Point building help please

[Pugsley]

I've got to the stage where I'm about to start fitting the tiebars to the points I've been building and I need to set the gap between the back of the open switch blade and the rails passing through, but I can't find the dimension anywhere.

 

How big does the gap need to be for EM please? Does it need to be flangeway width of 1mm, or does it need to be slightly wider?

 

TIA

[Gordon A]

Hi Martin,

 

1mm sounds fine.

However you can check the distance by placing a set of wheels that have been set up using a back to back gauge, on the track, pushed hard over to one side.

Then measure the distance from the back of the wheel that is furthest from its inner rail face, to the rail face

 

The switch blade needs to travel at least that distance.

 

Depending on the wheel and track standards used, a small amount may be needed to be added to the distance travelled by the switch blade. This to allow for any twisting, or sideways movement by the stock when it is being propelled through the points in the facing direction.

 

The travel on the prototype ranges from 3.75" for GWR joggled switches to 4.25 inches for NER straight cut switches.

 

 

There should be other members who from experience can give you a specific dimension that they find works.

 

This is a bit long winded, but I hope of some help.

 

Gordon

 

 

[Pugsley]

Thanks for the replies chaps - looks like it'll be flangeway gap plus an, ever so technical, smidge then.

 

Cheers :icon_thumbsup2:

[Cock Sparra]

Hi

 

If memory serves me BR switch back to stock rail gap is 4 1/2 inches which in 4mm translates to 1.5mm

 

GW switches were 6 inches which is 2mm.

 

HTH

 

Cheers Phil

[craigwelsh]

Its a flangeway gap at the other end of the planing from the toe of the switch rails I believe.

 

See the picture at the top of this thread where you can quite clearly see the extend of the planing on the open blade and how it gets wider to the tip from there http://www.templot.com/forum/view_topic.php?id=491

[Pugsley]

Thanks again chaps - the tiebars are curing as I type this, so I'll try it out on one and see how it goes.

[Colin_McLeod]

I have one point on a curve and because of the centrifugal forces acting on the rolling stock, I had to increase the movement of the tie bar in this particular case to prevent the wheels taking the "wrong road" when set for the inner radius.

[Russ (mines a pint)]

I winged it and guessed, and it worked, sorry thats not a helpful answer I know, but thanks to 'Cock Sparra' going to use 1.5mm in future!

[Mallard60022]

I winged it and guessed, and it worked, sorry thats not a helpful answer I know, but thanks to 'Cock Sparra' going to use 1.5mm in future!

 

For OO and (probably) EM the good old piece of copperclad is about right for flangeway spacing (& switch,wing/vee & check rail gaps). A very well known professional track builder suggested to me that I make a little jig using two vertical pieces (each about 20mm length) of cc attached to a short horizontal piece (about 40mm length). You drop the two vertical bits in between the rails and then do whatever it is you need (glue, solder etc.) whilst the rails are 'clamped' with hair clips or similar! Seems to work fine. (I've actually used wooden sleeper timbering from the EMGS for some 'spacing' on EM points I've made. It's a tad thinner than cc and possibly makes the EM spacing better looking?) A lot also depends on you average back to back or flange to flange widths. If you adjust all rolling stock to a good 'standard' for your gauge (can't remember off hand what the recommended standards are), running will be improved. Loco's are often more tricky to adjust without a faff.

ATB 36E

[Russ (mines a pint)]

For OO and (probably) EM the good old piece of copperclad is about right for flangeway spacing (& switch,wing/vee & check rail gaps). A very well known professional track builder suggested to me that I make a little jig using two vertical pieces (each about 20mm length) of cc attached to a short horizontal piece (about 40mm length). You drop the two vertical bits in between the rails and then do whatever it is you need (glue, solder etc.) whilst the rails are 'clamped' with hair clips or similar! Seems to work fine. (I've actually used wooden sleeper timbering from the EMGS for some 'spacing' on EM points I've made. It's a tad thinner than cc and possibly makes the EM spacing better looking?) A lot also depends on you average back to back or flange to flange widths. If you adjust all rolling stock to a good 'standard' for your gauge (can't remember off hand what the recommended standards are), running will be improved. Loco's are often more tricky to adjust without a faff.

ATB 36E

Indeed seem to remember using a piece of copperclad on my first points to set this gap, largely on the reasoning that it (the cc) would be wider than any loco flanges- it worked but no scientific basis other than that!