Alan's Workbench

[Tullygrainey]

The Kirtley comes unstuck.

Having arranged some chassis mounts for loco and tender and fitted an insulated drawbar, I stripped the Kirtley of its black paint to reveal some quite nice white metal castings.

 

Then this happened...

It's difficult to see in the photo but the crank on the centre axle has fractured. What seems to have happened is that inserting the crankpin into the crank - standard Gibson practice for wheels,  the crankpin cuts its own thread as it's screwed in - weakened the crank and caused it to break. On examination, 4 of the other 5 have cracks. I think John @Mayner may have alluded to this possibility in an earlier post above. I should've listened

Having a think about how to proceed. Repairing the crank is probably futile. The others may go the same way. I'm happy with the Gibson cranks but if I use them again I'll ream the holes a bit before inserting the crankpins and secure them with Loctite or similar.

Parked for now.

(It, not me)

Alan

[Galteemore]

That’s such a shame Alan! Frustrating thing to fix but if anyone can find a way….

[Mol_PMB]

Oh no! I was just thinking how good it looked in bare metal, and then that disaster!

Looks like a whole new set of cranks is needed - are they still obtainable? I'm sure you can sort it out. 

Get the body painted to inspire yourself?

[Colonel]

Likewise the bare metal looking good, though if you expand the photos, it makes you realise how etched brass moved things on - avoiding the chunky edges in particular. No need for extra ballast though!

 Indeed, wonder if the weight has contributed to the cranks fracturing?

[Tullygrainey]

3 hours ago, Colonel said:

 Indeed, wonder if the weight has contributed to the cranks fracturing?

Probably David. I'd say inserting the crankpins caused the cracking in the first place but in use, the weight would surely have finished the job in the end. Replacement rather than repair is probably the better option now, with a bit more care next time!

[Horsetan]

18 hours ago, Tullygrainey said:

....Then this happened...

It's difficult to see in the photo but the crank on the centre axle has fractured. What seems to have happened is that inserting the crankpin into the crank - standard Gibson practice for wheels,  the crankpin cuts its own thread as it's screwed in - weakened the crank and caused it to break. On examination, 4 of the other 5 have cracks. I think John @Mayner may have alluded to this possibility in an earlier post above. I should've listened

Having a think about how to proceed. Repairing the crank is probably futile. The others may go the same way. I'm happy with the Gibson cranks but if I use them again I'll ream the holes a bit before inserting the crankpins and secure them with Loctite or similar...

Not had that happen with AGW outside cranks before. Having said that, I have experienced some being loose on the axle, and a couple (the specific type for the 08 shunter) have actually split when eased onto the axle.

There are a couple of ways to alleviate this: 

1. Countersink from the back of the crank; once seated, Loctite 601/603 or Nutlock 242 should help the bolt keep its grip.

2. Don't overtighten the bolt when you get it in.

3. For the axle, partly running a 3.2mm drill from the rear will allow the axle to be inserted more easily. Then it's a case of either running Loctite in as the crank reaches its final position, and/or running a fine drill through the crank and into the axle so that the crank can be pinned in place - not easy.

 

Note: AGW and the old Sharman outside cranks seem to be based around a generic 22" stroke.

Ultrascale only produce outside cranks for their 08 shunter wheel, and these rarely if ever give problems. Their crankpin system seems to be more secure; some people redrill AGW wheels to take Ultrascale crankpins instead.

[Tullygrainey]

With the Kirtley's chassis out of commission for the time being, I've done some more work on the body shells, replacing handrails and  adding some missing details.

Still need to source some buffers. Nothing in the drawer to suit.

[Tullygrainey]

A strong sense of déjà vu hereabouts as another GNR(I) PPs 4-4-0 makes its way through the erecting shop. This one is destined for Patrick @Patrick Davey.

The kit is available from Studio Scale Models these days but it's essentially the same kit I built for Kieran Lagan recently (see 12/11/25 post above) from etches originally designed and marketed by Northstar. 

 

Chassis is compensated with a fixed rear axle and hornblocks on the other one which rocks on a horizontal beam fixed to a frame spacer.

 

Some of the lessons learn on Kieran's build are proving useful here though I'd forgotten just how tricky some of the jobs are. Those splashers, big and small,  take a long time to get right, as does the cab roof and the whole running plate is very floppy and difficult to keep straight as bits are gradually added.

However, it's a nice kit and it's coming together well so far. Boiler and smokebox next 

Alan

 

[Galteemore]

Fab work Alan. For my PP - and other builds- I use a wood block, custom fit for each model, to help keep it all supported. 

[Tullygrainey]

24 minutes ago, Galteemore said:

Fab work Alan. For my PP - and other builds- I use a wood block, custom fit for each model, to help keep it all supported. 

That's a sensible idea David and I always intend to do that. Then laziness takes over