Introduction

The following should hopefully be of help to anyone who wants to motorise the 00 gauge Peco turntable and get the best performance out of it. The turntable itself is a very nice model and straight forward to build but I found it was not just a case of bolting a motorising kit underneath to make it work well. There is a little bit of work needed to get the best out of it and this is described below.

The Turntable kit

Full and easy to follow instructions are supplied with the kit itself and assembly should present no problems for the average modeller. However if you are intending to motorise the unit for use on your model then Don't fit the locking ring that should be glued to the underside the well and retains the bridge in place, as this will prevent you removing the bridge if required in the future. There is a modification that you will need to do so that the bridge can be removed and has as little play as possible in operation.

Below left is a photo of the turntable almost completed. Just the three drains to fit, note the screw heads that they will hide. Also the well and table still have to be painted and weathered.

Note: When you cut the circular hole in your baseboard for the unit make sure it is an easy fit and drops nicely into place. If it has to be forced in you will find that it distorts the turntable body enough to give you some tight spots as you rotate the bridge.

Modification to the Bridge Pivot and the underside of the Well.

You will find when you hold the bridge down that the centre shaft (where the locking collar would have been fitted) extends out from underneath of the table well. Mark how much this sticks out and with a fine saw remove a little more than that amount from the shaft so that it is just recessed inside the collar of the table well.

On the one that I built, to make sure that the bridge continues to run on all 4 wheels while being rotated, I fitted a 12mm MDF thick support ring under the turntable well. Between this support and the base of the well I fitted a layer of cork the same thickness as the moulded joints and the three circular bosses under the "drains". This I hope will reduce the noise transmitted from the motor. This support also gives a useful mounting base for the motor/gearbox and the shaft end supports.

Below centre is a drawing of the turntable well support I fitted under the well. This is secured under the well by three screws through the three projecting flanges below where the drains are fitted. The drains will hide the screws and will be lightly secured for easy removal if required in future.

Below right is a photo of the suppoet ring fitted in place under the turntable well.

This is the almost complete turntable. I still have to add the finishing touches, paint and weather it. Note the screws holding the support plate, they will be covered by the drains.		This is the drawing I used to make the MDF support ring to fit under the turntable.		The underside of the completed unit showing the MDF support ring used to keep the turntable well flat so the wheels run properly on the ring of track.

Preparing the Motor / Gearbox

The following is based on using the kit available from Frizinghall Models. The kit comes supplied with 6 gear wheels in the gearbox and this gives you far too much reduction in table speed unless you have it running at full tilt which is very noisy and not good for the motor or gearbox. As mentioned in the notes that come with the kit, I removed two of the gears and replaced them with one of the plastic spacers supplied. I also added a thin 4mm stainless steel washer to the top, bearing against the case end plate, and this takes up all excess end float on the output shaft inside the case. Before fitting the worm gear which is a force fit on the long output shaft I made up a spacer from 5/16" brake pipe and fitted this along with a stainless steel washer each end on the shaft so that the worm can be pushed up tight against them. This takes up all excess end float on the shaft outside the case. I set the spacer length so that there is some of the shaft extending out beyond the worm gear. This extension is used to help remove any play between the worm and the gear on the turntable shaft. Before finally pushing the worm up tightly to the collar and gearbox applied some silicone grease to all the spacers and washers also all the gears in the gearbox case so that it is all well lubricated.

Preparing for fitting the motor.

The motor/gearbox and the bracket to support the end of the gearbox output shaft will be secured to the underside of the support ring. This end support bracket will hold the worm gear in correct alignment and engagement with the drive gear on the turntable spindle. The DCC decoder used to control the turntable, and the terminal block for the electrics will also be fitted on the support plate. This will make the whole turntable a self-contained unit and will simplify it's removel in the future, if required.
See the photos below for details.

Preparing the turntable bridge

Push the supplied shaft into the collar of the bridge until it is firmly home (I used a spot of glue on the joint as well so that it will not move in the future). Fit the bridge into the well and with the whole unit upside down rest the motor and gearbox unit on the underside of the well. I placed sufficient washers on the end of the bridge shaft so that the large supplied gear is at the correct position to mate up with the worm gear. I then measured the total stack, minus two washers, (20mm) and made a spacer to fit on the shaft. This was fitted plus a washer each end makeing sure that the washer nearest the table well is larger than the collar of the well. Now apply plenty of grease on the washers and on the bridge collar pivot then fit the large gear and tighten the grub screw to keep it all in position making sure all excess end float is eliminated but that the bridge turns freely.

Fitting the Gearbox

Now it's time to put it all together. With the whole unit still inverted hold the motor/gearbox so that the worm is a snug fit with the large gear then mark and drill two pilot holes to secure it in position on the support plate using two screws. Grease the worm and gear to prevent wear and help with smooth quite running. I now made up a right angled bracket from aluminium bar to hold the worm firmly against the large gear to eliminate any tendency for them to move out of alignment or engagement during operation.

The unit should now work and can be tested by applying power to the motor using a train controller or simply a PP9 battery acress the terminals. However you may find like I did that there is a tendency for the large gear and shaft to 'wobble' due to the hole drilled through the worm gear being slightly off-centre. I then had to make up another bracket to locate the end of the bridge shaft to prevent any movement, as seen in the photo below. Later I fitted washers between the gear and this bracket to prevent any tendancy for the gear to pull the shaft out of the turntable deck, which it did once. This time I used superglue to hold the shaft in, MEK did not do the job well enough.

Motor/Gearbox assembly and Brackets

The underside of the turntable showing the additional brackets made up from aluminium strip. One is to hold the worm on the output shaft firmly against the large gear and along with the spacer and washers between the worm and the case sets the end float of the output shaft. The other one is there to hold the bridge shaft central and prevent any tendence to 'wobble' due to slight mis-alignment of the hole bored through the centre of the worm gear.		Completed electrics for DCC operation of the turntable. The decoder is a NCE D13SR which allows controlling the max motor speed by tuning CV5. It also allows adjustment of the speed curve, by adjusting CV6, so that the lower speed steps are wider apart. This means that the turntable speed is more controllable as the bridge track is being lined up with the exit track.

DCC Operation

On my layout the turntable is operated by the DCC system. This was very simply achieved by fitting a Hornby R8215 loco decoder chip that I had spare, It was a NCE D13SR but I changed it as the D13SR is more use on an older type loco. This has been fitted underneath of the table well beside the motor and is fed from DCC bus along with the turntable bridge tracks. I wired up the motor so that forward is clockwise and reverse is anticlockwise. It is programmed as Loco address 11 and the top speed, CV5 is set up so that it gives a nice slow rate of rotation for the table. I have also set the acceleration and deceleration rates to zero so that it is easy to stop it when the tracks are lined up.