Making HO turnouts

Flexible point rails don't work very well under about a #7 turnout in my experience. I started building #8 minimums and it works better. The #10s flex nicely.

I've had rails pop off the throwbar, so I started using silver solder for that. Now after having had the aforesaid two #10 turnouts' point rails tear the copper foil loose, that what's I'm going to do. Just strip the foil off the PC board and screw/bolt/rivet a point rail-and-plate assembly down to it.

FWIW I have some ooooold Shinohara turnouts (my father's; at least 40 years old). Their approach then was to make a rigid point rail assembly that swiveled from the frog end. A brass strip at each end held the rails in gauge. One rivet in the center of that provided the pivot point. A very intelligent design.

Jay CNS&M North Shore Line - "First and fastest"

Do the point rails on the prototype turnouts flex? How do they make the points for the prototypes?

The solid connection between throw bar and point rails makes the whole assembly less flexible. A movable connection to the throw bar works much better. One way is to solder small pieces of wire to the point rails, drill the throw bar for the two wires, insert the wires into the holes and bend the wires on the underside to secure the throw bar.

You can see the principle in

I'm sorry it's in German but there are som rather good drawings that explains it nicely. Figs. 8 and 9 show the point rail and fig. 10 shows how the wire is soldered to the point rail.

I have tried this method on a speciel pair of N scale code 55 turnouts with a 290mm radius continous curve, using 0.4mm phosphor bronce wire. It works quite well.

No

On all of the actual turnouts I've looked at, the points are separate rails attached to the frog toe rails by special "fishplates" which are "loose" at the points end to allow the points to pivot from side to side. GQ

One club I frequented many years ago used some of the TruScale turnouts, and I've obtained some over the years in collections. They work pretty well as a new prefab turnout, but I recall there were problems as they aged. The issue is that they depend on having both the points and the moving frog rails contact the mating rails at the same time and with about the same pressure. It was easy to keep the points in contact with over throw spring arrangements, but the frog contact depended on no bending of the moving assembly rails or loosening of the pivot, and these could not be prevented.

When I hand lay a turnout, I start with the straight closure rail, then the frog heel rails, then the curved closure rails, then finish the frog with its toe rails, then the points and finally the guard rails. This lets the track "flow" most smoothly through the turnout, which is a major advantage of hand laid track. Using this approach in hand laying a TruScale type turnout would lead to installing the frog/point rotating assembly as a last step after the four closure and frog heel rails are installed. I think it would be difficult to get a bench assembled moving assembly into correct alignment of point and frog contact and gauge of the moving rails. These could be obtained by assembling the moving assembly in place, but I think that too would be difficult. (By difficult, I mean more difficult than the equivalent steps in hand laying conventional turnouts.)

Another disadvantage is appearance. The TruScale turnouts just don't look real. I never saw anyone successfully disguise the large central pivot plate in the moving assembly.

I believe it is these long term reliability issues that led to the death of this design on the market, and the assembly difficulties that result in the dearth of construction articles for TruScale type turnouts. GQ

Perhaps in the US but British practice was to flex the point rail.

Thanks for your answers. I may need to go back to the bench and try working with rail on pc strips and see what I can "turn out" after reviewing all the points.

Ed

If your local hobby shop doesn't have them try:

They have taps and screws in 00-90, and all manner of other stuff you probably didn't know you needed. I'm not connected to them, but have ordered from them and found them fast and reliable.

[ Snip ]

I'm getting an incomplete picture here. If you build the switch with a solid metal frog, the points will be shorted through the frog whether or not you cut the PC board foil. Do you isolate the points from the frog somehow?

There are similar metric sizes that should also work, but they are much harder to find in the USA.

Still smaller sizes, but much harder to find are 000-120 and 0000-160. These are VERY delicate.

Kadee, the coupler manufacturer, sells packs with a tap and matching tap drill in their regular coupler line, appropriate for mounting their couplers. The smallest, IIRC, is 0-80 ... these would work for the switch tie bars, but are a little larger than needed.

A hobby shop (or yourself) can order any of the above items down to

00-90 size from Walthers, among other sources.

Any good commercial fastener supplier should have screws this size as well, but they often want to sell at least 100 at a time. Machine shop suppliers should have GOOD taps this size (but they are more expensive, and not always needed for occasional hobby use).

As for the PC board, the e-g type is usually a gray or greenish color, with whitish strands (of glass fiber) imbedded in it. The phenolic is usually a brown or tan color, and shows a sort of layered or flaky appearance where cut or snapped off. E-g is much more expensive to buy, but can often be found cheap at surplus suppliers. Clover house either makes, or made, e-g pre-cut CB ties, and these can be used for the tiebars as well. One reservation is that they are fairly narrow, and using too large a screw for the pivots may weaken them more than desired.

Good luck,

Dan Mitchell =========

Lungshot1 wrote:

Close. Actually it's the frog that must be isolated from the rest of the switch, since it MUST change polarity when the switch throws. The only other possibility, as is done on cheap switches, is to use a plastic frog that carries no electricity.

The two point rails should each be permanently connected, electrically, to their adjoining wing rails. This eliminates a lot of the shorting problems found with solid (coupled) point switches like the old Sinohara ones. There the two point rails were always connected electrically (sometimes formed from one piece of metal). This meant that one of the point rails was always of OPPOSITE polarity with it's adjoining wing rail. That causes short circuit problems, especially with wheelsets that are a little narrow in gauge. these are known as "DCC UN-friendly" switches, though actually they are a problem with DC systems as well.

What makes a "DCC friendly" switch is a better switch for DC as well. Many who hand lay switches have been using this design for MANY years, long before DCC was ever thought of.

Dan Mitchell ==========

snipped-for-privacy@mtholyoke.edu wrote:

Micro-Trains (Kadee's N scale equivalent) sells 00-90 screws and taps.

My local Ace Hardware stocks Walthers screws. Not sure about the taps. I haven't needed one lately.

1) Cut a new plate around the saw blade that has zero clearance (use wood and raise the blade through it; have the blade rotating the proper direction). 2) Take a plywood table saw blade and turn it so it's rotating "backward". 3) Set the rip fence to the desired width. 4) Start cutting. 5) Watch out for your fingers! The smallest I can safely get the board down to is about 2" X 2".

Using my method, the board will tend to ride up and over the saw blade. Gently forcing it down will curb this tendency.

Jay CNS&M North Shore Line - "First and fastest"

Yes, a pair of gaps towards the frog will isolate the frog itself from the points. Since I make the frogs (and the other parts of the turnout except for the stock rails) on the bench rather than out on the layout where it is a lot more difficult, I can set each part of the turnout to a particular dimension and then just set them in line at the location of the turnout.

-- Bob May Losing weight is easy! If you ever want to lose weight, eat and drink less. Works every time it is tried!

PC board ties should only be about 1/8" wide. A smaller (model sized) table saw can cut down smaller than 2" with some safety, though a shear is probably the best way to cut the board. All PC board, especially the epoxy-glass kind, is VERY abrasive and will quickly dull saws and knives (10% of the time it takes sawing even very hard wood or most soft metals). You have to consider the blades to be somewhat expendable. They'll last a while, but eventually either have to be resharpened or junked.

'Score and snap' just doesn't work reliably for such narrow strips. They tend to crack all the way through and delaminate.

Someone suggested water jet or laser cutting a while back. That would be ideal, but it's beyond the resources of most of us. Perhaps you can find a friendly local business that might do such work in their 'off' time for a reasonable cost.

Just saw 'em and say 'RATS' when the saw dulls.

Dan Mitchell ==========

JCun>

Actually Harbor Freight has a tile cutter for about 12 bucks. Lever action and a friend bought one and says it does just fine for epoxy-glass boards. Almost as cheap as a saw blade and a lot safer.

I use a small Ryobi band saw to cut PCB and wood down to about 1.5 mm square ( scale 4 x 4 ) Essential to make a zero clearance insert instead of the standard large gap as supplied, and to use a fence.

Also do not try to use every last scrap of PCB or wood, I usually leave 30mm as waste, it can be used for some other project, that way you end up with intact fingers. Waste is better than medical bills.

My big bandsaw is much too coarse for this fine work but is good for cutting blocks and framework for the layout.

Alan in beautiful Golden Bay, Western Oz, South 32.25.42, East 115.45.44 GMT+8 VK6 YAB ICQ 6581610 to reply, change oz to au in address