As it turns out the heavy duty BJ's are made with hardened steel. A normal drill bit won't even scratch the surface. I tried many times and nothing I had would even make a mark. So I scrapped the spacer idea because I really didn't need them. I went with 1.5" lift springs as opposed to 3" lift coils and the angle wasn't bad at all.
Soon however, I will be installing the 3" coils so I will definitely need the spacers to help with the control arm to spindle angles. I will be upgrading to 33" tires this time around so once again cheap BJ's are not an option. I had to find a way to drill at least a 5/16" hole in the hardened steel.
4 years ago I asked the seasoned (30+ years) machinist at my work if hardened steel like this could be economically drilled. He said NO, that I would most likely need to have them EDM'd (electronic discharge machined). That type of work is expensive.
A few days ago I decided to order a carbide drill bit at a cost of $50. I figured if it didn't work at least I know for sure I can't drill these suckers out myself. Tonight I gave it a shot and the results surprised me!
This is the drill bit I bought:
McMaster-Carr part number: 8882A28 Carbide Straight Flute Short-length Drill Bittin-coated, 5/16" Sz, 2-1/2" O'all Lg, 1" Drill Dp
These bits are very brittle so you MUST use a drill press or mill and secure the BJ to the table. You cannot use a hand held drill.
Chucked up in my Craftsman 9" drill press:
Cutting fluid for machining is recommended but I don't have that on hand. Instead I used an ample amount of used motor oil for lubrication.
The result:
It cut through the hardened steel like butta!
The bolts fit very snug. The next size drill bit up is 3/8". I purposely did not buy that one because I didn't want any slop. It seems to me that the more slop you have the more likely the bolts are to shear under extreme force.
I hope this helps someone out. I would have found it EXTREMELY useful a few years back so I'm sure someone out there will benefit.
I have a video of the drilling but photobucket doesn't want to let me upload it. I will try again later.
