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It's been a while since I've posted anything here, mainly because I haven't done very much to this loco recently, what with holidays and so forth... and also because to be honest I'm struggling with getting the chassis/wheels etc to run smoothly, even before I try it with the coupling rods...

I don't think I've got the chassis entirely square, and even if I had it still seems rather flexible and can be twisted along it's length. This happens when I screw it to the body, so obviously I've made a pig's ear of that too, possibly because I pressed on with it whilst my chassis was AWOL, as you're all aware.

Even without the body on, I'm having trouble getting the drive axle to turn freely through the gearbox. Somehow I need to make something up to mount the motor and gearbox rigidly, that holds it in exactly the right place so it doesn't exert any pressure on the axle. One snag is I can't see any way to fix the motor to whatever I make (no screw holes on the rear face) and trying to fit anything to the same end as the gearbox looks to be a very awkward exercise.

Something I had to do was replace the springs supplied with the plunger pick-ups with softer ones, to exert less pressure on the insides of the wheels. I used spare Kadee springs for that, and have soldered in the wiring. Tried it on the rolling road and it didn't sound too good really, even with some grease on the worm & gear, and fiddling about with the position of the worm, it's still rather noisy (worse in one direction- why?!?) and with the motor not quite rigid, it was liable to stall as the axle binds a bit. I haven't got anywhere near testing it with the coupling rods on. :blink:

This is one uphill struggle for sure; there's obviously a lot more to building this sort of chassis than diesel bogies.

 

Feeling a bit mad0235.gif mad0235.gif mad0235.gif mad0235.gif mad0235.gif at the moment, I'm afraid...

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Feeling a bit mad0235.gif mad0235.gif mad0235.gif mad0235.gif mad0235.gif at the moment, I'm afraid...

 

Forget the motor, gearbox and pick-ups for the moment - the first essential is to get a rolling chassis.

 

You must get to the point where the complete wheeled, fly-cranked and rodded chassis will roll of its own accord when placed on a slightly inclined piece of track.

 

Start with the frames with just the wheels and fly-cranks in place - no rods.

 

If this rolls OK then add the first pair of rods between the first and second axles.

 

When this rolls OK, add the second pair of rods, and so on ......

 

Don't be tempted to move on from any stage until you're *totally* satisfied with the rollability.

 

This way, you know exactly where any binding has been introduced at each stage.

 

Best of luck.

 

John Isherwood.

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It's been a while since I've posted anything here, mainly because I haven't done very much to this loco recently, what with holidays and so forth... and also because to be honest I'm struggling with getting the chassis/wheels etc to run smoothly, even before I try it with the coupling rods...

I don't think I've got the chassis entirely square, and even if I had it still seems rather flexible and can be twisted along it's length. This happens when I screw it to the body, so obviously I've made a pig's ear of that too, possibly because I pressed on with it whilst my chassis was AWOL, as you're all aware.

Even without the body on, I'm having trouble getting the drive axle to turn freely through the gearbox. Somehow I need to make something up to mount the motor and gearbox rigidly, that holds it in exactly the right place so it doesn't exert any pressure on the axle. One snag is I can't see any way to fix the motor to whatever I make (no screw holes on the rear face) and trying to fit anything to the same end as the gearbox looks to be a very awkward exercise.

Something I had to do was replace the springs supplied with the plunger pick-ups with softer ones, to exert less pressure on the insides of the wheels. I used spare Kadee springs for that, and have soldered in the wiring. Tried it on the rolling road and it didn't sound too good really, even with some grease on the worm & gear, and fiddling about with the position of the worm, it's still rather noisy (worse in one direction- why?!?) and with the motor not quite rigid, it was liable to stall as the axle binds a bit. I haven't got anywhere near testing it with the coupling rods on. :blink:

This is one uphill struggle for sure; there's obviously a lot more to building this sort of chassis than diesel bogies.

 

Feeling a bit mad0235.gif mad0235.gif mad0235.gif mad0235.gif mad0235.gif at the moment, I'm afraid...

 

I know it's a bit late now, but this is where the Avonside chassis squared jig thingy comes into it's own.

It must be good, even I can build a decent chassis first time :D

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Hi Jordan,

 

Looking back on your thread when you finally had the chassis returned :diablo_mini:, I noticed that you did not mention how you set up the frames to keep them square when soldering the frame spacers or how you kept the axles in line before soldering ? This part of chassis building is VERY critical and you will not be the first or last to come across this problem. The Avon chassis jig is good but very expensive, I have the Master chassis jig which is also expensive over £100 but you do also get a rolling road thrown in as well, which has come in very handy. But don't despair as Four track models have a much cheaper solution which are just 3 rods that you thread through the axles and put the coupling rods on the ends to hold everything in place, I will go into more detail if you are interested in this method let me know. But it sounds like you have either got a twisted chassis or the axles are slightly out, also never tighten up the fixing screws to tight as that can easily break the soldered seams unless you used 188 degree solder. Let us know how you get on or how you built the chassis, we are here to help you :good_mini:.

 

ATB, Martyn. P.S. Just had a look at the current price of the Avon works jig :- pro £220.00 or the super pro £260.00 :O:o:o Bl**dy hell you could buy a good quality kit for that price. B)

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P.S. Just had a look at the current price of the Avon works jig :- pro £220.00 or the super pro £260.00 :O:o:o Bl**dy hell you could buy a good quality kit for that price. B)

 

Not meant to be a criticism, but,

 

Price is relative, it will assist you to build a good quality kit, surely that's better than wasting £260 on a kit you can't build?, and spread over a goodly number of kits the relative cost comes down, although an even better/cheaper bet is the maybe the master chassis jig, which I have no experience of.

 

No interest other than as a satisfied user.

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Hi,

 

Sorry I did not mean to sound derogatory to the Avonside jig in anyway only to the high price, I remember the read up in MRJ that it is a good aid to chassis construction. And if you intend to make enough kits it will be worth it in the long run, it's just that I think it's important to gain the fundamental basics in chassis construction to gain an idea of what's required to get a free running chassis first. I for one am first to admit I have been driven to distraction in the past and it's only through experience gained that I now feel (fairly) confident in my abilities to pass on my knowledge if anyone chooses to listen :blink:.

 

ATB, Martyn. ;)

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The Master Chassis jig is good, I have one but, you still need to know what you are doing to get a perfect result. JPL do a chassis jig at about £30, if cost is important to you. It keeps the rear axle fixed and you use axle rods with tapered ends and the coupling rods to align the others as well as keeping the chassis square. The advice about checking at every stage is paramount.

Regards

Sandy

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Hi Jordan,

 

Looking back on your thread when you finally had the chassis returned :diablo_mini:, I noticed that you did not mention how you set up the frames to keep them square when soldering the frame spacers or how you kept the axles in line before soldering ?

I first started the chassis back on Page 1 of this Thread, but to save messing about here's the gist of that post again...

 

The basic chassis (nickel silver) has been soldered up- two sideframes and three spacers. I have a small magnet (I think it's out of some long-forgotten motor) which is perfectly square, and a great help in keeping things in postion.

 

Class14B003.jpg

 

A tip I've seen is to put rods through the axle holes and put the piece on a grid to check everything's square... looks good to me..??

 

Class14B001.jpg

 

I appreciate now that it's enough to make you more experienced chassis Builders shudder in horror...

As for the various alignment jigs mentioned, while I can appreciate their value and the cost being okay if spread over several kits, for a one-off build like mine it's a bit much.

 

I am still really at the first stage of trying to get each axle free-running; the non-powered ones do, and so does the powered one until it has the gearbox frame in place as well. It was only because it's such a hassle removing the motor from that frame that I've tried that out earlier than I really should have.

I'll get some pics later which should help show my ineptness even clearer...

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Class14B003.jpg

 

Class14B001.jpg

 

There looks to be a lot of thin, unsupported chassis flexing about there - a perfect scenario for axle binding. The two bearings on each axle *must* be and remain concentric at all times.

 

I'd be much happier with a couple of L-shaped spacers soldered in to support the central section of the frames.

 

I'm no fan of sprung pick-ups, either - (AKA brakes in my book)! Better to arrange one of the central L-shaped spaces as a mount for some conventional phosphor bronze wheel-wiper pick-ups.

 

The Wild Swan chassis building book is a real bargain when you consider how much wasted money and grief a thorough read can save.

 

Regards,

John Isherwood.

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Oh man this is a touch embarrassing... :blink:

 

Thanks for all the advice... following it, I went back to basics and started again with just the wheels; then with the gearbox/motor assembly minus the worm; then one side coupling rods, then the other, trying to get it all to roll smoothly without power. Things seemed to go surprisingly well, so I pressed on...

It then seemed that a short video might demonstrate the current state of play rather than pictures...

 

 

... at least Thomas and the Naughty Trucks behind seemed to find it funny :rolleyes: and yes, the motor is currently held in place with *ahem* :huh: a cable tie :huh: but other than that it appears that miracles do happen..!!! B)

Of course I haven't yet tried it under the body, but on it's own the chassis seems okay..

 

I now have two questions that fall into the "Extremely Obvious if You Know" Category;

1- should I shorten (file down) the bearings for the coupling rods a bit as they're rather wider than the rods?

2- what's the best way to shorten the crankpins and secure the nuts?

 

Feel a lot better than I did about this yesterday..!! :)

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Hi Jordan,

 

Just a quick reply as I'm off to bed, yes it is best to file down the bearings, if you lay the bearing down (flange at the bottom) then place the coupling rod over the bearing which not only holds it in place but gives you a guide as to how much you are taking off leave about 2mm proud of the coupling rod. As for the crankpins, put the filed bearing on then put the nut on the crankpin and screw down finger tight. Then cut off the pin either level or 1mm out with a dremil, sharp cutters (xuron) whatever takes you fancy then gentley file the end of the thread, then as you take the nut off it should put the cut thread back on the crankpin. Hope this makes sense as I'm rather knackered. To hold the nuts on the crankpin when finished I use clear nail varnish (not mine the wife's).

 

ATB, Martyn.

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Before you cut down the bearings check you don't have any brake rigging or anything the coupling rods could possibly strike. Sometimes you have to put a washer behind the rods to pack them out a little but if you have no problem then follow the advice of 3-link above.

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There looks to be a lot of thin, unsupported chassis flexing about there ...

I'd be much happier with a couple of L-shaped spacers soldered in to support the central section of the frames.

 

I'm no fan of sprung pick-ups, either - (AKA brakes in my book)!

Thanks for your advice, John.

I did add some H-section brass channel inside each frame and as a crossmember to try and add some rigidity, partly visible here in this photo I posted on Page 9 of this thread;

Class14L01.jpg

 

As for the 'brake' effect of plunger pick-ups, that was why I replaced the supplied springs with 'softer' ones (ex-Kadees!). There is a minimal gap between the wheels and spring/hornblock castings, so the pick-up springs are quite compressed.

 

Also I have stuck with the cast Jackshaft counterweights. As Spud says they don't bear any load in the drive train, and with the limited amount of expected running time I don't anticipate any problems. I have used a thicker 10BA screw as crankpins, running through Slaters wagon axle bearings opened out slightly and press-fitted into the casting, and both lightly soldered in place.

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Well done Jordan you have kept going where many would have given up. Keep up the good work.

Bob

Must admit I have felt like that at times, but the cost of O scale kits is a great incentive to keep going...!!! :blink: :rolleyes: :D

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Hi Jordan,

 

Just a quick reply as I'm off to bed, yes it is best to file down the bearings, if you lay the bearing down (flange at the bottom) then place the coupling rod over the bearing which not only holds it in place but gives you a guide as to how much you are taking off leave about 2mm proud of the coupling rod. As for the crankpins, put the filed bearing on then put the nut on the crankpin and screw down finger tight. Then cut off the pin either level or 1mm out with a dremil, sharp cutters (xuron) whatever takes you fancy then gentley file the end of the thread, then as you take the nut off it should put the cut thread back on the crankpin. Hope this makes sense as I'm rather knackered. To hold the nuts on the crankpin when finished I use clear nail varnish (not mine the wife's).

 

ATB, Martyn.

 

 

 

I would go along with what Martyn has said but to reduce the end clearance to 0.2mm (about 8 thou), if you measure the coupling rods and see if you have any brass / steel stock that is about the right size drill it to suit the bearings (2.5mm) and use that, no marks on the rods then.

 

For the crank pin nut you could use the ones from C.P.L. or J.L.T.R.T. they do look a lot better than just a normal nut.

 

Glad to see you back, keep up the good work.

 

OzzyO.

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I would go along with what Martyn has said but to reduce the end clearance to 0.2mm (about 8 thou),

Must admit I did think 2mm clearance sounded a bit much, but didn't like to question it!! I don't think the clearance is that much now, before filing down!!! ;)

But thanks to everyone for the continued help and encouragement!! :)

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  • 2 weeks later...

jordan,

 

Hi, really impressed with your chassis so far! like the additional strengthers, wish i'd done the same with hindsight!

nearly finished mine now, time for buffers and weathering now!!!!!! a couple of pics of the story so far below.

 

my biggest problem now is the brake gear, you might find ( as i have) that the brake shoes actually rub the wheels as their hangers are a bit too close to the wheel rims. i'm currently in the process of cutting off the whitemetal shoes and making plastic ones to avoid inevitable short circuits!

if you still havent fitted the brake hangers, test fit them for the right distance before soldering them in place! Dont trust the etched holes in the frames!!!!

post-9368-127902202254.jpg

post-9368-127902204703.jpg

post-9368-127902206487.jpg

post-9368-127902210113.jpg

post-9368-127902217101.jpg

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...my biggest problem now is the brake gear, you might find ( as i have) that the brake shoes actually rub the wheels as their hangers are a bit too close to the wheel rims. i'm currently in the process of cutting off the whitemetal shoes and making plastic ones to avoid inevitable short circuits!

if you still havent fitted the brake hangers, test fit them for the right distance before soldering them in place! Dont trust the etched holes in the frames!!!!

Yes, I have become aware of that problem :( ... unfortunately I did trust the holes in the chassis, and I'd already soldered the brackets in place. The actual hangers will need a bit of tweaking. Not sure about totally removing the shoes- I was thinking more in terms of filing them back a bit and possibly facing them with thin plasticard sheet. I won't fit the sandpipes until nearly the end, as for one thing they'd foul the rollers on my Bachrus rolling road saddles.

Sorry to say I haven't progressed any further since getting the chassis to run. I need to file down the crankpin bushes still, and the Jackshaft crankpin at least needs shortening before I can test the chassis under the body, as it fouls the cab steps otherwise! I've been having a relaxing diversion recently though by finishing off some wagons and Brake Vans that have been in the "To Do" Pile for some time...

Re your model; did your cab overhang the footplate either side, or was it just mine? Yours looks fine. In fact the whole thing looks better than mine I reckon, so much so that I really do hesitate to point out only that the bonnet ends should slope back a bit, instead of being vertical... :unsure:

http://www.preserved-diesels.co.uk/2008c/9500_1.jpg

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jordan,

 

yes, the jackshaft crankpins foul the steps!!!! and my cab overhangs by about 0.5mm either side!!! ( it was more!!) the bonnet ends do rake in, but is more pronounced from the side view, the one thing i have omitted is the 'step' under the bonnet front where it meets the front running plate. ( oops)

I admire yours too, considering the setbacks you've had its a damn good job you've done! many folk would have melted it down and made the wife a nice pair of earings!!!

 

keep up the good work!

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Only just come back here after a long time away from this thread :(

 

It is good to see all problems being resolved.

 

I just had to put in a few penny worth on the subject of jigs and in particular the Masterchassis and Avonside ones. I'm not going to be too critical of them - I've seen them both in use but not in my hands and I am sure they do work very well.

 

But how have we managed for countless years without them (and probably will for years to come)?

Exactly the method you used - or a variant on it. Using steel rods (I would use 1mm graph paper not a rough cutting mat) is perfectly good but you have to remember that this is only one plane xy you need to be able to check the other planes as well by using a perfectly flat surface with the wheels on those steel axles. There is also something to be said for mounting the cranks as well - hey presto a jig :)

 

These jigs are only really for the professional kit builder who can justify the expense or the seriously well off who are seeking out the next gizzmo gadget to must have. Of course the manufacturers will do their utmost to convince you that you will never put a chassis together without their latest all singing version they want to sell one to you to improve their profits/make a living.

 

There is a lot to be said for learning by trial and error - at least you get to understand the faults in some chassis designs and how they can have a mind of their own twisting or even going out of true due to the positioning of the spacers ... or failure to make the spacers perfectly true. Anyway unsoldering a chassis and trying over is not a big task.

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... the bonnet ends do rake in, but is more pronounced from the side view, the one thing i have omitted is the 'step' under the bonnet front where it meets the front running plate. ( oops)

My apologies!! I think the camera angle has distorted the perspective, being close up. ;)

I don't think the "step" was there in the casting; I had to file it in... and at least it wasn't just me with the cab problem..!!

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