Another B1 chassis

Bellerophon
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Another B1 chassis

Postby Bellerophon » Mon May 18, 2020 1:04 pm

Inspired and learning a lot from David Barham’s superb progress on his Dave Bradwell B1 chassis; I thought I’d also start a thread so I could get some advice and make progress my B1 chassis, without interrupting David’s thread. I’ve already received excellent help from Dave but I’m sure he’ll chip in here when he’s time and hopefully it might inspire others to re-open their box of unfinished kits.

I started the kit a few years ago but somehow it ended up in the round-to-it box. Dave tells me it is the Mk1 kit, hence the need to use alignment jigs. The following pictures (assuming I upload them correctly) should show what I’ve done (badly) so far.

I’m using the Gibson drivers I bought when I got the kit. Unfortunately, there’s still no Ultrascale V2/B1 wheels. I’ve sanded down the bosses flush with the tyres (I might have over done it?) to give clearance between crankpin nut and con rod etc. I’m going to order Ultrascale crankpins and also bogie and tender wheels, I presume I need plain axles with plain ends.

The instructions (Mk1) say a Portescap C1 will fit nicely, driving the centre wheels. Great! I have one in my collection which was for my Brassmasters Jubilee…oh it’s a 1624! I’ve never used ebay so I won’t even look to see how much a 1616 is going for, even if there is one on there. So, I’m ready for more advice. I’m enjoying the learning experience as I did learning an instrument, it’s just 50 odd years too late…
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PeteT
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Re: Another B1 chassis

Postby PeteT » Mon May 18, 2020 8:01 pm

I have one in the queue too, so will watch with interest!

I doubt there ever will be Ultrascales, as Exactoscale did them. I'm lucky enough to have a set, and I believe they are to be re-released at some point - but are not currently available.

On my J39 I've fitted a High Level Roadrunner+ with motor driven via shaft from the tender - and I expect I will follow this method again.

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Horsetan
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Re: Another B1 chassis

Postby Horsetan » Mon May 18, 2020 8:47 pm

PeteT wrote:....I doubt there ever will be Ultrascales, .....


The same might be said of BR Standard wheels for the Pacifics and the 9F...
That would be an ecumenical matter.

davebradwell
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Re: Another B1 chassis

Postby davebradwell » Tue May 19, 2020 8:24 am

Mike Megginson started a couple of these chassis a while ago and the photos on his NER locos thread might be useful.....but I couldn't find it.

As an aside, how did long jig axles become popular? They must be a backward step. First, we are trying to get the axlebox centres within a couple of thou' of the coupling rods and they are likely to be bent significantly compared to this tolerance with the probability of further damage in storage. Longer rods are more flexible, too, so easier to inadvertantly move hornguide from correct position. Further, a key feature of the original length axles (which can be seen in the back of the photo) is they place the coupling rods in their final positions so that if they differ slightly in length (quite possible in the days of hand drawn artworks) then this will be reflected in the axle centres. There are other pitfalls when using these jigs, of course, but why introduce more errors?

DaveB

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Tue May 19, 2020 8:38 am

Thanks Dave, I tried both types but I'll re-check with the short ones before moving on.

davebradwell
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Re: Another B1 chassis

Postby davebradwell » Tue May 19, 2020 10:34 am

My comments were general and not pointed at this build and the bits will probably all fit together due to the clearances. Perhaps put pairs of jig axles in place and look at range of movement of tips compared with actual coupling rod centres. You want the real positions to be in the middle of the slogger rather than at one end of it. It's not worth correcting until you get the wheels on, anyway.

DaveB

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Tue May 19, 2020 11:08 am

Thanks again, Dave. You've probably saved me from messing up even more (I'm sure there's bigger messes to come but the experience will be worth it, I hope!). In the meantime I'll do the Ultrascale order. So it might be a while before I pester you again.

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Thu May 21, 2020 3:41 pm

I thought I’d prepare the bogie and tender chassis while waiting for the Ultrascale order. I have a couple of simple questions. Please forgive the naivety.

1. Which of the two screws in the picture do I fit at the front of the chassis for the bogie? It says fit long but the one on the right seems a bit too long for this, could that one be for the body shell.
2. I’m thinking of a high level roadrunner+ 30:1 and one of their coreless motors (1320c), is that ok?

As for which B1, I whittled it down to two. 61110 and 61013 (Topi). Neither had stones generators so I won’t need to fabricate one. I’ve more pictures of Topi so that seems most logical.
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Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Sat Jul 18, 2020 7:43 pm

Not perfect but a bit of progress. Weight and pick-ups to be added yet.
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Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Wed Jul 22, 2020 12:34 pm

After hours of faffing and second guessing things it now runs like, well.... I've managed to wear out the grooves on the grub screw so I can't loosen/tighten the final gear. So, maybe time to call it a day.
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davebradwell
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Re: Another B1 chassis

Postby davebradwell » Wed Jul 22, 2020 3:52 pm

Yes, you'll see why I redesigned the chassis to get rid of the dreaded jigging operation that I could never get to work properly, either. Of course it all depends on what you're prepared to accept as clearance in the bearings but I detect that you don't like too much slogger, either, Mr Bellerophon. Relieved to know you're over that hurdle but I'm sitting in a panic hoping you noted the previous correspondence on getting the coupling rod boss to clear the slidebars especially as you haven't taken advantage of the rather nice Ultrascale recessed crankpins.

Just check that the spring hangers keep the springs very close to the bottoms of the axleboxes or it will sit too low. A number of builders felt entitled to grumble as this wasn't initially made clear. If you've only soldered one end of the wire as shown in the instructions, encourage the spring to sit near the joint especially if you're planning a heavy model. I brought mine up to 325 gms eventually and found the springs a bit feeble - rather long - so some fiddling of supports required and I have double springs at the front because it is nose heavy. This was for the 10 coaches up 1 in 100 round curves so an extreme case.

DaveB

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Wed Jul 22, 2020 5:11 pm

I did think about calling this the "Flying B1" as it nearly took off from the workbench and across the room several times! I get one thing fine, adjust another thing and then have to start all over again, which probably compromises the whole chassis. No reflection on the kit just my inexperience at this level.

I realised I hadn't slotted the hornguides enough so had to go in with a thin file.

I fitted an ultrascale crankpin on the centre driver. I didn't use the ultrascale screw as the head seemed far too big behind the wheel and if I countersunk it there wouldn't have been any plastic left on the wheel to drill into after recessing the front for the crankpin shaft. It still wobbles now, using the Gibson screw, until tightened up. So, I didn't dare use ultrascale pins on the other wheels.

The front driver wheel boss is definitely level with the wheel rim. I'll thin down the crankpin nut and slot it (to screw it up) so that it fits in the recess.

I managed to remove the grub screw, just need to order a few now.

Sorry, but can I ask what a slogger is? Presume it's nothing to do with a lower order batsman.

The L1 kit will be a doddle after this.

Cheers,
Howard

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Horsetan
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Re: Another B1 chassis

Postby Horsetan » Thu Jul 23, 2020 8:20 am

davebradwell wrote:Yes, you'll see why I redesigned the chassis to get rid of the dreaded jigging operation that I could never get to work properly, either. ...


As I have two of the Version 1 chassis, maybe assembling them on one of those fancy chassis jigs might help?
That would be an ecumenical matter.

davebradwell
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Re: Another B1 chassis

Postby davebradwell » Thu Jul 23, 2020 9:26 am

I have fitted Ultrascale crankpins to many Gibson wheels and, as you've discovered, it's important to use a minimum depth of counterbore (the 1.25 location diameter). The Ultrascale drg used to show it too deep but I haven't looked recently. I followed these dimensions on my WD and found, like you, there's not a lot of plastic left by the time you've countersunk the rear. Later, more cautious attempts have been quite sound using a drill bit with depth stop - collar with grub screw. Early efforts just allowed the drill to locate in the crankpin hole but I now use a jig to get all throws exactly the same - they seemed pretty close before but there was some risk involved.

The benefit of the Ultrascale pins is they locate in a plain hole rather than on a screwthread which may itself have wandered. The fixing screw should have a clearance hole to avoid influencing this primary location but I'm not suggesting you change the ones you've done. I'm sure countersunk screws were supplied at one time but I've seen cheese heads recently which don't help. I now make a crankpin for the centre that is like the Ultrascale but tapped and this gives a more secure location for the return crank whose position can be tweaked by loosening the screw (and re-tighten of course).

You'll have realised that you have to be very methodical and suspicious with a chassis - do the wheels turn freely with no rods, for example? Then try each rod in turn to check length and confirm bearings and crankpins are square...and so on. You can judge the quartering by looking at the rods and wheel spokes - yours seem nice and straight.

Earlier post suggests you should be ok with your front crankpin possibly with thinned flange on bush. I might have to investigate the L1 as the K1 was all very close due to a shorter conn rod than the B1. Narrower slidebar, though.

Slogger is what you get in a bearing when it's buggered. It's something beyond clearance.

DaveB

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Thu Jul 23, 2020 10:01 am

Thanks Dave,

Slogger is what you get in a bearing when it's buggered. It's something beyond clearance.

DaveB[/quote]

Oh, I'm good at buggering things up.

Howard

davebradwell
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Re: Another B1 chassis

Postby davebradwell » Thu Jul 23, 2020 11:25 am

I'm sure you're managing fine, Howard. It's just occurred to me that I now supply lace pins so the valve gear can be assembled without soldering the pivots - I've described this elsewhere but let me know if you want more details.

Ivan, many people get on fine with jigging the axles and the principle is sound enough - we did stuff like this at work with batch production. I believe the weakness in the original jig axles concept is that the hornblocks are held against the frames so can end up at one end of the clearance in all the parts - the jigs allow a range of positions. The fancy jigs are an improvement as they allow bits to be floated to a nominal position and checked by feel before soldering. They also act like 3rd and 4th hands and get the axles square to the frames.

My preference now, as in my later kits, is to set the hornguide fronts at the design spacing and the holes in the rods will be etched accurately from a plotted artwork. If I'm building somebody else's kit then I resort to the milling machine and use the leadscrew dials to achieve the required accuracy with new hornguides cut from scrap fret. Axleboxes need checking too, of course. Getting frames square is easy using a dial indicator in the mill and this can be used to measure actual hornblock spacing. If you're hesitating buying a mill there's another use for one.

DaveB

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Wizard of the Moor
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Re: Another B1 chassis

Postby Wizard of the Moor » Thu Jul 23, 2020 6:47 pm

davebradwell wrote:. If you're hesitating buying a mill there's another use for one.


Of course, when you've bought a milling machine then, if you're anything like me, you are likely to stall the cutter, leading to a large current in the motor windings and the discovery that the power transistors on the motor control board melt more rapidly than the 'fast acting' fuse adjacent to them. So, all your lockdown modelling time will be spent designing and building a new motor control system, converting the spindle drive from gears to belts, fitting a 3-axis DRO, a tachometer, a power feed for the X axis, adding a ring light to the spindle, stop blocks to the table and upgrading the table locking screws to ones you can actually access when the thing is in use.

After that, spacing out axle locations is a doddle.

;) :D

Not everyone is like me, though.
James Dickie

My workbench

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Sun Jul 26, 2020 8:16 pm

I’m guessing this is a good position to be in regarding slidebars. Seems quite parallel and front of coupling rod misses nicely.

I’m still struggling with mounting the motor though. I’ve tried various ways. I presume it needs to “float” a bit or there wouldn’t be any point in springing the centre wheels.

Dave, there were brass lace pins in the pack thanks.

Howard
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davebradwell
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Re: Another B1 chassis

Postby davebradwell » Mon Jul 27, 2020 9:14 am

You seem to have been heading the right way regarding motor/gearbox location, the simplest I've seen uses a tab and I've shown it before. You may need to space the legs of the arch from the frames to allow the body to fit.
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Usual fault is to over-restrain and I'll confess that the motor on my Portescap B1 sits on a pile of lead and the body acts as upper restraint. Never quite got round to correcting it. You have soldered the trailing arm to the gearbox if it's a Roadrunner+ ?

DaveB

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Thu Jul 30, 2020 7:55 pm

I'm happy to say it now runs quite well. I'm sure a top class modeller wouldn't be satisfied but for me this is progress. Yes, it probably needs more fettling and it fits where it touches due to my duff technique. The motor is behaving itself very well despite the Heath-Robinson mounting and after I remembered to solder the trailing arm on the roadrunner+!

Thanks to Dave for his help and encouragement. Onwards and upwards...
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davebradwell
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Re: Another B1 chassis

Postby davebradwell » Fri Jul 31, 2020 9:46 am

Well done so far and it's sounding very promising. It's worth spending some time checking there aren't any tiny binds at this stage before you add the valve gear. Seeing the slidebar misses the front crankpin by a mile, does the crosshead clear the spacer at the rear end of the slidebars? Does the conn. rod slip between the lower slidebars even when the springs are compressed and axles moved sideways? I'd add the proper crankpin nuts as these are quite good at nipping the rods - you want visible end-play. See if it'll run with a 1.5v battery powering the track.

DaveB

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Mon Aug 03, 2020 10:33 pm

This is the stage I’ve reached and it’s beginning to look a bit like a B1. It does not run as well as all the others I’ve seen, so I must have made a mistake somewhere. I’ve spent ages looking but I can’t spot where the fault lies. Probably it was in setting it up from the start but messing about unsoldering things, undoing wheels, enlarging holes etc. will probably only make it worse.

Next in the instructions is the valve gear and it suggests you should slow down even more. I started adagio, then went lento and then largo, so next is grave which seems appropriate. Actually I think G.P. (Grand pause) or tacet would be better.
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DougN
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Re: Another B1 chassis

Postby DougN » Tue Aug 04, 2020 2:43 am

Your kicking goals there.

Ground to a halt on my V2's but the enthusiasm is rising to get back to them. Detailing the bodies is a challenge, small etches and castings to be attached. I have found the Irwell press "The book of" series can be good for detail shots of both sides of the loco to be modelled in combination with the Yeadons registers. I have these for the V2's but I think I will revist my B1 in the future... I need it to refettled back to running.
Doug
Still not doing enough modelling

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John Bateson
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Re: Another B1 chassis

Postby John Bateson » Tue Aug 04, 2020 9:23 am

Schubert: Unfinished Symphony No.8?
My B1 is one of the items in my cupboard of shame - right at the back - I think. :cry:
Slaving away still on GCR stuff ...
Avoiding the soaps ...
https://www.greatcentralmodels.co.uk

Bellerophon
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Re: Another B1 chassis

Postby Bellerophon » Tue Aug 04, 2020 9:47 am

Mahler 10, Elgar 3, et al, all finished by others. Then again, that was post mortem, so maybe not the best option.


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