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The Little House on The... (Part 2)

D869

Entry posted by D869

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... but he hasn't done anything at all!

 

blogentry-9623-0-54973400-1417819177_thumb.jpg

 

Well looks can be deceiving. Actually quite a lot of work has happened on the 45xx over the past week or so but the overall appearance is not hugely changed. Let me put it another way... here is how it looked a couple of days ago...

 

blogentry-9623-0-21468600-1417819264_thumb.jpg

 

When I stopped work on this project I really wasn't happy with the way it was running. The worst issues had been solved but it still had pretty poor slow running and a nasty tendency to stall. All in all not a candidate for having its cylinders fitted or being sent to the paint shop.

 

I was chatting with John Greenwood at Warley and the 45xx was one of the things we talked about. John suggested that the Nigel Lawton 8mm motor was a better option for slow running than the 10mm one. This surprised me. On getting back from the show I started by doing some sums and decided that the loco was already geared so that it should have better slow running than my Manor, but the practice did not match the theory.

 

Job number one therefore was to actually get around to making the third of the three motor mounts that I'd originally intended. This was a pretty quick job and with the 8mm motor installed the loco was given a quick test and I was pleasantly surprised to find that it could now put in a much better slow running performance.

 

The stalling issue was still there but now I had succeeded with one problem it seemed worth spending some effort on the other one. John also suggested top-acting wiper pickups. These were pretty easy to do, so I thought I hadn't much to lose by trying them. I tried them but couldn't see much improvement in the stalling issue.

 

The obvious next step was Simpson Springing, but this was not going to be a small task. Anyway, the soldering iron was applied to the muffs and the whole chassis stripped down. The bearings were opened out to 1.6mm. The springs were made in the prescribed manner from some salvaged 'N' gauge coupling springs (does anyone else have a hard time getting these to straighten out?) and soldered to the insides of the frames. Of course the frames were already painted, so I scraped some patches back to bare metal, tinned these and the springs and soldered the two together. It's not pretty but it seems to have done the job.

 

And so to reassembly... First I fitted the outer two driving axles using the quartering jig and checked that the chassis rolled freely. It didn't. It was binding with the cranks in the 45 degree position. To me this said that there was a quartering issue and on checking visually that seemed to be the case. I managed to shift the quartering on one axle and the chassis then rolled freely with the rods in place. Quite how this can happen when using the quartering jig I have no idea.

 

Next I fitted the centre axle and tried it rolling without the rods. The centre axle didn't rotate. Hmm... either the axle holes are not in a straight line or the wheels aren't all the same size. Now I should probably suspect the axle holes but I was pretty confident about the thoroughness of my original assembly checks. I did another test using a ruler to roll along the top of the driving wheels and once again the centre axle didn't rotate. Even using two rulers (one on top and one underneath) the centre axle still didn't want to play. I couldn't find convincing evidence of a variation in size using the vernier calipers but using a micrometer and taking lots of measurements (the coning makes it hard to be sure that any one measurement is right), I decided that the centre wheels were around 0.3525 inches but most of the others were around 0.354 inches (guess whether my mike is imperial or metric).

 

Scrap another set of muffs - just the outer axles though. I then mounted each wheel in turn in the mini drill and used 320 grit wet or dry to reduce the size. It took quite a while to do this but I'd rather take extra time than risk removing too much metal. Once the wheels were all a consistent size I repeated the ruler test and found that all three axles rotated nicely. The wheels were then cleaned up using progressively finer grades of paper followed by metal polish before yet another reassembly.

 

Here's the rebuilt chassis.

 

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That's about it for now. An initial test as an 0-6-0 proved that the stalling issue was improved but not entirely eliminated. Re-fitting the pony wheels improved matters further. I still have some work to do to reset the pony wheel springs - these have all been either damaged or removed during the chassis rebuild.

 

All in all a lot of work to get more or less right back to where I started but I now have a loco that inspires some confidence that it might actually be a decent performer when asked to do some real work.

 

EDIT: a couple more photos of the pony truck springs for Jerry

 

blogentry-9623-0-09521700-1417984624_thumb.jpgblogentry-9623-0-94663200-1417984641_thumb.jpg

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  • RMweb Gold
queensquare
  • RMweb Gold

An interesting and useful tail Andy. I also tend to use top acting wipers where there is room as they are much easier to fit, adjust and keep clean. I also open out the axle holes so that there is a little bit of slop - in much the same way as you do for Simpson springs.

I suspect things will improve even further when you fit pickups to the pony trucks. I seem to remember when we had a look at the loco at Warley that there was some self centring springing on the trucks, any chance of a bit more info on that.

 

Jerry

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D869

An interesting and useful tail Andy. I also tend to use top acting wipers where there is room as they are much easier to fit, adjust and keep clean. I also open out the axle holes so that there is a little bit of slop - in much the same way as you do for Simpson springs. I suspect things will improve even further when you fit pickups to the pony trucks. I seem to remember when we had a look at the loco at Warley that there was some self centring springing on the trucks, any chance of a bit more info on that. Jerry

 

Thanks Jerry. I guessed that the top acting wipers and Simpson springs are variations on the same theme so clearly the extra bearing play is an essential ingredient.

 

The pony springing is done in both horizontal and vertical axes by the same bits of 36 SWG P/B wire. I've tried to get a couple of better photos and added them above. As well as bearing down on the axles, they are also adjusted so that they are touching the insides of the pony truck frames... which is why they have a centering effect. This is definitely a better bet than having them bearing inwards onto the axle muff.

 

At the moment mine are still awaiting adjustment or replacement since being majorly disturbed during my other rebuilding activities... so the centering effect is currently an off-centering effect which is not a good thing!

 

Initial tests have had good results but this is not yet a tried and tested design. It has managed to navigate South Yard without mishap and also did a few successful trips back and forth on St Ruth during the Kidderminster show.

 

I'm in two minds about whether to substitute finer wire. This would allow more weight to stay on the driving wheels but the pony trucks are quite exposed so it may prove a bit too prone to being bent out of place during manual handling.

 

Regards, Andy

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  • RMweb Gold
queensquare
  • RMweb Gold

Thanks Andy, that's a natty idea. The balance between springing the leading and pony trucks for better pickup v taking weight off the drivers is a difficult one. I have one that is currently an inside cylinder 0-6-0 awaiting further progress so shall be following yours with interest.

 

Jerry

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Alan P

Hi Andy.  

Interested to find out your means of mounting motor at drive end.  Seems a distance from gearbox with short motor shaft?

 

Have you used a long extension shaft or fitted some form of coupling in there,  possibly so the worm is not producing end thrust on the motor?

Regards

Alan

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D869

Hi Andy.  

Interested to find out your means of mounting motor at drive end.  Seems a distance from gearbox with short motor shaft?

 

Have you used a long extension shaft or fitted some form of coupling in there,  possibly so the worm is not producing end thrust on the motor?

Regards

Alan

 

Hi Alan,

 

Yes, you are right. The latest photos don't show it because I added some more lumps of Plastikard when I did the top acting wipers. If you look at the first installment you will find a photo that shows it more clearly.

 

http://www.rmweb.co.uk/community/index.php?/blog/722/entry-13569-the-little-house-on-the/

 

The female part is made from an axle muff suitably chopped about. The part on the motor shaft is a Nigel Lawton shaft adaptor with some lumps filed out and a couple of bits of brass rod soldered on.

 

Regards, Andy

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Alan P

Hi Andy

 

That clarifies it nicely thanks. Neat way of doing it cutting a muff, I never thought of that, but it should be quiet.

It was those bits of plasticard that threw me as I could not make it out.

Interesting, the past discussion on individual wheels not in contact. I have just had the same problem on a Lambton Cab Austerity I built for Fence Houses. ( In mag shortly).   I had assumed the wheels were alright and cannot remember now if I did check diameters.  It is likely I did and I think I just used a digital caliper as accuracy is a problem with the radius. It was only a small difference but was noted after I removed the flywheel to make the motor worm combination removable. This altered the balance and the centre pair were no longer giving good contact.  I ended up increasing the clearance in the bearing and increasing spring tension.

 

Thanks

Alan

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