You are going to need a few things to get started.
- Teflon tape
Two crescent wrenches (pipe wrench optional)
BernzOmatic torch head
1/4" MNPT x 1/4" OD compression adapter
1/4" x close pipe nipple
1/2" x 6" pipe nipple
Two 1/2" female couplings
Two 1/2" x 1/4" bushings
Two 1/4" ball valves (male x female)
Optional: 1/4" street elbow
1/4" male auto coupling
These materials are shown below.
You need to start by adapting your torch head to 1/4" pipe threads for connection to your propane meter. To start off, grip the torch head's base with a crescent wrench, and the torch shaft with a pair of vise grips or a pipe wrench. Turn counterclockwise to remove the torch shaft from the needle valve. Next, remove the nut and olive from the 1/4" NPT x 1/4" OD compression fitting and wrap the straight (7/16"-24tpi) threads with teflon tape. All of your connections for this meter need to have a few wraps of teflon tape to seal completely. I use the pink "heavy duty" tape, but yellow gas tape will work as well. Do not use white water tape in gas connections. Finally, thread the adapter securely into the needle valve with a pair of crescent wrenches.
You can buy a throwaway tank adapter which covers the above for you, however, they are difficult to track down. I found this one in an adapter designed to convert throwaway cylinders to normal tank threads (like for your BBQ pit).
Now, simply thread the 1/4" threads of your adapter into the inlet of the pressure regulator. This is denoted by an arrow on the bottom of the assembly, usually. You should also aim to line up your fittings evenly throughout the construction of your fuel meter...
Now comes the majority of your pipe fitting. Thread the two 1/2" couplings onto the ends of the 1/2" x 6" pipe nipple. Do this by gripping the ridges on the couplings with a a crescent wrench and turning both counterclockwise simultaneously. Repeat this step for the two 1/2" x 1/4" bushings in the ends of the 1/2" couplings. Finally, repeat this procedure to attach the two ball valves to either end, again, trying to line them up evenly.
If you've never attempted joining two female components by a close nipple, it's best to wrap the nipple in teflon tape, start it into both components, and then tighten the connection using the two components themselves. This nipple has a hex in the center for grasping with a wrench, but not all do...
Last step. I added a street elbow to this part of the meter to make attaching the meter to the cannon a little more ergonomic. You can simply thread the auto coupling directly into the last ball valve if desired.
EDIT: TinyPic randomly deleted an image. Fixed.
EDIT 2: Reformatted for the new version of Spudfiles... a long time overdue.