Doing a jig

[petermeyer]

I bought a Hobby Holidays jig after reading Geoff Holt used one in his books on Locomotive Modelling (Wild Swan) and have not looked back since. I have used it for all chassis including tenders. I thought it might be useful to record its use here.

IMG_1690.jpg

I'm in the habit of using the jig to set up the chassis rigid in the first instance. This ensures that at least I get the axles parallel and square. This example is a GWR 3521 4-4-0 kit which is an old one from PeterK. This had the space for the hornguides already etched out, so I filled these in and added some bearings; usually kits come with holes for the bearings which I use but pre-cut them half way to ease cutting out later. This kit had spacers for EM but I swapped these for Comet P4 spacers which are Nickel Silver as are the frames in this instance. (apart from the front spacer which is brass from the scrap box). The spacers are soldered up whilst in the jig.

thumbnail_IMG_1230.jpg

I like to establish the fixing points for the footplate early on. This footplate is quite advanced. The front fixing holds through the bogie and up into the plate the secures the smokebox. The rear 10ba nut will be hidden under the cab floor.

thumbnail_IMG_1232.jpg

Next I made the coupling rods up. The rods in the jig are shouldered on one end down to 1.5mm (the other end being 1/8"). So I set the jig up by reversing the alignment rods and fitting both coupling rods over the 1.5mm spigots. This is a good double check to ensure they both match, which they do.

thumbnail_IMG_1229.jpg

Next stage will be to reverse the alignment rods with the 1/8" ends showing and to make a start on fitting the High Level Hornguides.

thumbnail_IMG_1231.jpg

[petermeyer]

Here's one I did earlier.

This shows the hornguide cutouts pre-slotted for a more traditional chassis with temporary bearings soldered in. This is a Wills/SEF GWR County 4-4-0

IMG_0029.jpg

In the jig:

IMG_0031.jpg

And soldered up

IMG_0032.jpg

The cutouts are then cleared with a piercing saw.

IMG_0035.jpg

Or sometimes they can just be snapped out

IMG_1683.jpg

The assembled horn blocks and bearings are soldered in with the help of an old-school spring to keep everything tight. This is a London Road LNWR 0-6-0 Coal Engine. I solder from the top and bottom and rotate the piece in the jig. This is the underside. The bearings are colour coded to make sure they go back in the same place.

IMG_1694.jpg

And just to check it all lines up.

IMG_1699.jpg

[Winander]

This is very useful as I have never seen the detail of one of these jigs and nor a demonstration of it in use. It appears the alignment rods are reduced at one end to 1/8th" and have the 1 or 1.5mm spigot for the coupling rods at the opposite end. The centre section being greater than 1/8th in diameter. Is this the case? I wonder why they didn't just put the spigot on the end of the 1/8th section?

[petermeyer]

This is very useful as I have never seen the detail of one of these jigs and nor a demonstration of it in use. It appears the alignment rods are reduced at one end to 1/8th" and have the 1 or 1.5mm spigot for the coupling rods at the opposite end. The centre section being greater than 1/8th in diameter. Is this the case? I wonder why they didn't just put the spigot on the end of the 1/8th section?

Hi Richard

Yes the alignment rods are as you say turned down to 1.5mm on one end to match the holes in the rods. I guess they didn’t turn down the 1/8th end because that may have caused too much deflection the rods only being held in place by the fatter centre section.

There are various screws adjusted with Allen keys that are used to lock everything down once the jig is aligned. There is a warning not to over tighten these.

Peter

[petermeyer]

I forgot to mention that the short ends with the spigot are also used to set up a rolling road that exactly matches the wheelbase set up in the jig. I’ll put a picture up.

[petermeyer]

Here you go: GWR Metro on rolling road

https://youtube.com/shorts/fZCro3uqoFQ?feature=share


Peter

[petermeyer]

The small Metro almost finished, buffers, whistles and numberplates to complete.

thumbnail_Metro.jpg

I'm not happy with the lining but since doing this I have got a Kern ruling pen from Jeremy. I was thinking of repainting it.