Third Rail Chairs - N Gauge 3D printed, pack of 100

[RBTKraisee]

@LASteve and @David7 both approached me yesterday to design and 3D print a pack of N gauge third rail chairs, following a brief discussion on Derek's (@degsy_safc) Humbledon layout construction thread.

I wondered if anyone else might be interested?

I'm designing two types - one for flat wood sleepers, and one for concrete sleepers that have an end that slopes.

I'm thinking prices would be about £5 for a pack of 100.   Shipping from me in Florida to customers in the UK will likely be somewhere in the £5 range too (I still need to confirm that with the post office tomorrow).

They are designed to fit lengths of Code 40 for the electrified third rail.

NOTE - the chairs are shown attached on top of a 'post', which is a support structure used during the 3D printing process and would normally be cut off, but some folk might like to use them to insert into holed drilled into sleepers, so I'm leaving them attached.

Ross.

[Capri_sam]

I'd be interested for the price!

[Southerngooner]

And me! Perhaps if there are enough of us we could economise on postage from US by having one order into UK? I'd probably need at least 300....

Dave

[PaulCheffus]

Hi

I'm puzzled by the slope under the baseplate. Shouldn't these be flat on the sleeper ends or have you designed these just for concrete sleepers?

Cheers

Paul

[snitchthebudgie]

Add me to the interested list, please

[Richard Taylor]

Hi

I'm puzzled by the slope under the baseplate. Shouldn't these be flat on the sleeper ends or have you designed these just for concrete sleepers?

Cheers

Paul

See Ross' first post:

"I'm designing two types - one for flat wood sleepers, and one for concrete sleepers that have an end that slopes."

Richard

[red_death]

Are you designing them to fit a particular brand of track eg Peco? I drew up some 3rd rail sleepers for 7mm for a friend but he was printing (and then casting) two different types of 3rd rail sleepers

To complicate matters slightly most 3rd rail is on concrete sleepers which are designed specifically for 3rd rail fitting and have a flat area rather than a slope where the pots sit - this has some good outline drawings of the myriad of different sleepers: http://www.mmrs.co.uk/technical-articles/modern-permanent-way-3/

Are the 6 bolts for the pots an LU or older design - IIRC most 3rd rail pots are 4 bolts like this: http://www.mmrs.co.uk/wp-content/uploads/2015/01/Photo58-3rd-rail-insulator-mounting-EF28-sleeper.jpg (not a particularly modern concrete sleeper!)

Cheers Mike

[Southerngooner]

While a lot of modern third rail is on concrete sleepers the original SR stuff from the 1920's to probably the 70's at least was on wooden sleepers. I would suspect the same applies to Merseyside/Newcastle and other earlier electrifications. Fitting onto Peco code 55 wooden sleepers is what I need!

Dave

[Bob G]

I'm very interested too. Code 80 wooden sleeper compatible for me (old skool layout).
I'm also interested to know what the sleeper spacing is for these fittings.
Bob

[red_death]

Hi Dave

That is undoubtedly true - the change to concrete sleepers was from the 50s onwards (see earlier parts of the article I referenced earlier).  Of course "modern" is subjective - the start of the 70s is 50 years ago!

Cheers Mike

[RBTKraisee]

Wow, I didn't expect this much interest; excellent!

So far I've been designing for Peco Code 55 track, with two variants; one for the wood (flat bottom) and another for the concrete (sloped).   I think this arrangement should work for just about everyone (I have some Atlas track here and the flat ones work happily on it).   Changing the angle of the slope isn't a big deal for me, so if a particular customer needs something else I can probably work something out.

These chairs place the top of the Code 40 third rail (I'm using Micro Engineering rail for my examples here, but there should be only small differences with other suppliers) approximately 0.5mm above the height of the main rail.   For accuracy you should be aiming to place the centerline of the third rails about 2.6mm offset from the centerline of the nearside main rail.

These should also work pretty well for anyone wanting to replicate a 4th rail running down between the main rails too.

I would recommend everyone interested do a check on all your own rolling stock, just to make sure they don't have any protuberances that might foul the third rail at this height.   I doubt many RTR trains will have any issues, but some home-built or modified units could have unexpected bits sticking out, and none of us want any derailments!

Interestingly, I didn't think the six bolts would print (the entire base of these is only 1.7gmm across!), but when I use a jewellers lens (40x25mm mag) I can actually see six microscopic 'bumps' around the perimeter of the base! LOL   They're so small that I suspect layer of paint would obscure them entirely.   I don't have the tools to photograph that, but they are there

As for spacing, these are usually spaced around 1 every 7th sleeper or so.   But for estimating the number's you'll need for your layout you should plan for about 1 every inch (25mm) - and keep in mind that turnouts don't usually come in concrete sleeper form, so if you're modelling the concrete you will need to get a mixture of flat and sloped, to fit the different sleepers.   It might be useful to know that LASteve and David7 are each ordering 5-6 packs.

If people would like to arrange a large single batch to the UK to reduce shipping costs, I'm happy to help with that.   Feel free to use this thread (though please don't post your address in the public forum, use the Private Messaging to send those to me directly) to organise it, as needed.   One person will need to be nominated to receive the initial delivery, who's willing to stick stamps on envelopes and pop them in a UK post box.   Once we have numbers arranged, I'll sort out the mail costs with that person.

In amongst other printing, I think I can print at least 5 packs every day, maybe more, so if we arrange a big order it might take a bit of time to print everyone's parts!

With my Gresley LNER Teak Restaurant Triplet Set kit now ready for its Beta tests, it looks like my little 3D printer will be nice and busy over the next few weeks!

Ross.

[RBTKraisee]

Quick update; First batch, hot off the printer!

Tried to print a thousand at once, but it looks like the centre ones got a bit "gloopy" and didn't come out well.   I'd guess I lost 3-400 there, but that still leaves quite a few.

Ross.

[RBTKraisee]

Oh, for Paul, here's the pic of the CAD for the 'flat' base versions.

Ross.

[RBTKraisee]

So I posted the first batches of these out to @LASteve and @David7 yesterday - both here in the USA, although both hailing from, and modelling areas around Southampton/Winchester which just so happens to be my own former stomping grounds too (small world eh?).   They should receive them in the next few days and will hopefully provide some feedback for us all to see.

In particular David7 has the Peco concrete track and will hopefully be able to confirm the slope on those work well with the sloped version of the chair bases.   I may still need to issue a redesigned part for those, based on his responses.

Once we see what those guys have to say I should be ready to take, and supply, some orders.

Ross.

[Tank]

Excellent idea, and something that I'd be keen to buy in the future.