The Bagnall Valve Gear

[ericcee]

As was suggested earlier, I have started this new section to record the progress of the valve gear and valve setting.
First - a summary of the modifications supplied by MW.

The connecting rods were fouling the underside of the slide bar brackets so the rear cylinder cover, slide bar, crosshead and slide bar bracket have been replaced. (These are not strictly part of the valve-gear, I know, but they are a critical part of the engine, so I'm including the before and after photos here.)

The "old" arrangement:-


and the "new":-



Apart from resolving the fouling problem, this is a significant improvement - the crosshead looks much more business-like. There are phospher-bronze slippers between the crosshead and the slide bar.

The vibrating levers have been replaced because (to quote the notes from MW) "there was no clearance between the levers and the return cranks". I had noted this problem earlier, and have resolved it, so I think I shall ignore this modification. The photo below shows the old (on the left) and new (on the right) levers in "plan and profile".



Unfortunately, MW have not supplied replacement bushes for the lower (return crank) bearing and the existing ones are well and truly Loctited in the old levers!

To get the weigh-shaft into the correct position in mid-gear, the reach-rod and reverser pole have been replaced. The photos below show the original reversing lever assembly:-



and the modified assembly:-



The reach rod is about 8mm shorter and pivots rather higher up the reverser pole. The "lever strap" has also been replaced.

The hornblock stops (or "spring spigots" as MW calls them) have been replaced with significantly longer versions. This will mean (to quote MW again) "the rear axle will bottom out and rest on the spigots ... most of the suspension will be provided by the front axle". I now have visions of quite a rough-riding loco - I hope I'm wrong!

It seems appropriate to quote a chunk from the notes that came with the re-worked components:-
"Modelworks purchased the design of the Bagnall from an experienced independent designer in the belief that it would provide a suitable and reputable locomotive. As our own control model started to be constructed it started to become clear that 'things' were not as they should have been or how we would have liked. As originally designed it would probably have worked but not in our opinion to an acceptable standard. We therefore have taken the decision to replace a number of components on the basis that it would be far better to face the pain now rather than wait and deal with the locomotive's poor performance on the track."
In my humble opinion, the engine would never have worked and they should have discovered these problems in their control model before starting to sell any kits!
Let's hope the modifications work - watch this space.

[baggo]

ericcee said:

In my humble opinion, the engine would never have worked and they should have discovered these problems in their control model before starting to sell any kits!
Let's hope the modifications work - watch this space.

Eric, I think the problem is that they obviously don't build a complete control model before starting to send out the kits. Surely it would be in their interest to do so. They must waste a lot of time and money having to redesign components, manufacture them, and then send them out. They'd save themselves a lot of hassle from disgruntled customers as well!

I hope Modelworks have asked for their money back from the so-called 'experienced independent designer' !!

John

[ericcee]

John - I heartily agree with everything you say. MW could and should save themselves a lot of hassle by completing the build of a control model before releasing it. And I've a feeling that they have too many products on the go for the resources they have available.

For various reasons (over-commitment in retirement!) workshop time is at a premium at the moment but I hope to get back in there on Friday. I would like to get on with re-assembling the valve gear, but I'm tempted to paint the frames and wheels first in the hope that I won't have to dis-assemble them yet again!

EC

[jvas]

Hi Ericcee,

I am reading your thread with great interest. I have just purchsed the Bagnall and I am just assembling the first kit together now. I have purchased 7 kits in total for the moment. Your notes will really be of benefit to me.

Currently I am just preparing the frames with an objective to get the whole locomotive functioning properly without painting.

J.

[ericcee]

At last - another person willing to admit that he has decided on the Bagnall!!
Although all sorts of other pressures on my time are conspiring to prevent me getting into the workshop at the moment, I have decided to strip the loco back down to the "bare bones" so that, at the very least, I can paint the frames, wheels and cylinders before re-assembling, hopefully, for the last time.
In my opinion (as I've already illustrated in this thread), the most serious design fault is the fact that the steam pipes go directly into the valve chest covers. This means that it is an unnecessarily complex operation to adjust the valve timing. So - I hope to get that set finally before I finish painting!
I wish you the best of luck in the build process - and please keep us informed of any new problems you may encounter.

By the way - I'm still waiting for a few missing and replacement components!

E.

[jvas]

Hi E,

Hows it going with the Bagnall. Would love to see some more photos. Do you have back head fittings in place yet?

My build has slowed down at the moment. I am waiting for bits from model works at the moment, which are unfortunately taking a lot longer than expected. It has taken a lot longer than expect to get the rolling chassis (without valve gear) to turn over freely. Alot of shimming and adjusted is required to get it to turn over in a way that I am happy with.

J.

[ericcee]

Hi Jvas,
Please accept my apologies for seeming to ignore you! This is the first time I've visited the board in weeks because I've been snowed under with all sorts of (voluntary!) non-model engineering work of late (and they call this retirement!). As a result I've not done any work on the Bagnall since early February.
I presume by "rolling chassis" you mean that you have the cylinders, pistons and con-rods attached. This is the state I've stripped mine back to (to fit the replacement slide bars, etc.) and, like yours, its all far too stiff. I've narrowed it down to the RH cylinder and I think the cause is mainly the piston rings. When I get a round tuit (pity Blackgates et al don't sell this most useful of tools) I shall investigate further.
The only components I'm now waiting for are a bypass valve, a check valve and the darned replacement die blocks, but I'm not harassing Debbie because I cannot honestly say that I'm waiting for them. I have all the backhead fittings except the aforesaid check valve, but it looks as if the regulator will need some careful attention - like the rest of the engine, I can't get it fitted properly without seizing it all up.
At the moment, it looks as if it will be the end of the month before I can get back into the workshop for some serious engineering!

Eric

[jvas]

Hi Eric,

Are you still around?

J.

[ericcee]

Yes, Jvas, I'm still around!
I have to admit that I haven't touched the Bagnall since February last year (yes - 2007)!! It's now acquiring a delicate coat of rust. As I've hinted in previous messages, I've had a lot of non-model engineering things on my hands and it's not getting any better.
I'd not even been on this forum for months, until I received the letter from the MW administrators. That kicked me into some sort of action and I've been watching developments for the last week or so.
However, I'm in the relatively fortunate position of having everything on hand except for one bypass valve. The dratted die-blocks have not been replaced and the chimney needs some re-work, but I'll not be bothering the administrators with anything.
Fortunately, I've been assured by a good friend that we'll have it up and running this year.
I did manage to do a full "dummy" assembly to get some photos of what it will look like when finished - but that's another story. In the next week or two, I'll try to get one or two of these posted here and bring the story up to date.
Enough of me - how are you getting on? Have you received the boiler?

Eric

[jvas]

Hi Eric,

Thanks for replying, ive only just noticed!!!

Things are looking a bit better at the moment. Dean and Steve have purchased the remaining kits from the Administrators as part of their new company (streamtractor). Hopefully all will be well and sorted through the coming weeks, which brings much relief.

Unfortunately I will no longer get any support from them, so if possible, I might be asking for some help or photos if things dont go together as expected. If thats ok by you?

I have most of the rolling chassis fitted out, apart form the valve gear. Have the boiler and most parts, just not the valve kit (which includes smoke box saddle) and the backhead fittings kit. Not too much work to do. I painted up the water tank a few weeks ago in a nice gloss red and she doesnt look too bad. Have some enthusiasm to work on the cab at the moment and will try and get some work done after Fairford and Duxford this weekend.

Regard

Jeremy.

BTW - what do you do that keeps you just as busy as me?

[ericcee]

Jeremy,
Yes, it's good to hear that something is being rescued from the ashes of MW.

It looks as if you have quite a challenge to get the Bagnall finished if you don't have the valve gear components, unless you are a rather more capable engineer than I am. The S/B saddle could be fabricated reasonably easily, I guess, especially if you have the smokebox to work to. I could get some dimensions and a drawing of the saddle for you, if necessary. And I'll certainly help you in any way I can - just remember that I'm a kit-builder rather than a true model engineer! When I work out how to do it, I'll email you off-forum (or whatever it's called).

As I've said before, I'll try and get some more photos posted here sometime soon (it's that old round tuit problem again). How about some from you? I'd be interested in hearing how you painted the tank, for example.

What do I do that keeps me out of the workshop? It's a long story, but can be summed up as volunteering for too many jobs! I've been deeply involved with a community association (now behind me) but throw in Friends of Beamish Museum, stewarding at Durham Cathedral as well as all the jobs round the house and garden - and now I'm president of Durham Rotary Club - see what I mean? All good fun, though, and it keeps me active! And, all in all, it beats working for a living.
Trouble is, I like to set aside best part of a day, at least, to get stuck into jobs in the workshop, and such things seem to be a bit of a luxury these days.

Meanwhile, I suggest we continue this discourse in the "Getting on with it" thread, since we are now well off the valve gear topic.

TTFN,
Eric