Finishing off a 5" Gauge Simplex Loco

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sbwhart:
Sorry that I've not done an update on this for some time chaps but a lot of my time for the last few months has been taken up with holidays (artic circle) birthdays and anniversaries, the biggest of which was our 40th, spent a lovely weekend with all the family around us, it was really nice seeing our three grand kids all playing together.

Any way on the simplex front I reworked the steam chest and made new slide valves. Next up was making new motion plates these were fabricated from 5/16" plate and angle iron riveted together. I simple stuck the two plates together with two way tape and a pin, then marked the part out and milled it out to shape.

This is the finished motion plate

I also made new lifting block for the reverser and the lifting link the block for the lifting link was an interesting job it has a 4" curve that required the use of the RT.

This is the block the little bit with a hole in it assembled in the curve of the link I made two together.

I also moded my engine assembly manipulator to fix the simplex this makes it easyr to turnthe engine over to get to each side far better than mauling it around to get to the part you want to

The rest of the work was all about fitting bit cleaning them and getting them to work correctly, I spent a good few days trying to chase out tightness in the end I traced it down to one of the piston rings standing proud by about 0.002" it was sorted by cutting the groove in the piston a little deeper.

This is the state of play so far

I hoping to try it out on air in two or three weeks time so keep your fingers crossed.

Stew

sbwhart:
Thanks for your interest :(

I remade the reversing quadrant the one that came with the loco was a bit rough so I remade it.

The notches still need cutting but that won't be done until the valve are set.

Now I wonder if any one can give me a bit of advice on how to sort out the next problem I've come across.:-

I've tried a number of time to assemble the coupling rods and get it so that the wheel rotate coupled together but no mater how I tried they lock up, if I open the bearing out by 0.032" they will rotate over half a turn but lock up.

I measured the axle centres in the frame and they are correct within 0.004" and everything is square, I've checked the crank pins quartering out at they are spot on all the same on all three axles, I've checked the coupling rod centres out and they are spot on the correct centre distance, the only way I can get the wheels to turn over anything like is two make the bearings in the coupling rods big by 0.40 that is far to slack to my mind. The only thing that I haven't worked on is the throw of the crank they are how the original builder made them, so checked the throw out

The throw should be 1.0625" but it is far more important that the throw on the crank pins are all the same:-

What I got was axle 1 :- 1.087" and 1.092" axle 2 1.074" and 1.083" axle 3 1.080" and 1.063" so they are far from consistent there is up to 0.030 variation.

Ok hers the ? is this too much variation

Do I need to correct this and how

The only way I can think of correcting it is to recut the crank pin hole in the wheel to the next size up and fitting new crank pins.

Is there any Loco builders out there who can point me in the correct direction.

Stew

ozzie46:
Stew, when you try turning the wheels do you have packing pieces between the axle boxes and the spring plates to bring the wheels to running height like it would be when fully assembled? The plans say to use 1/8 packing pieces.

Also I have read that fits on Locomotives are almost a worn out fit. Don;t know how true that is.

Great job on the rebuild so far by the way. :thumbup: :thumbup: :thumbup:

Ron

sbwhart:
Hi Ron

Thanks for you're interest, and pointing out the need for packing I haven't tried that so will give it a go.

You right about the fits on locos they need to be slack but that's where I have a problem knowing whats too slack and what is just right to guess the only way to find that out is trying it.

Cheers

Stew

chipenter:
If the wheels are off the axle you could reduce the pins , and either make sleeves or smaller bearings , using a jig on a face plate .

Jeff

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