A fix for 'wobbly wheel' syndrome

[Nickey Line]

On a number of occasions I've seen references to problems with 'friction fit' driving wheels, with some (who shall remain nameless!) denouncing said drivers as 'rubbish' and fit only for the bin, and others remarking how difficult it is to assemble the wheels square on the axle. This is particularly difficult, I feel, when fitting them to a rigid chassis, e.g. an un-sprung Comet chassis or similar.

Well, having had such an experience myself, I resolved to solve the issue, and think I may have found a solution...

 

 

The eagle-eyed will notice the brass wheel bearings inserted in the axle holes. To achieve this, I first trimmed the raised boss on the back of the wheels using a chisel scalpel blade, and then carefully reamed out the hole with a 3-4mm broach until the bearings were a close fit. Removing the boss ensures that the flange of the bearing sits flush to the back of the wheel, helping to keep it square. It may be necessary to also ream the bearing a tiny amount to fit the axle; the tighter the fit the better.

The axle is then secured with a little Loctite, so that the wheels will remain removeable if need be.

I've not fitted the wheelsets to the chassis as yet, but the results so far are very promising... hopefully I can add a postscript in the next day or so.

[cctransuk]

5 minutes ago, Nickey Line said:

On a number of occasions I've seen references to problems with 'friction fit' driving wheels, with some (who shall remain nameless!) denouncing said drivers as 'rubbish' and fit only for the bin, and others remarking how difficult it is to assemble the wheels square on the axle. This is particularly difficult, I feel, when fitting them to a rigid chassis, e.g. an un-sprung Comet chassis or similar.

Well, having had such an experience myself, I resolved to solve the issue, and think I may have found a solution...

 

 

The eagle-eyed will notice the brass wheel bearings inserted in the axle holes. To achieve this, I first trimmed the raised boss on the back of the wheels using a chisel scalpel blade, and then carefully reamed out the hole with a 3-4mm broach until the bearings were a close fit. Removing the boss ensures that the flange of the bearing sits flush to the back of the wheel, helping to keep it square. It may be necessary to also ream the bearing a tiny amount to fit the axle; the tighter the fit the better.

The axle is then secured with a little Loctite, so that the wheels will remain removeable if need be.

I've not fitted the wheelsets to the chassis as yet, but the results so far are very promising... hopefully I can add a postscript in the next day or so.

 

I await the outcome with interest.

 

At this point, I would merely observe that bearings are intended to move on axles; wheels are intended NOT to move on axles.

 

For a secure fixing of wheel to axle, I would not start with a fitting intended to allow movement.

 

John Isherwood.

[Nickey Line]

15 minutes ago, cctransuk said:

 

I await the outcome with interest.

 

At this point, I would merely observe that bearings are intended to move on axles; wheels are intended NOT to move on axles.

 

For a secure fixing of wheel to axle, I would not start with a fitting intended to allow movement.

 

John Isherwood.

 

Hence the reason I said...

 

28 minutes ago, Nickey Line said:

It may be necessary to also ream the bearing a tiny amount to fit the axle; the tighter the fit the better.

 

I'm perfectly well aware of the intended use of the bearings, but without the existence a specific item for the job, they will have to do.

[DCB]

The bearings sometimes prefer to stick to the axle and spin in the chassis if fitted to a used chassis.  I have never know an axle to turn freely in a bearing without it being reamed or drilled to give a bit of clearance.

[Colin_McLeod]

I'm lost!

[Il Grifone]

I fit the wheels using my drill stand which ensures they are true to the axle.

I would have thought that reaming runs the risk of making the axle hole go off true. Perhaps others are not as ham-handed as I am.

I've not had problems with bearings sticking to the axle. Good fortune?

[Nickey Line]

4 hours ago, Il Grifone said:

I fit the wheels using my drill stand

 

This is precisely what I did with this set of wheels initially. It was fitting the second wheel to each axle where I ran in to problems, made especially difficult because the axles had to be in the chassis.

How do you fit the second wheel?

 

4 hours ago, Il Grifone said:

I've not had problems with bearings sticking to the axle. Good fortune?

 

I've found (as has DCB apparently..) that bearings require a little easing with a broach to allow axles to run freely, though obviously that's not what I'm trying to achieve here!

[cctransuk]

11 minutes ago, Nickey Line said:

 

This is precisely what I did with this set of wheels initially. It was fitting the second wheel to each axle where I ran in to problems, made especially difficult because the axles had to be in the chassis.

How do you fit the second wheel?

 

 

I've found (as has DCB apparently..) that bearings require a little easing with a broach to allow axles to run freely, though obviously that's not what I'm trying to achieve here!

 

There is a bit of a difference between "a little easing with a broach" and the interference fit required for secure wheel fixing.

 

CJI.

[Nickey Line]

55 minutes ago, cctransuk said:

 

There is a bit of a difference between "a little easing with a broach" and the interference fit required for secure wheel fixing.

 

CJI.

 

No! Really?

Perhaps you missed the reference to Loctite being used to secure the wheels.

Edited October 21, 2022 by Nickey Line
More words!

[Nickey Line]

Anyway, having now completed the experiment, I can report that it works. Please excuse the shaky hand-held phone video...

 

 

Despite  some scepticism from certain quarters, I'm happy with the result. I think working with a 'virgin' set of wheels would be easier though.

[cctransuk]

2 minutes ago, Nickey Line said:

Anyway, having now completed the experiment, I can report that it works. Please excuse the shaky hand-held phone video...

 

 

Despite  some scepticism from certain quarters, I'm happy with the result. I think working with a 'virgin' set of wheels would be easier though.

 

....... and I am pleased for you.

 

My concern stemmed from the fact that, in my experience, turned frame bearings can be extremely variable in tolerance, and I feared for the security of the wheel / axle joint.

 

CJI.

[Nickey Line]

1 hour ago, cctransuk said:

....... and I am pleased for you.

 

Thankyou

[Jol Wilkinson]

A different approach is to ream the wheels using a 1/8" parallel hand reamer (preferably hand turned in a lathe or pillar drill) to ease the fit of the wheel on the axle. After lightly countersinking the axle hole in the back of the wheel. the wheelset can then be assembled.

 

This gives a close fit but doesn't distort the wheel centre as the axle is pushed in. The wheels can be secured more effectively if needed either using Loctite or by pinning to the axle. This latter can be done by cutting a small groove at 45 degrees in the end of the axles using a piecing saw and then drilling along the groove into the wheel centre after fitting putting some thin n/s wire into the groove and hole. Painting the axle end disguises the groove, If the wheels need to be removed the pin will pull out of the groove.

 

The rational for this approach is that wheels with a "lighter" fit on the axle (such as Ultrascale) are generally truer running. Wheels with a tighter fit, notably Sharman, seem to suffer more centre distortion and run out.

 

 

[Il Grifone]

19 hours ago, Nickey Line said:

 

This is precisely what I did with this set of wheels initially. It was fitting the second wheel to each axle where I ran in to problems, made especially difficult because the axles had to be in the chassis.

How do you fit the second wheel?

 

 

I've found (as has DCB apparently..) that bearings require a little easing with a broach to allow axles to run freely, though obviously that's not what I'm trying to achieve here!

 

I rest the loose wheel on the vice ensuring that the crank in in gap between the jaws and then carefully press down the rest of the chassis. Obviously attention has to paid to centring the other wheel and quartering, so I only push it part way on, completing the job once everything runs properly.

[Nickey Line]

5 hours ago, Il Grifone said:

 

I rest the loose wheel on the vice ensuring that the crank in in gap between the jaws and then carefully press down the rest of the chassis. Obviously attention has to paid to centring the other wheel and quartering, so I only push it part way on, completing the job once everything runs properly.

 

Takes practice I guess!