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EASY FROGS - any angle, no tears.

I was asked the other day which jig(s) I used to file up my crossing noses so accurately. Well I know the mention of jigs and the like for such operations usually produces much wailing and gnashing of teeth so I quickly admitted to not using any. I explained how I did do it to my correspondent and then thought I may as well share my method here with you. I don't always use this method but it has served me well over many years. Regards, Brian.

Why don't my pictures fit in their space? Brian.

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Photos looking good to me, Brian!

 

Best, Pete.

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What an absolutely brilliant idea Brian.

 

I'll definately try that on my next batch of turnouts :)

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Brian, Presumably with FB Rail a little filing is required before bending, or not?

 

Best, Pete.

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Does the rail head and foot still show on the straight side all the way to the nose? - the underside of what is shown in photo 6? I was under the impression that this had to be filed away to leave a solid nose. Otherwise, a great idea!

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Does the rail head and foot still show on the straight side all the way to the nose? - the underside of what is shown in photo 6? I was under the impression that this had to be filed away to leave a solid nose. Otherwise, a great idea!

Hello Weekday Cross. I wondered who'd be the first to spot that one. I had wondered if to include how I get around this but thought it might confuse the principal idea. However now it's out in the open I can reveal that I actually bend both rails away from the node of the crossing so that the material to be filed away bisects the crossing angle, although very much biased to the premier route, usually the straight but not always. Filing both sides away as in pic 6, which shows only one side being done, retains the solid material under the nose. Thank you for your interest, Brian.

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Thanks Brian. I was going to hack your mobile phone/email/bank account or bribe the police to get the information, but then I thought - seems an honest sort of bloke - why not just ask him :pleasantry:

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Lol!

 

Yes, thanks Brian for taking the time to explain all this (with the photos and whatnot).....

 

Best, Pete.

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That's damned clever. Thanks for posting it :drinks:

 

Regards,

David.

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Brian, Presumably with FB Rail a little filing is required before bending, or not?

 

Best, Pete.

Hello Pete, yes as ever FB rail will have to have the foot seen to around the area in question to be able to do this. With P scales this always has to be done anyway as the foot/base is always too wide to get a scale flangeway gap as it is, Best, Brian.

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Brian

 

Could you just explain the measurement - is it just 8 'units' long by 1 'unit' high or more complex than this?

 

Thanks - GRW184

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Brian

 

Could you just explain the measurement - is it just 8 'units' long by 1 'unit' high or more complex than this?

 

Thanks - GRW184

Took me a while to understand points but yes, as I understand it, the 8:1 (or whatever) is literally the rate at which the two lines diverge per unit distance. So for a 8:1 they would diverge 1 inch for every 8 inches past the frog.

 

 

 

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Took me a while to understand points but yes, as I understand it, the 8:1 (or whatever) is literally the rate at which the two lines diverge per unit distance. So for a 8:1 they would diverge 1 inch for every 8 inches past the frog.

That's right. There are 2 ways of measuring it, called RAM and CLM. Here's some info copied from the Templot forum:

 

RAM = Right Angle Measure = Templot default and some Continental European prototypes:

 

ram_angle_diagram.png

 

RAM unit angles are traditionally used by modellers because they correspond with normal engineering practice and are easily set out with dividers -- all measurements are either along the rail or at right-angles to it. Templot uses RAM angles by default for this reason.

_________________

 

 

CLM = Centre Line Measure = most US and UK prototypes:

 

clm_angle_diagram.png

 

CLM measurements are made along an imaginary centre-line between the vee rails, and at right angles to that centre-line. Neither measurement is along the rail. It's easy to do on the ground with gauging tools which fit across the rails, but more difficult on a drawing board. CLM unit angles are used because the rules-of-thumb formulae which are used by the p.w. gang when setting out pointwork on the ground are simplified, and produce closer approximations to the true mathematical result.

 

Nowadays with everything done on computers there is no real need for unit angles, we could work directly in degrees or radians. But tradition dies hard and the unit numbers are brain-friendly and easy to remember.

 

To convert the unit angles to degrees, for unit angle N:

 

CLM degrees = 2 x ARCTAN ( 1 / ( 2 x N ) )

 

RAM degrees = ARCTAN ( 1 / N )

 

So for 1:5 crossings (#5 frogs):

 

CLM = 2 x ARCTAN(1/10) = 11deg 25min 16.27sec

RAM = ARCTAN(1/5) = 11deg 18min 35.76sec

 

Note that for increasing N (flatter angles) the difference between CLM and RAM diminishes.For modelling purposes the difference in angle is insignificant, but it makes a measurable difference to the lead length of a turnout. Try swapping from RAM to CLM in Templot to see the difference.

 

So for 1:10 crossings (#10 frogs):

 

CLM = 2 x ARCTAN(1/20) = 5deg 43min 29.32sec

RAM = ARCTAN(1/10) = 5deg 42min 38.14sec

 

I shall leave you to dab your own calculator for the rest! Or you can use this trick in Templot:

 

peg_ram_degrees.png

 

Set a straight turnout, shift it onto the datum so that the rails are horizontal on the screen. Press CTRL-4 twice, and on the info panel read the angle in degrees for the peg. To find a different angle, press CTRL-0 (zero), change the crossing angle as required and repeat the process.

 

regards,

 

Martin.

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That's right. There are 2 ways of measuring it, called RAM and CLM. Here's some info copied from the Templot forum:

 

RAM = Right Angle Measure = Templot default and some Continental European prototypes:

 

http://www.templot.com/forum_img/ram_angle_diagram.png

 

RAM unit angles are traditionally used by modellers because they correspond with normal engineering practice and are easily set out with dividers -- all measurements are either along the rail or at right-angles to it. Templot uses RAM angles by default for this reason.

_________________

 

 

CLM = Centre Line Measure = most US and UK prototypes:

 

http://www.templot.com/forum_img/clm_angle_diagram.png

 

CLM measurements are made along an imaginary centre-line between the vee rails, and at right angles to that centre-line. Neither measurement is along the rail. It's easy to do on the ground with gauging tools which fit across the rails, but more difficult on a drawing board. CLM unit angles are used because the rules-of-thumb formulae which are used by the p.w. gang when setting out pointwork on the ground are simplified, and produce closer approximations to the true mathematical result.

 

Nowadays with everything done on computers there is no real need for unit angles, we could work directly in degrees or radians. But tradition dies hard and the unit numbers are brain-friendly and easy to remember.

 

To convert the unit angles to degrees, for unit angle N:

 

CLM degrees = 2 x ARCTAN ( 1 / ( 2 x N ) )

 

RAM degrees = ARCTAN ( 1 / N )

 

So for 1:5 crossings (#5 frogs):

 

CLM = 2 x ARCTAN(1/10) = 11deg 25min 16.27sec

RAM = ARCTAN(1/5) = 11deg 18min 35.76sec

 

Note that for increasing N (flatter angles) the difference between CLM and RAM diminishes.For modelling purposes the difference in angle is insignificant, but it makes a measurable difference to the lead length of a turnout. Try swapping from RAM to CLM in Templot to see the difference.

 

So for 1:10 crossings (#10 frogs):

 

CLM = 2 x ARCTAN(1/20) = 5deg 43min 29.32sec

RAM = ARCTAN(1/10) = 5deg 42min 38.14sec

 

I shall leave you to dab your own calculator for the rest! Or you can use this trick in Templot:

 

http://www.templot.com/forum_img/peg_ram_degrees.png

 

Set a straight turnout, shift it onto the datum so that the rails are horizontal on the screen. Press CTRL-4 twice, and on the info panel read the angle in degrees for the peg. To find a different angle, press CTRL-0 (zero), change the crossing angle as required and repeat the process.

 

regards,

 

Martin.

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.

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Hoping to start building my first point soon and this frog technique looks nice and simple.

 

Brian, you mentioned bending more, do you mean you bend the straight rail ( in your photo) so the bit that gets filed off is above the line in picture 4?

 

Prejumably solder fills in any holes after filing?

 

 

 

 

Thanks

 

 

 

 

Kat

 

 

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Hoping to start building my first point soon and this frog technique looks nice and simple.

 

Brian, you mentioned bending more, do you mean you bend the straight rail ( in your photo) so the bit that gets filed off is above the line in picture 4?

 

Prejumably solder fills in any holes after filing?

 

 

 

 

Thanks

 

 

 

 

Kat

Yes I think that's probably what I meant. There's no substitute though for getting hold of a piece of rail and having a go-real hands on stuff-you will learn a lot more that way than you will ever learn from what you read on here. Ever read a book on how to ride a bike? Have a go, don't let anyone scare you off, it's not as difficult as it's made out to be. Good luck and let me know how you get on, Best wishes, Brian.

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Indeed, I know what you mean Brian. Even though I'm waiting on sleepers I am SO tempted to us a bit of scrap etch as temporary sleepers to have a go at a frog. Must say I'm so far really enjoying working with metal, find it much preferable to plastic (been doing some etched brass work and other odds and ends while waiting for trackwork).

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Indeed, I know what you mean Brian. Even though I'm waiting on sleepers I am SO tempted to us a bit of scrap etch as temporary sleepers to have a go at a frog. Must say I'm so far really enjoying working with metal, find it much preferable to plastic (been doing some etched brass work and other odds and ends while waiting for trackwork).

Yes Kat, go for it-you won't know how easy it is and how satisfying until you try, Best, Brian.

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Just had a go and works really well, end result wasn't perfect but that's no surprise - first attempt.

 

The main problems were all related to me using FB rail. Technically I should be using BH but FB is what I've got so it's what I'm using and it's not hugely noticeable in 3mm. Next one I do I'll file the inside of the rail near the fold and up to the frog flat because otherwise the flat section seems to like to 'ride' over it's partner causing the two rails to be slightly different levels.

 

Other than that - very easy and probably 10 mins a point.

 

 

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Fettled first one a bit, made second one went together much better :)

 

As my epileptic friend would say post fit "Itty Appy!!!"

 

 

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post-5773-0-11801600-1313435107_thumb.jpg

No it doesn't but it does need to be longer than you have it and with two angles, PM or Email me if you want details.

Regards

Keith

Hello John, I seem to remember something about you not having the correct lead in on your check rails on the replacement pointwork for Matford. Well rest assured there are others out there who build prototype trackwork who take no notice of the 'thou shalt do it this way' manual. Regards, Brian.

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Only just caught up with this thread - thanks for all the techniques and tips! Ive built points in P4, but to date only with prefabricated common crossings and ready planed switch blades. The extra cost of this for a test track was fine, and helped ease the transition into building trackwork, but I can definitely see the merits of doing the whole lot - especially if I ever get round to a larger project!

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Hello John, I seem to remember something about you not having the correct lead in on your check rails on the replacement pointwork for Matford. Well rest assured there are others out there who build prototype trackwork who take no notice of the 'thou shalt do it this way' manual. Regards, Brian.

Ah yes, of course in the world of railways you can find exceptions to every rule, and lots of alternative rules. But the original question concerned planed check rail flares on flat bottom track to what I assumed to be UK main line practice, hence the answer.

Regards

Keith

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