For my steering I will be copying a crossover steering design that Blaine has perfected. Bumpsteer is virtually non-existent with this design. I'll try and cover the specifics and theory of why as I go through laying out the steering. It allows for straight linkages which are simple to make, stronger, and cleaner looking.
His steering page is worth looking at and studying if you're looking to build something similar.
Up until recently, Currie could optionally mill their upper steering arms to place a hole to be in shear with the lower arms. Unfortunately they will no longer do this custom work. Blaine and I brainstormed some ideas for placing the 3/4" hole on the upper arm to be in line with the lower, and this is what I came up with after combining some of our ideas into a simple and reproducible jig for projecting:
(Blank upper steering arm from Currie)
1) We start with a 1/2" countersunk bolt that is 2" in length. A longer 6" bolt would be better so that the drill bit does not deflect later but this is as long as I can find with it still being fully threaded and I don't want to spend the time threading and drilling the longer one.
2) At your drill press take a centering bit (or other small bit and work your way to a 1/4" drill bit) and place it upside down in the chuck, don't tighten. Run the bit down and clamp it into a lower vice so that the bit is centered with the DP chuck.
3) Place your 1/2" bolt into the DP, threads first, and tighten the chuck.
4) Spin up the DP and drill a 1/4" hole perfectly down the center. You might need to raise the bolt every so often to allow chips to clear.
Take the bolt and bring it over to your knuckles.
a) Place the bolt through the lower steering arm on the cast knuckle, from the bottom up.
b) Take a 1/2" washer and nut and tighten the nut down on the bolt. Torque it just enough so it won't move on you. Both sides of the steering knuckle are machined flat in perfect parallel with the upper arm. This jig is a 2 part method for projecting the lower hole onto the upper, #1 is that the countersunk head places the bolt perfectly in the concentric center of the lower steering arm hole, #2 is that by using a washer and tightening the nut down on the other side we perfectly center the bolt in the vertical plain.
c) The hole in the bolt should now be perfectly guiding a 1/4" drill bit to the top arm. I used a commonly available 12" long 1/4" drill bit. Use a hand drill to place the 1/4" hole into the top arm. Be mindful of how much pressure you're applying so that the drill bit does not flex and travel on the surface.
d) Once you're all the way through the upper arm with the 1/4" drill bit you can finish with a 3/4" drill bit in either a hand drill or drill press.
e) Finally drill your lower steering arms with the 3/4" bit to remove the current TRE taper. And test fit your 3/4"x8" grade 8 bolt.
If anybody is trying to recreate this and you do not have a drill press, I started this idea by playing around with a vented bolt that had a 1/8" hole down the center. Another idea is to use a tapered lug nut off your Jeep for the nut side and use a flat head bolt and washer on the other side. Alternatively, I can mail you the jig and 12" long 1/4" drill bit for the cost of shipping as long as you will return it once you are done.
