120mm

So, I've started my Shelby Drop, and I've mistakenly drilled my pilot holes 1 mm too wide. I used a center punch, and am looking at a nice 1/4 inch hole drilled completely through the metal, off-center.

I can see from the way the bolts misalign, that it's not a "little thing" and assume they need to be a "tight drive" fit.

Anyone care to share your tips for realigning pilot holes? I've considered affixing a washer with a slightly undersize diameter hole in the correct place and hogging the hole out using it as a guide, then finish boring to the correct dimensions.

But I'd appreciate tips or tricks.

LynnBob Mustang

If you got a welder, weld, grind flat, and re drill.
Lynn

fastbackford351

1mm? Isn't that like the equivilant of a royal ***-hair? If your pilot hole is only 1mm off then I think it would be a non-issue and your trying to leap over a mouse turd.

But if you really think it's a problem then yeah, like lynnbob said, weld, grind and redrill.

MonsterBilly

take your time and do it right. weld. grind, redrill

120mm

I have, can and will do that, now that you mention it.

120mm

The bigger the bolt, and the thicker the material, the more exact it needs to be, imo.

I just feel like a schlub, here. I had the location center-punched correctly, but it felt like the drill jumped off, so I corrected it. Turns out my "correction" was the culprit.

120mm

I was just thinking about this, and realize it really doesn't matter what I fill the hole with, as long as it is at least as hard as the surrounding metal. Whatever I fill it in is just to allow the bit to bore a hole evenly.

So if I filled it with epoxy, it would allow the bit to drill through, and in the end, it is all going to be "hole" anyway.

fastbackford351

1mm dude. That's less than 04/100th of an inch. I've never seen anything on a classic Ford front end that couldn't stand 1mm of wiggle room.

I'm positive that I did not get it any better than 1mm off center of the template when I did my drop. Only 1mm off and at most you'll have to hit it with about two swipes of a rat tail file and it'll mount just fine.

MonsterBilly

Yeah but it gets magnified over the length of the control arm. It is tuff enough to align these cars when all is perfect. so if you can, you might as well make it correct now.

120mm

I ended up just hogging out the pilot hole in the opposite direction of the error and just tapping the bolts through with a hammer.

Dang, once you do one of them, these things are stone cold stupid easy. For the next one, instead of screwing with the template, I am going to use the already mounted bolts as a guide. When you flex the arm down, they just naturally want to line up to the new holes.

One thing I've noticed; in the factory, things were really just slapped together. bolt holes are drilled sloppily and nothing is in the same location. Which is why the Unisteer units come with the "you may need to grind here, here and here, or you may not" instructions.