00-SF Princes Risborough

 

[Tony W]

If the track centers are different then there is no choice but to start from scratch.
Regards
Tony.

 

[Terry Downes]

Who, me?

It's been a while since I did the bricks, and now that I've changed the gauge I'm going to have to start again but hopefully with the benefit of experience! I never did get to write up my notes properly, but I've attached my scribbles to this post which I hope will be a good reference - it's just as I scribbled it, warts and all. These notes were out of date even as I was writing them (I do believe this whole area might be experimental!). The link posted in the previous message is the one I would have posted as well.

The bricks I made were not intended to be used with plug track so don't have sockets, other than blind "rail head" sockets to act as a guide. I've also attached box files and shape files - I wouldn't normally separate bricks out of the box file but I thought it might make things a little clearer. In the shapes file, the big squares represent my print area. That would be the first thing I sort out, allowing overlap for the clips. It's then a case of making bricks using lots of pretty colours! It's best to use colours from the default palette to make it easier to select by colour, and also to have adjacent bricks in contrasting colours.

Hopefully this will be of some help.

Cheers,
Paul

Paul, Martin,
Thanks for all the assistance, after reading through the long thread I initially thought this was going to be long winded but, with the obvious improvements and enhancements made since the topic began I breezed through and found the process a lot simpler than initially expected. And I'm now printing out some test samples of my first bricks.

 

[Martin Wynne]

Paul, Martin,
Thanks for all the assistance, after reading through the long thread I initially thought this was going to be long winded but, with the obvious improvements and enhancements made since the topic began I breezed through and found the process a lot simpler than initially expected. And I'm now printing out some test samples of my first bricks.View attachment 5511

@Terry Downes

Hi Terry,

Presumably that's a resin print with integral fixed-jaw chairs? It will be a miracle if you get that chair detail in an FDM print.

What are the extra bits of chair plug which you have included, and how did they get attached to the chairs on short spurs? Mystified.

cheers,

Martin.

 

[Terry Downes]

Hi Martin,
Yes its a resin print. brick size set to 120x120mm which suits my Formlabs 140x140mm printer bed. The Preform software automatically adds supports for 'delicate' areas which you can remove/add/amend as you see fit but, I've just left the auto settings. The other thing thats a little different with this test is I'm printing directly onto the bed e.g. no raft/supports etc. I have done this before with great success which creates a perfectly flat print with minimal waste. Note: I specifically talking about my Form3 resin printer and this will not apply to other printers!

 

[Martin Wynne]

The other thing thats a little different with this test is I'm printing directly onto the bed e.g. no raft/supports etc. I have done this before with great success which creates a perfectly flat print with minimal waste.

@Terry Downes

Hi Terry,

If you do that, check for "elephant's foot" problems on the connector clips from the long first layer exposure. There is a rebate in the design around the underside of the clips to protect against problems, but it may not be enough.

But where did the extra bits of chair plug come from, needing delicate supports?

cheers,

Martin.

 

[Steve_Cornford]

Looks to me as though the delicate supports are for the "keys" which the preform software must think overhang too far.

 

[Steve_Cornford]

Mind you that is viewing the picture on my mobile phone!

When I printed some resin timber bases this is the parameter that Martin advised me to adjust:-

I also printed the bases direct on the build plate just as output by Templot.
Steve

 

[Martin Wynne]

Looks to me as though the delicate supports are for the "keys" which the preform software must think overhang too far.

@Steve_Cornford

Well spotted Steve. The slabs looked like misplaced chair plugs to me -- I need new glasses!

The amount of key overhang is randomised, hence some of them getting extra supports and not others.

There is a setting to control the maximum overhang, I should probably reduce the default setting a little:

Many thanks for alerting me Steve.

cheers,

Martin.

 

[Martin Wynne]

@Steve_Cornford

Hi Steve,

I have reduced the default max offset from 1.75" (scale) to 1.5".

That means the key 6" long now projects 2.5" maximum from the chair jaw 4" wide.

It can of course be set more if anyone wants.

p.s. That key option was introduced in version 233a released 21st December 2021. That's getting on for 18 months ago! I really must try to progress this thing a bit faster.

cheers,

Martin.

 

[Phil O]

Hi Martin,

It's not often that you can't knock a key in, and end up with more than a couple of inches or so, sticking out, it has been unknown to knock a key straight through, in which case we hope that a spring key will do the job. Obviously not an option before spring keys became available.

 

[Martin Wynne]

Hi Martin,

It's not often that you can't knock a key in, and end up with more than a couple of inches or so, sticking out, it has been unknown to knock a key straight through, in which case we hope that a spring key will do the job. Obviously not an option before spring keys became available.

@Phil O

Thanks Phil.

But note that the 2.5" projection mentioned above is the maximum. Templot randomises the amount projecting up to that limit, so that the majority of keys will actually be less than that. Some a lot less.

That's why the software picked up only a few of them needing additional supports. With a reduced maximum it will be a lot fewer, and hopefully none. But if there are any, it can be prevented by reducing the maximum limit further. Every setting can be changed by the user in Templot. Apart from the ones which can't.

In the larger scales it might be necessary to allow the supports, and break them off each chair before use. In which case you might just as well leave a longer projection anyway. Or I might be able to modify the bottom edge of the key so that the projecting part will print without needing supports. There is so much still to try and do in this project. I wonder if anyone has noticed that already the keys on the loose jaws differ from those on the fixed slide-on chairs.

cheers,

Martin.