Advice on how to stop a Single slipping?

[Edwardian]

The motor is now mounted (I had removed a screw  holding it in place!)

 

However, performance issues remain unchanged.

 

Video to follow.

[Compound2632]

Plan B.

 

Sorry, not being very helpful here.

Edited February 2, 2021 by Compound2632

[Edwardian]

Motor securely mounted. Performance issues remain the same.

 

This was the best run I managed:

 

 

[Florence Locomotive Works]

41 minutes ago, Edwardian said:

Motor securely mounted. Performance issues remain the same.

 

This was the best run I managed:

 

 

That sir,

 

Is the sound of a dying work I believe. I’ve heard similar from my worms. A few questions:

 

How well lubricated is it? How worn are the bearings on the motor? It may be worth replace the motor entirely if the bearings are shot, a small pitman motor of yorn would have a thick enough stator for a 6BA bolt. 
 

Douglas

[Caley Jim]

I would agree with @Florence Locomotive Works.  How much play is there between the worm and the wormwheel?  Is there a lot of play in the motor shaft, laterally, not fore and aft?  I.e. is it loose in the bearings?  If so, the armature could be rubbing against the pole pieces.

 

Jim

[Edwardian]

1 hour ago, Florence Locomotive Works said:

That sir,

 

Is the sound of a dying work I believe. I’ve heard similar from my worms. A few questions:

 

 

Quote

How well lubricated is it?

 

It has a greasy sheen. I'm ashamed to admit I have no oil. 

 

Quote

 

How worn are the bearings on the motor?

 

 

I don't know. What are they and how can I tell?

 

Quote

It may be worth replace the motor entirely if the bearings are shot, a small pitman motor of yorn would have a thick enough stator for a 6BA bolt. 
 

 

Would not know where to start looking for the right type. 

 

Quote

Douglas

 

39 minutes ago, Caley Jim said:

I would agree with @Florence Locomotive Works.  How much play is there between the worm and the wormwheel? 

 

 

What is the difference between the worm and the worm wheel? Are you referring to the worm and the gear wheel it engages with? 

 

If so, I'm not sure how to judge this, but I would say that there is probably very little play. 

 

Quote

 

Is there a lot of play in the motor shaft, laterally, not fore and aft?  I.e. is it loose in the bearings? 

 

 

There seems to be no lateral play to the motor shaft. 

 

Quote

 

If so, the armature could be rubbing against the pole pieces.

 

Jim

 

Edited February 2, 2021 by Edwardian

[Ravenser]

I think at this point I would replace the motor, as it dates from the Lower Cretaceous

 

From memory Branchlines and  3 SMR can supply some kinds of motors , and MSE /Comet may also do. With the retirement of Mashima-san , I'm not sure what the best options are , but almost anything should be a good deal smaller than what you are replacing

 

The challenge then becomes getting the worm off the old motor and onto the shaft of the new one

 

We now know that the loco is effectively a rigid frame 0-2-2 with a massive front overhang resting on a bogie.

Not a great scenario. Whether it is possible to rebuild the chassis by cutting out the frames to take hornblocks on the trailing wheels, to create a set of nested  3-legged stools (the chassis has 3 fixed points as the trailing axle is compensated, the 2 fixed drivers + the bogie pivot create 3 fixed points at the next level.) I don't know. It may be theoretically effective - and impractical to do

 

Possibly additional pickup could be contrived from the tender on the other side. That would require an insulated drawbar or connection since the tender would then be live to one rail and the loco body to the other

[Edwardian]

2 minutes ago, Ravenser said:

I think at this point I would replace the motor, as it dates from the Lower Cretaceous

 

From memory Branchlines and  3 SMR can supply some kinds of motors , and MSE /Comet may also do. With the retirement of Mashima-san , I'm not sure what the best options are , but almost anything should be a good deal smaller than what you are replacing

 

OK

 

2 minutes ago, Ravenser said:

The challenge then becomes getting the worm off the old motor and onto the shaft of the new one

 

Hmm. No chance of matching the old worm with a new one?

 

2 minutes ago, Ravenser said:

We now know that the loco is effectively a rigid frame 0-2-2 with a massive front overhang resting on a bogie.

Not a great scenario. Whether it is possible to rebuild the chassis by cutting out the frames to take hornblocks on the trailing wheels, to create a set of nested  3-legged stools (the chassis has 3 fixed points as the trailing axle is compensated, the 2 fixed drivers + the bogie pivot create 3 fixed points at the next level.) I don't know. It may be theoretically effective - and impractical to do

 

Not keen to attempt any if this, to be candid. 

 

How would I even know if and when it became necessary?

 

2 minutes ago, Ravenser said:

Possibly additional pickup could be contrived from the tender on the other side. That would require an insulated drawbar or connection since the tender would then be live to one rail and the loco body to the other

 

That probably is do-able.

[Ravenser]

2 hours ago, Edwardian said:

 

OK

 

 

Hmm. No chance of matching the old worm with a new one?

 

 

Not keen to attempt any if this, to be candid. 

 

How would I even know if and when it became necessary?

 

 

That probably is do-able.

 

I don't know if you could match new worm with old gear. And in the current climate you can't take it to a show attended by Branchlines or Tony Wright and ask "what matches this"? . It's not a good start that you don't know what the current worm/gear set actually is, since you didn't build it yourself

 

Otherwise you might have to replace both worm and gear  - which means dismantling the drivers and removing the gear from the driving axle. If you can salvage the worm off the current motor, you do at least have a worm /gear set that you know matches

 

Someone who builds loco kits must be able to offer advice on how to extract a worm gear. Is it held on by a grub screw? Loctite?

 

I would leave attempting to rebuild the back chassis as compensated unless you get desperate / loco runs sweetly but can't pull the skin off a rice pudden. MJT do fold/solder hornblocks so you would "simply" need to cut out slots to take them in the chassis. But that , I think, is a theoretical possibility rather than a practical first step.

 

Tender pickup will depend on which side of the wheelsets is insulated. If it's the same as the loco, you would need somehow to remove the wheels - not necessarily simple if they run in soldered whitemetal frames

[DonB]

At this point I think that we have seen enough to realise that the Single is rather beyond James's current capabilities and understanding of the engineering requirements of the job in hand.

I suggest that he should admit defeat and shelve the attempt at repair until after the current pandemic when he could either find  a volunteer to visit and advise, possibly "hold his hand" while repairing it, which is the route I think  preferable, so that he would gain some knowledge of the work done and why, or send it to someone with the capability to do the job, obviously at a cost. The problem then becomes one of making decisions as to agreeing what is required.  

Not knowing how he obtained the beast, and how valuable it is to him, it is difficult, at distance, to advise a course of action.  

[Caley Jim]

3 hours ago, Edwardian said:

What is the difference between the worm and the worm wheel? Are you referring to the worm and the gear wheel it engages with? 

The wormwheel is indeed the gear on the axle with which the worm engages.  If there is a little play in the driving wheels when you try to rotate them ( as we did with the earlier patient) then the meshing may be OK.  If there is no movement then the meshing may be too tight and could cause the noise, but would also make it slow.

 

3 hours ago, Edwardian said:

There seems to be no lateral play to the motor shaft. 

In that case the bearings can't be all that worn, but may be dry and need some oil.  3-in 1 oil is not ideal, but readily available. a tiny spot is all that is needed.  the bit about the armature fouling the stator doesn't apply in that case.  How freely does the armature turn when the motor is off the loco?

 

Jim

[RodneyS]

Those old K's motors were very robust but tended to be quite noisy.

I would try and find some sort of oil for the bearings and see if that improves the screeching.  The X04 motors also tended to do that if they weren't oiled sufficiently.  Put it on between the worm and the bearing at the front so you don't get any on the commutator.

 

Give it a run before you put it back in and see if it is any better.

 

I gather that you did find a screw holding the motor in place.  The threaded hole in the motor is at the thinnest part of the pole piece so it will only have a couple of threads.  This makes it difficult to hold the motor firmly in place.  If the screw is too short it won't hold and if it's too long it hits the armature.

I well remember getting the screw to the right length and then finding the mesh too loose or too tight.  A bit of packing under the front or back of the motor and the screw was then too short.  Happy days.

 

Looking at the pictures I wonder if the chassis was designed for the X04 type of motor ?

 

The pictures show the worm has a grub screw.  That should undo but you will need a small watchmakers type of screwdriver.  Than a larger screwdriver twisted between the worm and the magnet should remove it.  I've never heard of one being glued.  Remember, the K's motor predated all these modern glues.

 

If there is no fore and aft movement on the armature shaft then perhaps the worm is too tight against the bearing.  Oil should help or moving the worm along a fraction.

 

I wouldn't rush into changing the motor though as that could open another can of worms.

 

The loco and the motor belong to a different era in which we thought we were doing well if something actually moved !

Rodney

[Edwardian]

On 02/02/2021 at 22:49, RodneyS said:

Those old K's motors were very robust but tended to be quite noisy.

I would try and find some sort of oil for the bearings and see if that improves the screeching.  The X04 motors also tended to do that if they weren't oiled sufficiently.  Put it on between the worm and the bearing at the front so you don't get any on the commutator.

 

Give it a run before you put it back in and see if it is any better.

 

I gather that you did find a screw holding the motor in place.  The threaded hole in the motor is at the thinnest part of the pole piece so it will only have a couple of threads.  This makes it difficult to hold the motor firmly in place.  If the screw is too short it won't hold and if it's too long it hits the armature.

I well remember getting the screw to the right length and then finding the mesh too loose or too tight.  A bit of packing under the front or back of the motor and the screw was then too short.  Happy days.

 

Looking at the pictures I wonder if the chassis was designed for the X04 type of motor ?

 

The pictures show the worm has a grub screw.  That should undo but you will need a small watchmakers type of screwdriver.  Than a larger screwdriver twisted between the worm and the magnet should remove it.  I've never heard of one being glued.  Remember, the K's motor predated all these modern glues.

 

If there is no fore and aft movement on the armature shaft then perhaps the worm is too tight against the bearing.  Oil should help or moving the worm along a fraction.

 

I wouldn't rush into changing the motor though as that could open another can of worms.

 

The loco and the motor belong to a different era in which we thought we were doing well if something actually moved !

Rodney

 

I am quite cheered by this. I must say, the motor seems, very willing and these old types seem to be built like T34s.

 

It is not clear to me how replacing the motor will help, because I'm not yet persuaded that the motor needs replacing.

 

If the problem is the worm, replacing the motor yet retaining the worm presumably won't really help. 

 

I want to try solutions short of a new worm, because that is likely to mean new gears and we're then close to starting from scratch.  

 

So, I think I will give it a good clean and obtain some suitable oil to lubricate where indicated and take it from there. 

[Regularity]

The worm is fixed with a grub screw, so could be removed fairly easily, assuming we know what it is - it looks like a Romford. The worm wheel, less so, as a wheel would have to come off...

 

When meshing, a piece of cigarette paper between the worm and the wheel usually provides an ideal mesh: just a bit of clearance, but no more. You also need to ensure that the motor is perpendicular to the axle: lining it up against the frames should be OK, and also the motor shaft centered over the worm wheel.

You may need to put some shim pieces between the motor and the support plate, or you may be lucky - the old Triang chassis blocks seem to have been accurately milled on a jig to locate the front fixing lugs of the good old X04, and the rear screw existing for the dual purpose of hold the motor in place and ensuring electrical connectivity to the live chassis.

 

A little bit of trial, test, adjust for the errors, and things should settle down nicely - and build your self-confidence with things mechanical, too.

[CF MRC]

It all sounds desperately dry to me. If you don’t have any 3 in 1 oil at home, go to the garage, check the oil in the car using the dipstick and then let a little bit of engine oil drip onto a bottle lid. It’s really far too thick, but a very small amount should quieten things down. Engineering single wheelers to pull decent loads is quite doable, but if you are starting with a white metal body you would need to work out where the weight is distributed: at the end of the day the driving wheels have to be capable of contacting the track all the time.  If the drivers are rigidly held in the chassis then that usually means that other wheels need some form of vertical movement. 
 

Tim

[RodneyS]

I didn't like to suggest car engine oil in case it was frowned upon but it is what we used on motor bearings when K's motors were state of the art.

Being a bit thicker it filled up the gaps in the bearings quite nicely.

Rodney

[Jol Wilkinson]

From the photo of the motor on the previous page I suspect the gears are from the old Romford range, possibly 60:1. These are still available from Markits.  The difficulty with these gears is that the worm and gear diameters are the same, irrespective of ratio. Hence the lower (higher number) ratios have more, finer, teeth and need more accurate alignment and meshing.

 

The 100dp type gears as originally offered by Ultrascale and now also offered by Markits all have the same teeth profiles and the gear wheel diameter varies to suit the ratio. A new, "modern" etched motor mount and gears would handle the meshing difficulty but would need a different motor. With Mashima being unavailable, a "gearbox" and small motor from High Level would be the best option. A Roadrunner with 60:1 ratio and the 10mm x 20mm Flat can would possibly suit.  Removing and refitting the wheels shouldn't present a problem if done with care.

 

 

[drduncan]

On 02/02/2021 at 00:55, J. S. Bach said:

From Wikipedia:

"Catgut (also known as gut) is a type of cord[1] that is prepared from the natural fiber found in the walls of animal intestines.[2] Catgut makers usually use sheep or goat intestines, but occasionally use the intestines of cattle,[3] hogs, horses, mules, or donkeys.[4] Despite the name, catgut manufacturers do not use cat intestines."

 

https://en.wikipedia.org/wiki/Catgut

 

 

 

Shame. I thought it was the one useful contribution the felines made to the world.

[drduncan]

James @Edwardian,

 

How is the single?

 

Duncan

Edited October 9, 2023 by drduncan

[kevinlms]

On 02/02/2021 at 10:10, Florence Locomotive Works said:

Is it the old K’s one with K’s motor? If so then weight isn’t the problem, it will almost certainly be the motor. 

How can the motor cause slipping?

[CKPR]

One thought - is the engine pulling the tender as 'dead' weight  or is the tender contributing to the effective weight & tractive effort ? There's a useful discussion of how to arrange the latter with reference to single drivers in Mike Sharman's booklet on compensation, but it essentially comes down to arranging the tender to rest on the engine via the drawbar.

Edited October 10, 2023 by CKPR