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Sprung point springs
Posted: Wed Jun 28, 2023 1:56 pm
by philipy
In Tom-tom-go's RWLR thread, on Page 9 he shows how he arranged the spring for his sprung points.
https://gardenrails.org/forum/viewtopic ... &start=160
I have it in mind to do something very similar but I'm struggling with what sort of spring to get, anyone got any suggestions? I really don't want to have to buy a box of 100 assorted springs in the hope of finding the right one!
Tom's picture shows an extension spring in S/S and at a guess it appears to be about 25/30mm long and 6-ish mm diameter, but heaven knows what gauge the wire is.
The science of springs is hugely complicated and I don't have enough life left to waste on trying to calculate it!
Re: Sprung point springs
Posted: Thu Jun 29, 2023 4:34 am
by GAP
philipy wrote: ↑Wed Jun 28, 2023 1:56 pm
In Tom-tom-go's RWLR thread, on Page 9 he shows how he arranged the spring for his sprung points.
https://gardenrails.org/forum/viewtopic ... &start=160
I have it in mind to do something very similar but I'm struggling with what sort of spring to get, anyone got any suggestions? I really don't want to have to buy a box of 100 assorted springs in the hope of finding the right one!
Tom's picture shows an extension spring in S/S and at a guess it appears to be about 25/30mm long and 6-ish mm diameter, but heaven knows what gauge the wire is.
The science of springs is hugely complicated and I don't have enough life left to waste on trying to calculate it!
Ask Tom Tom if he can measure the spring for you.
Then give these people a call and ask if they can help.
https://www.springmasters.com/
Re: Sprung point springs
Posted: Thu Jun 29, 2023 5:38 am
by philipy
GAP wrote: ↑Thu Jun 29, 2023 4:34 am
Ask Tom Tom if he can measure the spring for you.
Unfortunately, Tom dismantled his railway quite a while ago and went off to play with large scale live steam. He hasn't logged on to the forum in over 2 months.
Re: Sprung point springs
Posted: Fri Jun 30, 2023 2:11 am
by GTB
philipy wrote: ↑Wed Jun 28, 2023 1:56 pm
In Tom-tom-go's RWLR thread, on Page 9 he shows how he arranged the spring for his sprung points.
I have it in mind to do something very similar but I'm struggling with what sort of spring to get, anyone got any suggestions?
Making/designing springs is above my pay grade. Have you considered a fixed blade turnout for the return loop?
The photo below was posted by Tony Willmore some time back. I couldn't link to the original post, but I saved the pic in my files at the time, so I've posted it again.
- IMG_0622.jpeg (35.85 KiB) Viewed 3698 times
I haven't built one myself, but they do much the same job as a sprung turnout, with the advantage of no moving parts. (Always a plus out in the garden.......)
Regards,
Graeme
Re: Sprung point springs
Posted: Fri Jun 30, 2023 5:47 am
by philipy
Thanks. Yes I did remember that discussion about fixed points, which was mainly to do with urban tramway track, as I recall.
I'd prefer to use a sprung point if I can get it to work reliably, partly because I already have a scratchbuilt one which fits nicely where I need it and I neither want to butcher that one nor build a new one, if I can avoid it. Plus having a conventional turnout leaves me with potential options in the future.
I've got a couple of springs on order from Amazon which look to be similar to Tom's but I can send back if they are no good. I'm planning to see what they are like and how much spring force they have, then I'll have some sort of crude reference point if I need to look for a different one - stronger, weaker or whatever.
Re: Sprung point springs
Posted: Tue Jul 04, 2023 9:55 am
by philipy
Well the springs that I ordered from Amazon were no good for what I wanted and the more I looked at the turnout that I wanted to use, the less convinced I was that springing it was actually a good idea. It is a bit stiff and although a heavy steam loco would probably go through OK, I'm less convinced that the little locos I use would be able to push against a spring.
So to cut a long story short, I reverted to Tony W's non-moving point blades, as suggested by Graeme a couple of days ago. Was actually pretty easy, just needing the unit removing from its location, the point blades shortening a little and then a couple of straps soldering underneath the fix them in place before putting it back down.
I had time for a few test runs yesterday evening and it seems to be fine. I'll put some piccys over on my my redevelopment thread.
Re: Sprung point springs
Posted: Tue Jul 04, 2023 11:29 am
by ge_rik
philipy wrote: ↑Tue Jul 04, 2023 9:55 am
Well the springs that I ordered from Amazon were no good for what I wanted and the more I looked at the turnout that I wanted to use, the less convinced I was that springing it was actually a good idea. It is a bit stiff and although a heavy steam loco would probably go through OK, I'm less convinced that the little locos I use would be able to push against a spring.
So to cut a long story short, I reverted to Tony W's non-moving point blades, as suggested by Graeme a couple of days ago. Was actually pretty easy, just needing the unit removing from its location, the point blades shortening a little and then a couple of straps soldering underneath the fix them in place before putting it back down.
I had time for a few test runs yesterday evening and it seems to be fine. I'll put some piccys over on my my redevelopment thread.
That sounds like a neat solution. Be interested to see it
Rik
Re: Sprung point springs
Posted: Tue Jul 04, 2023 12:45 pm
by GTB
philipy wrote: ↑Tue Jul 04, 2023 9:55 am
It is a bit stiff and although a heavy steam loco would probably go through OK, I'm less convinced that the little locos I use would be able to push against a spring.
Thanks, that's why I've never gotten around to building and testing spring loaded turnouts.
I had definite doubts that a spring soft enough to allow a 250g gang motor to trail the points probably wouldn't be strong enough to reliably close the point blades and prevent an 8kg Garratt splitting the points when passing through in the facing direction.
Graeme