Re - Hinge pin wiggle
Hi Dr Geoff, Peter and all,
The alignment pins need also need a method to hold the modules together. Peter has the experience here, but G-clamps (C-clamps??) will probably suffice if nothing else is available and the alignment pins are mounted correctly. The X-Y-Z alignment across the module joint is assured by the alignment pins. Peter's clamping method beats G-clamps by a long way and ensures that "nothing moves" when the modules are locked together. For most home layouts that only come apart a few times (say less than a dozen times) wear and pin wiggle on the alignment pins shouldn't be a problem..
I haven'r seen much reported on damage/wear of alignment pins/pattern-makers dowels from the UK where these alignment pins are more widely used on exhibition layouts where the number of assembly-disassembly cycles may easily exceed 100. If wear causing pin wiggle is a problem, then there would have been reports of "rebuilding the alignment pins". These reports simply do not exist of rebuilding on exhibition layouts that are multiple years old. My feeling here is that worries about wear on alignment pins are probably unfounded. Remember these pins were designed for industrial use to ensure rapid and repeatable alignment of components multiple times.
Pin damage is another issue - If you hit anything HARD ENOUGH, then you WILL damage stuff. Perhaps the biggest risk is of damage that creates a burr on the machined diameter that prevents the pin from seating correctly when being inserted. But it would take a serious impact to damage machined steel pins, and "serious impacts" on any part of a layout are to be avoided at all costs because of the consequences.
However if you can't use alignment pins, then here's another way to achieve the same alignment accuracy that Peter has achieved across module joints "first time-every time" a module/section is connected to another .
We use another alignment method. Have a quick look at "Construction Concepts - Hinge Theory 101" These modules have been together and apart probably 30 times so far during construction and testing (and we still haven't got to exhibiting the layout yet) with no "pin wiggle" evident. This far exceeds the probable numbers of assembly/disassembly cycles or most home-use TOMA/sectional build situations. Please note the part about hinge selection - If you select sloppy hinges you will have sloppy joints and subsequent mismatches at track level.
The hinges and pins we use are a tight fit so that there is NO SLOP when installed, Somewhere on here I covered how we installed the hinges but I cant find that post at present. The installation summary is:
- Clamp your 2 modules together so that the module top is flat. Sand off any saw burrs/raised grain etc at the module joint before going any further. This gives you a flat surface across the join for your track foundation.
- Rigidly support your track on each side of the module joint. We use solid pieces of PC board but there are other options out there as discussed by Peter and Tim above. For us, the solid PC board gives a more bulletproof track support at the module joint. I gap the PCB boards at the joint with thin cardboard to ensure that there is no electrical path across the joint between the 2 pieces of PC board. Some paint and a thin layer of ballast will later hide the PC board sections. (I can supply photos if requested)
- The track is soldered to the PC board sections one rail at at time soldering to the outside foot of the rail. Gauge is checked and the second rail is soldered to the PC boards on each side of the joint. This gives you two continuous rails across the joints. DO NOT cut the rail now.
- Fasten your hinge to the module frame on one side of the module joint
- Fasten your hinge to the other module frame on the other side of the module joint
- Undo and remove the clamps. The hinges are now aligning the modules across the joint
- Gap the PC board sections between the rails. CHECK that there is no electrical continuity between both rails on each side of the module joint AND diagonally between the PC boards across the module joint..
- Cut the rails individually at the module joint using a thin saw blade (ZONA) or Dermel disc/saw (your preference)
- The PC boards also make excellent attachment points for jumper leads on either side of the joint. Install your jumper leads across the module joint We use automotive Molex plugs to carry the juice between modules.
- Check that you have track continuity and no short circuits between rails after the jumpers are installed
- Split the the plug and again CHECK that there is no electrical continuity between both rails on each side of the module joint AND diagonally across the module joint. The jumper lead should be the ONLY way of passing juice between modules.
- The hinge pins can now be pulled. Remember to disconnect your jumper plugs and then split the modules.
Yes there are ways to get bullet-proof track alignment across module joints "first time-every time". Alignment pins with over-centre fasteners and hinges with removable pins are just two of them.