[Sol]

I have posed this question to a couple of model groups I am associated with & are looking for as many bits of advice/info as possible.

For those who make their own points & solder the blades to PCB tie-bars - what type of point motors do you use?
I would think that solenoid type motors would tend to cause a separation of blade from tie-bar in time due to the heavy action needed even with additional soldered rod along the web ( flat - bottom rail) to the tie-bar.

 

[alastairq]

tortoise or fulgurex....ie motor-driven are best.

plus, some device to absorb over-pull? (omega loops spring to mind?)

I have preferred mechanical methods in the past.....less expensive than a motor if it goes pop?

If you have Iain Rice's book on building 'scale'track', check out his method of moving blades?

 

[Colombo]

Sol,

I use Fulgurex or Lemaco, a friend uses Tortoise. Producing the tie bar and moving it is difficult. C&L do offer glass fibre tie bars that are based on the moving sleeper principle and this is simple and effective. .

We do have a solution that looks more realistic but it is quite complex. Similar systems based on sliders under the baseboard have been published before. Ours for 4 mm scale was derived from Iain Rice's design, but we replaced his brass wire rods with vertical 22mm wide strips of thin double sided copperclad with very thin brass channel tie bars soldered to the top narrow edge. Electrical insulation is achieved by cutting a 15 mm long slit down the centre of the copperclad, through the slidebar and then scraping off the copper on each side at different heights. The other end of the copperclad strip is then soldered into slits cut right through brass square section tube sliding inside guides made of the next size up tube.

I think that the omega loop can put too much pressure on the blades and I prefer a free moving tie-bar with no slop in the linkage so that the blades move slowly across and stop in the right place. The travel on a lemaco or a fulgurex is too great for this system in 4mm scale, so you need an unequal angle crank to reduce the travel

Colombo

 

[SPROGman]

QUOTE (Sol @ 15 Jul 2007, 14:11) <{POST_SNAPBACK}>I have posed this question to a couple of model groups I am associated with & are looking for as many bits of advice/info as possible.

For those who make their own points & solder the blades to PCB tie-bars - what type of point motors do you use?
I would think that solenoid type motors would tend to cause a separation of blade from tie-bar in time due to the heavy action needed even with additional soldered rod along the web ( flat - bottom rail) to the tie-bar.
Radio Control servos can be had for as little as £2.50 each on Ebay (a lot less than Tortiose) and the electronics to drive them is not difficult (load of ideas by Googling). MERG members can buy a kit to drive four servos.

Andrew