Laying Exactoscale Chairs

[paratom]

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  I am about to embark on building an EM gauge layout and have been gathering as much information as possible with regards to track building. I will be using Exactoscale code 75 bullhead rail with four bolt chairs. I have been looking at several forums on track building and came across an article in the scalefour forum by David Thorpe regarding track laying. The track gauges the EM society supplied me were a mixture with some by DCC Concepts. I was not aware that you should use Exactoscale gauges with exact scale chairs because the chairs sit on the sleepers at a slight angle or are we only talking about P4 here. I would be grateful if any modellers out there could clarify if I should be concerned over this matter. Here is what David Thorpe said.
  “Without wishing to worry you, do make sure that you are using an appropriate track gauge when laying track using Exactoscale chairs. The reason is that these chairs hold the rail at a prototypical angle, with the top of the rail canting slightly in. If you use a gauge (as I did) that holds the rail straight up and then put a weight on it to hold it in place while the MEK sets (as I did!) you may find that when you remove the gauge the rail will gradually begin to cant inwards, leading to gauge narrowing. I had to carry pout a lot of remedial work to several sets of points because of this. It seems that you need a gauge such as an Exactoscale roller one that only holds the top of the rail. If the gauge holds both the top of the rail and the foot, as some do (including, I believe, the Society ones), then after removal the chairs may relax, leading to gauge narrowing.”
  
  
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[Boyblunder]

Not sure if this post got any answers elsewhere? I know 'nuffin about almost everything, however brief amateurish experience with Scale 7 track building confirms that laying rails using properly angled chairs will result in narrow gauge if you use a parallel cut roller gauge. This issue caused several problems for the Love Lane group and I'm not sure we came up with a really good solution for curved sections. Someone provided a flat gauge with shallow milled grooves for straight track which is perfect. Roller gauges with deep grooves machined at an angle should work but are hard to remove when the glue has set because the rails have to bend to release it. We talked about machining flats on ends to allow release, can't recall if anyone ever tried it?

 

[Eastsidepilot]

Exactoscale chairs do cant the rail and ideally a gauge that is over size would be useful, don't know about EM but in S7 ( 33mm gauge ) I'd suggest 33.75 mm for a track gauge which might let the track settle back to 33 mm.
We do have oversize gauges for track gauge widening on curves so maybe one of these would be the thing to use.

EM is 18mm so maybe try a 18.5 mm gauge ? . Maybe a trial and error job.

Edit. EM is 18.2mm so maybe 18 .7mm would work ?

Col.

 

[Mike Trice]

EM is 18mm....

From memory the EM Gauge Society currently use 18.2mm.

 

[Eastsidepilot]

From memory the EM Gauge Society currently use 18.2mm.

Mike I stand corrected ...not having worked in EM I was making a poor assumption

Col.

 

[JimG]

When I was Parts Officer in the S Scale Society I machined some track gauges for stock and I used 3/16" square brass bar and machined one side to provide channels for the rail head. The channels were 0.6mm deep and just over 1mm wide to accept the head of the SSMRS Code 87 bullhead rail. With the slight amount of play in the channels to allow easy placing on the rail head, the inclination of the rail could be accommodated and there was no problem with the rail being held vertical in the Society chairs which had inclined seats for rails. So if the gauge has channels deep enough to reach the base of the rail, reduce its depth so that it is only deep enough to fit on the head of the rail. And a bit of relief on the ends of the channels with a needle file could help matters as well without affecting the actual gauging of the rail.

Jim.

 

[Dog Star]

I use the roller gauges from the Scaleseven Group... these gauges are built up around a central spacer for the track gauge plus outer washers to hold the rail. There are two washers at each end of the gauge, the inner washer abuts the running face of the rail and the outer (sprung) washer holds the rail against (one end of) the central washer/spacer/washer assembly.

The late Paul Penn-Sayers modified my gauges to accomodate the cant of the rail, he replaced the parallel-faced outer washer with washers that had a taper to match the cant. Changing only the outer washers provided a tapered groove to the gauge.

regards, Graham

 

[simond]

if anyone wants roller gauges, let me know, we can make them to drawing, pretty much any sensible size you want.

Obviously, they won't be free...

 

[pcalkel]

The Scale 7 Stores sell a 33mm roller gauge which has the outside faces at the 1 in 20 angle to accommodate the cant of the chairs on the rail.

 

[OzzyO]

I've just reread this thread about laying Exactoscale chairs. If you do have a gauge that reaches to the bottom of the rail you could (will) have a problem with gauge narrowing to the extent of 0.159 mm (0.00626") so that over the track gauge that would be 0.378mm (0.01252"). So if you were using 32mm as your track gauge not a problem. But if you were using 31.5mm as you track gauge on plain track you should be OK but in the area of point vees you could have problems. If you were using 33mm as your track gauge I think that you could have problems on plain track and would definitely have problems around the point vees.

So in my limited time building track I would say that a gauge that only holds the head of the rail is better and one that holds the rail at the 1:20 will be the best that you can get. But let us not forget that the depth of the rail head is approx. 1mm so the cant in is approx. 0.05mm (0.002").

I'll let you all think about this,

OzzyO.

 

[Tim Humphreys ex Mudhen]

OzzyO,

The Guild stores now sells a 32mm gauge which holds the rail at 1:20.

atb
Tim

 

[richard carr]

If you are laying straight track or modest radius curves then there is nothing to worry to about with using a plain roller type gauge, everything will run just fine, it certainly does in S7.
If you are laying a tight radius curve I would advise you to use triangular gauges that will automatically give you some gauge widening, I'm sure the EM gauge society must sell some.

Richard