Point Operation

[Darren0269]

What's is the preferred method of operating a kit built point? I'll be using a tortoise motor to power it - what are your thoughts on how to connect the motor arm to the point? A PCB strip with soldered pins to the point blades are one idea but don't look great. I've also tried the available wire tie bar (with the insulated centres) but again attaching the tie bar to the motor arm what's the best approach?
thanks
Darren

[Paul Willis]

What's is the preferred method of operating a kit built point? I'll be using a tortoise motor to power it - what are your thoughts on how to connect the motor arm to the point? A PCB strip with soldered pins to the point blades are one idea but don't look great. I've also tried the available wire tie bar (with the insulated centres) but again attaching the tie bar to the motor arm what's the best approach?
thanks
Darren

Hi Darren,

That's a good question that you ask. It's also one of the areas where there are a number of different solutions, so I'm sure that you will have a number of suggestions. That gives you the opportunity to choose whatever you feel suits best, based on time/cost/complexity.

To start things off, there are a number of posts on my Beer and Buckjumpers thread about how I built some Turnout Operating Units and fitted them to a demo board. You'll find it at http://www.scalefour.org/forum/viewtopic.php?f=90&t=425&p=13048&hilit=tou#p13048

As you mention Tortoises, Chris Mitton followed with a post that specifically uses them. http://www.scalefour.org/forum/viewtopic.php?f=90&t=425&p=13119&hilit=tou#p13119

At the time, I was using the insulated wire tiebar above the surface to keep the blades the correct distance apart and the TOU to drive it below the surface.

I've since become severely disenchanted with the wire tiebars, and I'm now using the Masokits ones:

Masokits tiebars assembled.JPG

Despite Masokits having a reputation for being a little fiddly, I found these straightforward to assemble, realistic-looking, and more than robust for the job. Highly recommended.

I hope that this gives you some ideas to start with.
Cheers
Flymo

[David Thorpe]

Another vote for the Masokit tiebars from me (I use them with both Tortoise and Cobalt point motors).

DT

[dal-t]

Hi Flymo,

Are you still using your TOUs with the Masokits tie-bars? I've just stocked up with square tube and was about to copy your solution, so it would be good to know if you've found any problems with it.

For Darren: I agree absolutely with Flymo that this is a "What colour of jumper do you wear?" question, and there are a number of perfectly fine solutions, it all depends on what suits you. I have used the PCB and pins solution extensively and you're right, it doesn't look great, but it has the advantages of being pretty robust and relatively easy to install, and mend if need be. Personally, for my new test track I just wanted a change of outfit, so decided to try Flymo's style of TOUs (but with manual operation). However, if there is a better way, I'm open to adopting it, so it's always worth listening to other people's preferences (unless it's bright pink with a yellow motif ...).

[grovenor-2685]

The Masokits etc tie bars are nice for the cosmetics but don't sort out the Tortoise. Exactoscale do Tortoise mounts for their kits that provide the facility to transfer the drive from below the board. They are designed to fit the Tortoise but I have found them useful with other drives as well.
An alternative way to transfer the drive if you would like a scale crank above the board is to use an Ambis 'PALM' unit. Not easy to drive with a Tortoise though but works well with Servo motors.
Regards

[Jol Wilkinson]

I use the Masokits tie bars with Tortoise and Cobalt motors. I form a 1.5 - 2.0 mm loop in a piece of .5mm brass wire that is just overlength to fit into the two "lugs" on the tiebar (these are originally intended to take a drive rod). This is soldered in place and driven by the drive wire from the point motor which is mounted under the tie bar location. The wire passes up through a simple slot in the baseboard. I believe this approach is also used on Mike Norriss's large P4 Preston layout

This is quite unobtrusive and allows for the addition of cosmetic point levers, rodding, etc.

I also add a second tie bar (as per prototype). For this I use an Ambis tie bar which are slightly more flexible than the Masokits but I solder at one end only to reduce any "strain" on the components.

C&L also sold an Exactoscale TOU of the "traditional" type that uses two droppers to drive each switch rail and is designed to mount the Tortoise onto the base. Looking for a link, I found the reference number EAXX TAP0, but is currently listed as "Not in stock".

[Paul Willis]

Hi Flymo,

Are you still using your TOUs with the Masokits tie-bars? I've just stocked up with square tube and was about to copy your solution, so it would be good to know if you've found any problems with it.

Yes, they still seem to be robust and doing the job.

The turnouts, on the other hand, have been subject to earthquakes, famine and pestilence. Or in 4mm terms, dropped boards, loose joints and severe rusting

A rebuild of them is currently in progress, but the under-baseboard mechanisms will all remain the same.

Cheers
Flymo

[Darren0269]

Thanks for your replies - will give the Masokits ties a go
Darren.

[Paul Willis]

Thanks for your replies - will give the Masokits ties a go
Darren.

If you find yourself stuck, just ask here - I'm sure that it won't be too long before you have advice shared with you.

The one tip for me includes the very early stages. You have to cut a very thin (2mm width IIRC) strip of the copper clad provided.

I score it with a sharp scalpel held against a steel rule. This takes ages! As in five minutes or so of gentle scoring. Don't try and rush this, or you'll slip with the blade, ruin the part and have to start again.

The instructions are very good. Follow them carefully and it will all work really well

HTH
Flymo

[Terry Bendall]

The Masokits etc tie bars are nice for the cosmetics but don't sort out the Tortoise. .... An alternative way to transfer the drive if you would like a scale crank above the board ... .

I have used the Masokits stretcher bars very successfully on Ravenscroft Sidings and Elcot Road and in conjunction with a scale crank above the baseboard. The crank is on the end of a piece of 3mm dia rod turned down to fit in the crank which goes through the baseboard. This rod is driven by a crank linkage from the Tortoise point motor, again quite large and the usual drive wire on the motor is replaced with a lever made from 10mm x 3mm metal strip. Everything is very robust and because the drive cranks are fixed with grub screws on the 3mm rod, adjustments are done by loosening the screw, moving the crank as required and then tightening again.

Terry Bendall

[junctionmad]

I use Ambis stretcher bars, glued to glass epoxy strips to provide electrical isolation . I then drive the blades separately via bent pins that go through the baseboard to the TOU,

my TOU is a piece of caravan curtain track ( slientGliss 1025) , with a tufnol insert and two vertical brass tubes that locate into the blade drive pins. Its a common solution , drive is via bar and omega loop to associated servo. The beauty of servos is final mechanical positioning can be done electronically

My new baseboards are ( will be) foam core epoxy bonded and about 100mm thick, with 5mm ply each side, Im not sure yet if the TOU I used, will reach up 100mm+ , there could be a degree of lost motion , due to the vertical distance and the rigidity of the brass tubes ( I will switch to NS tubes I think anyway )

[DougN]

Flymo I have successfully used a piercing saw to cut strips of the very fine copper clad. One issue is you can go through blades due to blunting.

I have made my own tie bars due to Masokits being difficult for me to figure out. I have used a strip of the fine copper clad with the isolation cuts in the copper off to one side and slightly off set. I then use a peice of .45 brass wire bent into a U but the curved end bent through 90 degrees so it will tightly fit into the foot of the rail and the legs clipped around the copper clad as per the below sketch This allows the drive to be relocated to anywhere it needs to be... this can be as simple as a loop of wire off to one side or the other or in the middle.

Untitled.jpg

[Terry Bendall]

I have made my own tie bars

A neat idea.

One issue is you can go through blades due to blunting.

My solution to this problem is to cut the board with a hacksaw or junior hacksaw using a good quality blade. On thicket board a standard hacksaw fitted with a high speed steel blade will resist blunting since the blade is hard. Not quite so easy with a junior hacksaw since I don't think HSS blades are available. For the thin board that might be used for this application I score it with a scriber and snap it.

Terry Bendall

[steve howe]

[quote="Jol Wilkinson"]I use the Masokits tie bars with Tortoise and Cobalt motors. I form a 1.5 - 2.0 mm loop in a piece of .5mm brass wire that is just overlength to fit into the two "lugs" on the tiebar (these are originally intended to take a drive rod). This is soldered in place and driven by the drive wire from the point motor which is mounted under the tie bar location. The wire passes up through a simple slot in the baseboard. quote]

I am looking at Cobalt motors to drive the four turnouts on my current Plank, having found fundamental flaws in my home-made slow action devices. I too use the Masokits tiebars and have found them very reliable and fairly easy to make. I like the sound of Jol's loop in the operating wire engaging with the motor rod underneath. Jol mentions a 'simple slot' under the tiebar, but my problem is, and I'm sure others have found this when 'retro fittting' things, my points are already laid and have been for some time. It suggests drilling a suitable hole dead centre beneath the tiebar (I would discard the existing tiebars and build new so that they can be thoroughly bench tested before installation.) but what size hole? as I have not used the Cobalt motor I don't know how much throw the operating rod has.

Steve

[sebring115]

Saw these today at leamington show on the Kineton layout.

Has anyone used them with p4

https://www.shapeways.com/product/VCZ9P ... d=57480497

[steve howe]

At 20 quid a pop plus the cost of a Cobalt it makes it a pricey option

Steve

[Dave Searle]

Hi Steve,

You get 6 units for £20

Cheers,

Dave

[Alan Turner]

Hi Steve,

You get 6 units for £20

Cheers,

Dave

I would hope so as you can make your own using readily available plastic sections for about 50p each.

regards

Alan

[grovenor-2685]

I don't know how much throw the operating rod has.

The throw is not defined by the motor underneath but by your stretcher bar settings above. The throw should be 4.25" which scales just under 1.5mm. So allowing for a bit of slack, the thickness of the drive wire etc. a 4mm hole should be comfortable.
Regards