The Gantry was a idea I had for a while to make, once the track was completed for our requirements. It was then the right thing to make next, to bring a bit more realistic touch.
The first thing to do was work out the size required that would not look stupid but would also work correctly with the lap monitor, So with the assistance of Franch the owner of Lap Monitor in France.
We also decided to go with the latest version of the Transponders to eliminate the problem with side bounce with the old style transponders, which suited the idea of having a vertical mounted Lap Monitor, fitted at the top of the Gantry.
I also wanted something strong enough to hold its self up and also heavy enough not to get knocked over with the slightest knock, and of course to look the part, which I think I managed that with the completed item.
There is also some electronics that was required to allow the the lights to switch between colours, the lights them self were from full motorway signs you see on the road, I will go into greater depth further in to this build.
DESIGN & CONSTRUCTION
First was what shape was we going to do , well for this I looked through the internet to see what sort of Gantry's there were out there, I was amazed at the mount to choose from. I opted for the ladder style uprights with a box construction as this we going to be straight forward to build. and nothing special was required to aid the build. So I started to make a drawing of what I wanted to build, once I had this the materials was the next on the list as depending on what I use would then allow me to think how to connect it all together. I choose to build from Brass and Aluminium tubing as I have made previous items before and connecting together you just solder, and this was easy and it made less work to tidy up after before painting.
I decided to make the Gantry in 5 sections, this was to make the build stages easier, 2 up rights, 2 base feet and the bridge, the bases need to be removable so you can fit them under the track tiles. The outer tubing is brass and the inner tubbing used for joining the tubes together are aluminium. these metals are very good for soldering together. The base feet are just 1mm steel plate with 5mm socket head screws going into a couple of M5 nutserts so the brass tube slides over the screw heads.
also shown in the drawing is the coupling by using the aluminium tubing sticking out just a little to slide into the next brass tube that is drilled the correct size of the aluminium tubing so to create a good strong solder joint.
TOOLS REQUIRED
- Fine saw or Dremel with cutting disc
- Sharp knife or scalpel
- Drill set
- Fine file
- Set square
- Centre punch
- Panel pins
- Flux pen
- Thick solder
- Small gas torch
- 9mm sq hardwood
- Wire brush
PARTS
- 5/8 Brass tubing
- 5/16 Aluminium tubing
- 2mm steel sheet
- 1mm aluminium sheet
- M5x40mm skt/hd screws
- M5 nutserts
- 1.6mm or 2mm skt/hd screws
- 3 off 15 second relay pcb's 12v
- 1 off 30 second relay pcb 12v
- 1 off remote unit 12v
- Velcro
- .5mm colour wires
- 3 cell Lipo
First part of the build is to make a frame which is square, its worth taking your time with this stage, as you will build two of these frames , and they will be identical. now mark the central positions on the two straight outside brass tubes and also mark the hard wood as well then both frames will be identical. Now with the marks on the up rights mark the centre's on all lines and then centre punch the centre's, now cut the cross members from the brass tube and place them were they are going to be fitted. the holes can now be drilled to a maximum of the size of the aluminium that will fit inside the brass tube.
When you start to drill the holes in the uprights drill them in the jig because all are held tight together, Only drill in to the top do not go through both sides this will weaken the brass tube. Now cut the aluminum longer then the brass tube cross sections, they need to go in to the brass tube uprights by 2/3's of the width of the brass tube on both sides.
1st picture shows the marking and center punched pre drill holes, 2nd picture shows the drilled holes to take the aluminum tubing and the 3rd picture shows the joints soldered before cleaning. The soldering is done while the uprights are in the jig, and using a small blow torch and a flux pen, the solder runs nice a smooth.
You can see the burn marks on my bench I would say have a bottle of water in case of any flames , I didn't get any but you never know, now you can clean the joints with a wire brush. Solder the front side and then turn the upright frame over and do the other side.
The middle part of the bridge is next with two identical lengths made for the front and back after you have made the jig once again just like the uprights were done.
Once they are all soldered and cleaned the cross members now require fitting, always give plenty of flux so it runs in to the joints well, so the solder flows all round the joint.
The front and rear bridge panels can now be stood up in the jig so the marking out for the cross members can be done, but do not put the cross members in the same place once this is done remove both panels and lay one of them down so you can dot punch and drill the holes , then do the same to the other one. Then start to cut both the brass and Aluminium tubing for the cross members but stagger them from the all ready fitted cross members so to not weaken the brass tubing.
The adjoining angle now has to be made this is done by drilling the hole for the brass tubing to go through the upright piece at the top shown in the picture, this is done once again by placing the uprights back in to the jig so you get no movement and the tubing will also stay in shape. the position will then be the same on both uprights as you make a mark on the hardwood jig you will see underneath om the lower two brass rails that they are short.
This is do because this will be a removable section on all 4 rails of the bridge, there are 4 brass tubing's soldered to the uprights that stop where they meet the other brass tubes from the bridge , what joins them is the Aluminium tubing that fits inside, this is soldered to the bridge side of the brass tubing that then slides into the upright end of the brass tubing. At all times use a set square to make sure everything stays straight. Once you have made this end you can cut away any unwanted tubing that sticks out from the upright.
you will find that doing both ends at the same time is easier but it would be better if you can get the uprights held in to place. To stop any movement
