of one job needing more jobs to complete the first does this sound familiar :lol: :lol: :lol:
Never mind learning a lot from this and none of the things will be a waste of time as they can be used time and time again.
I am sure there will be more like this in the future

 

[CHJ]

..... learning a lot from this and none of the things will be a waste of time as they can be used time and time again.
.

I wonder how long it will be before you unearth some bits of jig 'specials' and wonder "what did I make those for".

 

[Dalboy]

..... learning a lot from this and none of the things will be a waste of time as they can be used time and time again.
.

I wonder how long it will be before you unearth some bits of jig 'specials' and wonder "what did I make those for".

I still have jigs from making the wooden models from way back luckily I can remember each one I had made, when I start forgetting then I will start to worry :lol: :lol: :lol:


Just an update.

One job ticked off before getting back to the Rob Roy. Mind you there is still one more to do which I needed this one for.

And that is a stop for the milling machine vice as I have multiple parts to make for the rotary table and this was one that I should have made before now as I knew I would need it.

It is only a basic design but should do the job required of it

 

[Dalboy]

This is the set up I have been preparing as well as a connecting rod having been machined still in place



This is the first stage as can be seen two holes drilled and one end rounded. Still needs a taper milling from the rounded section up to a square section where the large hole is and also machining the two sides to thin the part.

This requires two of these I did have some problems mounting the piece on the rotary table but beat it into submission in the end. The next one will be easier as will the 4 coupling rods

 

[CHJ]

Good work on getting that done on the rotary table, in days gone by I could see that being done with a hand file and some case hardened buttons.

 

[Dalboy]

Good work on getting that done on the rotary table, in days gone by I could see that being done with a hand file and some case hardened buttons.

With the time it took filing with buttons would have been quicker :lol: . But at least if I have to set up again it will be quicker as learnt a lot.
I do have some case hardening powder so could have made a set of buttons

 

[Dalboy]

Anyway finished the connecting rods with all the bronze bearings and the brass oiler which is only 5/32" diameter.



I also managed to quarter the wheels and fit them to the frame I now have a rolling chassis just a few things to make before starting on the cylinder assemblies.

 

[CHJ]

Fantastic progress Derek, fingers crossed for the fitting of all the rods and free rolling.

 

[Dalboy]

Have started the coupling rods and have marked where they go on a piece were they will eventually be machined off just there while I do the ends of each one as I need them handed.
Also the note book for some vital measurements which need to be taken from the build rather than direct from the plans(this is stated on the plans).

Just going to set the front pair on the mill to drill the holes used for reference these will then be opened up for various bushes later on

 

[AndyP]

What some people are able to produce in their sheds still leaves me in awe.
Were you any sort of engineer in a previous life Derek?

 

[CHJ]

.......
Also the note book for some vital measurements which need to be taken from the build rather than direct from the plans(this is stated on the plans).

Yes in the real world, be it full size or scaled, individual fit inevitably provides the best outcome.
Multiple Zone tolerances have a habit of biting when least expected.

 

[Dalboy]

What some people are able to produce in their sheds still leaves me in awe.
Were you any sort of engineer in a previous life Derek?

Previous life before retirement I was a plant mechanic, I only had to measure in thousands of an inch then now with this I have to make lots of bits to that kind of tolerances.

I am still only learning as well as digging back to school days of trigonometry in some cases.

Yes in the real world, be it full size or scaled, individual fit inevitably provides the best outcome.
Multiple Zone tolerances have a habit of biting when least expected.

They do say that the real world things never measures up :lol:

 

[Dalboy]

Started on the centre joint for the coupling rod. All the marking out lines are only there as a sanity check at which parts need cutting away I will be using the DRO for final machining



The two rear coupling rods centre joint shaped and machined to thickness



Still need to slot the two on the left so the ones on the right will fit inside them they will be held in place with a bronze bush. Once they are complete I will then need to do the other end followed by slimming them down both height and width

 

[Dalboy]

Front coupling rods now slotted. some fine turning as the cutter left the surface a little ridged I think this was because I only had a long cutter of the size I needed. Next will be to open the holes to fit a bush the one on the left needs to be a tight fit where as the right hand needs a sliding fit. Then onto test fitting and final drilling of the holes at either end once I am happy with all that all the waste material will be removed as for now it helps keep the pieces more ridged for working on

 

[Malc2098]

Nice.

 

[Dalboy]

No real updates as I managed to stuff up one of the coupling rods then remade it twice
Still doing the machining on it as I had to wait for some metal to turn up.

I did however manage to get the slide valves made.

 

[CHJ]

It's progress, and it rarely comes without the odd frustration.

 

[Dalboy]

More progress after a break to make a Rubbish truck for a little boy.

Anyway managed to machine some reference surfaces on the cylinder block and the steam chest, this gives me somewhere to take all my measurements from



The steam chests almost complete by that all the main surfaces now machined and turned to final dimensions. since this photo I have driled and tapped for the packing material just a nut to machine and the mounting holes which will be done when the cylinder block and steam chest covers are finished.



More work on the cylinder blocks the mounting flanges machined on the tops and the port face brought to size to match the steam chest sizes. Still need to mill the ports but no cutter so have to wait for those. I have since mounted these blocks and started to bore the cylinders using a boring head on the mill

 

[droogs]

I thought the truck for the little boy was rather good :| :lol:

 

[Dalboy]

Spent the other day boring the cylinders quite pleased with the finish.







I also managed today to take the mounting flanges down to 1/8" and do a test fit to the frames a very light filing was needed to get them to fit comfortably with no slop I must get back to the coupling rods before I go to far

 

[CHJ]

Great progress, have you got a couple of meters of track section available for rolling tests?

 

[Dalboy]

Great progress, have you got a couple of meters of track section available for rolling tests?

No test track but will make myself a simple rolling road from some channel and 12 ball bearings

 

[Dalboy]

Things on the loco build have been a bit slow what with the excavator build and gardening preparing for our winter, digging up some of the dahlias for winter storage and dividing, picking some brussel sprouts and freezing them for the wife I hate the things.

Anyway I have managed some work on the cylinder end caps one end is pretty simple case of just turning to the correct size the other end has the gland nut and packing for the piston rod they still need a little work as they still need the gland milling to the correct size and the hole enlarged to be threaded for the gland nut.



I also managed to turn the two crosshead gudgeon pins which also needed a slot for a scewdriver to fit them. I did have to make one of them twice as they are fiddly to make they only have 1/2" diameter heads

 

[Malc2098]

Nice.

 

[CHJ]

Very neatly done as usual.

 

[SamQ aka Ah! Q!]

Spent the other day boring the cylinders quite pleased with the finish.

DSCF2712.JPG

Gad, just for a moment I thought you were boring that out with the hole gauge...

 

[Dalboy]

Spent the other day boring the cylinders quite pleased with the finish.

DSCF2712.JPG

Gad, just for a moment I thought you were boring that out with the hole gauge...

Looks like it from the first photo in that post just measuring to see if more needed to come off