Turntables

Started by BlythStationLad, April 13, 2012, 03:38:28 PM

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BlythStationLad

Help! I need to scratchbuild a 50' turntable for my DCC layout of Blyth, Northumberland. It will only have one track leading to/from it.

Does anyone have any advice on how to do it? Of particular concern for me are:

1. Getting the 100mm or so hole for the turntable well cut precisely (through 12mm MDF...)
2. Curving the circular rail to an accurate shape
3. Powering the turntable track for DCC simply
4. Operating the turntable. Obviously it will only need to turn 180 degress at a time, and I'd prefer a mechanical means rather than electrical. Has anyone tried the Meccano-type system promoted by Frizinghall?

Thanks in advance for any help!

davieb

hi there  :wave:

not got a clue about the first three questions  ???

but regarding your last question about operating the turntable

at preston exhibition this year PLD of this parish was there with "hoglington" and IIRC that had a hand turned turntable

so you could try sending him a PM with your question as i'm pretty sure he will be only too willing to help you out

dave  :thumbsup:

Oldman

Answers as below.
Hole : Homebase/Wickes etc for a holesaw, close to a 4" pipe so maybe something suitable
In the plumbing dept..
See my turntable pics in Lyne End.  Was a nightmare to sort out.
Modelling stupid small scale using T gauge track and IDl induction track. Still have  N gauge but not the space( Japanese Trams) Excuse spelling errors please, posting on mobile phone

Tank

As said above, you'll need a holesaw and arbour to fit into a drill.  Screwfix do an adjustable one for £50 which will give you the 100mm, or for £30 you can get a 111mm holesaw.  Ebay do them a LOT cheaper, and I'd presume they'd be cheaper quality, but fine for a singe cut.

Also, you can get 100mm Forstner bits for your drill.

PLD

#4
Quote from: davieb on April 13, 2012, 04:08:21 PM
at preston exhibition this year PLD of this parish was there with "hoglington" and IIRC that had a hand turned turntable

Indeed we were Dave.  :wave:

The turntable on Hoglington uses the pre-formed well from a Peco kit and some parts of the deck... for that the hole in the baseboard doesn't have to be exact nor even a perfect circle, as long is it isn't undersized. (iirc we did it approximate with a jigsaw then filed back any areas that needed it!). I'd suggest you build the well seperately off site and then fit to the board when completed.

We used the hand operated version of the Frizinghall kit. The only major issue was slipping of the gears on the shafts, which was sorted by filing flats on the shafts where the gears sit so the grub-screws get a better grip.

Powering for DCC should be exactly the same as for DC. You need to switch the polarity of the rails on the deck when it turns half way round. The Peco well has two brass semi-circular contact strips in the bottom which you wire permanently to the apropriate rail of the approach track. The deck then has plunger type contacts that run on those to transfer the power to the deck. I know of a couple of scratch built examples in larger scales that use the same principle but using the well rail for the contact strip.

Hope this helps...

Paul

BlythStationLad

Many thanks to everyone for all the advice. Food for thought!

EtchedPixels

Quote from: PLD on April 14, 2012, 08:45:42 AM
Powering for DCC should be exactly the same as for DC. You need to switch the polarity of the rails on the deck when it turns half way round.

For DCC you can also use a DCC reversing loop/frog autoswitching unit and let that sort things out for you.

"Knowledge has no value or use for the solitary owner: to be enjoyed it must be communicated" -- Charles Pratt, 1st Earl Camden

longbridge

I usually mark out the hole then cut it out with a Jigsaw with a fine blade, used to use a keyhole saw years ago.
Keep on Smiling
Dave.

Zunnan

Remember to cut the hole slightly oversized or build the deck slightly undersized. A 100mm hole when the well material itself has been inserted will be closer to 97mm in diameter if its a snug fit. Even if you directly fix paper to the inside edge of the cut MDF it will mean a 100mm deck will probably not fit. An oversized tank cutter would be my preference and then build the well with an overlap to cover the gap around it.

Forming the rail is easy, once you have a (perfectly) circular well formed produce a simple jig to hold the rail a set distancefrom the well wall while it is fixed in position. When the rail is fixed at that spot you simply move the jig round a few degrees and repeat the rail fixing, move and fix, move and fix etc.
Like a Phoenix from the ashes...morelike a rotten old Dog Bone


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