westernfan
Western Thunderer
For my next O gauge project I would like to build a traverser fiddle yard instead of a cassette type. Is there a ratio for the pivot point of the traverser ?
Sector Plates
- Thread starter westernfan
- Start date
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SteveO
Guest
You mean a sector plate? A traverser slides up and down, a sector plate rotates.
I would imagine you'd have to measure the weight of what's going to be on it at any one time, and what material it's going to be made of and how you're going to fix the pivot. Assuming we are indeed talking about sector plates and not traversers.
I would imagine you'd have to measure the weight of what's going to be on it at any one time, and what material it's going to be made of and how you're going to fix the pivot. Assuming we are indeed talking about sector plates and not traversers.
westernfan
Western Thunderer
Thanks . Yes thats the one, sector plate. I was going to make the bed with angle iron running down the edges to stop it bowing with those heavy heljans on it its where to put the pivot point, the length of the plate would be 4ft
Phill Dyson
Western Thunderer
Mine works fine 
.......It's in my garden thread 
.......It's in my garden thread 
BrushType4
Western Thunderer
I was thinking about a sector plate just today. I'm not sure if there is a mathematical answer, though I'm sure there is. I was going to take the practical approach and play with track and bits of wood until I got it.
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SteveO
Guest
No worries. The best place is always in the middle unless you support it on the longest side. If you have it off-centre it would be wise to introduce another set of supports, like this:
BrushType4
Western Thunderer
If you move the pivot towards the end, don't you increase the radius of the pivot so that the track coming off will be at a reduced angle?
That's assuming the sector plate was to feed parallel tracks...
That's assuming the sector plate was to feed parallel tracks...
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SteveO
Guest
That's right Phil, it's directly proportional to the pivot from the centre; if you sector plate had 10 degree movement on a centre pivot, it would have 5 degree movement with a pivot between the centre and the edge.
BrushType4
Western Thunderer
If I didn't need to turn stock or locomotives, I think I'd favour the pivot to one end so that the track alignment would be easier and less of a curve to get back to straight.
Osgood
Western Thunderer
I guess you could combine the two and have a sector plate pivoted (black) at one end with a 'just big enough' turntable (red pivot) built into it for turning locos or individual stock items?
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SteveO
Guest
That's nice. I developed an extended version of that for a scrapped 2mm project I was working on. It's a sector plate FY with a turntable in the middle. Lots of storage space plus turning facilities too.
http://www.rmweb.co.uk/community/index.php?/topic/52690-gillet-bay/?p=622775
Phill Dyson
Western Thunderer
My Sector plate is here http://www.westernthunder.co.uk/ind...rden-railway-the-withercombe-branch.31/page-3 .....post #60 onwards 
Dog Star
Western Thunderer
This is like Albion Quarry which is going to the York Show this year... with Peter and myself helping the owner Bob Alderman.
Stevesopwith
Western Thunderer
My Wantage Tramway fiddle yard has a double sector plate, with a common pivot. The whole thing is made from 10 mm birch ply, in two laminations to provide the Loco Plate recess and cross bearers, which rest and travel directly on the main baseboard. The pivot consists of a series of telescopic brass tubes and bushes, around 6mm in diameter, retained by a through bolt. Plate location is provided by a simple lifting brass pin which engages in bushed holes in the baseboard. Though it's very simple engineering, it's been well sanded, varnished to keep moisture out, and given a final coat of Mr Sheen. It has so far , ( 6- 8 months. ) remained stable and smooth in operation.
Electrical supply to the main plate is provided by the home made spring plungers and rubbing tracks, while the loco plate has brass rubbing strips bearing on PCB panels. The strips also ensure that the tracks remain in vertical and horizontal alignment.
The size has been determined by the very short locos and trains operating on this part of the line, but I imagine the structure could easily be extended to 4 feet without any problems.
Electrical supply to the main plate is provided by the home made spring plungers and rubbing tracks, while the loco plate has brass rubbing strips bearing on PCB panels. The strips also ensure that the tracks remain in vertical and horizontal alignment.
The size has been determined by the very short locos and trains operating on this part of the line, but I imagine the structure could easily be extended to 4 feet without any problems.
Dog Star
Western Thunderer
Very nice piece of work. To help us understand, how about a vertical section to show the different levels and the material thicknesses used for each level?
Oh, go on... a sketch will stop me getting a headacher from working out which piece is bushed etc..
regards, Graham
BTW - please convey my compliments to the Good Pup on the tracklaying... and ask him why there is a sizable gap in the sleepering to the RH track just beyond the engine release sector plate.
Stevesopwith
Western Thunderer
10 mm birch ply throughout, cut to various widths by the supplier. The main baseboard is set 20 mm, ( two laminations ) down from the adjoining board; thus allowing the levels required for the loco plate, and also the self aligning 'tongue' for the other end of the main sector plate. This feature makes it necessary to have a removeable pivot pin. I hope the diagram makes the design clear.... ask again if not.
The gap in the sleeper is the result of inadequate forward thinking by the design dept.
. An arbitrary sleeper spacing ended up with a sleeper at the optimum position for the uncoupling electro-magnet, whose pole can just be seen in the middle of the gap. Having established that the magnet works when flush with the baseboard top, the missing sleeper can eventually be fitted over it.
The gap in the sleeper is the result of inadequate forward thinking by the design dept.
. An arbitrary sleeper spacing ended up with a sleeper at the optimum position for the uncoupling electro-magnet, whose pole can just be seen in the middle of the gap. Having established that the magnet works when flush with the baseboard top, the missing sleeper can eventually be fitted over it.
Dog Star
Western Thunderer
It is not fair to assume that Sopwith-the-Pup knows anything about electromagnets so He cannot be held to be responsible!The gap in the sleeper is the result of inadequate forward thinking by the design dept.