Some details are unthinkable in 1/144 scale. But the trouble is, once you start thinking about them it is very difficult to stop. 🫤
When I started getting into scratchbuilding WW1 aircraft models about five or six years ago there were plenty of challenges and I've slowly been working my way through them. However, the absolute speed limit for what is possible in 1/144 always seemed to be the spoked wheels that many early aircraft carried.
Over the years it became a habit to imagine various solutions and run through them in my mind. I would do this when going to sleep, or if I was feeling bored or anxious or whatever. I must have gone over it hundreds of times. The biggest problem that I could see was how to hold the wheel hub in place and keep it centred so that the wires of the half-assembled wheel didn't cause it to deflect. Also: how do you handle the thing and mount it on the axle afterwards?
A couple of weeks ago I was in the kitchen, puttering around, when I suddenly had a thought; I was originally going to cast the hub. But what if I cast the hub, the metal axle and the jig itself -
all in one piece? The hub would then be pre-positioned centrally and at the right height every time. Plus the axle would strengthen it and in its turn be braced by the jig itself.
I stood there frozen for quite some time... this might work! 😮
It took several days to make the jig, plus the masters for the tyre and hub. Then a few more days to do a silicone mould and make some castings. Eventually, it was time to do some very delicate weaving.
I used 0.02mm copper wire, which scales out to 2.88mm spokes in real life. A pretty reasonable match. The threading process went okay, after a couple of false starts. There is a sequence that needs to be followed and it is easy to get out of sync. The inside spokes are the hardest to reach, but the outer ones are better. I think it took about 3 hours to do each side.
I was able to tack the 2nd half of the wheel to a short length of silver tube and use it as a handle to hold the piece so that it glued flush with the opposite half of the tyre. It wasn't the best idea, as I had to hold it like that for about half an hour until the resin dried. My hand went numb after the first ten minutes...
Once it was cured I could snip the external wires and shave off the supporting struts around the tyre. When I first cast the jig, I pushed the .4mm axle into the resin so that it would be an integral part of the wheel hub. Luckily I had the presence of mind to coat the axle in a suitable release agent. I didn't have a proper mould release, but went to the bathroom cabinet and used some of my wife's pawpaw-scented lip balm instead 🤫. It made the axle oily enough that I now just had to give it a push with my fingernail, and the wheel lifted easily off of the surface... Cor!
Here are some photos of the whole sequence, starting with the tyre. I'll be doing two more over the next few weeks and choose the best of them to use. With a bit of luck, there will be an aircraft attached to them too!
Spinning some styrene on my rotary tool to make the half-tyre.
Drawing the jig layout (not a pizza). The outside diameter is 55mm wide, which makes it something like 1/10 scale. However it is the bit in the middle which matters. That is 5.6mm across.
The sequence for threading the spoke wires. It's best to start down near 6 o'clock and start working anticlockwise.
How it looks when you put it all together:
A picture of the assembly jig with the recessed middle and setout holes around the outside
The wheel hub is part of the jig with the .4mm (and pawpaw-scented) axle tube embedded into it and protruding out the back.
The two halves of the tyre drop into the space between the supports. The first layer of spokes will hold the tyre down.
Starting the process of threading the wires... This might actually work 😲
Day 2 of the threading process and both halves have been done. A pause to catch my breath as I wonder how to put the lid on 🫤
Got it. Thankfully no wires shifted as I glued the 2nd half of the tyre down.
Snipping away the wires and supports. A push on the axle tube from below and the wheel lifts off of the jig.
It worked! A bit of a sand and we'll tidy up the seams later. But rather unbelievably it's a success. 😃
And lastly, a shot on my rather relieved palm for scale:
