Jump to content
 

Quartering - trying to get it right before it goes all wrong


chrisveitch
 Share

Recommended Posts

For as long as I've been modeller I've hated quartering, and after some decades I still detest it. Hence my build of the apparently simple Association 57xx chassis kit has reached the part I've been dreading. 

 

I've been good and followed Nick's Jubilee series assiduously, preparing the components to as high a standard as I can, inspecting and measuring everything multiple times, buying all the relevant jigs and aids and being pleased with myself - up to the point where I now have two axles in the chassis with the help of the Association quartering jig, and they're nowhere near right. They have two very tight binds at 180 degrees to each other, which to me signifies that the rods are too short (or long) for the crankpin distance at these points. I have broached out the crankpin holes lightly unit they're a good running fit, but to no avail. I'm terrified of proceeding further and ending up with oversize crankpin holes that still don't solve (or perhaps worsen) the problem, so I'm trying to analyse the issue. So far it goes like this:

  • I have to assume the wheels are quartered correctly - they only went in the jig once and haven't been tweaked or twisted in the muffs, so I'm looking at one of the following:
    • The crankpins are bent (I've checked them visually and they look OK, but I did bend one and had to restore it);
    • The rods actually are different lengths - which seems unlikely, I've been carefully with them and they've not been bent or stretched (as far as I know);
    • The 3-layer rod joints have been soldered up to provide a hole that's not perpendicular to the rod face - I have tried to broach them as square as possible;
    • The axles are not parallel in the chassis;
    • Something I've not thought of...

 

I'm keen to hear the wisdom of my betters in suggesting a way forward, before I blunder on and ruin the whole thing. Or take up O gauge tinplate. 

 

Thanks in advance,

 

Chris

  • Friendly/supportive 1
Link to post
Share on other sites

Taking up 0 gauge sounds the better option :) .

 

Joking aside, there have been a couple of threads regarding quartering (I believe touched upon on Tony Wright's thread as well). The last time I had a go, I used Romfords that came with the square axle ends that automatically quartered the wheels.

 

I expect someone will be along with help.

 

Best of luck,

 

Philip

Link to post
Share on other sites

2mm Magazine Archive (on the website, members only area), Feb and April 1995, articles by John Greenwood on building a Buckjumper.   Includes systematic approach to solving quartering issues. 

 

A common mistake is to make things too tight.  Many good running locos are surprisingly sloppy, but the slop has to be in the right places. 

 

 

- Nigel

  • Agree 1
  • Thanks 1
Link to post
Share on other sites

  • RMweb Premium

Get a Farish coupling rod conversion set - 3-205 - which have a 57xx set on them. These will be a sloppy fit on standard 0.5mm crankpins and are a bit beefy but will be easy to use and help tell if the quartering is okay or well out. Once all is okay you can then decide if using the finer ones is for you or not.

 

Bob

Link to post
Share on other sites

Nigel's last comment is very true and was something we discussed at our last group meeting.  At a meeting about two or more years ago one of our members had a 4F chassis that he couldn't get to run freely with just the wheels and rods (no gears or worm).  I spent the afternoon gently reaming out the holes in the rods, checking with them only on the front and centre wheels and then only on the centre and rear ones, until we eventually got it running freely.  He was surprised at how much play there was in the rods at that stage.

 

Jim

Link to post
Share on other sites

1 hour ago, Miss Prism said:

How are you matching the rod centres with the axle centres in the chassis?

 

The kit has an assembly jig included which ensures that the two match (unless I’ve subsequently messed it up somehow).

10 minutes ago, Izzy said:

Get a Farish coupling rod conversion set - 3-205 - which have a 57xx set on them. These will be a sloppy fit on standard 0.5mm crankpins and are a bit beefy but will be easy to use and help tell if the quartering is okay or well out. Once all is okay you can then decide if using the finer ones is for you or not.

 

Bob

Thanks for this (and Nigel and Jim for their valuable contributions as well). At least you have assured me that I’m a) not alone and b) possibly not a complete incompetent. Even more patience is clearly the way forward.

Link to post
Share on other sites

  • RMweb Premium

Hello Chris, I always make a first check on a quartered chassis by fitting the rods on one side only (retained by small lengths of plastic insulation) then turning the chassis over and comparing the angles of the wheel spokes on the free side. If the quartering is out on one of the wheel sets it is usually noticeable. Then try dropping the rods onto the crankpins to see where (or not) they fit.

 

good luck

Alex.

  • Agree 1
  • Thanks 1
Link to post
Share on other sites

Possible causes

 

The wheels are not quartered to the  same angles.

The axles are not parallel in the chassis

The crankpins are bent or not in the same plane as the axles

The Crank throws are not equal

The rods  are different lengths

The rods are dragging on the wheel face..

Connecting rods dragging on the coupling rods

 

 

 

 

 

Edited by DCB
Link to post
Share on other sites

  • RMweb Gold

Its probably not much help to say that Ive never had much of a problem with quartering and have always done it by eye. Nigel and the late Paul Martin organised a workshop (scarily nine years ago!) which I participated in and my method of quartering starts at around 47 minutes.

 

 

 

Jerry

Link to post
Share on other sites

3 hours ago, queensquare said:

Its probably not much help to say that Ive never had much of a problem with quartering and have always done it by eye. Nigel and the late Paul Martin organised a workshop (scarily nine years ago!) which I participated in and my method of quartering starts at around 47 minutes.

I do mine in exactly the same way and have never used a jig.  To make the tiny adjustments necessary as you get close to having the quartering perfect, I insert a small jeweller's screwdriver between two spokes of the offending wheel and use that to gently tweak it round.  I always use the driven axle as the reference one and adjust everything to that, having made it as near 90° as I can judge.  A few degrees either side of that on that set will make no difference, as long as the other axles are adjusted to match.

 

@DCB, as Nigel says, I think you are ignoring the fact that this is a 2FS Forum, so the only wheels under discussion are those from the 2MM Scale Association, which are of a completely different design to those you mention.  They are designed for live frame pickup, having integral half axles which fit in insulating muffs.

 

Jim

  • Thanks 1
Link to post
Share on other sites

  • RMweb Premium

I also find the jigs don’t help me with quartering. Much of the advice given is spot on, but something I always do is check the quartering before the wheels are fully squeezed to the correct back to back, using a watchmaker’s vice across the crank webs. I make sure that they are a very tight fit on the muffs so that they are unlikely to move once at gauge. John Greenwood’s article is an excellent description of how to make errant rods work and Jim’s advice to never adjust the driven axle crank pin holes is very wise, other than opening up for running clearance. 
 

Tim

  • Thanks 1
  • Informative/Useful 1
Link to post
Share on other sites

  • RMweb Premium

I always check the rod lengths first, by setting the wheels at 3 o'clock and then at 9 o'clock on one side. If the rods fit nicely in both positions, you can be sure that crank throw, rod length and wheel centres are OK. If there is any tightness doing this check, no amount of correct quartering will eliminate it, so that needs sorting before the next stage.

 

Then, with the rods on one side and set at 12 o'clock, I look at the other side to see that the driven axle is as near 3 or 9 o'clock (depends which side or which way up it is!). Then, holding the driven axle in a fixed position, just with finger pressure, with the rod still at 12 o'clock on the other side, I wiggle the other axles to see if the crankpins move an equal amount either side of the position of the driven axle crankpin. If they don't,  I alter the quartering until they do.

 

I have done this many times with push on wheels in 4mm scale but only a couple of times in 2mm. The method works just as well in either scale.

 

Quartering wheels is one of those tasks which can be accomplished in many different ways but once an individual finds a way that works for them, they wonder why some people struggle. Once you find a method that suits you, it really isn't too difficult to get right.

 

I hope you find something that works for you.

  • Agree 3
  • Thanks 1
  • Informative/Useful 1
Link to post
Share on other sites

Many thanks for the many words of wisdom - and that's without any irony, it really is appreciated. There are clearly a number of different ways to achieve this and I need to have a careful look at what suits me best. As my original post probably indicated, I've tried various things over the years without any consistent success and I'm keen to get this one right without causing irreparable damage to the rods, chassis or my faith in my modelling abilities.

 

On a related note, I have to say that I fell upon @queensquare's Kirtley article in the latest MRJ with glee and then realised that...the chassis is in the next issue. It's still very good though!

Link to post
Share on other sites

On 29/09/2021 at 09:43, t-b-g said:

I hope you find something that works for you.

I'm pleased to say this has borne fruit. A careful reading of the above and the various references led me to discover that the axle spacing on one side was slightly less than 0.1mm out on one side between the leading and driven axles (and a microscopically bent crankpin didn't help) so I now have the first four wheels quartered. 

 

One of the important tips was in John Greenwood's article, where he advised testing each rod separately before trying both together. For some reason this had never occurred to me previously, but it's pretty obvious when you think about it. By swapping rods between sides I managed to narrow down the problem to the axle spacing on the RHS being very slightly off, which I could adjust by reaming out the leading crankpin hole. 

 

Thanks again everyone. 

  • Like 1
Link to post
Share on other sites

1 minute ago, Miss Prism said:

So the assembly jig (whose purpose was to match the rod centres with the axle centres) wasn't quite as good as it should have been?

 

No, I suspect it was 100% correct and that one of the bearings subsequently shifted in my ham-fisted attempt to resolder one of the PCB spacers back in when it came adrift. 

  • Like 1
Link to post
Share on other sites

  • RMweb Premium
49 minutes ago, chrisveitch said:

I'm pleased to say this has borne fruit. A careful reading of the above and the various references led me to discover that the axle spacing on one side was slightly less than 0.1mm out on one side between the leading and driven axles (and a microscopically bent crankpin didn't help) so I now have the first four wheels quartered. 

 

One of the important tips was in John Greenwood's article, where he advised testing each rod separately before trying both together. For some reason this had never occurred to me previously, but it's pretty obvious when you think about it. By swapping rods between sides I managed to narrow down the problem to the axle spacing on the RHS being very slightly off, which I could adjust by reaming out the leading crankpin hole. 

 

Thanks again everyone. 

 

Glad to hear it.

 

Rod length doesn't need to be much out, especially in 2mm scale where the holes in the rods are smaller than in other scales. I even had a tight spot once in a 7mm loco which had Slaters self quartering wheels, which was down to a tiny error in the fixing of a bearing into a frame. 

 

Once the penny has dropped with the technique of quartering, you will wonder why you ever thought it difficult.

 

I do find it interesting to read all the different hints and tips and I am always learning new tricks. The idea of putting a screwdriver between the spokes to adjust the wheels is one I hadn't thought of but will allow much finer adjustment than my fingers gripping the tyre as I have done previously.

Link to post
Share on other sites

On 02/10/2021 at 20:31, t-b-g said:

 

I do find it interesting to read all the different hints and tips and I am always learning new tricks. The idea of putting a screwdriver between the spokes to adjust the wheels is one I hadn't thought of but will allow much finer adjustment than my fingers gripping the tyre as I have done previously.

Even better than a screwdriver is a home made tool which uses an X-Acto holder no.2 fitted with an adapted no.18 (chisel shape) blade. To adapt the blade, grind off, or at least blunt, the sharp end and then grind a slot in it wide enough to take the wheel boss (so that it looks rather like the special screwdriver for Romford wheels but with a wider slot). For 2FS you may need to grind a taper in the sides of the blade too so that it will fit within the rim. Of course, the canny ones among us will utillise a well-used blade that has already become less than sharp. It is easiest to use in wheels with an even number of spokes but it seems to work OK with an odd number too even though it can't quite be centred on the wheel.

Edited by bécasse
typo
  • Like 2
Link to post
Share on other sites

  • RMweb Premium
36 minutes ago, bécasse said:

Even better than a screwdriver is a home made tool which uses an X-Acto holder no.2 fitted with an adapted no.18 (chisel shape) blade. To adapt the blade, grind off, or at least blunt, the sharp end and then grind a slot in it wide enough to take the wheel boss (so that it looks rather like the special screwdriver for Romford wheels but with a wider slot). For 2FS you may need to grind a taper in the sides of the blade too so that it will fit within the rim. Of course, the canny ones among us will utillise a well-used blade that has already become less than sharp. It is easiest to use in wheels with an even number of spokes but I have it seems to work OK with an odd number too even though it can't quite be centred on the wheel.

 

An interesting idea but a good friend of mine might have come up with an easier to make version.

 

I mentioned the tip to him and he told me about his home made tool, which was a strip of brass, big enough to stay stiff and straight, with two holes drilled through it and two brass pins soldered in, making his own wheel quartering wrench. Imagine a brass tooth brush with just two brass bristles.

 

 

 

  • Like 2
  • Informative/Useful 3
Link to post
Share on other sites

1 hour ago, t-b-g said:

 

An interesting idea but a good friend of mine might have come up with an easier to make version.

 

I mentioned the tip to him and he told me about his home made tool, which was a strip of brass, big enough to stay stiff and straight, with two holes drilled through it and two brass pins soldered in, making his own wheel quartering wrench. Imagine a brass tooth brush with just two brass bristles.

 

 

 

That certainly sounds just the job. 

 

If I were to make one, and I might well do, I think that I would use the smallest size (1/16"?) of square brass tube instead of a strip of brass (easier to drill holes through and stronger for its size) and then solder a pair of household pins through the holes in it, trimming the pins to length after soldering (again the steel pins would be stronger for a given diameter than brass wire).

Link to post
Share on other sites

4 hours ago, chrisveitch said:

No, I suspect it was 100% correct and that one of the bearings subsequently shifted in my ham-fisted attempt to resolder one of the PCB spacers back in when it came adrift. 

 

Unless I've missed something, the assembly jig included with the kit doesn't match the frames to the rods - it just makes the job of assembling the frames squarely a bit easier. Using it to check the rods match the frames would require jig axles with turned down ends to fit the coupling rods onto (as used in 4mm).

 

The accuracy of the rods and the frames matching is purely down to the etch designer having drawn them correctly and the etch artwork not getting stretched in some weird way.

 

PS. Glad to hear you managed to resolve the quartering issue.

 

Andy

Edited by 2mm Andy
Link to post
Share on other sites

14 hours ago, 2mm Andy said:

The accuracy of the rods and the frames matching is purely down to the etch designer having drawn them correctly and the etch artwork not getting stretched in some weird way.

Indeed it is and you’re right, the jig only really aligns the frames in the correct planes and gets the bearings in the right place. My assumption is that the artwork does indeed provide the same spacing for the rod centres and bearing holes.

Edited by chrisveitch
Link to post
Share on other sites

  • RMweb Gold
56 minutes ago, chrisveitch said:

Indeed it is and you’re right, the jig only really aligns the frames in the correct planes and gets the bearings in the right place. My assumption is that the artwork does indeed provide the same spacing for the rod centres and bearing holes.

 

If the chassis etch is an Association one designed by Higgs/Hunt/Jones et el then there should be no problem regarding the spacing of rods and bearing centres. I've erected numerous of them and they have always been spot on. Etching isn't an exact science. The holes can vary slightly in size (though not centres) which is why they tend to be etched under size so they can be reamed to be an exact fit  to the bearing. The most likely cause of issues in this case is if bearing holes are reamed over size which results in a sloppy fit and the matching centres being lost.

 

 

Jerry

  • Like 1
  • Agree 2
  • Thanks 1
  • Informative/Useful 1
Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...