VCCA Home Forums TECHNICAL - GENERAL Trucks and Vans Drilling '66 Chevy pickup frame

Hello guys.

I could sure use some help. I made a cross member to support the TH350 transmission my son will be using in his '66 Chevy pickup. The cross member turned out great. My son, a Marine Corps aircraft mechanic turned mechanical engineer, then positioned the cross member and attempted to drill holes in the pickup frame web to bolt in the cross member.

The drill bits didn't even make a chip, just a very shallow crater, and we tried several drill bits. Apparently the pickup frame is not mild steel, but is some high strength material. I should have checked before making the cross member, but hindsight is always 20-20.

Any experience dealing with this will be appreciated. I have a home machine and welding shop and will return the favor to anyone who helps me. I'm the guy who successfully converted my '36 Chevy PU from 4.11 to 3.55 gears, so I'll try anything that has a chance of success.

Thanks!

Ray W raywaldbaum@gmail.com

I do believe you are correct, if my memory serves me, the frames are made out of chrome molly, and I believe that is much harder than the mild steel we are used to today.

I have drilled a dozen or more holes in my 65 Chevy PU frame. The key to success for me was to use a center punch, start with a small sharp (new) bit and progressively move up to the size hole needed. I will normally use 3 drill sizes to get to a 3/8th hole.

Another thing that helps is slow the drill speed down a little, and use a lubricating oil whuile drilling.

Jim

I have found that the slow low speed and lubrication is best for chassis drilling, I mean slow low speed and as Jim said several steps.
Tony

Thank you so much for the suggestions guys. After I finished making the cross member I handed it to my son and he attempted the drilling while I cleaned up the shop from the cutting and welding. I will try and see what results I get.

I am encouraged to hear that you have drilled that era frame successfully. The cross member is 1 1/2" X 2 1/2" 1/8" wall tubing with 4-hole flanges on the ends drilled for 4 5/16" bolts on each end. I was planning to use at least grade 5 bolts.

Thanks again guys!

Ray W