Wheel quartering

[KeithT]

Is there an idiot's guide to wheel quartering?
I have made 5 attempts lining up by eye and on the last occasion drilling a hole in my cutting sheet, inserting the crankpin of one wheel and using a protractor to align the opposite wheel at 90degrees visually. It looks spot-on but whilst the loco runs perfectly forwards the rear axle hops in reverse.
My concern is that many more attempts and the plastic wheel centre will be wrecked not to mention the new plastic gear.:wits:
Any advice welcomed please.

 

[bobg]

My advice would be to make a small jig (not necessarily easy), but remember that exact 'quartering' (90 deg) is not necessary, only that both axles are exactly the same.

However, a little odd that it is OK in one direction!

 

[beavercreek]

Hi Keith
I have tried to quarter a Bachamann Annie (with the complicated metal running gear ) and an Aristocraft Mallet. Everything seemed dead-on but there was always a small deviation. BUT I also found out that it was not necessarily the quartering but it can be the tolerances (or lack of them) in the running gear itself. After some research on the web I did find that sometimes the gear has to be slightly altered ( mounting holes reamed out etc). The other thing is that if the wheels slip, at all, on their axle then the quartering process is useless anyway.

 

[ge_rik]

As Bob says, if both axles are powered (as most G scale models are) then you need to make sure both pairs of wheels are accurately aligned with each other on their worm-gears. If not it can lead to kangaroo-ing (I may have just invented that term - but you get the drift).

Rik

 

[Gizzy]

Keith, a picture of the gears may be useful to help dianose the problem?

I think that this loco has one driven axle from the motor and the other axle is linked to the driven axle by a drive belt.

This belt is possibly the cause of your problem....

 

[ntpntpntp]

If only repairing one axle, don't assume the others are going to be exactly 90 degree quartered anyway! It depends how it was assembled at the factory.

The way I do it is to line up all wheels on one side to top-dead-centre (TDC) and then check the other side are all in line. As folk have said, sometimes there is some tolerance in the gearing, particularly where only one axles is driven directly by the motor and the others are driven through the rods. In this case try and find the maximum amount of turn that the slop in the mechanism allows, then set your quartering to be in the middle.

If possible, try and line up the spokes and counterweights by sight. This isn't always easy. Also be wary of the relationship of the axle gear to the worm, this can throw out your careful line-up, and you have to remove turn the wheel by one spline.

G scale is easy - you wanna try doing this sort of thing in N and Z as I have to from time to time!

 

[KeithT]

Gizzy: Yes this loco does use the toothed belt drive from one axle which I thought would make it easier to set. I will take a photo of the drive.

Nick: It is the one spline difference that I am having a problem achieving. When I pull the wheel off the axle it is well nigh impossible to do it gently and allow the fractional rotation when I replace it.
When you refer to aligning the TDC do you mean all wheels at TDC? It occurs to me that as these locos are not cylinder driven that it is proably immaterial if the wheels are not quartered. Of course, that would involve me pulling a wheel off the other axle and replacing it.&:
N and Z gauge quartering: I daren't even contemplate it!!!!&:&:&: It is the eqivalent of a camel through the eye of a needle.

 

[KeithT]

The drive area. Not too much help with the rear axle off but it shows the layout.

A thought, should there be a thrust ball-bearing at both ends of the shaft? There is only one at the rear(left) end but a possible housing at the front.

It is perverse, this is possibly the smallest LGB model but whereas the large locos have perhaps 4 screws retaining the baseplate this has 8!

 

[Neil Robinson]

A thought, should there be a thrust ball-bearing at both ends of the shaft? There is only one at the rear(left) end but a possible housing at the front.

Yes, at least according to this diagram (parts number 72).
http://lgb.vanelten.nl/Database/explosietekeningen/20140-1.pdf < Link To http://lgb.vanelten.nl/Da...tekeningen/20140-1.pdf
The absence of one may be a major part of the problem.

 

[KeithT]

A thought, should there be a thrust ball-bearing at both ends of the shaft? There is only one at the rear(left) end but a possible housing at the front.

Yes, at least according to this diagram (parts number 72).
http://lgb.vanelten.nl/Database/explosietekeningen/20140-1.pdf < Link To http://lgb.vanelten.nl/Da...tekeningen/20140-1.pdf
The absence of one may be a major part of the problem.

Yes, that must be the cause of the problem. In one direction the bearing takes the thrust of the motor shaft but in reverse the shaft moves a millimetere or so hence the froghopping.
Time to find a magnet and comb the carpet!!!!!

Must go and collect grandson No1.
Thanks for the help.

 

[Madman]

I have one or two LGB locos with split gear boxes. I have only taken one of these beasts apart, in my time, and that was with Tim Brien's excellent description of the procedure. My point is that he stressed clearly, not to loose sight of those teeny tiny thrust bearings. I have yet to dismantle a 2015 motor, due to lack of concentration powers. I must be in the right frame of mind before one of those gear boxes gets taken apart.

 

[KeithT]

I have lost count of the number of occasions I have seen the warning about not losing the thrust ball bearing but it never occured to me that there might be two!
A search of the carpet and worktop failed to locate the missing one.:-
I am now in the market for ONE 2mm ball bearing....8|
Another thing I have discovered - don't use Hobbylube Gear Oil in the presence of a drive belt.
I applied a single small drop to the worm drive and only ran the loco for a few seconds but the belt is splattered with oil - not good.

 

[Neil Robinson]

I have lost count of the number of occasions I have seen the warning about not losing the thrust ball bearing but it never occured to me that there might be two!
A search of the carpet and worktop failed to locate the missing one.:-
I am now in the market for ONE 2mm ball bearing....8|
Another thing I have discovered - don't use Hobbylube Gear Oil in the presence of a drive belt.
I applied a single small drop to the worm drive and only ran the loco for a few seconds but the belt is splattered with oil - not good.

http://simplybearings.co.uk/shop/product_info.php?products_id=35908 < Link To http://simplybearings.co.....php?products_id=35908
Any Help?
I'll put my Mr Pessimist hat on and state that that may not be the only problem. If the motor shaft moves axially its worm will rotate the one driven axle a little and the belt will then rotate the other so I don't think the absence of one ball will affect the quartering. What's more I fear some steel balls are made of non-magnetic steel making the search using a magnet less likely to be successful.
Hat off, there's a good chance the problem was with the motor mounting and will be solved by fitting a replacement ball. That link appears to be U.K. based with reasonable prices and P&P.

 

[stevedenver]

keith its so difficult to do this remotely

heres some thoughts-perhaps of no use , perhaps otherwise.....
first and most importantly-does it run smoothly w/o the rods?
if so then it may well be quartering
of course if it runs with rods well, but only for a bit of time, then the quartering would seem in order and as neil observes, something is slipping a tooth

if you are getting ths skipping regardless of removing the rods, consider this
i had a rather heavily used loco-2076- which had the same directional issues-good one way and skipped the other

what in fact was the issue was the axel holes in the gear box had worn, allowing for axel slop-and caused tooth skipping under even modest load or only loco -but this was a normal double worm gear LGB gear box- but the principal may be the same with the gear belt- if this is the case-its a big problem as you will need some sort of sleeve for the axel to sit in...beyond my skills

also
i would not worry about oil on the belt so long as it is plastic compatible-(i actually add LGB and teflon grease on mine as it makes them a bit quieter-in fact as they are delrin-they need no lube-there has been no issue in many years of use )
however grease is best on the worm as it will cling at higher revs, where oil doesnt

if it is indeed the lack of a thrust bearing
as for the ball bearing-while a proper replacement is best-
there is nothing wrong with using a bit of some alternative shim-what might work you ask???-
using goggles and protective cautions-i have used razor blades, cut with rail nipping sheers-the metal is very hard and very slick-if you can get a decent cut-its superb
you will need a tiny sliver-if this puts you off-perhaps some very thin steel strip from the hobby store?? or even brass-obviously with a touch of grease

i am thinking that what might also be causing the issue is, somehow, as neil mentioned, there is an issue of proper tension, either via the belt-ie tight one direction and loose enough to slip another-or, the motor slipping against the worm (which should not affect anything it would seem, as there is only a a single worm and everything else is connected via rods or belt-so the slip, it would seem must be in belt and or belt driven axel)

 

[KeithT]

Neil
Thanks for the link in fact I ordered from them earlier this afternoon!
It will be the worlds most expensive mini ball bearing at £2,35? although for that i get a pack of 10 - anyone need 9 2mm ball bearings?
I am pretty certain I have got the quartering correct which is why I was so puzzled that there was a problem with the froghopping.
Steve
I runs the same with the rods off. What happens is that in one direction the ball absorbs the thrust but when it runs the other way the shaft shunts forward and obviously jumps out of mesh with the axle gear that was when I peered down to find there was a space where a ball should have been.
I did wonder about an alternative shim but decided that as I intend keeping the loco I would opt for the ball bearing. When i bought it it had clearly been a shelf queen/display model, it was immaculate and hasn't had a huge amount of running since so is in good shape and has no slop in the axle slots.

If it does eventually turn out to be the belt then that will be another search exercise because as I recall from a previous query it is a non-standard size.

I am suspicious that the damage to the original gear was as a result of previous lubrication with the Hobbylube gear oil. It just doesn't seem to be dense enough to me. The worry is that all my locos have been treated with it.

 

[JRinTawa]

I'll pop a cover plate of one of mine when I get home but I'm pretty sure mine only have the rear thrust bearing. I had a bit of "fun" getting the quatering right after slipping on the belt after some modification's on my diesel (same motor block). Was a while ago now so I can't remember with any reliability just how I did it but I think I got the belt even first and running right on that and positioned with wheels on one side at top dead centre.

Could I suggest two checks. First remove the motor and bench test it, just incase there could be some fault in it. Then second while motor still out does the chassis free wheel, and if not requarter it so it is free wheeling before putting the motor back in.

And good luck

 

[KeithT]

John
The major problem I had was that I had to remove the wheels in order to fit them to a new axle. I believe that I have now got that aspect right. The jerking was totally unexpected.
It will be v interesting to learn if yours has only the one ball bearing. I had long been under the impression that only one was used but the LGB drawing for the 20140 does show two. Incidentally the underside of the top plate of the block has 20140 moulded into it. It would also be interesting to know if the one on your diesel has the same marking however, it might be hidden behind the front axle and the belt.
I might not get a chance to get back to it until the weekend but I will try what you suggest by running it 'freewheel'. Checking the coupling rods at various stages of rotation hasn't shown any tight spots though.