Steam loco wheels - assorted questions

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the fatadder
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Steam loco wheels - assorted questions

Postby the fatadder » Wed Jul 04, 2012 9:09 pm

A couple of questions arising from last weekends work on rewheeling a Bachmann 4575

The loco in question has had its chassis rebuilt to widen the frames with plasticard, replace the pony trucks with Mitchell parts, along with fitting Mitchell coupling rods.
Upon first trial free running (without the motor or the driving rods fitted) there is an element of binding jamming up the chassis.

Impatience resulted in buying a set of Gibson wheels for the project at last years scaleforum, without realising that they were not predrilled for crank pins. It appears that the drilling is not exactly at 90 degrees, and this is causing the bind. Would it be possible to rectify this by filling the holes with epoxy and redrilling? Or is it going to be a case of having to fork out for a new set of wheels?

At the same time, I also had a look at getting my 4500 etched chassis running. This was purchased almost complete (in that I just need to solder up the cylinders) and is compensated on the lead 2 axles. The problem I have is fitting the fixed driven axle, in that I cant get a back to back gauge in place when pushing the wheels onto the axle with my GW models tool.
Am I missing a trick here, as each time I have tried to do it by eye it has been tight to gauge (and twisting to rectify ends up mucking up the quartering. I soon want to make a start on a High Level chassis for my first 2251, but the thought of fitting a fixed wheel set is making me seriously consider alternative approaches (CSB). which then starts getting me concerned that I will end up biting off a bit more than I can chew.

Regarding Ultrascale driving wheels,
I am looking at ordering Ultrascale drivers for the 2251 (along with more for a mitchel 43xx I got off ebay sans wheels and a 58xx that is next inline for High Level bits after the 2251). I'm interested to hear how they compare to the Gibsons in terms of fitting.

Finally, back to 5512. The final issue I have encountered in testing is with the driving rod (afraid I am unsure of the technical term). When I put the con rod and driving rod onto the crank pin there is barely any room for the crank pin nut. What am I doing wrong?

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Mike Garwood
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Re: Steam loco wheels - assorted questions

Postby Mike Garwood » Wed Jul 04, 2012 9:45 pm

Fill the crank pin holes with Devcon plastic steel (takes ages to go off, at least 24 hrs if not more) and re-drill is your best bet, personally I'd replace the wheel set though. A tip I had for drilling Gibson wheels was to use the long crank pin bushes as a guide for the drill, increasing the length of the drill until you're through the wheel.

As far as your gauge problem is concerned, get a wheel/gear puller, saved my bacon on several occasions.

Mike

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the fatadder
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Re: Steam loco wheels - assorted questions

Postby the fatadder » Wed Jul 04, 2012 9:48 pm

Mike Garwood wrote:Fill the crank pin holes with Devcon plastic steel (takes ages to go off, at least 24 hrs if not more) and re-drill is your best bet, personally I'd replace the wheel set though. A tip I had for drilling Gibson wheels was to use the long crank pin bushes as a guide for the drill, increasing the length of the drill until you're through the wheel.

As far as your gauge problem is concerned, get a wheel/gear puller, saved my bacon on several occasions.

Mike


Thanks, I will get some Devcon and give it a try. if not, will get them replaced.

As for the wheel puller, cant believe I hadnt thought of using that, Will bare that in mind in the future!

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45609
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Re: Steam loco wheels - assorted questions

Postby 45609 » Wed Jul 04, 2012 10:34 pm

When Alan had the business he would happily remould a wheel centre for you FOC if you returned it to him. I don't know whether Colin will still do this but it is worth asking.

Cheers....Morgan

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David Thorpe
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Re: Steam loco wheels - assorted questions

Postby David Thorpe » Wed Jul 04, 2012 10:40 pm

I was going to suggest that very thing when I saw you had beaten me to it!

DT

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Flymo748
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Re: Steam loco wheels - assorted questions

Postby Flymo748 » Thu Jul 05, 2012 4:16 am

the fatadder wrote:I soon want to make a start on a High Level chassis for my first 2251, but the thought of fitting a fixed wheel set is making me seriously consider alternative approaches (CSB). which then starts getting me concerned that I will end up biting off a bit more than I can chew.

To answer this bit - as a convert from compensation to CSBs, I personally would say that they are actually just as easy to use, if not easier.

And of course they do allow you to drop all of the wheels out, just by removing the springing wire. Just make sure that the body of the motor is narrower than the distance between the inside of the frames!

Flymo
Beware of Trains - occasional modelling in progress!
www.5522models.co.uk

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45609
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Re: Steam loco wheels - assorted questions

Postby 45609 » Thu Jul 05, 2012 7:54 am

Flymo748 wrote: Just make sure that the body of the motor is narrower than the distance between the inside of the frames!


Or make sure you arrange the motor to gearbox mounting screws horizontally so that the motor can be separated from the gearbox prior to wheel removal. Some gearboxes give this option as designed (High Level in particular). A lot don't. I use the HL gearboxes almost exclusively these days.

Morgan

martin goodall
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Re: Steam loco wheels - assorted questions

Postby martin goodall » Thu Jul 05, 2012 11:04 am

Going back to the original query, I wouldn't automatically assume that the binding is necessarily caused by the out-of-true crank pins (although it won't help).

I had terrible problems trying to convert a Bachmann 45XX chasssis, and it is still waiting for me to have a second go at it. The root of the trouble was the centre axle being out of alignment in the frames - a problem with the original casting/machining of the chassis block. A number of other perople have encountered the same problem. I don't think it would be advisable to try to 'true up' the axle slot in the chassis block; the solution most people seem to choose (and which seems to work) is to adjust the coupling rods to match the actual wheel centres.

Ultrascale wheels are far, far better than any other make of loco wheel, and well worth both the price and the wait. Ready assembled converison sets for the 45XX and other Bachmann and Hornby locos are available, as well as the separate wheels and axles. Getting Ultrascale wheels on their axles (if you are not using a ready assembled conversion set) is a doddle. The crank pin holes are pre-drilled (or moulded in).

Experience with RTR conversions seems to vary but (subject to anyone else's experiences), the Bachmann Collett Goods (2251) and Panniers (57XX and 8750) seem to be no problem, whereas the 45/55XX and the 08 diesel shunter can be problematic (due to the chassis block machining mentioned above). It seems to be luck of the draw - some people have exprienced no problem with the 45s and 08.

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45609
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Re: Steam loco wheels - assorted questions

Postby 45609 » Thu Jul 05, 2012 12:08 pm

Martin,

That is very pertinent point you bring up. I've had a similiar nightmarish experience with converting a Bachmann Hall to EM gauge. I'm sure it was down to a degree of misalignment of the chassis slots for which the huge slop on the 3mm diameter axles compensated. Taking a precision approach I decided to use replacement 1/8" axles after tickling out the slots a little to get a nice running fit. Only then did I find the problems with misalignment. Careful construction of some replacment rods to match the true wheelbase did the trick. AFAIK there is no finish machining done on cast chassis provided with RTR models. Except perhaps if you count the drilling and tapping of screw holes but those seem to be mostly self tapping. It would cost too much.

Cheers....Morgan

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Horsetan
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Re: Steam loco wheels - assorted questions

Postby Horsetan » Thu Jul 05, 2012 1:16 pm

mlgilbert30 wrote:Martin,

That is very pertinent point you bring up. ....


...and he's done it without advocating the use of EMF flanges :D ;)
That would be an ecumenical matter.

martin goodall
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Re: Steam loco wheels - assorted questions

Postby martin goodall » Thu Jul 05, 2012 4:54 pm

Horsetan wrote:...and he's done it without advocating the use of EMF flanges :D ;)


Oh, yes. I forgot. The new wheels for my 45XX are made by Ultrascale to their EMF profile! :mrgreen:

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Horsetan
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Re: Steam loco wheels - assorted questions

Postby Horsetan » Thu Jul 05, 2012 8:07 pm

Drat. :evil:
That would be an ecumenical matter.

Philip Hall
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Re: Steam loco wheels - assorted questions

Postby Philip Hall » Thu Jul 05, 2012 9:17 pm

I have found that the rod centres don't match the chassis slots on quite a few Bachmann engines, resulting in much grief. The new ROD was OK though, but the 45Xx, the BR 76XXX and 82XXX the worst. I now always check the correlation with 1/8" jig axles pushed down as far as possible into the slots, and set up the reducing washers in the rods to suit. This, along with the rods opened up to 1.6mm, seems to solve most problems.

However, the checking of rod centres may be more difficult with the advent of Bachmann's new very odd axle size (2.14mm approx.) and - at last - hooray! - brass bearings in the chassis. I think I may have to indulge in some turning when the first one with the crazy size comes my way. I'm still not going to trust them.

Philip

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the fatadder
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Re: Steam loco wheels - assorted questions

Postby the fatadder » Thu Jul 05, 2012 9:24 pm

Thanks for all the advice, I'm currently working away from home but will have a proper look at the loco when I get back and work accordingly

I think for the remainder of my 4500/4575 (2 more) I will go straight for etched replacement chassis and save the work!
I'm just determined to make this one work given the amount of effort that has gone into improving it so far!


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