- Bexhill West
Hi Martin,@James Walters
Looking at that again it is fine for single turnouts, but is going to be a minefield for complex formations. Even ordinary double track is going to fall to bits:
View attachment 5164
I think we possibly need a range of options for this function (more tick-boxes!):
View attachment 5165
The question is -- which one should be the default setting for cutting a kerf line? Or something else? Do we need an option to change the setting individually for each end of each timber?
Also, if it is undesirable for loose bits to remain on the laser bed, presumably something similar will be needed for the sockets? Without affecting the bash fit.
Is it reasonable to assume that everyone with a laser-cutter will have some CAD software and an ability to use it, to edit the Templot DXFs? It's my firm intention that it should be possible to make plug track using the files from Templot without needing any CAD software or skills. I'm confident I can achieve that for FDM printing, and hopefully also for CNC milling.
But I'm beginning to wonder for laser-cutting. The output at present can put a kerf-adjusted line around every timber and socket. But if it is laser-cut as-is, it's going to fall apart on the cutter bed and how will you know which timber goes where? Is there any backing sheet which the plywood can be attached to, which is unaffected by the laser beam?
I know some users of plywood bases put a linking web somewhere between the timbers. I put the sprues option on the timber ends so that they could be easily trimmed off after tracklaying without distorting the timbers. But they have similar problems to the above in complex formations. Some users put a web under the rails, where it is very difficult to remove after tracklaying without distorting the track, but if not removed it makes ballasting very difficult and destroys the realism of bullhead track -- no webs between the timbers here:
View attachment 5166
A noticeable detail in that photo is the clean square end on the check rail. One of the advantages of the loose-jaws option is that you can have such neat flat rail ends, because the chairs never get threaded onto the rail.
To answer your questions in reverse order:
3. It is reasonable to assume most (if not all) laser users will have access to CAD software. That is to say the laser driver software (I use Lightburn) has some CAD functionality, and it is not difficult to adjust/delect vectors within that environment. I suspect that most (if not all) will also be using CAD software such as AutoCAD or Fusion360 etc. which they are using to create their own files. In which case they are probably more likely to use that to adjust the .dxf file Templot produces.
2. I hadn't given thought to the bits dropping out of the chair sockets when we spoke before, but these fiddlesome bits are the most likely to drop into honeycomb bed holes. But to attach them with nibs would likely require a modification to the chair plugs, as the remaining 'half-nib' which is left behind after breaking-out the waste will be difficult irksome to sand away.
I hope that makes sense, here's how I suggest the chairs might need adapting:
You will see I've added a clearance groove up the end of the plug.
I think that to modify the chairs to suit perhaps a minority of users with as laser might be to the detriment of the FDM/Milled plug track and if I were you I'd discount chair modification.
However, having just written that, and produced a drawing of a modified chair, I'm now having second thoughts, the half-nib would almost certainly compress - it might even help the bash-fit quality of the plug.
So, after all that I'd say a single "nib" in a chair socket would be a good way to go. Preferably on the 'long side' to avoid compressed nib residue affecting the gauge.
1. Given my answer (3) above, I'd say option 1 of the five you present would be the most useful and the one which I personally would like to see as a default, with the option to switch it off to leave an option 3 situation. If there was the facility to adjust the length of the upper vectors which cross I should think all bases would be ticked. It would be no hassle whatsoever to make further adjustments to these in CAD post Templot if someone chose to do so.
I'd be happy to do some testing, I can recreate what you have proposed above in CAD or can cut something from a test file which you produce.
With regard to the timbering falling apart when lifted from the laser bed, there are a few simple solutions, I'd suggest that either of the following would do the trick.
A. Draw a rectangle around the timbering, so that in-effect becomes the fret, The additional nibs we are discussing here keep the whole thing together, and importantly allow the fret to be snapped away either after the timbers have been glued down or the turnout built. The rectangle could be produced in Templot, or drawn in the laser software mentioned above (3).
B. Stick a line of making tape over the plywood across the timbering after it has been laser cut to keep all the bits together.
As I mentioned before, I think Templot currently has all that is required for laser cutting to be useful. And that most people doing the laser cutting themselves will have the skills to achieve what they required with everything as it is. Personally though, I'd find the nib function really useful and I'm sure others would too.
Finally, I couldn't agree more regarding sprues between the sleepers/timbers.
I hope the above is clear/useful,
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