Improving PECO Turntable

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When building the PECO turntable for my layout I discovered it had a number of mechanical short comings, so when I was asked to build another turntable for a friend I decided to rectify these problems during construction.

(a)With the heavier weight of modern RTR locos the turntable is unable to cope, the turntable well will sag in the middle.

If you mechanise it, the centre spindle can start to move within the bridge bearing. The springs which hold the current collectors can cause the bridge to move up and down as a loco rolls on and off the bridge.

All these problems can be over come with a little ingenuity.

 

I first glued the three pieces that form the’ well’ together, then I filed the outer lip on the bottom to the same depth as the locating lugs on the which join the three pieces together. Using a thick piece of plasticard, 125 thou thick, I cut a circle the same diameter as the bottom of the turntable well with an appropriate sized circle cut in the centre to allow for the bearing assembly (photo A), this was glued to the underside of the turntable and allowed to thoroughly dry on a flat surface, it is essential this is flat. You could use a piece of ply instead as long as it is rigid.

 

The next problem to be solved is that of fixing the spindle to the underside of the bridge, although a tight fit, even if glued this can twist and slip if the loco is heavy or the bridge encounters any friction.

Insert the metal spindle into the boss assembly and then drilled a 1 mm hole at right angles through the boss and the spindle, then inserted a piece of wire, this locks the two together(photoB)

The turntable can be made as per the instructions, until you get to the part where you fix the retaining collar piece (21), the instructions suggest that this is glued, I do not recommend this as it is quite easy for the glue to lock the bridge to the rest of the turntable, in which case you have a serious problem, also by gluing you are then unable to take it apart for any future maintenance.

Replace the plastic collar with a metal washer with an inside diameter of 7.5mm and then made a 1mm hole in the spindle through which is placed a piece of wire (photo C) This stops the any vertical movement of the bridge but does not hinder its rotational movement.

I decided to make the turn table hand operated using Meccano components as per the instructions, I filed a flat on the spindle so that the large gear wheel (Meccano 27c) will not slip (Photo D). Note the thrust bearings at each end of the bracket; these keep the worm in position against the gear.

There can be a tendency for the gear and worm unmesh under load, so I added a strap to the frame holding the worm, this keeps the spindle gear in mesh with the worm (photo E), note the spacing washers between the strap and the plasticard, this allows you to make small adjustments to the meshing by the addition or removal of these washers.

Photo F shows the addition of a motor using another set of gears and worm if you wish to motorise the turntable.

Finally when installing the turntable into your base board I would recommend that you addionally support the base with a couple of battens.

Meccano components are easily available on Ebay

These simple improvements will make your turntable much more reliable and smooth running,