Pin point bearings

[RonnieS]

I decided to start the annual service to my goods wagons today. Wheels out, clean, check back to backs, if stiff Wizard reamer etc. All are brass bearings/ pinpoint axles. In the past I have assumed  as brass is self lubricating no oil or grease was best. However a mate claims the latest silcon grease lessens drag so I have tried it on the frst dozen or so. 

 

Is it my imagination or is he right? It feels to me like less free running!

[DonB]

Brass is not necessarily self-lubricating. There are grades which contain Lead which does confer such properties. I don't know which grades of brass are used for pin-point axles.

The bearing area of a pin-point axle is tiny and it would be easy to over-fill with the grease. Greases by their nature have a higher viscosity than oils.

Personally I would avoid any grease and if essential would opt for one of the specially formulated oils offered in the model market.

There used to be a "Dermic" syringe-type oil dispenser which could apply the tiny amounts of oil required. I have one, but haven't seen an advert for it or a similar item in many years.  

[Kenton]

Is it my imagination or is he right? It feels to me like less free running!

Sticky stuff where before there was no sticky stuff?

 

I use watch-makers oil - and expect to always add too much and it to last forever. (it doesn't, of course, as the bearings pick up all sorts of crud from the air)

 

There used to be a "Dermic" syringe-type oil dispenser which could apply the tiny amounts of oil required. I have one, but haven't seen an advert for it or a similar item in many years.  

Still available and often seen at shows. I think Eileen's Emporium and Squires etc sell them.

 

I would be suspicious of the oil - it is quite dark in colour. This requires a very light oil (as used to service watches) The heavy oil (used to service cars) might be OK on Gauge 1 and live steam mechanisms but not really for micro mechanisms. Anyway one drop from a syringe is still way too much.

[34theletterbetweenB&D]

It is ideal to polish and work harden most brass bearings by running dry against steel. No doubt about it in the brass grades supplied in pinpoint bearings; with a group of wagons it is possible to readily measure that they become more free rolling after significant running time has accrued. No significant wear after many years running in wagons, including whitemetal ABS kits which are forty years old, so no need for lubricant at up to 40g per wheelset in my opinion.

 

On a few heavy vehicles I have been using plastics compatible bike spray Teflon lube sold as GT85, in bearings various including steel axle in brass pinpoint. Again, by measurement it reduces rolling resistance, effect good for at least 2 years. No plastics degradation after more than 10 years; the amount applied is miniscule, still on my first can.

[RonnieS]

It is ideal to polish and work harden most brass bearings by running dry against steel. No doubt about it in the brass grades supplied in pinpoint bearings; with a group of wagons it is possible to readily measure that they become more free rolling after significant running time has accrued. No significant wear after many years running in wagons, including whitemetal ABS kits which are forty years old, so no need for lubricant at up to 40g per wheelset in my opinion.

 

On a few heavy vehicles I have been using plastics compatible bike spray Teflon lube sold as GT85, in bearings various including steel axle in brass pinpoint. Again, by measurement it reduces rolling resistance, effect good for at least 2 years. No plastics degradation after more than 10 years; the amount applied is miniscule, still on my first can.

Thanks. I tried an experiment using my "can't pull the skin off a rice pudding" Bachmann 2mt 2-6-0. Max load with grease 10 wagons. Max load with no grease 12!

 

Now if I could find what Bachmann coated the wheels with on this loco I really could reduce the rolling resistance on trains!

[34theletterbetweenB&D]

You are not alone.

 

How much has the loco run? The driving wheels on Bach steamers are sometimes very slippy when received. My example of the similarly sized 3F 0-6-0 was beginning to slip with less than twenty wagons when it came out of the box. After some hours (truly hours) running it will now take sixty wagons. Most Bach steamers improve in traction with running, this was one of the most extreme examples among those I own.

 

Other possibilities.

Lots of drag from either or both of the tender and the pony truck wheelsets. Being a wired together unit you may not have assessed the tender on its own? My J11 was similarly gutless to your 2MT: heavy tender braked by the pick ups. Fixed that and it is pulling as it should following some running. I know the 2MT doesn't have pick ups on the tender, but one sticky axle bearing is enough.

 

Drag from the wiring link rubbing on the track.

 

The tender lifting the back of the loco, taking weight off the driving wheels. Worst for this were the early A1s, but several other models are mnarginal for this, usually the bottom of the slot in the tender front too high so that the drawbar rests on it.

[RonnieS]

You are not alone.

 

How much has the loco run? The driving wheels on Bach steamers are sometimes very slippy when received. My example of the similarly sized 3F 0-6-0 was beginning to slip with less than twenty wagons when it came out of the box. After some hours (truly hours) running it will now take sixty wagons. Most Bach steamers improve in traction with running, this was one of the most extreme examples among those I own.

 

Other possibilities.

Lots of drag from either or both of the tender and the pony truck wheelsets. Being a wired together unit you may not have assessed the tender on its own? My J11 was similarly gutless to your 2MT: heavy tender braked by the pick ups. Fixed that and it is pulling as it should following some running. I know the 2MT doesn't have pick ups on the tender, but one sticky axle bearing is enough.

 

Drag from the wiring link rubbing on the track.

 

The tender lifting the back of the loco, taking weight off the driving wheels. Worst for this were the early A1s, but several other models are mnarginal for this, usually the bottom of the slot in the tender front too high so that the drawbar rests on it.

 Thanks

 

It's not done too many miles. I had close coupled it using a wire coupling and hard wired it. The tender is free running. The spring on the pony is not as strong as some so I think its down to the wheels and the fact that all the weight is at the front. In fact if I put a 70g weight on the cab roof and a strip of wood under the centre drivers and it's still biased to the pony!

 

I might add some weight to the cab but then I might leave it as it's only used on a 2 coach local.

[Tiptonian]

If you do this annually, I would have thought, on metal to metal, grease was a bit of an overkill. The slightest of light oiling should be sufficient. I have a small bottle of light oil, (supplied by MGR if I remember correctly) and have spilled more than I have used!

 

However, If you like trying different things, I was playing..... erm,...inspecting and cleaning an ancient wagon a few days ago and the oil was not to hand. Thinking of what people have said on various forums, I took an HB pencil and "scribbled" inside the bearings and on the axle points. It seems to have worked very well, and there is less danger of over-lubricating and having to start again.

[black5f]

Grease no, it collects dust and turns into glue. The very lightest of machines oils (used to be called sewing machine oil) and only what can be held on the tip of a pin. Or ... Theres a lock lubricting thing you can get for the likes of Halfords, graphite again applied with a pin which becomes dry but slippery or, a pencil (proper one not the waxy type).

T

[9403]

It is ideal to polish and work harden most brass bearings by running dry against steel. No doubt about it in the brass grades supplied in pinpoint bearings; with a group of wagons it is possible to readily measure that they become more free rolling after significant running time has accrued. No significant wear after many years running in wagons, including whitemetal ABS kits which are forty years old, so no need for lubricant at up to 40g per wheelset in my opinion.

 

On a few heavy vehicles I have been using plastics compatible bike spray Teflon lube sold as GT85, in bearings various including steel axle in brass pinpoint. Again, by measurement it reduces rolling resistance, effect good for at least 2 years. No plastics degradation after more than 10 years; the amount applied is miniscule, still on my first can.

I am wondering about wagon weights. Would 32 40gram wagons have as much drag as 40 32gram wagons? If I increase the weight of my wagons a long train would be more stable on the 180 degree bend at the top end but would the drag get the wheels spinning on the locos? At present all my locos can move at least 28 wagons and I would not like to lose this. I use a min of 2' 3" on curves and no pointwork less than  2' 6".

[The Bigbee Line]

 Thanks

 

It's not done too many miles. I had close coupled it using a wire coupling and hard wired it. The tender is free running. The spring on the pony is not as strong as some so I think its down to the wheels and the fact that all the weight is at the front. In fact if I put a 70g weight on the cab roof and a strip of wood under the centre drivers and it's still biased to the pony!

 

I might add some weight to the cab but then I might leave it as it's only used on a 2 coach local.

Have you tried getting some of the tender weight to sit on the read of the loco?  I remember Mike Sharman used to do that on some of his models of early single driver locos.

[Fat Controller]

Grease no, it collects dust and turns into glue. The very lightest of machines oils (used to be called sewing machine oil) and only what can be held on the tip of a pin. Or ... Theres a lock lubricting thing you can get for the likes of Halfords, graphite again applied with a pin which becomes dry but slippery or, a pencil (proper one not the waxy type).

T

There is a form of powdered PTFE available, which you can put a small amount of in each axle, in the same manner as graphite. The other thing to do is to use one of the devices that you insert instead of the axle into the bearings, and which cuts the two bearing cones square to one another (someone will remember the name). Quite often, you'll find that bearings you thought of as 'true' are slightly off. One thing to make sure of, though, is to ensure any track you put wagons so treated on (on a high shelf, for example) has stop blocks at both ends...

One of the French mags suggested using an adustable incline to check free-running- the previous comment about stop blocks applies..

[Jeff Smith]

Kadee graphite powder might work but the design of pin-point bearings should mean that only the very tip of the axle is in contact with the brass with very light centering from the bottom of the internal brass cone.  The surface area in contact is miniscule so any liquid lubricant will bridge between the axle and bearing and increase the drag - and also accumulate dust.  I would say keep them dry and clean them occasionally.

[RonnieS]

 The other thing to do is to use one of the devices that you insert instead of the axle into the bearings, and which cuts the two bearing cones square to one another (someone will remember the name). 

 

Thanks. That will be the "Wizard Reamer" I mentioned in the first post. Worth it's weight in Gold

[Jeff Smith]

You mean something like this (from Micro-Mark)?

[RonnieS]

I am wondering about wagon weights. Would 32 40gram wagons have as much drag as 40 32gram wagons? If I increase the weight of my wagons a long train would be more stable on the 180 degree bend at the top end but would the drag get the wheels spinning on the locos? At present all my locos can move at least 28 wagons and I would not like to lose this. I use a min of 2' 3" on curves and no pointwork less than  2' 6".

 The yankshttp://www.nmra.org/...rp/rp-20_1.html reckon on 1oz plus half oz per inch as an ideal wagon weight. That would mean a normal steam era box van would be just shy of 2.5 oz or 70 grams! I make mine 38g and Bachmann make their about 10g less. On a 48 wagon train (30 inch rad curves)  derailments are very rare. Extra ballast is required in some locos to  haul trains of this length. A 4-6-0 tender loco needs to be about 350g but all the diesels cope. 

[RonnieS]

You mean something like this (from Micro-Mark)?

Wizard Models

 

 do these

[decauville1126]

Kadee graphite powder might work but the design of pin-point bearings should mean that only the very tip of the axle is in contact with the brass with very light centering from the bottom of the internal brass cone.  The surface area in contact is miniscule so any liquid lubricant will bridge between the axle and bearing and increase the drag - and also accumulate dust.  I would say keep them dry and clean them occasionally.

An HB pencil can do the same job! I also run a lead pencil over loco wheel treads and where pickups run and find it helps greatly. And I have to add I was very sceptical when given this tip with particular concerns about adhesion, but it turned out not to be a problem.

[Jeff Smith]

This is also an old cabinet maker's trick for wooden drawer runners.....

[RonnieS]

Have you tried getting some of the tender weight to sit on the read of the loco?  I remember Mike Sharman used to do that on some of his models of early single driver locos.

I have never tried this but Tim Shackleton used this method on a 4f. I will add some weight in the cab. I think I can get about 30g in there. I am a bit more concerned with balance than hauling power.  It should be able to haul 280tons  that’s about  30 wagons/8 coaches. With the added  weight and the wheels run in that should be on.

[34theletterbetweenB&D]

...Would 32 40gram wagons have as much drag as 40 32gram wagons? ...

On straight and level track, the answer is yes - all else being equal in terms of free running bearings - drag is directly proportional to mass.

 

Around curves, and especially the small radii we use in models, effect of train length kicks in. But the worst case scenario for this incremental drag is usually a 180 degree curve fully occupied by the train. Since both the 32 and 40 wagon trains will fully occupy 180 degrees of your worst case 2'3" curve they will likely perform much alike. There's slightly more mass to accelerate on the curve with the heavier wagons, you may find a loco that's near the limit for traction with these loads struggling : more slipping, or unable to start the train of heavier wagons if the curve is fully occupied with the train.

[davefrk]

As 34theletterbetweenB&D says the drag on a tight curve has a great effect and not just on models, see videos of trains trying to restart on the west side of Newcastle.

When testing out the EM rewheeled Bachmann 4F (posted elsewhere) the 4F actually lifted 100 wagons but as soon as the train got onto the 6ft curves at the layout ends the poor old 4F was loosing it's feet. The 4F just managed 75 without slipping. The point in mentioning this is that all the wagons have had the pinpoint bearing holes cleaned out, whether they were brass bearings or RTR plastic underframes, I used the 'Ultrascale' tuner which matches their pinpoint axles and, it seems the Gibson axles too. One thing I've noticed over the years though has been the variation in the coning, both the axle end and the bearing bore. I've had axles which didn't even reach the end of the cone in the bearing due to the cone angle being incorrect. I don't know who's make the bearings were but all have been replaced with either Markits or Gibson bearings.

The axle bearings were lubed with Carrs white grease which does 'slow' a wheel when spinning in the hand but on the rails it's a different matter as a vehicle when pushed hard round the layout just keeps on going. I've used this stuff this way for years and haven't found any problems with it drying out and causing stiffness. Only the tiniest drop is used in the bottom of the bearing just where the pinpoint actually runs.

 

Dave Franks.

[Bob O]

 The yankshttp://www.nmra.org/...rp/rp-20_1.html reckon on 1oz plus half oz per inch as an ideal wagon weight. That would mean a normal steam era box van would be just shy of 2.5 oz or 70 grams! I make mine 38g and Bachmann make their about 10g less. On a 48 wagon train (30 inch rad curves)  derailments are very rare. Extra ballast is required in some locos to  haul trains of this length. A 4-6-0 tender loco needs to be about 350g but all the diesels cope. 

I make mine 40g. There must be an optimum weight, Too light and they float off the track too heavy and the trains are too short, I don't know if pin point/brass bearings are worth while? The Bachman wagons don't seem to wear out,

[34theletterbetweenB&D]

Pinpoint steel axle in coned brass bearing has been the long term available option for kit and scratchbuilders, at least in the UK. There are better possible combinations, the most free running model I have are a set of Trix bogies, moulded in a polymer which is extremely slippy and hasn't worn in near fifty years use. This 'finds' gradients on very level layouts. (Difficult to test with enough precision using domestic grade equipment, suffice to say these will roll away on shallower than a 1 in 250 gradient.)

 

The current RTR material combination choices are not that good, but usually good enough. I reckon to have vehicles roll away on a 1 in 100, or worst case to at least maintain speed once started on this gradient, as the minimum acceptable free-rolling standard. Sometimes needs a few hours running to get everything polished up nicely before this standard is attained, the test circuit isn't just for the locos.

 

The plastic kit and RTR 4W wagons I have are typically in the 30 - 40g range; get down to 20g and that is too light, I add some weight to these. There's a fair number of whitemetal kit wagons weighing up to 80g randomly mixed in. Have no trouble with this combination in 60 + wagon trains, running on 30" minimum radius, at scale speeds for the class of train.

[Bob O]

Pinpoint steel axle in coned brass bearing has been the long term available option for kit and scratchbuilders, at least in the UK. There are better possible combinations, the most free running model I have are a set of Trix bogies, moulded in a polymer which is extremely slippy and hasn't worn in near fifty years use. This 'finds' gradients on very level layouts. (Difficult to test with enough precision using domestic grade equipment, suffice to say these will roll away on shallower than a 1 in 250 gradient.)

 

The current RTR material combination choices are not that good, but usually good enough. I reckon to have vehicles roll away on a 1 in 100, or worst case to at least maintain speed once started on this gradient, as the minimum acceptable free-rolling standard. Sometimes needs a few hours running to get everything polished up nicely before this standard is attained, the test circuit isn't just for the locos.

 

The plastic kit and RTR 4W wagons I have are typically in the 30 - 40g range; get down to 20g and that is too light, I add some weight to these. There's a fair number of whitemetal kit wagons weighing up to 80g randomly mixed in. Have no trouble with this combination in 60 + wagon trains, running on 30" minimum radius, at scale speeds for the class of train.

So what about Hornby/Bachmann tenders that are not pin point? Lube or not?