Low Friction Bearings in 4mm

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Will L
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Low Friction Bearings in 4mm

Postby Will L » Wed Dec 20, 2017 12:21 am

Calling Andy Reichert

In the now rather misnamed “Flexi Chassis an Appreciation” thread you are clearly keen on proposing the use of small ball bearing bearing units. While I’m certainly interested in the concept of these bearings, and I can certainly see some applications where they must be a very good idea, I do have a couple of issues I think its worth kicking about a bit.

Firstly, you clearly see them as being significantly more free running than a classic pin point bearing. I’m wondering why, and by how much. I can understand that this is probably true for a pinpoint axle (metal or moulded plastic) running against a relatively soft plastic moulded axle box, but I find it much, um, harder to believe it is true for a metal pinpoint axel running on a hard metal pinpoint bearing, which is both highly effective and simple to use. I would point out at this, er, point that I don’t accept the idea that fitting a pinpoint axle requires a very careful and accurate fit into the bearings, no matter what Bill may have said in the past. While this may be true for watch makers fitting gears into a watch, for our purposes ramming the point into the base of both bearings isn’t the best option. What is needed is that the axles pinpoints runs against the sloping surface of the bearings gives the smallest contact surface and the best result.


Secondly, considering ball bearing units for use as bearings on driven axles. In these circumstances, I’m not sure there is actually any advantage to be had in taking the trouble of fitting a low friction bearing. The presence of a drive system attached to the axle will almost certainly prevent the free rotation of the axle when not under drive. Then, even with plain bearings modern motors provide more than enough power to spin the wheels if the load exceeds the locos pulling abilities, so what advantage is there to be had from taking the trouble and expense of fitting a low friction bearing?

Essentially that leaves any un-driven axle with an inside bearing as the place where your ball bearing bearing should be just the job.

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MarkS
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Re: Low Friction Bearings in 4mm

Postby MarkS » Wed Dec 20, 2017 2:37 am

Will, doesn't answer your question why, but shows it can and has been done.
Note that the ballraces are applied to inside bearings.

Ballrace and CSB's from 12 years ago or so...
http://www.clag.org.uk/ballrace-bearing.html
and here
http://www.clag.org.uk/midbogie.html
Cheers,

Mark.
"In the end, when all is said and done, more will have been said than done..."

proto87stores

Re: Low Friction Bearings in 4mm

Postby proto87stores » Wed Dec 20, 2017 4:45 am

Will,

Here's some of my current thinking.

RE Friction:

My layman chronological off the wall thinking is that extremely small dia bearings (for low friction) originated in clock mechanisms and later watches. And that pin points are the logical extension of small dia. bearing low friction theory.

Following that thought, I found this linkhttp://www.dg-chrono.de/fotohome/images/2010-03/55a4f31df675b3ee045a520e5.pdf

Which I recommend reading all the way though and which comes up with some amazing low coefficient of friction values for - Taa -Daaa! - 2mm id lowest quality (cheapest) ball bearings, when comparing them to the usual tiny shaft bearings nowadays used in clocks, including jeweled bearings. And of course at low rotation speeds, like our model vehicles.

But I have to admit my original own interest was to just keep the friction as low as possible when I increased the weight to achieve greater inertia and better (heavier and 100%) trackholding reliability. And ball bearings are of course noted for low friction under load.

RE Just some of the Fitting benefits:

Ball bearings handle a good amount of end and/or side loading if firmly set on their axle. Also the inner and outer rings are a strong integral unit. Therefore the outer surface does not have to be supported in a fixed manner, or held exactly orthogonally to the axle or shaft. The bearing mounting and the running axle or shaft will be concentric to a very high degree. The width of bearings and their smooth outer surface means that they can often also be used to link multiple different moving beams and and axles simultaneously. Tilting and or sliding through a mounting hole can be used to allow axle bearings to tilt in frames or shafts to move linearly or sideways without extra mechanical systems. Flanged versions are available which can used in pairs to hold axles or shafts with no detectable end movement. So even gearboxes can be very simply onstructed with little skill but with great running precision and very low stiction.

RE The top level design ideas for the N7:

In beams, ball bearings can be used to replace hornblocks with no added components or complex sliding assemblies, and with almost zero slop. Their low friction under load is even such that simple and low cost tension belt drive is practical between adjacent axles on the same beam. in the case of my N7 I'm seriously considering powering the bunker wheel from the #3 driver using plain turned pulleys matching the wheel dia. ratio. That would effectively make it a 0-8-0 for maximum tractive effort with easily set equal weighting on all axles.

The front beams supporting the axle bearings would link wheels #1and #2 and the rear beams would link wheels #3 and #4. Each of the sideframes will be partially hollow due to being made of a sandwich of 2 sheets of 0.010" Stainless clipped together and half etched internally using the hollow spaces to hold the separately etched solid 0.010" stainless moving beams and allow them to pivot against the top centres of the hollows. The sideframes could tip fore-aft independently, just like the side beams of the 16 Ton mineral wagon and thus provide a similar four point suspension to the rigid body. Thus the interior between sideframes should be completely free of any suspension parts and open for any type of drive system to be mounted. Alternatively the beam pivots could be small coil springs and the sideframes kept locked rigid and firmly attached to the body. The latter design would emulate the track holding of a bogie coach with equalized bogies and 4 point body springing. E.g as per the current 100% reliable Amfleet coaches.

FWIW, the hollow side frame construction has been long term tested and proven in the design of the Amfleet passenger trucks. :thumb That's exactly how they are constructed. In addition their bearing holding beams are open below the bearings, so the wheelsets with bearings can be "snapped" in and out for easy assembly and any later maintenance. That should work on the N7 also, so its wheels can be precision bench assembled and quartered separately from the chassis. The gearbox and motor would "float" on probably the #2 axle and likely share the axle bearings for the worm wheel.

One quite wild idea would be to allow the beams sufficient side flexing room, and or sliding bearings (or somehow separately swivel) so that the loco would effectively be a Bo-Bo and happily and safely run around 18" radius curves, even though it is fitted with P4 wheels. But I'm not committing to that. :P

Food for thought.

Andy

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Guy Rixon
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Re: Low Friction Bearings in 4mm

Postby Guy Rixon » Wed Dec 20, 2017 10:12 am

One great virtue of pin-point bearings is that they are tolerant of misalignment. With a cylindrical, plain bearing, any tilt in the bearing relative to the axle takes away from the running clearance. If the machining is a bit rough, that can possibly turn a running fit into an interference fit and a bind. Do we know how the ball races behave when the axle tries to tilt?

Proto87stores

Re: Low Friction Bearings in 4mm

Postby Proto87stores » Wed Dec 20, 2017 6:24 pm

Guy Rixon wrote:One great virtue of pin-point bearings is that they are tolerant of misalignment. With a cylindrical, plain bearing, any tilt in the bearing relative to the axle takes away from the running clearance. If the machining is a bit rough, that can possibly turn a running fit into an interference fit and a bind. Do we know how the ball races behave when the axle tries to tilt?


Image

The whole bearing tilts. And it's mounting should allow for that.

Andy

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jim s-w
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Re: Low Friction Bearings in 4mm

Postby jim s-w » Sat Dec 23, 2017 6:28 pm

proto87stores wrote:Will,

And of course at low rotation speeds, like our model vehicles.



Not sure about that. The rotation speeds would be the same as the prototype. I would expect the RPM of a model at a scale 60mph would be a lot higher than we might assume.

According to this http://www.csgnetwork.com/tirerevforcecalc.html a 3ft wheel at 60 mph would be running at 560rpm. Of course it depends on what you define low as.

Cheers

Jim

Proto87stores

Re: Low Friction Bearings in 4mm

Postby Proto87stores » Sat Dec 23, 2017 9:10 pm

jim s-w wrote:
proto87stores wrote:Will,

And of course at low rotation speeds, like our model vehicles.



Not sure about that. The rotation speeds would be the same as the prototype. I would expect the RPM of a model at a scale 60mph would be a lot higher than we might assume.

According to this http://www.csgnetwork.com/tirerevforcecalc.html a 3ft wheel at 60 mph would be running at 560rpm. Of course it depends on what you define low as.

Cheers

Jim


I'm not sure why that's relevant? Most miniature ball bearings can run freely from 0 to many thousand RPM. You are wondering about 0 to only 600 RPM

But if you check the past posts regarding slow speed friction claims, it's Bill that is merely quoting Ted Scannell, who felt that ball bearings were not any freer than pinpoints and that he thought that the outer ring could rotate in the mounting. But then his test vehicle was a single brass coach chassis. And both those symptoms together are also those of still greased as shipped, or damaged bearings. And I couldn't repeat any of those effects after testing hundreds of bearings and whole rakes of coaches. But please note, you can easily damage very small bearings by force fitting them using just the outer ring.

I define low speed as stopping and starting start stiction. Because that what the prototype does mostly when being modeled on those popular typical short plank layouts. That's why I was so taken with the idea of the slow pendulum decay as a credible friction test set-up.

Have you found any problem with the N7 chassis concept? I think it answers all your earlier concerns. OTOH I posted my reply on the Flexichas topic with my concerns about not (and apparently no-one) evaluating the needed spring rates prior to setting out spring mounting locations on both Bill's wagons and CSB's, but it seems to have got lost so far.

Andy

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jim s-w
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Re: Low Friction Bearings in 4mm

Postby jim s-w » Sun Dec 24, 2017 3:52 pm

Proto87stores wrote:
I'm not sure why that's relevant? Most miniature ball bearings can run freely from 0 to many thousand RPM. You are wondering about 0 to only 600 RPM


It’s no more or less relevant than you mentioning low speeds in the first place :thumb

Have you found any problem with the N7 chassis concept? I think it answers all your earlier concerns. OTOH I posted my reply on the Flexichas topic with my concerns about not (and apparently no-one) evaluating the needed spring rates prior to setting out spring mounting locations on both Bill's wagons and CSB's, but it seems to have got lost so far.
Andy


lost indeed, as I’m completely lost as to what you are talking about. Are you sure you aren’t confusing me with someone else?

Jim

proto87stores

Re: Low Friction Bearings in 4mm

Postby proto87stores » Sun Dec 24, 2017 6:39 pm

jim s-w wrote:
Proto87stores wrote:
I'm not sure why that's relevant? Most miniature ball bearings can run freely from 0 to many thousand RPM. You are wondering about 0 to only 600 RPM


It’s no more or less relevant than you mentioning low speeds in the first place :thumb

Jim


As per my post, I wasn't the one who originally queried low speed operation of BB's. That was Bill and I was answering it again.

And Yes I'm sorry, I just confused you with Will, partly because about 2/3 rds of my answers to Will and Bill last week are still missing. (holiday absence issues perhaps?) So I'm trying hard to cover all such missing situations with my later posts, although not very successfully in this case.

Andy

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Will L
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Re: Low Friction Bearings in 4mm

Postby Will L » Mon Dec 25, 2017 11:20 pm

proto87stores wrote:My layman chronological off the wall thinking is that extremely small dia bearings (for low friction) originated in clock mechanisms and later watches. And that pin points are the logical extension of small dia. bearing low friction theory.

Following that thought, I found this linkhttp://www.dg-chrono.de/fotohome/images/2010-03/55a4f31df675b3ee045a520e5.pdf

Which I recommend reading all the way though and which comes up with some amazing low coefficient of friction values for - Taa -Daaa! - 2mm id lowest quality (cheapest) ball bearings, when comparing them to the usual tiny shaft bearings nowadays used in clocks, including jeweled bearings.

Certainly impressive figures but I wasn't entirely sure if they included results that were truly resprestative of pinpoints as we use them. For instance the testrig measured a single bearing, while a pin point instaltion on an axle must have two, so you have to question if we are comparing apples and pears?. Even if, as seems quite possible, the result still favour the ball bearings, the question remains is the difference significant enough to make it worth us modelers doing anything about it? I'm not sure modellers will ever be as driven on this one as the clockmakers who, after all, have very good reason for wanting the lowest possible frictional losses. A 7 1/2 day clock doesn't have quite have the same ring. At very least, for ball bearings to make inroads into the model train market beyond a few hardened scratch builders who like trying things, you are going to have to have commercially available bearing carriers and kits specifically designed to fit them.

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Will L
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Re: Low Friction Bearings in 4mm

Postby Will L » Tue Dec 26, 2017 12:25 am

proto87stores wrote:RE The top level design ideas for the N7:

In beams, ball bearings can be used to replace hornblocks with no added components or complex sliding assemblies, and with almost zero slop. Their low friction under load is even such that simple and low cost tension belt drive is practical between adjacent axles on the same beam. in the case of my N7 I'm seriously considering powering the bunker wheel from the #3 driver using plain turned pulleys matching the wheel dia. ratio. That would effectively make it a 0-8-0 for maximum tractive effort with easily set equal weighting on all axles.

I think we are going to have to agree to differ as to the complexity of our sliding horn block assemblies. I know they frighten a lot of people who have never attempted to use them, but once the plunge has been taken and the basic skills acquired I find them simple and strait forward enough. As to component counts I suspect they don't work out that different.

The nice thing about the N series tanks from the modellers point of view is that they present lots of opportunity to add weight in helpful places so load haulage isn't a problem, so if you do make it 8 wheel drive I think you will be doing it for your own amusement(a valid enough objective) rather than any real need.
The front beams supporting the axle bearings would link wheels #1and #2 and the rear beams would link wheels #3 and #4. Each of the sideframes will be partially hollow due to being made of a sandwich of 2 sheets of 0.010" Stainless clipped together and half etched internally using the hollow spaces to hold the separately etched solid 0.010" stainless moving beams and allow them to pivot against the top centres of the hollows. The sideframes could tip fore-aft independently, just like the side beams of the 16 Ton mineral wagon and thus provide a similar four point suspension to the rigid body. Thus the interior between sideframes should be completely free of any suspension parts and open for any type of drive system to be mounted. Alternatively the beam pivots could be small coil springs and the sideframes kept locked rigid and firmly attached to the body. The latter design would emulate the track holding of a bogie coach with equalized bogies and 4 point body springing. E.g as per the current 100% reliable Amfleet coaches.

FWIW, the hollow side frame construction has been long term tested and proven in the design of the Amfleet passenger trucks. :thumb That's exactly how they are constructed. In addition their bearing holding beams are open below the bearings, so the wheelsets with bearings can be "snapped" in and out for easy assembly and any later maintenance. That should work on the N7 also, so its wheels can be precision bench assembled and quartered separately from the chassis. The gearbox and motor would "float" on probably the #2 axle and likely share the axle bearings for the worm wheel.

I think I see wht you mean, but I'm not sure it sounds like all that simple a build. I would have though the frames on the N7 would be much deeper than on a coach bogie so could present different set of issues. But that will all probably depend on the detail of the design so we had better wait and see on that one.

One quite wild idea would be to allow the beams sufficient side flexing room, and or sliding bearings (or somehow separately swivel) so that the loco would effectively be a Bo-Bo and happily and safely run around 18" radius curves, even though it is fitted with P4 wheels. But I'm not committing to that. :P

You seem to be forgetting the coupling rods which aren't going to enjoy bridging across a pare of "bogies". By the by, there is nothing that says P4 wheels wont go round 18" curves any less than any other 4mm scale gauge. Bogies and 0-4-0s are no problem, your ability to get multi axle chassis round such a bend invokes just the same design compromises as any other gauges, its just that P4 tends to attract people who are less willing to consider making them. The same would be true of Proto87 I would have thought.

Proto87stores

Re: Low Friction Bearings in 4mm

Postby Proto87stores » Tue Dec 26, 2017 11:35 pm

Will L wrote:
proto87stores wrote:My layman chronological off the wall thinking is that extremely small dia bearings (for low friction) originated in clock mechanisms and later watches. And that pin points are the logical extension of small dia. bearing low friction theory.

Following that thought, I found this linkhttp://www.dg-chrono.de/fotohome/images/2010-03/55a4f31df675b3ee045a520e5.pdf

Which I recommend reading all the way though and which comes up with some amazing low coefficient of friction values for - Taa -Daaa! - 2mm id lowest quality (cheapest) ball bearings, when comparing them to the usual tiny shaft bearings nowadays used in clocks, including jeweled bearings.

Certainly impressive figures but I wasn't entirely sure if they included results that were truly resprestative of pinpoints as we use them. For instance the testrig measured a single bearing, while a pin point instaltion on an axle must have two, so you have to question if we are comparing apples and pears?. Even if, as seems quite possible, the result still favour the ball bearings, the question remains is the difference significant enough to make it worth us modelers doing anything about it? I'm not sure modellers will ever be as driven on this one as the clockmakers who, after all, have very good reason for wanting the lowest possible frictional losses. A 7 1/2 day clock doesn't have quite have the same ring. At very least, for ball bearings to make inroads into the model train market beyond a few hardened scratch builders who like trying things, you are going to have to have commercially available bearing carriers and kits specifically designed to fit them.


Wherever there there are etched kits, there can be drawn holes that the bearings sit in. I don't see any significant part count difference to the bearing mounting holes provided currently in commercial kits.

As to comparing with pin points, has no-one in the Society performed a similar test over the past 50 years to find out what the pin point's "mu" might be? I have noticed that there don't seem to any other applications pin points are used for. E.g model gearboxes, or model steam locos with outside frames mostly seem to use plain bearings AFAIK.

Andyu

Proto87stores

Re: Low Friction Bearings in 4mm

Postby Proto87stores » Wed Dec 27, 2017 1:44 am

Will L wrote:
proto87stores wrote:RE The top level design ideas for the N7:

In beams, ball bearings can be used to replace hornblocks with no added components or complex sliding assemblies, and with almost zero slop. Their low friction under load is even such that simple and low cost tension belt drive is practical between adjacent axles on the same beam. in the case of my N7 I'm seriously considering powering the bunker wheel from the #3 driver using plain turned pulleys matching the wheel dia. ratio. That would effectively make it a 0-8-0 for maximum tractive effort with easily set equal weighting on all axles.

I think we are going to have to agree to differ as to the complexity of our sliding horn block assemblies. I know they frighten a lot of people who have never attempted to use them, but once the plunge has been taken and the basic skills acquired I find them simple and strait forward enough. As to component counts I suspect they don't work out that different.

The nice thing about the N series tanks from the modellers point of view is that they present lots of opportunity to add weight in helpful places so load haulage isn't a problem, so if you do make it 8 wheel drive I think you will be doing it for your own amusement(a valid enough objective) rather than any real need.
The front beams supporting the axle bearings would link wheels #1and #2 and the rear beams would link wheels #3 and #4. Each of the sideframes will be partially hollow due to being made of a sandwich of 2 sheets of 0.010" Stainless clipped together and half etched internally using the hollow spaces to hold the separately etched solid 0.010" stainless moving beams and allow them to pivot against the top centres of the hollows. The sideframes could tip fore-aft independently, just like the side beams of the 16 Ton mineral wagon and thus provide a similar four point suspension to the rigid body. Thus the interior between sideframes should be completely free of any suspension parts and open for any type of drive system to be mounted. Alternatively the beam pivots could be small coil springs and the sideframes kept locked rigid and firmly attached to the body. The latter design would emulate the track holding of a bogie coach with equalized bogies and 4 point body springing. E.g as per the current 100% reliable Amfleet coaches.

FWIW, the hollow side frame construction has been long term tested and proven in the design of the Amfleet passenger trucks. :thumb That's exactly how they are constructed. In addition their bearing holding beams are open below the bearings, so the wheelsets with bearings can be "snapped" in and out for easy assembly and any later maintenance. That should work on the N7 also, so its wheels can be precision bench assembled and quartered separately from the chassis. The gearbox and motor would "float" on probably the #2 axle and likely share the axle bearings for the worm wheel.

I think I see wht you mean, but I'm not sure it sounds like all that simple a build. I would have though the frames on the N7 would be much deeper than on a coach bogie so could present different set of issues. But that will all probably depend on the detail of the design so we had better wait and see on that one.

One quite wild idea would be to allow the beams sufficient side flexing room, and or sliding bearings (or somehow separately swivel) so that the loco would effectively be a Bo-Bo and happily and safely run around 18" radius curves, even though it is fitted with P4 wheels. But I'm not committing to that. :P

You seem to be forgetting the coupling rods which aren't going to enjoy bridging across a pare of "bogies". By the by, there is nothing that says P4 wheels wont go round 18" curves any less than any other 4mm scale gauge. Bogies and 0-4-0s are no problem, your ability to get multi axle chassis round such a bend invokes just the same design compromises as any other gauges, its just that P4 tends to attract people who are less willing to consider making them. The same would be true of Proto87 I would have thought.


This response should probably go back to the Flexichas topic. But while we are here, we'll' have to keep differing on horn blocks ;) . Each Horn block needs a surface to support the wheel bearing plus two pairs of precision parallel vertical freely sliding edges with double sided retaining grooves. Whereas each equalizing beam mounted bearing needs half of a beam, and half a hollow gap in the side frame for the beam to reside in. No precision, positioning or sliding clearances except the usual standard etching, nor any basic assembly skills needing to be acquired.

Jus' put t' bearing in t' ole. :)

Or even more mundane, just snap the bench pre-assembled, quartered wheel set and bearings up into the chassis.

More to the point, the need for chassis and axle assembly jigs has gone away. All the coupling rods, if etched on the same sheet as the side frames and beams, will fit perfectly first time, Only the rods coupling wheels on different beams will need any extra hole clearance. And it's possible to not need even that for x-4-x and x-6-x wheel arrangements.

Only my wild idea swivelling bogie x-8-x arrangements might need some hole slop on the center rods. And compared to what existing hornblocks need to accommodate their worst-case differential up-down movement, I'm not sure it would need to be much greater, if at all.

Way back, I did a wild idea you tube of proto87 wheels running continuously on a 8" radius oval at up to 100 mph, on a flexing foamcore sheet using equalized bogies. So I wouldn't have much more to do to deliver even the wild idea on a sound, and indefinitely reliable basis basis.

Andy

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Will L
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Re: Low Friction Bearings in 4mm

Postby Will L » Sat Jan 06, 2018 11:17 pm

Proto87stores wrote:...As to comparing with pin points, has no-one in the Society performed a similar test over the past 50 years to find out what the pin point's "mu" might be? I have noticed that there don't seem to any other applications pin points are used for. E.g model gearboxes, or model steam locos with outside frames mostly seem to use plain bearings AFAIK.


Not that I'm aware of. Given that the introduction of pinpoints (within my modelling lifetime) were clearly such a huge improvement over the plain bearings that went before, i doubt there was much interest in quantifying it. With pinpoint bearings prototypical plus train lengths became easily possible, which certainly wasn't true before they arrived, so its not clear why we need be interested in anything better. Part of this is the fact that, as used on rolling stock, pinpoint application gives very good performance from an easy installation that doesn't require a particularly accurate fit, despite anything Bill may have said in the past, and are ideal for the kitchen table modeller.

It is true that pinpoints are not fit for universal application, and it certainly seem that 4mm is the largest scale that uses them routinely suggesting they are only suitable for carrying axles when the loads are relatively light. I suspect that used in the imprecise way we do would also make them unsuitable for any driven axle or gear box.

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Will L
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Re: Low Friction Bearings in 4mm

Postby Will L » Sat Jan 06, 2018 11:43 pm

Proto87stores wrote:... But while we are here, we'll' have to keep differing on horn blocks ;) . Each Horn block needs a surface to support the wheel bearing plus two pairs of precision parallel vertical freely sliding edges with double sided retaining grooves.

Just like your equalising beams, if horn blocks are designed in from the start, all the bits just become part of the etch and are much simpler to use than you are suggesting. See some of Bills chassis kits where you have the chassis frame etch and the bearing and that's about your lot. As you said further on, rods and chassis on the same etch can do away with the need for jigs to get the axle spacings accurate.

Then if your trying to retrofit horn blocks on a chassis which doesn't come so equipped, the design of the Highlevel item is well worth looking at. It is a neat little fold up assembly that has designed away much of the complexity your thinking of. In a world were the loco you want often does have a kit out there already buts doesn't have an acceptable designed in suspension system, the Highlevel item is proving to be a popular and relatively simple answer.

As to the rest, we'll see when the N7 comes.

proto87stores

Re: Low Friction Bearings in 4mm

Postby proto87stores » Mon Jan 08, 2018 2:44 pm

Will L wrote:
Proto87stores wrote:... But while we are here, we'll' have to keep differing on horn blocks ;) . Each Horn block needs a surface to support the wheel bearing plus two pairs of precision parallel vertical freely sliding edges with double sided retaining grooves.

Just like your equalising beams, if horn blocks are designed in from the start, all the bits just become part of the etch and are much simpler to use than you are suggesting. See some of Bills chassis kits where you have the chassis frame etch and the bearing and that's about your lot. As you said further on, rods and chassis on the same etch can do away with the need for jigs to get the axle spacings accurate.

Then if your trying to retrofit horn blocks on a chassis which doesn't come so equipped, the design of the Highlevel item is well worth looking at. It is a neat little fold up assembly that has designed away much of the complexity your thinking of. In a world were the loco you want often does have a kit out there already buts doesn't have an acceptable designed in suspension system, the Highlevel item is proving to be a popular and relatively simple answer.

As to the rest, we'll see when the N7 comes.


Miniature ball bearing races are a fully complete, technically proven and ready to use recent commodity that has no internal assembly required. I have no particular interest in promoting them as merely replacements for plain or other bearings per se. My reason for adopting them is to take advantage of their weight bearing strength and preformed dimensional shape and accuracy for usefulness integrated as multi-functional pivotsand fastenings in modern, model equalizing beam suspension systems.

My ongoing input regarding the advantages of more modern beam suspension sytems, N7's etc., is most appropriately posted on the Flexichas topic. So I'll continue there instead if I may.

The only ball bearing specific comment that I would like to add here, is to point out that standard ball bearings will also act as very low friction thrust bearings for reasonable longitudinal load purposes. That factor alone should massively reduce the friction caused to model loco driver wheels by restraining their side play with only plain bearings. As to wagons, coaches, etc., I have no idea what the frictional effect of significant side thrust on pin-point bearings is. But I suspect it isn't particularly good.

Andy


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