Progress on the 3/4" scale 0-8-0 switcher

Where users can chronicle their builds. Start one thread and continue to add on to it.

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Old England
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Joined: Thu Oct 05, 2006 1:44 pm
Location: Bath, UK

Progress on the 3/4" scale 0-8-0 switcher

Post by Old England »

Hello folks, work has been a little slow as summer is dragbike time and I have been desperately trying to get it ready for the track - too many projects I think!
Back to the railway track: I cut out balance weights from blanks parted of some steel bar, the cast in ones were totally wrong and just to make things worse one pair had completely odd weights like the old 'American' style (concentric with the wheel tread). Not impressed Reeves!
Next problem was cutting the keyways; couldn't get a 2mm broach so in the end I made one from gauge plate, and with the aid of three 0.25mm shims managed to do the job with relative ease. The keyways in the axles were done using a setup like the one Roy Johnson used (Modeltec July 1986), but with a small mod to the indexing clamp.
The keys shown are temporary ones just to test the fit.
One final job over a quiet weekend was carving the pilot beam coupler pocket from solid brass. This took 4 hours on lathe and mill using rotatry table and dividing head, a case for CNC perhaps Bill! It still needs a bit of cleaning up but doesn't look too bad. Fortunately the tender one is a few years away.
Looking forward to Autumn when I can get cracking on with things.
Attachments
keyway.jpg
keys.jpg
coupler pocket.jpg
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LVRR2095
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Location: Maine, USA

Post by LVRR2095 »

Your "drag bike" would happen to be a Vincent, would it?
Keith
Bill Shields

Pocket

Post by Bill Shields »

Your pocket looks just fine.... :D

CNC doesn't always make it better, just less time-consuming in the dial-spinning area....of course if you are going to make many, then the choice is clear....

My big problem is that I write programs 20 years ago, and cannot find them now, so I start over, have 'better ideas'...and end up making one-offs anyway...

oh well...such is old age...
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Old England
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Post by Old England »

Hi Keith,
No not a Vincent, based on the auction of a 1000cc Vincent recently at £73,000 + premium and tax (over $100,000 I guess) I couldn't afford the air in the tyres of one!
No, my bike is based on a 1975 Honda 500 twin (the one with torsion bar valve springs) and the whole philosphy behind it is to go racing at minimal cost. I make everything myself: pistons , cams, cylinder block etc etc, bit of a long term project at 5 years and counting!

Thanks Bill, I am trying not to get too carried away with detail; I would like the finished loco to look good but then I want to finish it!
I based the pocket on one in the 1930 Locomotive Cyclopedia which has some very tricky undercut tapers. 5 axis CNC would have made short work of it, we can all dream. I must say I did enjoy making it though, and one of the great pleasures for me in engineering is figuring out how to make something. I must be a sad old git!
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Old England
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Location: Bath, UK

Post by Old England »

Back again! Things with the dragbike have gone better than planned so with a holiday weekend ahead I decided to tackle the weightshaft mounting and motion plate.
The weightshaft mounting first, all going great until I milled some cosmetic detail into the top instead of underneath, oh well out with the welder to put the metal back! The holes in the top of the bracket are tapped to take screws from underneath so will be filed flush when the whole thing is finished, bearing in mind this is supposed to be a cast bed frame.
The bearings where carved from gunmetal and are secured from underneath, the bearing cap studs and nuts are dummies.

I pondered for a while how to make the motion plate; I particularly wanted to get the whole thing very accurate and replicate the cast appearance of the real thing. Eventually deciding to machine it from 19mm X 130mm cold rolled steel plate, trusting that the symmetrical nature of the thing would avoid distortion (I would have been really sick if it had gone banana shaped after 6 hours maching!).
Naturally there was a lot of material to remove as most of the plate is only 4mm thick but I have a hefty turret mill so that wan't a problem, mind you I wouldn't have tackled this without a digital readout and electronic edge finder. Just remember to make sure the edge finder and material are clean before 'edge finding' as many of them can give a false reading by shorting across quite large gaps.
You can see four centres in the plate, these were used to centre the plate on the rotary table which was in turn centred under the milling machine spindle. Using these centres I was able to profile the guide bar supports.
Unfortunately the photos I carefully named to get them in the right order are back to front, "such is life" as we Yorkshiremen say.
All that remains is to spend hours cleaning it up with files and emry paper.
Attachments
motion_plate_3.JPG
motion_plate_2.jpg
motion_plate_1.jpg
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gwrdriver
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Post by gwrdriver »

Old England wrote:No not a Vincent, based on the auction of a 1000cc Vincent recently at £73,000
In 1966 I was riding a 1958 Triumph Tiger Cub and I knew of a guy way out in the country who had a roadside bike repair shop and his personal favorite bikes were Vincents. He had four beautiful ones, including a Black Shadow. Before long an unfortunate series of events caused him to have to liquidate the shop, and the Vincents, and he offered me my choice for $500. I declined because I was going into the service (and in 1967 you never knew if you were coming back), and I didn't have a place to store it. Would'a, could'a, should'a.
GWRdriver
Nashville TN
Bill Shields

WOULD'A....

Post by Bill Shields »

Killed yourself on one of those critters.

Hell for fast in a straight line..didn't handle all that well and the brakes weren't up to the task..

Better to have you off Vincents and around for steaming... :shock: :D

Old E:

VERY NICE PLATE...6 hours or 20.......beautiful work....
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Old England
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Re: Progress on the 3/4" scale 0-8-0 switcher

Post by Old England »

Hello again folks, I believe it's not unknown for live steam loco projects to have substantial periods where not much happens, though perhaps 16 years is pushing it a bit! Work and motorcycle projects got in the way. Anyhow as of January work on the 3/4" scale 0-8-0 is back on and this time it is the only project as I finished my final racing motorcycle in 2016, I'll post some photos of this in the IC section when I have time as it fits in with a number of the conversations there.

Most of January's spare time involved working on the CAD drawings with the help of a great photo of a N&W S1a by Winston Link, a lot of time also vacuum cleaning the model after retrieving it from the top of the bookcase! After examining it closely I decided to bin the motion plate, just not up to scratch. Also remade the driving axle balance weights to replicate the larger ones used on some S1a locos.
Next up all the crankpins were made, the intermediate and trailing ones have castellated nuts and the leading ones a recessed stainless M2 cap screws. All these have 1mm diameter dowels to stop the rod retaining washers rotating; nuts hide the dowels and the leading ones fit in blind holes on the underside of the top hat washer thing. Must remember not to bend those split pin ears like that on final assembly, a hangover from motorcycle building!

I can't promise to update regularly as I 'm still working full time but will make an effort now and then :)
Attachments
lead1.jpg
lead1.jpg (61.7 KiB) Viewed 7315 times
lead2.jpg
lead2.jpg (90.37 KiB) Viewed 7315 times
lead3.jpg
lead3.jpg (111.4 KiB) Viewed 7315 times
pins.jpg
pins.jpg (115.42 KiB) Viewed 7315 times
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JBodenmann
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Re: Progress on the 3/4" scale 0-8-0 switcher

Post by JBodenmann »

Hello My Friends
Very cool set up for the recessed bolt side rod retainer. The anti rotator pin should work well.
Jack
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Old England
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Re: Progress on the 3/4" scale 0-8-0 switcher

Post by Old England »

Hello Jack,
I've being gazing with wonder at your work on here in 3/4" scale for a few days, sooo impressive! I wasn't quite sure if I could do the leading crankpin like this until I found a company here that supply tiny precision screws in stainless, the M2 cap screws have the perfect head size.
Carl.
Pontiacguy1
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Re: Progress on the 3/4" scale 0-8-0 switcher

Post by Pontiacguy1 »

Are you sure the lead axle crank pin will clear the cross-head? The rear one will be free and clear but there is often very little room between the back side of the cross head and the lead driver crankpin. It is possible that I misunderstood where this is supposed to go.
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Old England
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Re: Progress on the 3/4" scale 0-8-0 switcher

Post by Old England »

The leading crankpins are the ones with the recessed cap screws. Clearance between the outside of the top hat washer and the crosshead piston rod boss (widest part of crosshead) is 1.6mm so no problem.
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