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Welcome to the G3 Clubroom. This is the friendly online forum where members share ideas and inspiration, suggestions and advice, modelling tips, pictures and drawings, and general chat about our fine hobby of Gauge 3 railway modelling. A warm welcome, and enjoy your visit here today.

Recent posts

#1
Locomotives (steam outline) / Re: LNWR Precedent
Last post by Nick - Mar 25 2024 20:07
Haha! Actually I do quite like the Crewe 0-8-0s, particularly the ones that had to have a kink in the valve rod to avoid the front axle, but I might want to negotiate a discount for quantity on wagons.

Now, where were we? Oh yes, tyres. Warning: this post is about turning tyres, so if you have no interest at all in lathe work, you may decide it is not for you. Feel free to move on.

And if you're one of those annoying people with a toolroom quality lathe and a zillion years' experience, this post certainly isn't for you. I'm not in your league. I'm one of those people who thought it would be fun to have a lathe and went on from there.

The first task is to reduce the blank to thickness and bore out the ID to the correct size. My chuck was only just big enough, but it did hold them securely. I used a headstock backstop so that each blank goes in the same position, and a carriage stop to avoid running into it with the boring bar. All the tyres were done using this setup before moving on.

The lesson here was the layer of hardened material that is formed by the heat of the laser at the cut edges. Reminiscent of the skin on the sand casting beloved by model engineers of a certain generation. Not tool steel hard, it does cut, but takes it out on the tool.

I was expecting that, but I was surprised how deep it was - up to 0.8mm in my case. It dulled the edge of an HSS tool very quickly. Yes, I'm still in the 20th century for lathe tools but I mostly use HSS tools because so much of the turning that I do requires a special tool form to be ground and it's a lot easier in HSS.

That was certainly true until I discovered that the awkward bits could be 3D printed.

Anyway, I switched to a carbide insert boring bar which did a much better job of cutting. The only tool I had available is much longer than I needed so it vibrates a bit and the quality of the finish is not great. But I will be gluing the centre in place, and a slightly rough finish (this isn't an argument for a ploughed field finish) means a greater surface area in contact with the glue which is all to the good.

Tyre_1.png

Once the ID is correct the tyres go on this fixture. Where the tyre is mounted it is turned in situ to a good running fit on the tyre ID. Then it never leaves the chuck until the whole batch is done to ensure that the tyres are concentric.

Tyre_2.png

Each tyre is clamped in position, and the first task is to reduce the OD to the diameter over the flange. Again there is a layer of hardened material to get rid of and I used a carbide insert tool for this. Incidentally, when I ordered the tyre blanks from the cutting firm, I did add enough margin on both ID and OD  - just. Phew.

Tyre_3.png

Now to form the profile. Lock the saddle and set the top slide over at 3 deg to give the correct taper on the tyre. The tool is moved exclusively by the top and cross slides in this operation. The leading edge of the tool is set at the correct angle for the flange. Then cut to final diameter plus a very small margin (say, 0.05 mm or a couple of thou in old money).

Tyre_4.png

Now for the controversial bit! I get the final shape using a form tool (from Mark Wood). I like it because the final profile is entirely consistent. Lock everything that can be locked on the lathe, use a very slow speed and feed the tool in slowly. If you do it right and keep the final cut very fine, it doesn't chatter.

People have told me they can get just as good a finish with conventional tooling and the form tool isn't worth the cost. I just checked and I see that the cost is almost double what I paid about eight years ago, so you might think twice about it. Anyway, I've done about 40 tyres in G3 so far so it's beginning to pay for itself.

Tyre_5.png

We're still not quite finished. The surface needs some attention with a fine file (I know, sacrilege) and wet-and-dry paper. Then it is finally done.

Tyre_6.png

Rinse and repeat twenty times. A pile of finished tyres is gradually building.

Tyre_7.png

That's it. There are lots of instructions on the web about how to turn wheels from castings, but I decided to set out how I did it from laser cut blanks, which isn't quite the same. If you stayed the course, thanks for your company.

Nick
#2
Locomotives (steam outline) / Re: LNWR Precedent
Last post by MikeWilliams - Mar 24 2024 13:43
Two tenders!  I can't wait to see what the second engine might be.  If its a goods engine you'll be wanting plenty of LNWR wagons  ;)

Mike
#3
Locomotives (steam outline) / Re: LNWR Precedent
Last post by Nick - Mar 22 2024 18:39
The loco has now gone to the paint shop, where it will be for some time because painting isn't my favourite task and I'll happily take any excuse to do something else. The present excuse is that bits for the tender have arrived and are just asking to be worked on.

The wheels, as before, have 3D printed nylon centres. Previously, I made the tyres for the loco wheels from some large diameter steel bar. This time I got blanks laser cut in steel. It actually worked out roughly the same price (large diameter bar isn't cheap) and should be quicker to cut because there is much less material to bore out from the centre.

Carrying wheels.png

So why so many wheels? Well, I decided to get enough parts for two tenders. The LNWR must have built lots of these tenders because I've seen photos of them trundling around behind many different classes - so I have options for future (undefined) projects. I might even build two because it's usually quicker to build together rather than one after another. I also needed a new wheelset for the loco to replace the existing one that has the wrong number of spokes (oops), and I added a few more just because. Actually I think I got a price break on either the centres or the blanks. It's worth seeing where this cuts in when placing an order.

Along with the tyres, I ordered the steel parts for the tender frames. Again there's enough for two tenders. When I get bored of turning tyres I can start assembling this lot.

Tender frames.png

Nick
#4
G3 / Anyone for Dual-Gauge?
Last post by Peaky 556 - Mar 17 2024 19:34
Sorting through my GRS plastic sleeper units I find that I have quite a few dual gauge ones (G1 & G3), mostly new.  Would anyone with standard G3 sleeper units like to do a swap? 

It seems a shame to use them just on a G3 layout. I have no intention of using 45mm gauge, but if someone is of half a mind to, one day, then instal these now and add the 3rd rail later!

Failing that I shall just use them myself.
#5
Items Wanted / Re: WANTED: LNER B17 'Long Ten...
Last post by Doddy - Mar 15 2024 20:33
Ashley, John,

I am pleased to have just had a conversation in which Richard confirmed that he can supply the 4200 tender etches for this project.

Apart from the addition of an extra set of buffers, the snowplough blade and the removal of the beaded flares of the tender, Doncaster Works appears to have left most of the tender in its original condition. Including the water pickup, dome and toolboxes.
#6
Items Wanted / Re: WANTED: LNER B17 'Long Ten...
Last post by John Candy - Mar 14 2024 21:38
J39s were fitted with two sizes of Group Standard tenders : 3500 gallon tenders (J39/1) or 4200 gallon (J39/2).

Not sure without checking which is fitted to RT's models.

John.
#7
Items Wanted / Re: WANTED: LNER B17 'Long Ten...
Last post by AshleyW - Mar 14 2024 19:03
you could also buy the etches and all the parts for a group std tender off richard toplis, as he's made plenty of J39'S
#8
Items Wanted / Re: WANTED: LNER B17 'Long Ten...
Last post by Doddy - Mar 14 2024 17:18
Thank you John,

Steam engines is a rather new topic for me, at £85 Blackgates drawings are a bit too...

I'll order the Isingglass drawings as a starter.

Robert
#9
Items Wanted / Re: WANTED: LNER B17 'Long Ten...
Last post by John Candy - Mar 14 2024 16:57
The larger tender fitted was the LNER Group Standard 4200 gallon tender and there will be a drawing in the Isinglass collection. Although they do not list drawings up to G3/2.5 ins  in the catalogue, they have, in the past, produced drawings in our scale by request. I have a number of GCR and GNR drawings produced by them.
Regards,
John.

P.S. Have tracked down my copy of catalogue and drawing is listed as "GROUP 304-B Gresley 4200 Gallon Group standard tender".
#10
Items Wanted / Slips Wanted
Last post by Peaky 556 - Mar 14 2024 11:45
This is a superb piece of track engineering. The traditional 'station throat' pointwork, eminently suitable for a terminus with four platforms, as either approach track can service any of the four roads. It comprises a pair of opposing points, a crossover then two double-slips. All close-coupled and fitting within an 8-foot length yet having point radii of around 6m.

My regret is that I don't have a terminus station. What I do need are a couple of single (or double) slips, for feeds out of my through station.

I'd very happily swap this formation for a couple of slips, but I'm pretty certain that a couple of new slips with code 330 rail would cost more than I'd realize for this complete formation.

Regrettably, I think I'm going to have to butcher it to extract the two slips I need, unless anyone steps forward with a swap...

Regards, Tim