Liftout sectionPosted by lennart Thu, July 17, 2008 17:25:18
The liftout section is back in business again. Sturdier and actually better working than before. So in the end it was a good thing it started to malfunction. While I were at it I remade the opposite end as well.
As can be seen in the picture I screwed the track to the plywood. Ought to prevent it from ever moving again. The large screw to the right goes down through the foam and into the benchwork beneath. The plywood is glued to the foam but the screw is there just to prevent it from moving sidewards anyway. Cautions and pre-cautions ;-)
Liftout sectionPosted by lennart Tue, July 15, 2008 19:01:13
I removed the liftout yesterday for the purpose of screwing some masonite siding to it, to keep engines and rolling stock from falling to the floor should they ever derail. When I reinserted the section today I found out that the track did not align correctly at one end. Bad luck! Easy and repeated track alignment was supposed to be the hallmark of the design in the first place.
After having stared at the misaligned track for some time I came to the conclusion that the trouble was the cork sub roadbed. The tracks make a tight curve before entering the liftout so there is quite a lot of stress on the cork, from the curved flex track. Nothing had broken loose but my guess is that the soft cork has been deformed making the tracks misalign. Not very much, but enough to make cars derail (good for me that the new siding was in place).
The cure is to lift the track closest to the layout edge, remove a slice of cork (about an inch or so) and insert a piece of plywood instead (along the layout edge). The plywood will be rigid enough to prevent the track from ever shifting again. I hope.
The other day I mentioned some drawbacks (in my opinion that is) of using PCB ties. One issue was that it is hard to get a color match with the rest of the ties. Not everyone agreed that this is a problem. On the prototype not all ties are the same color and if you place your PCB ties somewhat randomly the track will not get a stripy appearance. Good point!
Liftout sectionPosted by lennart Sun, May 18, 2008 16:53:25
Today I finished the liftout section. All jacks are in place and I screwed a piece of plywood on top of the beams. I also connected the electrical leads to terminal strips. Eventually, track power will be routed from those terminals. Below the underside of finished the liftout is shown.
The next photo shows the liftout in place, i.e. connected to the rest of the layout. As you can see the electrical leads from the jacks first go up through the plywood and then down again through another hole. It certainly looks as if they will be in the way when I finally lay track! That is however not the case. I will glue a layer of extruded foam on top of the plywood, both on the main layout and on the liftout section, and then the leads on the liftout will be buried deep in foam and not interfere with any track work.
Lessons learned: I choose to use 6.3 mm (1/4") stereo jacks. They might be a little to sturdy! There is a problem lifting the section straight up, since the jacks do their best holding back, and they do not snap loose all at the same time. As a consequence the section tends to come off an angle (one end first). This might perhaps damage the track, at the joint between the layout and the liftout. The future will tell. Anyway, if I was to do another one like this I would try smaller, 3.5 mm (1/8"), jacks instead.
Liftout sectionPosted by lennart Tue, May 13, 2008 20:18:38
Construction of the liftout section has made some progress, as shown in the pictures below.
As I see it, the two main issues when building a liftout, or some other removable part of a layout, are
1 - Assuring that the tracks align every time you attach the removable section. This should be an automatic feature of the device, i.e. the device should only be possible to attach in one way and that way shall automatically make sure all tracks are correctly aligned.
2- Providing good electrical contact between the main layout and the removable part. Ideally this is done automatically when the removable part is attached.
In this case I choose to try using standard 1/4"stereo jacks for both purposes. The jacks will make sure that the liftout is properly aligned and convey power from the main part of the layout. The picture below shows one pair of jacks (one male and one female) as bought and another pair where I have attached leads for the elictrical connections.
In order to ensure a stable and repeatable alignment of the liftout section I decided to use a total of four jacks - one jack in each "corner" i.e. two at each end.
For each jack I started by drilling a pilot hole through both the (liftout section) beam and the support block, after having clamped the beam to the support. The picture below shows how I drill such a hole.
After that I used larger and larger drill bits to widen the hole until I got one large enough to house a jack. It is important to increase the drill bit width in small increments. Otherwise the woood will probably split. Once the pilot hole was done I drilled separately in the beam and the support.
I then inserted the female connector in the support block and secured it with a "heavy duty" construction adhesive. The male connector was glued in place in the hole in the beam, as shown below.
The last picture for today shows what this looks like when the jacks are connected.
Now I have to repeat this process for the remaining three jacks.
Liftout sectionPosted by lennart Tue, May 06, 2008 22:45:10
I have started to construct the liftout section that will span the doorway. It will serve as a bridge, connecting the two ends of the layout, and making continous running possible. The liftout section will also serve as a small 3-track staging area.
The first thing I did was to screw supports to the underside of the benchwork. One support at each side. The liftout section will rest on these supports. The picture below shows one of the supports sticking out from under the benchwork.
I then cut the actual support beams to length. At the ends I attached some extra pieces of wood in order to make them wider. In the picture below the beams are just resting on the supports. Nothing yet that keeps them in place.
That is as far sa I got today. More will follow, and reveal the reason for widening the beams at each end.