1/32 A Loco for the Garden

JimG

Western Thunderer
After a few weeks, with a fair bit of frustration, there's been a small amount of progress. :) One job was to model the axlebox springs which would have to be removable. So I re-designed the hornguides with lugs to accept the springs, and designed the springs to fit them. I opted to use 14BA screws to hold the springs in plce and that was the first hold-up. I thought I had some 14BA taps and screws, but couldn't find them, so it was on to the Internet and order some. They came quite quickly but I had ordered screws which were a bit too short, so I re-ordered a longer version, but they got held up since the supplier was changing his courier and that incurred a few days delay. But we got the act together by the start of this week. :)

Here's the centre hornguide with its springs and screws.

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Apologies for shallow depth of focus. :(

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This shows the lug a bit better being fitted on the front of the existing model spring mount and I've also taken the opportunity to represent the spring mounting brackets on the frame.

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The springs fixed with the 14BA coutersunk screws. The countersink on the spring is drawn in 3D and printed. The screws will be fitted through the spokes of the wheels

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The rear axle on the locomotive has coil springs, so I drew some up and printed them. They actually work as springs although I don't know how well they might survive in service. :) The 14BA screws here are on the underside, so fitted from underneath.

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Here's the frame assembled so far with all the springs fitted. The resin taps quite well with the 14BA tap and the screws screw up quite tightly without stripping the threads. I was a bit worried that the 14BA thread would be too fine and that I might have to resort to coarser threads, but so far so good.

I've also probably got an answer to a bit more frame staying between the rear two axles. I've drawn up a firebox to fit in the area and that will supply good staying.

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I haven't printed one yet. I'm waiting to get the gearbox first so that I can tailor the print to suit. An order has gone out to ABC for a gearbox and motor so work will probably go on the back burner until the gearbox appears.

Jim.
 

JimG

Western Thunderer
Over four years later, we pick up the story again. :)

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The frames in the same state as they were four years ago with the centre areas having the ability to wave about in the breeze with no transverse frame members. I had thought about using the firebox to create a frame member and had drawn one up in Fusion 360 at the time. But I'm now using Solid Edge for 3D CAD and I haven't now got access to my original F360 files.

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So I re-drew a firebox in Solid Edge with the upper part to be the width between the frames to act as a frame spacer. Here's the basic box as printed alongside the frames...

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...and roughly in place in the frames. I'll re-draw the ashpan area to give a lot more detail once I've decided how the ABC motor and gearbox are going to sit when driving the rear axle. I'll have to adjust the internal dimensions of the firebox to suit the motor and gearbox.

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The next job was to turn up the three axles. I will be using split axle pickup so two of the axles are in two parts and the driven axle is in three parts to keep the gearbox insulated. The axles will be glued together using standard 24hr setting Araldite. The axles are silver steel and this turning took a bit of time on the Cowells. I was tempted to take the work out to the Myford in the garage to get it done quicker but my old dog had had dental work during the week and I wanted to keep an eye on him in the house as he recovered. The stubs on the axles are 3mm diameter and the sockets are 4mm diameter - so an 0.5mm gap which should avoid any shorts. :) I machined some 1mm thick washers from styrene on the CNC machine to form the insulated spacers between the axle sections. The axle parts are machined to be about 2mm overlength overall, to be machined down to length when the Araldite has set hard.

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The setup on the drilling machine to drill the 1mm holes to allow the Araldite to escape at the ends of the sockets.

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Gluing the parts together. The Araldite is poked into the socket then the stub is introduced and wiggled into position, trying to ensure that there is plenty of glue all the way down the joint. A bit of paper is placed in the "V" block to avoid any excess Araldite getting between the axle and the block. You can just see this excess oozing out of the bleed hole and the joint between the two parts. The heavy steel weight ensures that the axle is located firmly in the "V" block. I'll check the axle when it has been sitting for about eight hours and trim off this excess before it fully hardens.

Jim.
 
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Dog Star

Western Thunderer
How do you get the drill to start cutting on the diameter of the axle? Put another way, what stops the drill from skidding on the metal surface?
 

JimG

Western Thunderer
How do you get the drill to start cutting on the diameter of the axle? Put another way, what stops the drill from skidding on the metal surface?

You can just about see the centre punch mark on the axle piece under the drill. Otherwise, as you suggest, that 1mm drill would have been everywhere but where it should. :) I use a spring centre punch on the bench with the axle on another "V" block.

The driven axle is now glued up and left to set.

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With the three bits, this was a messier job with more excess Araldite about. So I let it start setting for a couple of hours, then took it out of the block and cleaned off the excess Araldite using acetone to get the surfaces clean, then replaced it in the "V" block to harden off.

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The other axles have been cleaned off after about sixteen hours setting, and returned to the "V" blocks with light clamping.

The acid test will be tomorrow when all the axles have fully set, when I chuck them up in the lathe and see how straight they are. :)

Jim.
 

JimG

Western Thunderer
Jim
What ever happened to your thread on building your garden railway. I have looked but can't find it.

Jon,

Here it is. :)


Not a lot has been done for a few years mainly down to other things getting in the way and my broken hip/Covid episode. Meanwhile the garden started approaching jungle status and I only really got back into it this year to try and re-establish some order. I got a fair bit of tidying up done in the good weather in the May/June period, but the poor weather in July and August (so far) has put a damper (literally) on more work. We are promised some better weather at the end of this week and I note some newspapers are now threatening a very hot period for the end of August. So something might get done.

The station boards next to the house are in good order and I might set up the station and goods yard on it to get something running in a limited fashion.

Jim.
 

Jon Nazareth

Western Thunderer
Thanks, Jim, it was nice to catch up with how far you had managed to get. I had forgotten that your posts were in the 'Area 51' slot. I now know where to look and can follow the progress with your garden layout.

Jon
 
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