We’ve Been Workin’ On The Railroad VII

Notes on the Millhouse Turntable

I have been working on the Millhouse turntable to get it operational. The adjustable targets have worked out great for the indexing. With that working I added the rest of the details to the bridge following the instructions that came with the table.

I have the pewter details and they are very soft. I noticed that all four of the bridge bearings were not in full contact with the ring rail. So, off came the bridge and I leveled out the bearing carriers with shims. The newest tables have water-jet cut aluminum carriers for the bearings so this may not be an issue anymore. However, it does not hurt to check as it is easily corrected.

The instructions say to glue the arch onto the bridge deck and the sides of the bridge girder. I realized that if you do that you will not be able to remove the bridge from the table. (Why would you need to do that, you may wonder? Read on.) So, I attached the lower support arms to the bridge girder with 00-90 screws. I positioned the arch on the bridge, clamped it upright and square, and then drilled through the support arms into the girder with a #65 bit. I removed the arch from the bridge and drilled the support arms to clear the 00-90 screw with a #55 bit. I tapped the girder to take the 00-90 hex head screws and reinstalled the arch on the bridge. You can see the screws in the photo below.

With the bridge in place and all pretty, the next thing I did was dirty up the pit floor with gravel and ballast. Then I decided to line the pit with ties. I had a bag of Kappler ties that were already stained and I used these to line from the bottom of the pit up to the ring rail. This looked so great I wanted to line the entire pit wall this way.

A quick check, however, indicated that my Kappler standard ties would not fit between the end of the bridge and the pit wall. I determined that if I used Kappler low-profile ties there would be enough clearance between the bridge and the lined wall, so I ordered the low-profile ties.

After I stained these and let them dry for a day or so, I began to line the upper wall. I did it over a few days with the bridge in place, moving the bridge as needed. Once I got about half way up the wall I noticed that the table would slow down in one particular spot. I could see the bearing carrier was scraping along the ties in one area.

I hit on an idea. I have some sandpaper with adhesive backing. I could out the sand paper on the wall and run the bridge past the “high” spot which would “sand down” the carrier until it cleared the area. Well, rather than sand anything down, the bridge jammed in place. I needed to figure out what was going on, so I had to pull the bridge. (See, good thing I didn’t just glue it all in place!)

When I pulled the bridge off I could see that it was the entire end of the bridge that had hit the sandpaper, not just the bearing carrier. I proceeded to sand down both ends of the bridge with the carriers in place making sure they were square and did repeated test fits to make sure I got the clearance needed. Ultimately, I ended up with about 0.010″ clearance on both ends. I think my table is off-center by a tiny amount. If I had not lined the walls, I would never have noticed it.

So, as I have another table to do I have some lessons-learned to impart:

• If you are going to line your pit, do it first without the bridge attached.
• Square up the ends of your bridge if they are not square from Millhouse.
• Check the bearing carriers to make sure all 4 bearings contact the pit rail. Shim if needed.
• Once the pit is lined, put the bridge back but don’t screw it in place. Run the bridge all the way around and listen/look for binds. Resolve binds by sanding the bridge ends or the liner.
• Don’t add any details to the bridge deck until you are certain the bridge runs smoothly.
• Screw, don’t glue, the arch supports to the bridge girder.
• Detail the bottom of the pit without the bridge in place.

Don’t get me wrong: the Millhouse tables are built like tanks, made to last, and are a great value. Plus, I have two very early 2-rail units and they’ve made many improvements since I bought them.

Here are some photos of the table installed and operational. Click on the images to get larger views.

 

 

Tags: featured, O Scale, turntable

Category: !Joe's Projects