Building my new p4 layout

Help and advice for those starting in, or converting to P4 standards. A place to share modelling as a beginner in P4.
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grovenor-2685
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Re: Building my new p4 layout

Postby grovenor-2685 » Sun Feb 19, 2017 4:58 pm

They need to be filed at the crossing angle, 1:8, 1:7 or whatever.
Image
Image
Particularly important with FB to solder upside down in the jig so the heads are properly aligned against the strips although the foot will be overlapping.
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Keith
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Paul Willis
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Re: Building my new p4 layout

Postby Paul Willis » Sun Feb 19, 2017 7:23 pm

grovenor-2685 wrote:They need to be filed at the crossing angle, 1:8, 1:7 or whatever.
Image
Particularly important with FB to solder upside down in the jig so the heads are properly aligned against the strips although the foot will be overlapping.
regards


Keith beat me to mentioning the use of a jig...

This is the set of lashed-up jigs which I use for both checking the angle I am filing the point of the vee rail to, and also holding them at the correct angle when both are finished and I need to solder them together.

Crossing vee jigs.JPG


They are just made from a couple of sleepers glued on top of each other to give some depth, and then glued to an offcut of hardboard at the appropriate angle.

HTH
Flymo
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Julian Roberts
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Re: Building my new p4 layout

Postby Julian Roberts » Mon Feb 20, 2017 10:03 am

HI Thomas

I was starting this lark just over a year ago, so I am not yet long in the tooth as a pointmaker, but hopefully there won't be people saying this is misleading advice!

The wing rails bend is the inverse of exactly the same angle as the crossing V. There are lots of ways of doing this simple stage - I had a jig for making the V, so I used it to get the wing rails the correct angle too. With bullhead rail you just need to smartly bend the rail (holding the pliers at 90 degrees to the rail), but with FB you may need to make a nick in the foot - others will or have advised no doubt.



20151127_115655.jpg


20151127_115919.jpg


Then it's "just" (haha!) a matter of fixing the wing rails the correct alignment to the V and the correct distance from it, but that's a bit easier if you know the bend is correct before you start. The aim is as in the next photos, a straight run through the crossing for the wheel on both routes, with the wing rail the distance away from the V as given by the flangeway gauge, though the curve of the turnout may start immediately after, depending on what sort it is.

2017-01-11 14.21.07.jpg


2017-01-11 14.21.24.jpg
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Colin Parks

Re: Building my new p4 layout

Postby Colin Parks » Mon Feb 20, 2017 10:53 pm

Hi Thomas,

I have not made many P4 turnouts and none to completion yet, so I could be wrong, but several practical observations come to mind here. Firstly it is quite difficult to use a template drawn for bullhead rail combined with flat bottom rail - you just lose sight of the position of the rail head, it being obscured by the wider flat bottom rail foot. Secondly, as effective as the Brian Harrap 'folded' crossing vee method is for bullhead rail, it just cannot work with flat bottom rail unless the rail foot on the inside of the fold is removed enough to be flush with the rail head.

On the subject of removal of the rail foot on flat bottom railed track, portions of the foot will have to be removed to allow the wing rails to come close enough to the crossing vee to give the correct flangeway gauge. Similarly, the check rails will also need to have the inner edge of the rail foot thinned to bring the check rails close enough to the stock rails to keep the gauge within limits at that point.

From recent personal experience, construction of turnouts using flat bottom rail is not quite the same as with bullhead. Lastly, I have not found the need to nick the rails to from knuckles in flat bottom rail, but the bending process was done with the rail clamped firmly in a small vice, allowing the rail to be bent to shape without producing a defined sharp angle. For inspiration on fashioning crossing vees, you could do no better than to refer to Howard Bolton's article in S4News 194. It covers quite a lot of information on common crossing construction applicable to both types of rail and switch fabrication too.

Colin (Edited to correct S4News number. Stretcher bars are discussed in S4News 181.)

Terry Bendall
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Re: Building my new p4 layout

Postby Terry Bendall » Thu Feb 23, 2017 7:43 am

Colin Parks wrote:Firstly it is quite difficult to use a template drawn for bullhead rail combined with flat bottom rail - you just lose sight of the position of the rail head, it being obscured by the wider flat bottom rail foot. Secondly, as effective as the Brian Harrap 'folded' crossing vee method is for bullhead rail, it just cannot work with flat bottom rail unless the rail foot on the inside of the fold is removed enough to be flush with the rail head.


One solution is to use the flat bottom turnout kits available from Colin Craig see http://colincraig4mm.co.uk/ . These are similar in style to the Exactoscale kits with bullhead rail with all the key parts machined and the common crossing made up. If you ask Colin may sell you the crossing only and he might be able to supply the templates needed.

Terry Bendall

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Winander
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Re: Building my new p4 layout

Postby Winander » Sun Feb 26, 2017 11:23 am

Tom,

You may find this discussion useful, although it is for bullhead rail, it shows how to fashion a vee crossing using the jigs.

viewtopic.php?f=5&t=1914&p=21893#p21893

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Julian Roberts
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Re: Building my new p4 layout

Postby Julian Roberts » Sat Mar 11, 2017 11:24 am

Hi Tom I hope your project is going well.

I happened to come across this yesterday, written by Brian Harrap one of the most experienced of modellers

http://www.rmweb.co.uk/community/index. ... k/page-2?&


All very well I'm sure but I think the reason that Mr blueeighties and so many others are having trouble with their wheelsets binding just slightly on their 'curved' route is because of the natural tendency when constructing a model turnout to position the frog knuckles opposite one another on a plane that is along the 'straight' route. Placing knuckles opposite one another at 90deg to the bisecting angle of the frog circumvents this binding or clipping of the straight knuckle on the curved route and also allows for the increased angle of attack of the flange on the diverging route on LWB vehicles especially. Has always worked for me and I think it looks better. If anyone thinks this is a load of twaddle please carry on in your own way. Regards, Brian



The look of the knuckle was something that bothered me and the above advice which I had not seen anywhere would have saved me the bother of restarting my first few wing rail assemblies!

If your flangeway gauge can sit in the crossing as I showed earlier you shouldn't have any running problem and it will probably look as Brian has described.

There is all sorts of advice on the Forum on various issues in track and pointmaking. I would suggest that investing in the set of C&L roller gauges is invaluable in checking your track is not undergauge anywhere. A tad overgauge does no harm but derailments are most often caused by undergauge issues particularly at the switch area.


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