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Discussion in 'G3' started by Jon Nazareth, 25 July 2015.
A lovely shade of green. Very fitting for such a locomotive.
Up on it's wheels now. I didn't want to rely on a scale piece of rope to act as a linkage so, I fitted this 5 link coupling.
Congratulations - that is looking rather nice.
Thanks, Adrian, much appreciated. It could do with some black lining but, I don't think that I could get the transfers dead straight. Still, it looks okay with out.
Ive put off lining my Neilson for similar concerns. Ive tossed up the idea of making some lasercut vinyl spraying templates but Ive never gotten to it.
Frames, axle boxes and guides. I messed up the first set of frames, the first set of axles and, the first set of axle boxes. Hopefully, I'm now on the straight and narrow and all mistakes are behind me.
There are two horns per axle box with a spacer in between. The prototypes look to be a castings of some sort but I am going to use some rectangular brass instead of the castings. If you care to go back to page one, entry five, the strange looking castings/spacers can be seen top right of the drawing. Originally, they were riveted to the guides/horns with the rivets cleaned back flush both sides at least, that's how it looks in photographs. I will eventually rivet the ones on the model but leave the domed heads showing on the outside but flush on the inside. The horns are marked out for drilling the holes for the rivets and I shall get back to that now.
Actually, I'm waiting for the day to cool down and then, I shall go out and mow the lawns
I had spent some time riveting up the double axle box guides and temporarily bolted them to the frame sides. I then placed the axle boxes onto the axles and dropped the whole lot into the frame sides. None of it looked right and so, I placed a scale drawing of a side elevation behind to see what was what. Surprisingly it does look right and I'm quite leased with the outcome. I shan't bolt the buffer nor the drag beams on just yet as I want to make up the axle tie rods and I think this will be easier with the frame sides lose or simply as they are.
By the way, I was going to use just a single axle box guide per bearing but Jamie Page persuaded me to use two as per prototype. I'm glad that he did as it looks much better this way.
P.S. None of the axles are to length which is why it looks a bit odd.
Tie rods fitted and that tapered piece, not sure what it's prototype function is, that butts up against the buffer beam. The trailing axle has been machined to length and runs well as do the other axles. In fact, it rolls very well when given a push. I couldn't help but add the tender to this shot just to see what ithe whole looked like. I was going to try and chemical blacken the whole of the chassis but, looking at the tender paintwork, it may look a little odd. I need to drill some holes in the tie rods for the other side and then, I shall move onto the outside cranks. Not sure how I'm going to make these but I'm sure I'll come up with a cunning plan .
The drawings show the bolt heads that hold the axle box guides in place on the outside but when I tried the axles with the wheels, they fouled on the nuts/protruding threads and so, I had to swap them about, putting the bolt heads on the inside. It's a bit of a shame as the heads looked scale to me. With the nuts on the outside they look far too big but I don't fancy turning down the thickness of those nuts to make them look a bit more scale, hey ho.
Thats looking fantastic!
For the cranks, could you secure them with a grubscrew in the crank. Annoying to quarter and align, but removable.
Or see about modifying Slaters offering?
Thank you for that. I can't think of another way of securing the crank on the axle other than with a grub screw unless, someone out there has a different idea that would 'look' better. I've never seen any of the Slaters cranks but will go to the website now.
Slaters haven't illustrations for a lot of their bits and pieces and, I couldn't find any for G3. I shall have a go at making my own.
Below is a picture off the coupling rods. The oilers may be a little on the large size but any smaller and I wouldn't have been able to handle them. As it was, I lost two in the making when they fell into the swarf on the lathe, never to be found. I did look to see if there were any for sale on the Cornwall Model Boats website but couldn't see any there.
If there was a way to, easily, make rectangular slots, I would have a go at fitting some cotters. I did think of fitting some dummy round ones but thought that that would be worse than none at all.
I managed false cotters with a multi-layer lamination, but those round rods youve managed look very good. Would take a lot of filing with my method to get such a shape.
You could drill a hole and fit a pin flattened to shape in the visible area? Would probably look the part.
I did try that but to no avail. The coupling rods are made up from two ends which are drilled and then the rod silver soldered in place. I went for the silver solder so that it would form a web and mimic the forging of the original rods. When I tried the false cotter idea, the drill broke into the hole that I had made for the round bar and then, it wandered off when it came out the other side. I gave up on that idea and plugged the hole with some nickel and then cleaned it back. The problem with that was the nickel, and the silver solder don't have the same appearance as mild steel and so I thought, I know what, I'll blacken them and then all will be fine. Wrong. The steel came out one shade of grey and the silver solder another making both types of material noticeable. By this time, I was thinking about remaking the rods by turning a piece of flat between centres and see how that would work. Not tried it yet as I'm about to go onto making the cranks. There hangs another tale, fixing the cranks to the axles. I did think about cone pointed grub screws. I found some that are 1.6mm in diameter but, they are too long and would protrude from the crank. Jamie suggested drilling and pining which would give a more acceptable finish once they were filed flush. The only problem would be drilling the crank with the wheels, axleboxes and, for the driving axle, the motor all in situ. With the wheel so close to the crank, I'm not sure that it is a feasible option i.e., the chuck would foul on the wheel. I'll think all about that once I have made the cranks. If there is anyone out there who has made a loco with outside cranks, how did you fix them?
You could get them nickel plated to get an homogenous colour. I have used that technique, admittedly on probably bigger components.
Well, that's a first for me - a 2mm scale modeller telling a Gauge 3 modeller that he is used to bigger components!
Thanks, Tim, I'll keep that in mind.
Getting back to the problem of securing the cranks on the axles. These may sound like the words of a drowning man but, would Loctite on it's own be strong enough to secure them?
Model engineers have been using cyanoacrylate adhesives to fix driving wheels on axles for some years now so I would think that would be a possible solution. But I believe you have to leave some clearance in the joint to allow space for the adhesive which might cause problems when fitting the cranks to the axle ends and getting them truly concentric.
Here's one thread from the Model Engineering forum on the topic
wheels and loctite | Model Engineer
Here's another thread from another forum
Loco Wheels and Loctite | Model Engineering Clearing House
Note that in this thread a contributor mentions turning a one thou deep channel on the axle end to provide space for the adhesive yet allowing the wheel to align on the axle on either side of the channel.
There also seems to be a tendency to pin the wheels after gluing for a bit of "belt and braces".
3/4 ton of traction engine is a bit bigger than G3...
Thanks there is some very useful information there.