Bachmann 45xx conversion

[TEZBEDZ]

Hi
I am converting the Bachmann 45xx using ultrascale wheels, but also have replaced couipling rods and connecting rods with Gibson alternatives,

I would like to make some improvements to the model itself, one of which is replacing the coal in the bunker with real coal and adding a bit of weight.

Does any one know if it is possible to remove the modelled coal from the plastic superstructure, there are a couple of screws which hold it together, but, have not had the courage to unscrew them in case I can't get it together.

Otherwise I will have to start drilling, cutting and filing

Thanks for your help and Happy New Year

[Tim V]

Have you looked at the exploded diagram that comes with it?

[TEZBEDZ]

Have you looked at the exploded diagram that comes with it?

If I could find it, I would................... I put things in a safe place and forget where they are, I must have safe places all over my shed

[Tim V]

http://www.bachmann.co.uk/pdfs/37-901.pdf

may help, it appears to show the coal missing!

[TEZBEDZ]

Thanks Tim.

A guy on RMWEB has said that removing the plastic superstructure from the metal footplate allows removal of clips which hold the coal, rear lamp housing and cab backplate in place.

I will give it a go

Terry

[martin goodall]

This is not a reply, so much as an extension to this thread. I was going to post a separate note, but saw this topic had recently been opened.

I made an unsuccessful attempt last week to convert a Bachman 45XX to P4 using the Ultrascale conversion set.

Testing of the Bachmann chassis before conversion proved conclusively that it ran smoothly and quietly, but after conversion (which turned out to be less than straightforward in the absence of any instructions - even the data sheet on the Ultrascale website was of no practical use) there was a distinct 'knock' once in every revolution of the driving wheels, and the model occasionally stalled altogether, and had to be switched off quickly to avoid burning out the motor. It was so bad on one occasion that the (pre-set) quartering went.

On inspection, there were definitely no clearance problems between the cross-heads and the crank-pins on the leading wheels; there was ample room here and no possibility of fouling. I tentatively concluded that the problem is either (1) an eccentric or inaccurately cut brass gear wheel (although this seems surprising, bearing in mind the usually excellent quality of Ultrascale products) or (2) excessive slop of the re-used Bachmann coupling rods on the crankpins (especially those on the leading wheels - where the crankpin measures 2.0 mm, whereas the hole in the coupling rod measures 2.3mm diameter - (or possibly a combination of both). But I am not sure why this should cause the mechanism to stutter so badly and to seize up altogether sometimes.

The Ultrascale gear wheel came under suspicion because, when the rods were removed so that the centre wheelset alone would be turned by the motor, a distinct change could be heard in the note from the motor once in every revolution of this axle, accompanied by a slight 'graunching' sound (also once in every revolution of the axle). However, I don't think the gear-wheel can be held responsible for the derangement of the quartering, which must have been caused by the driven (middle) axle continuing to turn when the leading axle had seized up for some other reason.

Susbstituting the original Bachmann nylon gear in place of the brass gear wheel supplied by Ultrascale is no longer an option, because the problem I had with the quartering, which once it had slipped kept going out of adjustment, led me to pin the wheels to the axles, using the generous moulded bush on the backs of the wheels,so that the wheels are now well and truly fixed to their axles.

Replacment of the Bachmann coupling rods might be part of the answer, but before seeking out an alternative set of rods, I would be interested to hear whether anyone else has encountered problems with this conversion and, if so, how they resolved those problems.

Subject to any comments, I am currently thinking of fitting a new set of wheels, using the Bachmann nylon gear wheel for the final drive, and a new set of coupling rods, making sure that these are a close running fit on the crankpins. The other option might be to bush the Bachmann couplng rods to achieve the desired running fit on the crankpins.

[Russ Elliott]

Prem Holdaway converted a Bachmann WD 2-8-0 a while ago using AG wheels. Despite accurate quartering and closely-fitting rod bushes, the converted loco 'knocks' slightly once a driver revolution, although not as much as to sieze things up as noted by Martin on his small Prairie. In our case there was no new primary gear. The cause of the knock is the Bachmann chassis block, where the axis of one axle (the rear one in our case) is not machined square to the chassis. In 00, the inherent slop in the Bachmann rods on their pins does not always reveal a rod to chassis mismatch, but in P4 with closer rod tolerances the fault becomes all too evident.

The machining of Bachmann chassis blocks does vary - even in original 00 mode there are good and bad specimens, so you might get a good one or you might get a bad one. Whether good or bad, the accurate spacing and squareness of the chassis block axle axes cannot be guaranteed, and a set of third-party replacement rods might not provide any better running. Possibly AG 'universal' rods (whose axle pitch can be varied) could provide an answer, but I've no idea how one could jig them up accurately using a given Bachmann chassis block.

Bachmann seems so unconfident of its chassis accuracy and rod stampings it has chosen to drive both axles of City of Truro.

[Wizard of the Moor]

Any tips on how to identify the axle that is ill machined, Russ? And what, if anything, can be done about it?

My Bachy 08 Ultrascale conversion exhibits these symptoms and throws the quartering regularly. Almost immediately with the replacement Brassmasters rods, but only after a while with the original Bachy rods. Annoyingly, that 'while' was in the middle of Scaleforum 08...

[Tim V]

I have reasonably successfully converted a 45XX.

I did get problems as you describe, but by running it on my rolling road (Bachruss) I spotted the problem.

I ended up making a new larger crankpin for the middle wheels in the end.

[Philip Hall]

I've converted a 45XX (to EM) with no problems at all, using the Bachmann gearset and Alan Gibson wheels. However, I have also recently completed a G2A (to P4)where I had exactly the problem that Martin describes. Ran like a watch before conversion, like a pig with a limp afterwards. I eventually tracked this down to the coupling rods on one side being half a millimetre longer than the other! I used some jig axles resting (almost) in the chassis slots to find this out. Oval holes in the offending rods (!) solved the problem.

Philip

[Russ Elliott]

Any tips on how to identify the axle that is ill machined, Russ? And what, if anything, can be done about it?

Running in original 00 mode, and trying to ignore any wheel eccentricity, rod to chassis mismatches usually manifest themselves by one of the wheels moving fore and aft. We can perhaps ignore any imperfections in the as-supplied quartering, because we'll be replacing the wheels, but it's always difficult to put a finger on a single cause of non-smooth wheel rotation. In most cases, there are probably several inaccuracies adding up to thwart us.

In our WD case, the skewness of the rear axle machining was evident to the naked eye. (In that respect, we were perhaps mugs to hope that the conversion would be successful.) But if an axle had not been skewed, there is no way we could check that the overall pitches of the axle axes were 'accurate', even if retaining the original rods.

The chances of any foreign rod sets aligning with a specific chassis block are not high, and I think your post confirms how much stress the quartering is under when such rods are applied. On another Bachmann 08 chassis though, your Brassmasters rods might be perfect.

Our mistake is to assume that anything is correct, but I don't think we can get away from the blunt fact that if there is an underlying rod to chassis mismatch of some kind, then one or the other needs to be remade to fit. Or do we adopt the old Sharmanism of opening up the rod holes in the (vain?) hope that everything will turn out ok? Or run the whole thing in a bath of Brasso for a couple of weeks? I dunno.

[martin goodall]

I am extremely grateful for these responses to the query I raised.

On the one-hand, I am re-assured to learn that it's not just me! On the other hand, these exchanges show that the business of converting Bachmann locos is not so simple and reliable as people seem to think it is.

In view of the very helpful suggestions that have been made, I will see if I can devise a way of checking the machining of the Bachmann chassis block on my 45XX. My usual method for checking that loco chassis (or frames and axle bearings) are accurately aligned is to insert long lengths of axle rod (each about a foot long) through the axle holes/bearings. If any of the holes/bearings are out of true this will immediately show up, as it can clearly be seen whether or not the long lengths of rod are parallel with each other and level. However, the rods I use for this purpose are 1/8-inch, and I will have to check whether my stores include some similar 3mm lengths of rod with which to check Bachmann chassis. If not, I might perhaps invest in some longer lengths of 3mm rod for this purpose.

Meanwhile, (in view of some of the warnings given by others) I propose to defer getting any replacement wheels or rods for the 45XX for the time being and to put this project on the back burner and get on with some of the other conversions. My other experiences so far have been quite encouraging, having completed successful P4 conversion of two 8750 chassis (one fitted to an old 57XX body as described in a separate post) and a Collett Goods, although the tender conversion didn't work, and it is due to have a Perseverance tender underframe fitted instead. An 08 was next on the agenda, but this too may now have to await checking of the chassis in view of the warnings given. I have also made a start on a a 'do-it-yourself' conversion of the Hornby 14XX.

[Russ Elliott]

On the other hand, these exchanges show that the business of converting Bachmann locos is not so simple and reliable as people seem to think it is.

Indeed, Martin. I often feel the "P4 conversion is so easy, all yer do is drop in yer dropins" evangelist brigade need a reality check sometimes.

[TEZBEDZ]

Hi

I am so glad that my query started this discussion.

I originally got the 28xx Coupling rods from Gibson as they had the right size rods 5 1/2ft and 6ft, in my niaivety (sp?) I thought that would work, I tried them jointed and then 6 coupled, using both Ultrascale and Gibson crank Pins.
I then bought some Universal Coupling rods, I used dividers to measure the distance between the axle slots and then built up the coupling rods one at a time using a broach to enlarge the hole.
I eventually got it quartered and have now managed to 'loctite the wheels onto the axles and the nuts onto the crank pins.
I replaced the pick ups with .033" straight wire again from Gibsons a la Iain Rice, the inside screwheads need filing down to stop them catching on the pick ups.
I am currently working on the brake gear, I bought Gibsons GWR Loco Brakegear, but they are too long, (scrap box) but, I had removed the Bachmann brake gear and driiling out the top I plan to connect it using the Brass Wire supplies in the Gibson Kit.
I used a soldering iron to melt the wire into the Brake linkage which runs under the loco.
I will write and let you know any progress.

[Will L]

Our mistake is to assume that anything is correct, but I don't think we can get away from the blunt fact that if there is an underlying rod to chassis mismatch of some kind, then one or the other needs to be remade to fit. Or do we adopt the old Sharmanism of opening up the rod holes in the (vain?) hope that everything will turn out ok? Or run the whole thing in a bath of Brasso for a couple of weeks? I dunno.

While not suggesting that it is in any way good practice, I have found out the hard way that even if the axles aren't exactly parallel to each other, so long as the rods match the axle centres on the side of the chassis they are on, the thing will run freely. So soldering up a set of Gibson "universal" rods to suit the chassis as it is may well work. You may find the result to be a bit finicky about the track work, or you may never be bothered by it again.

I thought the Sharmanism was to make things that fitted each other rather than an exact dimension. So his method fitted the the horn guides to the chassis using the rods as a jig so they did match. Hence, if the rods where not as identical as they might have been, the discovery that you can have a working chassis with none parallel axles. Much as it may offend the p4 sensibilities!!

Will

P.S. Also let us not forget that limping loco syndrome can also be due to a mismatch in crank pin throw which regretfully does happen. I had one loco which I despaired of ever getting right till the crankpin web on one wheel broke. The problem disappeared when I replaced the wheel.

[LesGros]

I thought the Sharmanism was to make things that fitted each other rather than an exact dimension. So his method fitted the the horn guides to the chassis using the rods as a jig so they did match. Hence, if the rods where not as identical as they might have been, the discovery that you can have a working chassis with none parallel axles. Much as it may offend the p4 sensibilities!!

Will

WIll,
This is very interesting, and also relates to the hornguide discussion on the split frames thread. The Exactoscale assembly intruction follows the same procedure of using the Connecting rods as a jig to position the horn guides for glueing. INS 1003/2 refers. (there is a link available on the split frames thread)

cheers,

[Russ Elliott]

Les - the plastic Exacto method uses a turned jig to position to guide, followed by shaving off the block etch cusps to fit the guide. There are potential errors inherent in such a process, etches (and turnings) being what they are. The traditional Sharman method uses the rods to position the combination of guide and its fitted block. I feel that would be a more sensible Exacto approach.

[Philip Hall]

Re Martin's comments about 3mm rod to check the axle slots, I think this is available from some of our usual suppliers. However, as I hinted in my earlier post regarding the Bachmann G2A, I found it was possible to use some 1/8" tapered jig axles to check the coupling rod holes, simply by resting the axles in the slots. True, they won't go all the way into the slots, but enough does to give a positive location. I actually fixed the keeper plate back in place with a couple of screws to roughly clamp the jig axles in place whilst I fiddled about with the rods. It was quite easy to see where the errors lay.

I haven't had a chassis (yet) where the slots are not machined square, having converted quite a few Bachmann engines in recent years. But all this business does tend to reinforce my opinion that Hornby chassis are far better engineered than Bachmann as a general rule. I don't think I've ever had a really duff one, they're square and true with decent brass bearings instead of a slot in the diecasting. My only minor gripe is that the final gear is a loose fit on a replacement axle which means that pinning is essential.

Philip

[Tim V]

I've never been satisfied with the running of my 45XX, so I had a good look at it - and found that the wheels are loose on their axles!

I've decided to pin them, so new axles are called for.

These axles are 3mm.

IMG_0918.JPG

The challenge will be the middle axle, the other two are easy.

[grovenor-2685]

I've decided to pin them, so new axles are called for.

Out of interest, why can't you pin the existing axles?
regards
Keith

[Tim V]

Keith

I do not like drilling from soft plastic into hard steel - chance for it to wander. However I may have to use the middle axle as I do not want to disturb the gear wheel.

I shall move this particular project onto my workbench thread.

[grovenor-2685]

What puzzled me was the 'new' bit. To use new axles you have to take the wheels off, at which point what is the problem with re-using the existing axles? I assume you would use the method discussed earlier of drilling at an angle through the axle end.
Regards
Keith

[Tim V]

The method from earlier has longer axles - so I've got to make new ones.

Don't forget the wheels are already loose, so they slide off fairly easily.

The problem with drilling into the end of the axles, is getting the drill to start into the metal. Any ideas?

[grovenor-2685]

Any ideas?

Drill into the end a bit, then start the drill inside the hole where it has nowhere to slip to.
(Not that I've tried it mind, and it looks as though its a bit late for this job.)
Regards

[Tim V]

Using what drill? 0.55mm drills are fragile.