Sloppy wheels

[Kenton]

A kit with W-irons 43mm apart leaving over 4mm slop from side to side with the bearings pressed home. Slaters wheelsets.

 

Solutions:

1. Push bearings back onto axle - side effect makes the bearing-W--iron join very weak and virtually prevents wheel removal.

2. Washers to pad out - 4mm washers is quite a lot, washers tend to accumulate dirt and have a drag effect on the wheel, tend to rattle

3. Brass tube over the axle stub - same issue as 2 though less rattle.

 

Have I exhausted the list too late in the evening to think straight?

How would you approach it?

 

Scratch building a new chassis or converting to S7 are NOT an option.

[Adam]

That sounds like my experience of building wagons in O: a frightening amount of slop designed in. Assuming that the bearings have a flange, I'd fit spacers between the back of the axlebox and the flange. Is this the same as option 1? Is there any special reason why you might want to remove a wagon wheel? I can't think of any occasion post-painting when I ever have, though this is in 4mm.

 

Adam

[Ian G]

I have found this many a time, washers between the flange and the wagon iron works

 

Ian G

[bertiedog]

The best would be PTFE (teflon) tubing, cut to length needed., electrical PTFE insulation sleeve, Hard nylon tubing, old plastic ink tube from a ball point pen.....cheap and available. I can't remember the Slaters diameter for the stub?

Stephen.

[boxbrownie]

But surely the whole 'point' of pinpoint bearings is that the end of the axle runs into the end of the bearing tube, thus giving the smallest area of drag. All that happening if you use a spacer is run on the thrust side of the axle and bearing.

 

It probably doesn't make any practical difference, but why bother with expense of pinpoint bearings just use brass tube cut to the correct length to be supported fully by the W irons and long enough to stop side play of the axle......simples B)

[Kenton]

But surely the whole 'point' of pinpoint bearings

Sorry, did I forget to mention 'O' gauge Slaters wheels ? They are not pinpoint axles and the bearings (also Slaters) are top hat type.

 

Yes guys, how many times do we see this problem !!! Far too often. Though I think this is the worst I have seen.

 

I would normally go for the washer approach but after using a whole pack I was getting mean and thinking there must be a better way.

 

Stephen I like the idea of a plastic tube 'original' - I was looking for brass tube with sufficient internal diameter and hadn't any so that meant a wait till the next show of sufficient standing to attract good trade or a postal order. (1.7mm dia., 5.5mm long)

 

Ian, a combination of 1 and 2 - should at least solve the weakening effect but still has the same problem of locking the wheels in place and using the world supply of washers

 

Oh, why remove wheels. As, although I'm not known for painting brass , that should be the intention and I like to be able to remove wheels to do so. Also you never know when / if a conversion to a finer scale might overwhelm me

[boxbrownie]

Not pinpoint, fair enough, even more reason that you could just use a length of brass tube, one end supported fully in the hanger the other long enough to stop the wheelset sideplay.

[Boris]

In the past I have also found quite a lot of sideplay in Slaters kits with their own wheelsets, especially in the older kits. Personally I cheat and allow the bearings to stand slightly proud in the axleboxes to eliminate some of the slack, I still leave a little bit as I find a small (less than 1mm) amount of slack helps a well weighted wagon run slightly better. However to illustrate a point, I have used Slaters wheels in both my MMP kits, which are designed to the finest scale tolerances, and in both cases I have had to shorten the Slaters axles by several millimetres to get them to even go between the W irons.

 

As an experiment, in one case I spent quite some time reprofiling the shortened journal back to a nice fine point, and left another set squared (although burrs removed), I found that it makes no difference at all to the running qualities of the vehicle as long as there is nothing else fouling the wheelsets and there is some weight to the wagon.

 

But, more to the point, my experiences with MMP kits and Slaters wheelsets lead me to wonder if the solebars or the W irons are made too far apart on Slaters kits for ease of construction? Thoughts anyone?

[boxbrownie]

 

As an experiment, in one case I spent quite some time reprofiling the shortened journal back to a nice fine point, and left another set squared (although burrs removed), I found that it makes no difference at all to the running qualities of the vehicle as long as there is nothing else fouling the wheelsets and there is some weight to the wagon.

 

As was pointed out to me above, the slaters wheel sets and top hat bearings are not pinpoint, so forming a point at the end of the axle would make no difference as the axle will run on its thrust side not the point.

 

I still reckon using a length of brass tube of the correct length to reduce slack in place of the top hat bearings would do the trick.

[Kenton]

I'm afraid Slaters have nothing to do do with this problem. It isn't one of their kits - just their wheelsets and bearings.

 

I disagree with the suggestion of replacing the top hats altogether, the option with the brass tube was really only to be an effective 2mm washer/spacer between the wheel itself and the face of the top hat. But I don't have any 1.7+mm id brass tube and I'm afraid that if I stop/delay building a kit for more than a few hours it will get boxed up and neglected as I'm drawn to the next kit OKWB.

 

I like Stephen's idea for a big plastic washer/tube and am having a rummage to find potential donors to slice rashers off.

[boxbrownie]

If you still run with the top hats and use spacers you are effectively only using a small part of the top hat as a bearing as a lot of the axle will be out of the bearing "cup" with a spacer around it.......

[Kenton]

David, I don't think you understand me. the Slaters axles simply do not run in the top of the top hat bearings. The Slaters axles are 47.7mm long the W-irons are 43mm apart, the top hats are 4.8mm. So the axle has 43+2*4.8-47.7 = 4.9mm (approx ok left off thickness of the hat top) of slop or mvement of the axle from the top of one bearing to the other.

 

All 3 solutions prevent the movement of the axle by setting a fixed point of friction between wheel face and back of W-iron/bearing face.

 

If the movement was small then packing the bearing with a washer would be ideal or even just option 1. as long as this forced the axle to the top of the bearings.

 

The obvious solution would be to dismantle and chop off the W-irons. padding then with scrap brass behind the solebar and moving them inboard.

 

To me that is paramount to scratch building and something I am not prepared to entertain with a kit.

 

on the left the slop on the right the axle fully home in the bearing:

[boxbrownie]

Kenton, I am sure I understand, I think it is me who was not being very clear. I hope this piccy shows what I mean by replacing the top hat with brass tube to reduce the clearance on the inner side of the hangers. No spacers required and the axle is supported on its full length of the outer axle.

I know it means a certain amount of alignment (although easily accomplished by using a length of dummy axle rod between the bearings when they are soldered). But a far more elegent solution IMHO and better engineering than using spacers.

[Kenton]

Ah, I see, I think, but am not all that certain that the solution is much different than the simple add a tube spacer solution - other than the tube is now an integral part of the W-iron and becomes the new bearing.

 

It does mean removal of the bearings (not a particularly difficult job) but does require the same access to suitable tube stock ... not currently available in the spares box. Probably easy to source and will go on my list fr the next show attended but that delay will mean the kit going into the dust collection pile and essentially forgotten. Where as the simple spacer has immediate potential.

 

There is one other issue with the replacement tube approach. Once again, like option 1, it reduces the strength of the bearing-W-iron as only the tube to W-iron join provides any strength (no face on the tube unlike the bearing).

 

I am kicking myself for not measuring the W-iron distance prior to build. snapping off the W-irons at the fold and padding them beck from the solebar would have been far simpler and more elegant.

 

Once the axleboxes are on the options become more limited.

 

I have decided to do the obvious. Though it wasn't yesterday. I'm going to file some of the thickness off a 2mm bore mainframe bearing and to use this as a spacer. At a little over 2mm thick this should work, essentially removing all the slop and negates any removal/unsoldering of the present top-hats.

 

left a 2mm main frame bearaing super-glued to the wheel bush, right the gap/slop reduced to a negligble amount:

[boxbrownie]

Ah, I see, I think, but am not all that certain that the solution is much different than the simple add a tube spacer solution - other than the tube is now an integral part of the W-iron and becomes the new bearing.

Thats the point, the tube becomes the bearing giving the axle the correct length of bearing area.

 

 

There is one other issue with the replacement tube approach. Once again, like option 1, it reduces the strength of the bearing-W-iron as only the tube to W-iron join provides any strength (no face on the tube unlike the bearing).

Well that depends upon the soldering and just how much you use and how strong you think four brass bearings need to be to support 100grams or so of wagon

I am kicking myself for not measuring the W-iron distance prior to build. snapping off the W-irons at the fold and padding them beck from the solebar would have been far simpler and more elegant.

 

Aha, you see....more kits need to come with hindsight as standard

 

Seriously I do not think I have ever bought a 7mm kit that really worked straight from the box and didn't need a little "flexibility in construction", I agree with you we should expect a little more, I guess thats the legacy of what was once nothing more than a cottage industry.

[djgriff]

Hi all here's my twopence worth, could you put a spacer between the bearing and the w iron all solerd up it would retain its original strength.

 

Dave

[Sandy Harper]

Or, drill right through bearing, reverse in the W iron hole (so that the tophat is on the outside), and trim to length required. The bearings are usually too long to fit into the cast hole in the axle box anyway.

Regards

Sandy

[Kempenfelt]

Please don't shoot me down here as I have no experience of 7mm, but it would almost appear that the kit was designed for pin points as appose to top hat bearings with that ammount on slop!

 

As you are reducing slop by the addition on the spacer it may well be worth reducing the length of the top hat bearing and possibly the axle too. This will reduce the possible need to remove any material from the back of the axlebox and help reduce friction/offset any additional friction caused by the spacer. I know parallel bearings in 4mm noticably increase drag, alought this may not be such a problem in 7mm with larger motors etc.

 

Best Wishes

 

Paul