Fold up chassis - how to do it?

[Irish Padre]

I have to build this fold up chassis. Any tips on how to do it please ? Thanks !! 

[doilum]

Cut it out carefully leaving as many other components as possible on the fret.  Keep it flat. It looks quite thin. MY preferred method is to use an Exacto#2 knife cutting into the grain of a small ply or softwood offcut.

Drill out all the pilot holes 1mm whilst it is still flat. This is the time to consider plunger pick ups. Also check the fit of the axle bushes.

There appear to be two folding operations. Lacking any folding bars I rely on an offcut of steel bar to clamp the brass to the edge of the folding bench ( a60x30 offcut of chipboard).  MY advice is to burnish the brass before folding so that onc⁹e you are happy you can run a bead of solder down the fold line to retain that perfect 90° fold.

The complication is the double fold. I would do the short centre fold first before turning the work round to clamp the frame sides and bend up the rest of the work. A good set square is essential. Turn around and repeat. 

It is now time to say a quick prayer and test fit the wheels and axles. Hopefully it sits perfectly flat on a short length of straight track. I do have some plate glass but recalling Brian Clough's famous quote regarding Leeds Utd, I need to see it sit and roll on real rails.

It shouldn't be too far off and a little vertical adjustment to the axle holes with a small file will resolve the issue. Old school books remind you to ensure that a six coupled loco doesn't rock on the centre axle by filing the hole about 0.5mm . Don't solder the axle bushes until you are totally happy with the whole mechanism including rods.

Now have a coffee and wait for a completely alternative method to arrive. 

[DCB]

I have never had any luck with fold up chassis but that looks like an absolute B*****  with two folds needing to be made simultaneously front and rear with a gap between. I would use a very stout 12" steel ruler clamped to the brass sheet to make the bend around.  The second side bend is going to be really awkward.  It's very pretty but is it  a basis for a working loco?  

[fulton]

Do not know what scale this is, if 4mm I would use an etch bending tool, they seem expensive but make bending etched kits easy, particularly where there is not a lot of "meat" to get hold of, I have two a short and a longer one.

[Izzy]

I’d want to know a lot more about the rest of the etch and what the loco is before deciding how to tackle it. Am I right in thinking it’s a 2-4-2 of some kind? There is I presume another vertical frame spacer to fit just to one side of the lower axle hole? All the small bits that fold down with holes in them and the large end spacer will need doing first, especially the latter with the smaller one right next to it. Hm..  Would be tempted unless it folds up really easily by hand to break it up into separate parts and make it up that way. Just because an etch had been drawn up a certain way doesn’t mean it works, that the designer knew what they were doing. I’ve encountered quite a few etched kits like that down the years…….    
 

Bob

[Irish Padre]

Thanks everyone. It’s 7mm. An Irish 2-4-2T from Alphagraphix. Being an Irish modeller I have to scratch build most chassis so this is a bit of a novelty. Roger’s kits are generally top notch but the process involved here had me foxed. Thanks - you’ve given me some inspiration! 

[Izzy]

Ah, I kind of wondered if those small fold down flaps with the holes were for some form of radial truck rather than a pony truck working inside the frames. Couldn’t see and still can’t what the narrow fold down parts inside the centre of the frames are meant for. Hope it all goes together well for you. 
 

Bob

[doilum]

My guess would be the radial axle.

What gauge are you working to?

Edited April 28 by doilum

[Irish Padre]

6 minutes ago, doilum said:

My guess would be the radial axle.

What gauge are you working to?

They are indeed for the radial axles. I model to Irish 5’3” - 36.75mm gauge. This is one of my scratch built locos 

[doilum]

And you are nervous about folding a chassis! Excellent work.

[Bucoops]

9 hours ago, fulton said:

Do not know what scale this is, if 4mm I would use an etch bending tool, they seem expensive but make bending etched kits easy, particularly where there is not a lot of "meat" to get hold of, I have two a short and a longer one.

 

I have a large and a small one, both from ebay and both very good prices.