Assembly Tips for the Heljan Turntable.

[Anonymous]

There 's been a few times here in Forums where someone mentioned having problems in assembling a Heljan / Walthers 90' turntable. I posted this before in a reply to a few other threads. So instead of posting this to someone ele's thread and getting off topic or providing a link to another thread and hope they can find my reply, I'm setting this info up as a new post.
I hope it helps.


I built a Heljan TT and it works fine. If you are not careful in the assembly, then yes it is junk. The instructions are a little more than an exploded view and I deviated from the instructions by throwing away the part with the gear on it and made my own driveshaft so I can remove my bridge. I also modified the electrical pick up for the bridge track. The drive coupling is a home made version of THIS

One very important step in the assembly is the lower bearing plate. The bridge hight has to be just right. The trucks on the ends of the bridge should ride very lightly on the pit rail, most of the weight should be carried by the bearing. The Heljan kit has a lower bearing plate that glues into the center hole of the pit. That has to be positioned just right (I found that out too late and had to use a .010 shim from a generator pully on an old VW bug to raise the bearing). The bridge is attached to the upper bearing plate and my drive shaft is attached to that. The shaft has to be centered perfectly. I did that by slipping a brass tube through the factory hole, to use as a locating tool and slid the new drive shaft over that. Once the driveshaft was attached, the tool is removed.

I also mounted the electrical pick up differently. I seperated the two wipers and mounted them on the ends of square brass tubing and attached to the wooden base.. They wipe the brass rings which are mounted on the drive shaft and connected to the bridge rails. I made the driveshaft out of brass tubing and insulated it from the power pick up rings with heat shrink tubing. The rings are made from brass tubing. The connection of the motor side of the driveshaft was made from of the guts out a Eurostyle strip connector. On the other end of the connector I made a "T" from round brass rod which fits into a slot cut into the driveshaft. The polarity is corrected by a MRC power reversing module.




If you want the bridge to turn smoothly, you have to be very careful with how the bridge rides on the bearing. The trucks on the end of the bridge must be free wheeling and aligned correctly. Build the basic bridge, without gluing down the track, and dry assemble the bridge / pit / drive parts (without glue) to see how everything fits in the pit. Note the rail hight too. Take into acount the weight of the locomotive and the sag of the plastic pit too. Plastic pits flex and will sag a just a wee bit. It can benifit from bracing or support.

In fact you might want to build a stand or jig to hold the pit up while you work on it. Just cut a hole in a piece of plywood and put short legs under it.

If you plan on building a roundhouse too, both turntable and roundhouse should be built on the same platform or base. The turntable comes first, then the round house base and tracks. Makes track alignment easier than to try to put a turntable in after the roundhouse is built.

[johnny.5]

Gary, your machanic's skills are showing! [(-D] ("Locating Tool") Nice Work!!! [swg]

John