Templot Club forums powered for Martin Wynne by XenForo :

TEMPLOT 3D PLUG TRACK - To get up to speed with this experimental project click here.   To watch an introductory video click here.   See the User Guide at Bexhill West.

  • The Plug Track functions are experimental and still being developed. Some of the earlier pages of this topic are now out-of-date.

    For an updated overview of this project see this topic.   For some practical modelling aspects of using Plug Track see Building 3D Track.

    The assumption is that you have your own machines on which to experiment, or helpful friends with machines. Please do not send Templot files to commercial laser cutting or 3D printing firms while this project is still experimental, because the results are unpredictable and possibly wasteful.

    Some pages of this and other topics include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files. All files derived from Templot are © Martin Wynne.
  • The Plug Track functions are experimental and still being developed.

    For an updated overview of this project see this topic.   For some practical modelling aspects of using Plug Track see Building 3D Track.

    The assumption is that you have your own machines on which to experiment, or helpful friends with machines. Please do not send Templot files to commercial laser cutting or 3D printing firms while this project is still experimental, because the results are unpredictable and possibly wasteful.

    Some pages of this and other topics include contributions from members who are creating and posting their own CAD designs for 3D printing and laser-cutting. Do not confuse them with Templot's own exported CAD files. All files derived from Templot are © Martin Wynne.

Experimental Plug Track: 3D-printed, CNC-milled, laser-cut

Quick reply >
@Steve_Cornford

Hi Steve,

:confused:

Not taken a holiday here:

p_chairs.png


You may need to start a fresh box file rather than look at your existing files.

p.s. P chairs are the slide chairs, I haven't done the switch block chairs yet -- the ones beyond the slide chairs (there are 6 P chairs per side in a B-switch).

cheers,

Martin.
 
_______________
message ref: 3568
When Templot had updated & restarted, I took the option "restore previous work", that gave me a turnout template without the P chairs.
Alsmost as though I had used the shove timbers option and unticked all the chairs on each of the relevant timber.
I have since all the templates (control & contents of box) and created a new template and the chairs have returned from their holiday.
Also tried opening recent file, and that had all the chairs.
All is working fine now.
Thank you, Steve
 
_______________
message ref: 3569
.
We now have some REA S1J joint chairs:

joint_chairs_3d2.png


joint_chairs_3d1.png


These joint chairs appear adjacent to rail joints in pointwork.

And also at each end of plain track panels if you set the option for wider sleepers adjacent to the rail joints:

joint_chairs_3d3.png


S1J chairs have the same jaws and screw patterns as ordinary S1 chairs, but on a wider 10" base to support the rail closer to the joint:

joint_chairs_3d4.png


There are lots of prototype ifs and buts relating to the use of joint chairs, so expect a fresh sprinkling of tickboxes. :)

cheers,

Martin.
 
_______________
message ref: 3588
Hi Martin,

Don't forget that keys are driven in the same direction on each sleeper, yours appear to be in opposing directions, as shown in the middle shot.
 
_______________
message ref: 3589
.
Two more tick-boxes: :)

flip_key_dir.png


Flip the driven direction of the keys on chairs 1 and 4, and/or on chairs 2 and 3.

No room for proper labels at present. Those boxes may move elsewhere eventually.

They will mainly be needed for rail joints on partial templates -- I'm hoping to get the key direction automatic on the normal joints in turnouts (and also joint chairs).

Also for the keying on bonus timbers -- there is no practical way to automate the keying on those, it will be random and likely need the above options. I'm writing this now while I'm working on it, because the chances of remembering to mention it later are nil. :(

cheers,

Martin.
 
_______________
message ref: 3594
.
I have added some blue markers to the 2D trackpad view:

key_offset_indicator.png


These marks on the rail gauge-face are intended only to indicate the direction of chair key offset (the direction from which the key has been driven into the chair). For use when making changes to the chair key settings.

The actual 3D key will be a different length, and on the opposite side of the rail. The centre of the key will be opposite the centre of this blue mark. The amount by which the mark is offset from the centre of the chair is randomised -- only the direction of the offset is significant.

On the control template only, not shown on background templates (or anywhere else).

cheers,

Martin.
 
_______________
message ref: 3602
@Phil O

It's been a battle of wits but we now have the keying direction under control:

keying_options.png



The default setting is for single track branch lines on level track, with the keys swapping direction in the middle of each track panel, driven towards the nearer of the two rail joints:

s1j_keying.png

For gradients and double-track running lines the other options can be set. These settings are template-specific, i.e. each template has its own setting.

But regardless of any other setting, the keys adjacent to a rail joint are always driven towards the fishplate. This applies for both S1J joint chairs on widened joint sleepers, or ordinary S1 chairs on standard sleepers.

Both keys on a timber are always driven in the same direction, but by random amounts.

All this is a bit academic and really applies only to CAD renderings such as above. In practice the chairs are likely to be resin-printed separately from the timbering base, and can therefore be mixed and matched at assembly time to suit any desired keying practice.

cheers,

Martin.
 
_______________
message ref: 3610
The default sizes are derived from the centres of the base corner radii -- that's not set in stone, but would now require a lot of work to change. Here again is the stuff I posted a few days ago, see item 6.

With the experimental chairing switched on, this is the additional detail which you see on the trackpad when zoomed-in:

index.php
@Steve_Cornford

Hi Steve,

Just an update on my previous reply to you. It's been another battle of wits -- but I have now undone the silly mistake I made months ago, linking the socket rectangles to the centres of the chair corner radii. That was causing headaches for the special switch and crossing chairs. The socket rectangles are now spaced from the chair outline independently of the chair corner radii:

socket_corners_mod.png


This makes no practical difference to the chairs already done, although it would now be easier to change them if necessary.

1. timber outline.

2. black lines -- cutter kerf line for laser cutters. Outside the timbers, inside the sockets.

3. extent of the timber flanges.

4. chair base outline.

5. chair base corner radius.

6. socket outline.

7. chair plug outline at the top. There is a small clearance from the socket on the sides, and a smaller clearance at the ends.

8. outline of the chair plug at the bottom inset section.

9. plug corner relief angles. Small for FDM and laser-cut sockets. Larger for CNC milled sockets.

10. outline of the top of the support pyramid below the plug.

11. outline of the bottom of the support pyramid.

12. chair screw/bolt centres.

All the above can be adjusted via the buttons on the DXF export dialog (except 4, 5, 12). They are shown on the trackpad so that you can see the effect of any changes (after rebuilding the templates). The chair dimensions 4, 5, 12, are set in the custom chairs dialog (not yet done).

More evidence of progress -- another line on the info panel: :)

chairs_in_info.png


In due course I will add a breakdown of that to show the number of each chair type.

I'm posting this stuff as I go along now because I just know I will forget to mention it later. It's mainly for my own benefit to refer back to. I hope no-one minds. Just keep in mind that everything in this topic is experimental and might change or never be seen again.

cheers,

Martin.
 
_______________
message ref: 3622
.
It's all too easy in Templot to create inadvertently duplicated identical templates. For the most part that doesn't matter for the 2D paper templates.

For the 3D chaired exports however, there will be problems. Where the chair is identical the mesh repair tool will discard the duplicated elements. But where features are randomised the duplicated elements will get combined with strange results:


duplicated_chair.png


See the strange spanner which will be needed for the chair screws! Also the key has grown to almost the full width of the chair.

I'm hoping duplicated templates will be easily noticed when extracting the timbering bricks from the plan. But if you see such strange results in your 3D prints you now know the likely answer -- which might not always be immediately obvious. :)

Sometimes when using partial templates in complex formations the templates are duplicated intentionally, or left overlapping. If it's intended to export them in 3D, it will be necessary to switch off the duplicated chairs, or make sure overlapping rails do not extend across a timber.

cheers,

Martin.
 
_______________
message ref: 3626
.
Currently working on the 1PL, 2PL and 1PR, 2PR switch block chairs:

pl_pr_chairs.jpg


These chairs are essentially short slide chairs, the difference from the P chairs being that the stock rail is conventionally keyed instead of bolted, and the switch rail has an outer jaw support.

I have increased the length of the slide table a fraction, to allow for the wider model flangeways and increased switch opening (even P4 flangeways are significantly over scale):

plr_seats.png

The intention for these chairs is that they will be in two parts, separately plugged, so that the rails can be plugged in one at a time. There is a very tiny gap between them, so that the mesh repair tool doesn't merge them into a single chair print (having two plugs).

If that is actually wanted for a more robust chair the gap can be set to zero. That would require horizontal threading of the rails into pre-fixed double chairs of course, rather than vertical plugging of a single chaired rail. Doable for a single turnout, but tricky within more complex formations.
plr_seats2.png

There is an issue with these chairs which is not immediately obvious.

Unlike on the prototype the one is not a mirror image of the other. There is a very small difference in the offset between the two rail seats. That's because the switch timbers are square-on instead of being equalized to split the deflection angle. This means that chairs printed for a left-hand switch will not be usable on a right-hand switch, and vice versa. When making plug track it will be important to keep the chair sets carefully labelled for the matching timbering brick and template.

The prototype gets round this by shifting the set in the diverging stock rail forward from its true geometrical position, so that the blade tips are exactly opposite each other. The consequence of this is that the track gauge is fractionally reduced over the diverging part of the switch, although I have never seen this actually marked on a prototype drawing.

Templot puts the set at the true geometrical position (shown as the "set advance" on some Templot diagrams) in order to preserve an accurate gauge through both roads of the switch. I'm not about to change that after 40 years just to make the chairing easier. :)
plr_seats3.png

Now for the jaws and key.

cheers,

Martin.
 
_______________
message ref: 3636
Does this mean that you will treat them as 4 separate chairs on the shove timber window pane?
@Steve_Cornford

Hi Steve,

At present no. It's one chair which is printed as two half-chairs. I haven't made any plans to export one half without the other. The S1O and S1N half-bolted chairs will be separate designs.

But everything is still very experimental -- I haven't made a grand master plan. I'm just seeing what works best as I progress each part. I may go back and change things later if I get better ideas. I may also want to improve the detail rendering of some of the chairs once the basic process is up and running.

I am keen to stress the vertical plug-in assembly of chaired rails, rather than fitting the chairs into the base and then sliding the rails into the chairs. Only vertical plugging allows the creation of complex track formations, although hybrid methods will be possible in some situations. But plugging one rail at a time does require that the special double chairs are treated as two halves. For example the check rail chairs, especially where the check rails merge together or run into parallel-wing crossings or check lumps.

In the smaller scales the half-chairs might be quite fragile, but I have to bear in mind how it will work in the larger scales too.

For "threading" chairs onto the rail which don't have an inner jaw, my thought is to use a tiny dab of Blu-Tack or similar as a temporary inner jaw. I've been looking for something like Blu-Tack in a tube which can be extruded as a thin bead. I feel sure the electronics industry must have something of the kind, but so far I haven't found it. Anyone?

cheers,

Martin.
 
_______________
message ref: 3638
.
Currently working on the 1PL, 2PL and 1PR, 2PR switch block chairs:

View attachment 3161

These chairs are essentially short slide chairs, the difference from the P chairs being that the stock rail is conventionally keyed instead of bolted, and the switch rail has an outer jaw support.

I have increased the length of the slide table a fraction, to allow for the wider model flangeways and increased switch opening (even P4 flangeways are significantly over scale):

View attachment 3160
The intention for these chairs is that they will be in two parts, separately plugged, so that the rails can be plugged in one at a time. There is a very tiny gap between them, so that the mesh repair tool doesn't merge them into a single chair print (having two plugs).

If that is actually wanted for a more robust chair the gap can be set to zero. That would require horizontal threading of the rails into pre-fixed double chairs of course, rather than vertical plugging of a single chaired rail. Doable for a single turnout, but tricky within more complex formations.
View attachment 3158
There is an issue with these chairs which is not immediately obvious.

Unlike on the prototype the one is not a mirror image of the other. There is a very small difference in the offset between the two rail seats. That's because the switch timbers are square-on instead of being equalized to split the deflection angle. This means that chairs printed for a left-hand switch will not be usable on a right-hand switch, and vice versa. When making plug track it will be important to keep the chair sets carefully labelled for the matching timbering brick and template.

The prototype gets round this by shifting the set in the diverging stock rail forward from its true geometrical position, so that the blade tips are exactly opposite each other. The consequence of this is that the track gauge is fractionally reduced over the diverging part of the switch, although I have never seen this actually marked on a prototype drawing.

Templot puts the set at the true geometrical position (shown as the "set advance" on some Templot diagrams) in order to preserve an accurate gauge through both roads of the switch. I'm not about to change that after 40 years just to make the chairing easier. :)
View attachment 3159
Now for the jaws and key.

cheers,

Martin.

Martin

Now this is really exciting, one of my biggest bugbears is the total lack of detail in this area. Even some of the best track builders ignore this detail

There may be an issue in both the coarser gauges where the slide chairs need lengthening, this may also occur on the dreaded symmetrical Y turnouts people love and possibly the short 9' switches again in the coarser scales.
Len Newman made available longer slide chairs for EM & P4 gauges, this may go against the grain a bit but is practicable
 
_______________
message ref: 3639
Martin

Now this is really exciting, one of my biggest bugbears is the total lack of detail in this area. Even some of the best track builders ignore this detail

There may be an issue in both the coarser gauges where the slide chairs need lengthening, this may also occur on the dreaded symmetrical Y turnouts people love and possibly the short 9' switches again in the coarser scales.
Len Newman made available longer slide chairs for EM & P4 gauges, this may go against the grain a bit but is practicable
@Hayfield

Thanks John.

At present I am doing only the REA switches, i.e. "A" rather than 9ft.

I want to get as far as a fully chaired REA turnout with flexible switches as the initial goal. With matching rail filing jigs for the vee rails. When I've got there I can go back and add all the other options such as the straight switches and loose-heel options, GWR and custom chair designs, etc.

At present the P slide chairs lengthen automatically in the coarser gauges. I haven't yet done that for the block chairs, I'm waiting to see how it works out in practice. It may be necessary to remove, or loosen, the inner jaws on the 3P and 4P chairs to achieve sufficient opening. In any event I think the joint in the switch rail will need to be a dummy joint in all except S4-X and S7 to ensure the flexing rail is adequately secured.

cheers,

Martin.
 
_______________
message ref: 3640
(I'm not well-acquainted with how these older-style web forums operate so I apologize in advance for any inconvenience. I also have no idea whether what I've asked has been answered previously, but this thread is pretty long to go looking through.)

I was referred here by someone online and considering I have a laptop and a resin printer, it looks like a prospect I want to get into! I couldn't tell what software this was all being done with outside of slicing for printers, so if someone could do me a huge favor and direct me to a comprehensive "getting started" thing I would be grateful. I'd also be glad to help out in any other way should you find something.
 
_______________
message ref: 3650
@ThatMKTGuy

Hi,

Welcome to Templot Club. :)

This is a support forum for my Templot software, which creates designs for hand-built model railway track and layouts using such track. It is very strongly biased towards UK prototypes using bullhead rail, but can be fully customised for other prototypes if you have the relevant data.

More info about Templot is at:

https://85a.uk/templot/companion/templot_explained.php

https://85a.uk/templot/companion/

You can download Templot (free) from:

https://85a.uk/templot/companion/installation.php

If you have any questions about Templot, just ask away here, there's lots of friendly help.

Templot has been my hobby project for over 40 years now, and has been available to other modellers for over 20 years.



This particular topic is about an experimental project which I am working on to create 3D-printed track parts directly from Templot designs. There is still a long way to go before it is finished, or even much usable, although we have got as far as creating 3D-printed plain track in UK-bullhead pattern, in any scale or gauge.

If you read through the topics at:

https://85a.uk/templot/club/index.php?forums/plug-track.34/

you will get a better idea of what we are doing and where we have got to. :)

cheers,

Martin.
 
_______________
message ref: 3651
.
We now have some outer jaws for the switch block chairs:
sc_outer_jaws.png





switch_block_chairs.jpg


These 2-screw outers are common to several of the special crossing chairs, and also the check rail chairs.

(They might also be used with the REA 2-screw S1 inners to provide a generic 4-screw plain chair design for those who want that for their prototype.)

cheers,

Martin.
 
_______________
message ref: 3654
Hi Martin, you are making excellent progress in your experiments.
I wonder if in the smaller scales using ply timbers it is practical to have two sockets so close together, it might need to be one socket but with the two plugs shaped to meet at their adjoining faces so that when you insert the 2nd plug it presses against the first plug?
Just a thought.
That is an interesting photo. What is the name of the strap between the switch rail and the stock rail?
Is it for electrical bonding or for minimising the longditudinal movement of the switch blade?
Like the soleplate rarely modelled in 4mm scale apart from a wire soldered underneath the rails that is for electricl continuity.
 
_______________
message ref: 3658
@Steve_Cornford

Hi Steve,

The strap is a switch anchor. As you guessed It prevents any longitudinal movement between the stock rail and the switch rail, which is important to preserve the geometry of the planing fit against the stock rail at the toe. It's not often modelled, although there are some etched parts available from Ambis. The most prominent part of it in normal model viewing is the bolt and fish-washer in the rail side. I'm hoping to make all these bits of pointwork furniture available for 3D printing along with the chairs in due course. Also the fishplates of course, which I've already been working on. If the rails are plugged in vertically, the obvious consequence is that the fishplates will have to be applied from the side (just like the prototype).

The question of sockets for the double chairs has been on my mind for a long time. I'm hoping to make every single thing an adjustable option, so that you could adjust the size of the socket/plug on every single chair individually if you wanted to. So you might prefer to make the plugs smaller on one or both of the half-chairs. Or larger so that they fit against each other in a single merged socket -- that prevents the first one being a press fit of course, or providing any gauging or alignment until the second one is added. Or put a radius in the corner of the socket similar to the CNC milled sockets, to stiffen the narrow web between the two sockets. Or an angled corner.

As I keep saying there is a long way to go, and a million adjustments and modifications to try out before the project can be "signed off" so to speak. It is also very likely that what works best in one scale will differ from in other scales. At present I'm pressing on (!) with the chairs so that I can at least see a complete turnout before I start making modifications and changes.

An obvious difference in the photo is the hollow spring steel keys used instead of solid wooden keys. But no, I'm definitely not going to try that in the smaller scales. :) In the larger scales, who knows?

cheers,

Martin.
 
_______________
message ref: 3660
.
I thought something didn't look right. I was scaling the fillet radii twice. :(

This is better:

sc_outer_jaws1.png

sc_outer_jaws2.png

cheers,

Martin.
 
_______________
message ref: 3663
There seems to be no stopping you at the moment, I am finding it difficult to keep up with all the improvements to the standard Templot usage let alone 3D printing. I do have an FDM printer sitting in the corner but still no time to play with it and now I have to start saving up for a resin printer!:)
 
_______________
message ref: 3665
There seems to be no stopping you at the moment, I am finding it difficult to keep up with all the improvements to the standard Templot usage let alone 3D printing. I do have an FDM printer sitting in the corner but still no time to play with it and now I have to start saving up for a resin printer!:)

Hi Stephen,

It's not compulsory! And it's probably unwise to buy machines just on the strength of this project -- there is still plenty of time for the whole thing to bite the dust. :)

Martin.
 
_______________
message ref: 3669
Hi Martin,
I'm trying to set a custom rail size for Peco 00 code 75 Bullhead rail but I'm getting some weird results. I'm pretty sure its to do with the last three variables relating to fish centres & angle.
custom rail settings.PNG


here are the Peco code 75 bullhead Rail dimensions I have measured
Peco code75 bullhead rail dims.PNG

Any advice or guidance would be much appreciated.

Terry
 
_______________
message ref: 3681
@Terry Downes

Hi Terry,

The fish angle on all UK REA bullhead and jointed flat-bottom track is 1:2.75. Here is the way the rail section is dimensioned:

index.php


You can see that the all-important fishing faces are dimensioned from their intersect on the rail section centre-line. The head and foot depths can then be derived if needed.

Your dimensions show that the Peco rail is not a proper bullhead, having head and foot of equal depth. I believe they have done this for easier manufacturing, so that the rail can be threaded into the sleeper base either way up, and the machined pointwork parts are not handed and can be used for left-hand or right-hand versions of each item.

If the fishing faces really are as square as you have drawn them, you need to enter a very large number for the fish angle, say 500000.

cheers,

Martin.
 
_______________
message ref: 3682
Hi Martin,
I have been playing around with trying to create chairs which will be compatible with the new Peco code 75 bullhead rail. I know you are working on may aspects of Templot and this is all still experimental so, please do not feel compelled to answer or adress these queries if you are focusing on other elements etc.
Anyway, I have re-measured the new Peco code 75 bullhead rail section using a vernier gauge and adjusted the custom rail settings as shown below.
1644601270140.png


This has produced pretty good chairs 3D models (3Ddxf/stl) but, I now need to remove some chair material from the lower fixed jaw side as shown below. Is this something I have initiated from within the settings or should I try and fix post-export from Templot within a 3D dxf/stl environment?
1644601187557.png



Also, the wedge appears to have generated weirdly as shown below. Do you think this is because I have set one of the variables out of scope? or maybe the fish angle of 1:5 is too shallow?
1644601842053.png


I did check the 'fill below key' box and this proved successful but, I was looking for the button/function/area which enabled the chair jaws to be beefed up. has this been remove or moved or am I imagining I have seen this in the past? I was hoping I may be able to adjust the fixed jaw upwards (not prototypical) and avoid the clash shown above.

regards, Terry
 
_______________
message ref: 3695
@Terry Downes

Hi Terry,

Many thanks for posting your feedback from the experimental functions in Templot. It's a great help. :)

Do Peco now supply their code 75 bullhead rail separately? If not it might be better to use a more readily available rail, such as the EMGS/C&L code 75 rail for your experiments. Not least because your dimensions indicate a very poor representation of BS-95R bullhead rail:

terry_peco_s1.png


There is an obvious bug in Templot on the lower face of the part I call the "grip" (ringed red) which explains this strange feature:

index.php


Thanks for finding it, I will get it fixed for the next program update.

This is what the prototype rail looks like (Templot simplified), the wooden key being symmetrical about the rail edge:

bs95r.png


Overlaying the two looks like this:

peco_bs95r_overlay.png


In order to maintain the track gauge, the rail, chair base and jaws are all referenced from the gauge-face of the rail. Your rail is significantly under scale width, which causes significant distortion to the shape and appearance of the key. I will change the top angle on the exposed part of the key to match the prototype 1:2.75 fish angle, instead of matching the model fish angle. This will reduce the excessive height of the key above the top of the jaw.

However, I can't find what is going wrong with the end of your key, it seems fine here in TurboCAD -- which 3D rendering software are you using?
terry_peco_s1_3d.png


I tried adding some fill below the key, which seems to be working ok:
terry_peco_s1_3d_fill.png


Have you tried running the STL file through the mesh repair tool at:

https://www.formware.co/onlinestlrepair

It will probably fix the key problem.

I did have a chair "beefing" option in some earlier versions. I removed it because it was causing difficulties for the special switch and crossing chairs, and it was one degree of complexity too many. After trials with my Elegoo 3D printer and "ABS-like" resin I found the chairs were adequately robust, at least in 4mm scale, and didn't need beefing up.

Eventually it will be possible to enter custom chair data in addition to custom rail sections, to create other prototype chairs and/or beef up existing chairs if needed. Sorry we are not there yet though.

Thanks again for posting you feedback.

cheers,

Martin.
 
_______________
message ref: 3696
Hi Martin,
I'm not sure if Peco supply their new code 75 bullhead rail separately but, the only reason I'm pursuing this rail section is because I want to add a new templot scissor/slip crossing into an existing layout which uses the new large radius points and flexitrack. I will look into whether the rail you have suggested can be joined to the Peco rail and decide which rail to utilise in my scissor crossing. I'm still refining this crossing and will try to find a relevant post to discuss timbering etc. separately.
1644654537300.png


Regarding key generation errors, I was pulling the 3D dxf file into Solidworks but, when I import the stl file the key appears fine (grey image). Also when I import the 3d dxf into TurboCAD it appears fine (coloured image). therefore i believe this glitch was down to the Solidworks import facility.
1644655478987.png
1644656210194.png


going forward...
A nice feature in the future would be to export a 3D solid file step, .stp or .sat as well as the current 3d surface formats .stl & .dxf but, this is only required for people like me who like to play. I'm not sure which version of TurboCAD you are using but I believe the Platinum edition (mega bucks!) is the only version which enables 3d solid exports. So, I'll look at exploring converting surface models into solid models via SolidWorks and Inventor.

Once I have a stl file of all the various chairs for a point/template they will be spaced apart beyond the print area of my printer. Will there be a feature to export chairs only AND close up the individual chairs into a condensed area to facilitate resin printing of a whole point in one go?

Terry
 
_______________
message ref: 3699
@Terry Downes

Hi Terry,

Wow. A fully-chaired scissors crossover and two double slips is going to be a sight to behold. :)

However, in Plug Track I am still doing the switch chairs. I've given some thought to the V-crossing chairs and check chairs, but so far I haven't even thought about K-crossings and slips. It's going to be a while before I get that far. Until then you will need to design all those chairs yourself unless you use non-plug moulded chairs from C&L/Exactoscale.

Or you could do some kit-bashing on Wayne's Finetrax kits -- he is just now doing the diamond-crossings. Also of course Peco have just announced the availability of their diamond-crossings and slips matching their "large" radius 00 bullhead turnouts. The difference with those options of course is that the sizes are fixed and straight -- FinetraX is only 1:7 so far and Peco is all 1:4.7 for 00. Plug Track will be for any angle, scale, gauge, or radius.

The C&L rail is a much better section than the one you are using. Many users of it are now using the Peco bullhead fishplates with it, so it must obviously be compatible. The smaller rail foot would make it easier to design the inside chair fixings and retain a clearance for RTR wheel flanges.

I have no plans to export the files in any format other than DXF and STL. There are plenty of online conversion tools to create other formats if needed. I don't know why you feel you need them, bearing in mind that the Chitubox and Cura slicer programs work fine with STL files. Likewise with the online STL mesh repair tools -- which are currently needed with the Plug Track export, although I'm hoping one day to export clean STL files which don't need fixing. The 2-D DXF files will also be available in EMF for users without any CAD program.

I'm currently using TurboCAD DeLuxe to create the DXF renderings, although not for any design work on the chairs. That is all done in Templot.

Yes, there is already a button on the DXF dialog to export only chairs in the 3-D files, and several tickboxes to control which chair elements are wanted (click chairs only first before changing them):

chairs_only.png


Yes, there will be a bunching function to close up chairs (and timbers if wanted) for resin printing. However that's not yet ready -- and it's much more complex than might at first appear, because the chairs are all at different angles. And a paper printed map sheet is needed to indicate which chair is which. Again not simple because a timbering brick may contain some very similar chairs from different templates but which are not actually interchangeable.

cheers,

Martin.
 
_______________
message ref: 3700
Sorry to butt in but another vote for Turbocad Deluxe, mine is 2015, which I use for preparing DXF files for etching by PPD, so haven't really used it for 3D except for visualising a chair that was posted some time ago.
 
_______________
message ref: 3701
I tried adding some fill below the key, which seems to be working ok
@Terry Downes

p.s. Terry,

Just to add that if you use the fill below key option, you need to check that your actual rail foot width matches your custom rail setting. The filler chunk will be in contact with the rail foot, and if the rail foot is too wide the chair is likely to fracture.

The rail fit - fine adjust setting applies only to the key, not to the filler chunk. The key has a taper on each end and a small pressure pad area at the centre. This is intended to aid threading the chair onto the rail, and possibly to wear the pad a fraction as the chair slides into position to reduce any stress on the chair. The filler chunk does not have any such allowance.

Resin-printed chairs are likely to harden and become more brittle with age, especially if not painted, so any residual stress may lead to age-fracture. The jury is still out on this for all resin-printed chairs, not only Plug Track.

Generally I have found that the chairs work well and hold the rail without undue stress if used without the filler chunk. i.e. as the prototype with the rail held only by the key.

cheers,

Martin.
 
_______________
message ref: 3707
_______________
message ref: 3777
.
Sorry there was no update for a while, I've been busy with some electronics work.

But back on Templot today, working on the P chair (slide chair).

I've decided to go with the PJ version of the REA chair:

index.php


because it's a bit beefier and stronger on model rail sections. Maybe I could do the older P type later as an option.

View attachment 3035
Outer jaw still to do (you noticed :) ) but I've got the slide table and stock rail bolt and boss done. The bolt is at 1:20 to match the prototype, even though the model rail will be vertical.

The slide table is 7" wide, which means for REA switches the switch blade tip should align exactly with the edge of the table. Which will be a convenient guide when track building. The length of the chair and slide table is increased from the prototype to suit the model gauge/scale in use where needing an over-scale switch opening (for 00, EM, etc.).

The nut rotation on the stock rail bolt is part-randomised in 15-degree steps (the chair-screw heads are infinitely randomised).

I'm omitting the spring washer under the nut, the screw-thread on the exposed end of the bolt, and the domed end of it -- I have to draw a sensible line somewhere. Otherwise it will take forever and the STL file size will go through the roof.


View attachment 3036

View attachment 3037
Now to get the jaw done.

cheers,

Martin.
Hi Martin,
I've just modelled up the P chair referencing the PermanentWay1928.pdf and it appears shorter than your PJ chair you have modelled. Does this sound correct? I can not find a drawing of the PJ slide chair within the 1928.pdf or am Going blind?

Terry
 
_______________
message ref: 3867
@Terry Downes

Hi Terry,

The PJ chair was a 1950s revision of the P chair, so not shown on the original 1928 REA drawings.

The PJ has a separate insert spacer in the rail web, instead of a one-piece outer jaw as in the P chair. The original P chair was subject to frequent breakage in heavy traffic. The PJ version is beefed up and stronger -- the jaw has a solid base and does not have to fit the rail section. Also for maintenance, the slide-out spacer means the toe timber and chaired soleplate can be dropped below the rails and replaced in one piece, instead of needing to have the chairs removed and reassembled:

index.php


Sorry, I don't have a detailed drawing of the PJ chair, only a small-scale outline drawing. Looking at what I've done with it so far, I think perhaps the jaw could be a bit beefier.

The Templot chairs are not exact scale models for several reasons:

1. in Templot the model rail is vertical instead of inclined. This changes the inner and outer lengths of the chair relative to the rail gauge-face.

2. model rail sections are generally a poor representation of the BS-95R prototype, usually with a significantly excessive web thickness. This affects the design of the outer keys and spacers, and the inner chair jaws.

3. most model gauges have over-scale flangeway gaps (including P4) which affects the special chairs design and the amount of switch opening needed -- the model P chairs are adjusted in slide length accordingly.

4. the prototype chairs are iron castings from smooth patterns having draft angles and fillet radii all round, which if included in the 3D file sends the file size through the roof.

However, if/when I get all this finished, it will be possible to enter custom chair designs in Templot for any prototype -- it will be for the user to make it fit the model rail and deal with the 3D file sizes.

cheers,

Martin.
 
_______________
message ref: 3868
.
It's a long time since I posted any evidence of progress, so here are some chairs on a test brick.

It is all but impossible to photograph the translucent chairs as 3D-printed -- they have to be translucent so that the UV light can cure them all through. They need a scoosh of rattle-can primer to be properly photographed.

EM gauge. Spot the deliberate mistake*:

aug22_1.jpg



S1J joint chair, S1 ordinary chair, P slide chairs:

aug22_3.jpg



5 L1 bridge chairs and 5 S1 ordinary chairs:

aug22_2.jpg


It's proving tricky to get the socket sizing right for the L1 bridge chairs where they are close together. Making them a tight push fit means the first one distorts the base a fraction and makes the second one more difficult to fit.

It's no problem on the CNC-milled base, where the MDF material is soft enough to give, but the FDM polymer is made of tougher stuff.

I've got a few ideas to try. It's important, because there will be similar issues with the special crossing chairs.

*I used one wrong joint chair -- keys have to driven towards the rail joint, because of the fishplate. :)

Martin.
 
_______________
message ref: 4738
Back
Top