00 Bullhead Printed Point/Turnout Bases

[Dave John]

Some interesting research Andy ID. 

 

The idea of printing the rails as well might seem odd since most folk are used to the idea of the rail being the power for the trains. But I see others doing wonderful research with battery power and radio control, and I have tried it myself in the bigger scales in the past. ( Really , I made an armoured simplex that ran on 0 track and had a mini lead acid battery in way back when it was 27 MHz rc ) Throughout my entire model railway life the whole rail >wheel > bits of brass > motor thing has caused more hassle and repair time than any other aspect of the hobby. I know that it has frustrated others to the point of giving up. 

 

The whole CAD/CAM thing has now dropped in price to the individual user level. Modellers now regularly use software to design and print out track plans. All the variables can be set, even odd stuff for dafties like me that go for pre group 8' 11 1/2 " interleaved sleepers and my own slightly wider than EM gauge.  So, thinking forward its not a huge step to go from printing a track plan on paper to hitting a send button and getting it 3d printed by a specialist 3d model railway track printing company. Oh, and the obvious other thing is ballast. 3d print that as well, or rails set in paving.

 

Looking about at the young folk of today that is the sort of thing that might get them into model railways. 

 

So Andy, please continue with your pioneering efforts. I can see a huge potential in what you are doing.

[AndyID]

Thanks for the encouragement Dave.

 

This is an example of what I'm on about.

 

 

This was printed in PLA on my home printer. To reduce assembly time the six check rails and the wing rail extensions are printed. The PLA printing process has some limitations. It should be much nicer printed in sintered nylon.

 

Andy

[unravelled]

I think the printed wing/check rails could be a good idea. They would solve the problem of shiny  non running surfaces. The only downside I can see is that metal wing rails can help with pickup, through back of flange contact, but perhaps that's a need which should be designed out.

 

As someone  who has a layout on hold, partly because of the various promises of bullhead points "soon", I'm interested in all the possible systems. I want to avoid hand building if possible, but am not averse to a bit of assembly, so your approaches continue to look hopeful.

 

Thanks

 

Dave

[AndyID]

New and "improved" three bolter.

 

 

To some extent I'm probably wasting my time  here. The printing process degrades a lot of the detail and you end up with more of a suggestion of a feature rather than a good facsimile. At larger scales the detail would be reproduced much more faithfully. The key in this version is a bit of a fudge. It's centered rather than handed.

 

[martin_wynne]

The key in this version is a bit of a fudge. It's centered rather than handed.

 

Hi Andy,

 

Centred is ok for a spring steel key. But don't forget to have daylight showing through it.

 

 

Martin.

[Jeff Smith]

I think the printed wing/check rails could be a good idea. They would solve the problem of shiny  non running surfaces. The only downside I can see is that metal wing rails can help with pickup, through back of flange contact, but perhaps that's a need which should be designed out.

 

As someone  who has a layout on hold, partly because of the various promises of bullhead points "soon", I'm interested in all the possible systems. I want to avoid hand building if possible, but am not averse to a bit of assembly, so your approaches continue to look hopeful.

 

Thanks

 

Dave

If you are not worried about a bit of assembly try an SMP plastic based 36" BH point kit. Easy to build and less than a tenner! These are small radius but may get you on your way in a yard - there are matching catch point kits too.

[AndyID]

 

Centred is ok for a spring steel key. But don't forget to have daylight showing through it.

 

 

Hi Martin,

 

It is possible to print horizontal pipes with this process so a little daylight might be possible, but it's not going to look much like a steel key

 

Andy

[AndyID]

"Let the sunshine, let the........"

 

 

I like the idea of not having to worry about the direction of the keys. I hope this works.

 

 

[Colin parks]

Thanks for the encouragement Dave.

 

This is an example of what I'm on about.

 

DSCN2540.JPG

 

This was printed in PLA on my home printer. To reduce assembly time the six check rails and the wing rail extensions are printed. The PLA printing process has some limitations. It should be much nicer printed in sintered nylon.

 

Andy

Hi Andy,

 

That diamond crossing is looking promising.  The printed wing and check rails give quite a convincing contrast with the bright metal running rail tops. That must save a great deal of assembly time.    

 

All the best,

 

Colin

[AndyID]

Here's a sample of the 3-bolt chair. I printed it on my home printer in PLA while I'm waiting for Shapeways samples to arrive.

 

Oh, and you can actually see daylight through the keys although that's really more a necessary artifact of the printing process than anything else.

 

[AndyID]

Still mucking about trying to get the chairs right. Here are the samples I received today:

 

 

The sample on the left is sintered nylon. The detail isn't very good, but the chairs are robust.

 

"Frosted Ultra Detail" resin is on the right. The chair detail is pretty phenomenal but they are a bit fragile.

 

More work required!

[AndyID]

Plan B.

 

The detail possible with "Frosted Ultra Detail" (see above) is pretty phenomenal but the resin isn't very robust and I'm concerned that threading the rail will tend to break the chairs (it can, and does!)

 

So, why thread the rail at all? Why not print the rail in resin along with the timbers and chairs? All you need is a conductive nickel-silver "cap". Something like this:

 

 

 

[stadman]

Hi Andy,

 

Centred is ok for a spring steel key.

 

Nicely done but steel keys should really only be inserted at start to a 3rd, taking another 3rd for maintenance, when centred they are to worn.

Wooden keys for check rail and the like.

Rather than include fixing screws maybe a centre point to make a hole and insert some square plasticard? OK so perhaps defeating the one stop solution but if you're after appearance?

[hayfield]

The other alternative is to go the other way, that is to print the turnout timber bases and use existing commercial available plastic chairs, or even print half chairs (inside for stock rails outside for switch rails) on to the timbers and stick half chairs to the timbers.

[martin_wynne]

or even print half chairs on to the timbers and stick on other half chairs

 

Brilliant! The best ideas are always the simplest.

 

No chair threading. Rails easily and accurately located. Second half-chair easily located and fixed.

 

Martin.

[AndyID]

The other alternative is to go the other way, that is to print the turnout timber bases and use existing commercial available plastic chairs, or even print half chairs (inside for stock rails outside for switch rails) on to the timbers and stick half chairs to the timbers.

 

Hi John,

 

That's certainly a way to do it. To simplify construction I would print "posts" on the underside of the detached half-chairs that plug into "sockets" in the timbers. They might not even require any adhesive.

 

But first I'm going to plod on with my conducting rail head method and see how that turns out (groans from the cheap seats   ).

 

Cheers!

Andy

[hayfield]

Brilliant! The best ideas are always the simplest.

 

No chair threading. Rails easily and accurately located. Second half-chair easily located and fixed.

 

Martin.

 

 

The next question is how easy is it to stick plastic chairs to the better quality material

 

Or the half chairs could be attached to the timber ends by a pip and cut off

[martin_wynne]

That's certainly a way to do it. To simplify construction I would print "posts" on the underside of the detached half-chairs that plug into "sockets" in the timbers. They might not even require any adhesive.

 

Hi Andy,

 

The beauty of John's idea is that it is self-adjusting for any variation in the web thickness of different model rail sections. That is the main reason folks have trouble threading chairs -- the rail web thickness is way over scale and varies a lot.

 

Solid-plugging half-chairs onto the timbers would lose that advantage. Also assuming the half-chair is the outside key side, it can't be plugged vertically because the key won't pass the rail head. I suggest a short slot so that the post on the half-chair can be located in it, and then pushed forward against the rail.

 

I see the base timbers containing a support for the rail 0.58mm above the timber surface and the inside chair jaw.

 

Some folks use Loctite-type adhesive to fix half-chairs. This has the advantage of also sticking to the rail, for the positions where the rail is not supported on the other side, such as the slide chairs.

 

regards,

 

Martin.

[AndyID]

Hi Andy,

 

The beauty of John's idea is that it is self-adjusting for any variation in the web thickness of different model rail sections. That is the main reason folks have trouble threading chairs -- the rail web thickness is way over scale and varies a lot.

 

Solid-plugging half-chairs onto the timbers would lose that advantage. Also assuming the half-chair is the outside key side, it can't be plugged vertically because the key won't pass the rail head. I suggest a short slot so that the post on the half-chair can be located in it, and then pushed forward against the rail.

 

I see the base timbers containing a support for the rail 0.58mm above the timber surface and the inside chair jaw.

 

Some folks use Loctite-type adhesive to fix half-chairs. This has the advantage of also sticking to the rail, for the positions where the rail is not supported on the other side, such as the slide chairs.

 

regards,

 

Martin.

 

Hi Martin,

 

Ah, but as usual, there's a snag

 

Just like the real thing, with bullhead rail the gauge is determined by the web position, not the head or foot of the rail. Unless both jaws are adjustable, the gauge is a function of the web thickness.

 

Because the web is printed to quite tight tolerances the cap method doesn't have that problem. Also, one cap can be used on a lot of different rail weights and types, including flat bottom. It's also very inexpensive and I think it should be very simple to construct a reliable turnout using this method. Of course that remains to be seen.

 

Andy

[trustytrev]

Hello,

       This 3D printing is springing up all over. At the MERG forum  there are some very encouraging results being achieved by member Bobg who is even sharing his designs with the group.

trustytrev.

Edited December 27, 2017 by trustytrev

[martin_wynne]

Just like the real thing, with bullhead rail the gauge is determined by the web position, not the head or foot of the rail. Unless both jaws are adjustable, the gauge is a function of the web thickness.

 

Hi Andy,

 

Yes, but the effect of overscale web thickness would be to increase the gauge. A specified track gauge is always a minimum, gauge-widening is allowed.

 

The tricky one would be the check rails. They always need to be set with gauges, so need separate functional chairs.

 

regards,

 

Martin.

[hayfield]

Hello,

       This 3D printing is springing up all over. At the MERG forum  there are some very encouraging results being achieved by member Bobg who is even sharing his designs with the group.

trustytrev.

 

 

Any chance of a link to it please

[hayfield]

Hi Martin,

 

Ah, but as usual, there's a snag

 

Just like the real thing, with bullhead rail the gauge is determined by the web position, not the head or foot of the rail. Unless both jaws are adjustable, the gauge is a function of the web thickness.

 

Because the web is printed to quite tight tolerances the cap method doesn't have that problem. Also, one cap can be used on a lot of different rail weights and types, including flat bottom. It's also very inexpensive and I think it should be very simple to construct a reliable turnout using this method. Of course that remains to be seen.

 

Andy

 

 

Andy

 

Sometimes I think we all are guilty of over complicating things, or trying to make things too simple. I have been unable to do much modelling as we have completely altered our house downstairs and ended up doing a lot more ourselves after builder problems, thankfully in the decorating stage now and waiting for the last few bits of the electrical installation to be finished

 

However all this has given me the time to reflect on various issues, especially track building. When I got serious with building track it was always a belt and braces approach which was taken by me and many others, even though we had spent 40 years sticking plastic chairs to sleepers we concentrated on what this method could not do rather than what it could do. I have come to the following conclusions

 

1  The method we use depends on what material we use for sleepers. If using plastic sleepered plain track then why are we using ply for turnouts and crossings

 

2  If using ply sleepers and timbers then either sub assemblies or using rivets/vero pins are required

 

Turning to plastic chairs on plastic sleepers and timbers, why are we so worried about using these for turnouts and crossings ? We know the issues with thin sleepers and timbers, so either stick them down prior to fitting the chairs or use thicker material.

 

The next issues are the common and obtuse crossings, why are we making sub assemblies or using rivets/vero pins. We know once set the chairs will hold all together, we also know we can hold common and obtuse crossings in place providing we use the appropriate chairs and of by modifying the odd chair. So why over complicate the issue ? We know with the rivet construction the issues with expansion and rust, neither of which affects plastic

 

On my next layout (EM gauge) I will use the Exactoscale Turnout and crossing plastic bases or plastic Timber strips, not only for speed but for strength. The vees will be soldered but every thing else will be held together using the full range of chairs. To be quite honest its a no brainer

 

Coming back to your own experiments, in my opinion the commercial option would be to print the Turnout and crossing bases in plastic with half chairs where appropriate with some being inside others outside. Thought on how the turnout or crossing would be constructed especially in the common or obtuse areas, but this would be an easy process. Again thinking of it as a commercial project, the process must be made as simple as possible, ease of construction being the goal

 

Still enough of my ramblings

[trustytrev]

Hello,

      Unfortunately the forum is only available to subscribing members of the Model Electronic Railway Group.

However I am pretty sure a lot of other stuff would be of interest to railway modellers in general making membership worthwhile anyway.

trustytrev.

[AndyID]

Almost time to send the model to Shapeways. This is a B7.5

 

Everything you see here will be printed. It should come out very close to the rendering. I will add fishplates and probably webs between the timbers for added strength.

 

I've created a library of the chairs required to produce a turnout. This set is centered on a B 7.5 but they can be applied to some turnouts either side of that. Once you have the chair models it doesn't take long to plonk them on to the timbers in CAD.