Bigelov's projects

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Bigelov
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Joined: Wed Sep 04, 2019 4:51 am
Location: Albury Australia

Re: Bigelov's projects

Post by Bigelov »

Late last year I was talking a bit about handrails and jigs, initially related to the Meeker Southern caboose and I mentioned that I would go into more detail. Better late than never...

Here are a few of those jigs. They are basically 1mm (0.040") piano wire poked into holes drilled in 3mm (1/8") MDF.
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The trick is to know where to drill, and accurately drill the holes. Although more low-tech than the 3D printed bending jigs above, they are (probably?) more heat resistant for soldering. And you can see scorch marks on the jigs.

Below is the jig I used for making the Meeker Southern SW9 handrails. They are very different than the MTB railings as used on a lot of SW9's. You really need to know where the handrail mounts to the chassis or body, and the dimensions between these points, and the thickness of wire that you will be using.
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A good straight-on photo of what you want to make is also very handy, but you can make an educated guess with an angled photo based on the mounting points and also heights measured against body details. I use a pair of calipers to measure points and to lay out for drilling holes.

You can see the styrene drilling template that I use. You can also see (zoomed in on the Flickr page) score lines on the styrene where I have used the calipers to mark out drilling points. I use a predetermined point below, and to one side of the template to take all my measurements from. Something like 10mm is easy to add onto the measurements you need to transfer. Just make sure the edge of the material is square! The SW9 handrail is quite complicated and so I have penciled in marks where the wire needs to lay on the jig. The smaller holes are where the end of the handrail bends over into holes in the pilot.
Steve B
Russia in Narrow Gauge
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Bigelov
Posts: 106
Joined: Wed Sep 04, 2019 4:51 am
Location: Albury Australia

Re: Bigelov's projects

Post by Bigelov »

Below is the jig and a pair of handrails I started for the Caboose end platform. It was at this point that I stopped working on the caboose as I couldn't get my head around how to make the rest. But back to the jig...
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You can see on the wires in the jig above that there are three pins against each wire. This allows the wire to be held by three points in a triangular arrangement. For laying out the jig, you mark the first hole, then add the thickness of the pin and the thickness of the wire to know how far apart the pins need to be. On the styrene SW9 template I measured all the vertical spaces first (horizontal lines), and then the distance from an edge was marked with a point.

Below shows the caboose jig in action.
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Wires are cut longer than needed and placed in the jig. Masking tape holds these extra long wires in place. You may have noticed in the first caboose jig photo that there is some gaps between the pins and the wire. An error in drilling... Masking tape holds the wire in the right place and stops it moving while soldering. You can also see some brass strip (0.5 x 6mm) that I also use to hold the wires down flat.

This last image shows the shorter Cryogenic car handrail with the wires in place and ends taped down. It also shows a hobby blade for a sense of scale.
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The weight of the brass strip is good for holding the wires in place and can be moved around to hold multiple pieces of wire close to where you are soldering.

I hoped this makes some sense? Please ask about anything that you find confusing or would like more information on.
Steve B
Russia in Narrow Gauge
Bigelov's Flickr Account
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ConducTTor
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Re: Bigelov's projects

Post by ConducTTor »

Looks really good. Do you find the jig fixtures shifting at all in the wood as they are used? Does a metal base make any sense? Or is that too much of PITA to make for just one or two pieces?
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Bigelov
Posts: 106
Joined: Wed Sep 04, 2019 4:51 am
Location: Albury Australia

Re: Bigelov's projects

Post by Bigelov »

The most I have made from these jigs is two items and haven't had any problems. The pins stay in the MDF, except in the bending jigs, so it would just be moisture absorption, hard handling and heat that would affect the jigs. Two pieces are just not enough for any problems.

I don't think a metal jig would be good as it would act as a heat sink while you are trying to solder the pieces together. There is probably some heat resistant sheet that would be better, like unclad PC board or something, but with so much MDF, and so few replicas to make, I haven't looked into that at all. If you were going to do a batch of things, like photo etch kits wagons or something, I think it would be a good idea to get some better material and make jigs to hold things precisely and repeatedly.
Steve B
Russia in Narrow Gauge
Bigelov's Flickr Account
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ConducTTor
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Re: Bigelov's projects

Post by ConducTTor »

PC board is an intersection idea, thanks.
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