Technical Redrill a Ford axle?

junkman, the "big" 5 lug 9" Ford's I've seen, are 5 on 5 1/2. Like Broncos and F100-150s (and old Jeeps and Samurais are 5 on 5 1/2 too). I think they are the 9"s with the big flanges. The OP wants to go from 5 on 4 1/2 to 5 on 5. I could find a picture of a re-drill to 5 on 4 3/4, but not 5 on 5. People have drilled Explorer axles to 5 on 5 1/2 for Jeeps and such. They use screw-in studs because there is not enough meat for the pressed stud's OS holes and heads. They do do it though. With big tires and off-roading. I think you could easily drill for 5 on 5 using either kind of stud. There was plenty of meat left in the 5 on 4 3/4 picture above. I say drill 'em ! I use CAD. Tell it to make a pentagon inscribed on a 5" circle with it's center at 0,0. Then, highlight and jot down the X,Y coordinates of the 5 corners of the pentagon. Doesn't really matter how it's clocked, just turn the work to line up when you set it up. Or, take a minute to rotate it to where you want it when you draw. Note: If you told it to circumscribe the pentagon (rather than inscribe), the circle fits in it, and the corners are outside of the circle. Take these coordinates to your DRO mill, center the flange and drive around to the 5 spots and drill holes. It's a bunch easier to do rotors, drums and wheels. You have to have a machine that can work off of the table, so your axle can hang down, to do axles. I use Auto Cad LT '97 (for Windows '95, had her since she was new !), there are plenty of free CAD methods today. I think Bridgeport mills have the head on dovetails that can work off of the table. Mike

 

Ford went to the 8.8 in the F150 & full size Bronco in 1987-1996, you could use the drums and backing plates off of one of those as they have the 5.5” bolt circle. I don’t know if the axles can be cut and resplined but something to look at.

 

AccurateMike: First off, forget about CAD and the X,Y coordinates and DRO mills, get out some paper, a ruler, and a compass. You'll be drawing three circles using the same initial point, one 6-1/4" in diameter, one at 5-1/2" in diameter, one a 5" in diameter. The 6-1/4" diameter circle represents the small-pattern Ford axle flange, the 5-1/2" and 5" circles represent big Ford and big Chevy lug stud patterns. Please keep in mind the 5" and 5-1/2" circles are through the center of the lug stud,, not the outside edge of the stud, so with a 5" bolt circle you'll end up with, depending if you use thread-in studs, a maximum of 3/8" of material from the side of the stud to the edge of the flange but 1/4" or less if you use press-in studs as the shank of the stud is larger in diameter than the threaded portion. The question is are you willing to bet your life (and the lives of others) on a 1/4" ring of steel?
With a 5-1/" bolt circle things get seriously sketchy as even with screw-in studs you'll end up with 1/16" of material between the side of the stud and the edge of the flange. Even though "off-roaders do this modification all the time" we also need to keep in mind they carry portable welders so when their rig falls apart on the trail they can glue it back together.

The truth is AGELE55 needs to talk to some true axle professionals before making a decision, not us blowhards here on the HAMB.

 

I'm curious why you'd want to re-drill them? Do you have some cool or special wheels you want to use that have the larger pattern? Is there a chance you could just sell those wheels, and put some more money with that and buy 4.5"x5 hole wheels, and skip the whole drilling thing?

 

I was a pen and ink draftsman before there was CAD. I know how. If time means anything to you, as in doing axle, wheel, drum, and rotor re-drilling professionally, it makes sense to use it. There have been DRO's in every shop I've been involved with since at least the 80's. A bunch of folks have them. I made mine. I'm glad you have your way. I won't be forgetting mine. I also understand axle flanges. I think there is enough meat there for 5 on 5, especially in light of people doing 5 on 5 1/2. That is sketchy, I think 5 looks fine. It sounded like he wanted to drill his own, then he makes up his mind. Or, he can walk into a shop and see what they say. If he doesn't have equipment and was thinking about a hand drill, he should go to a professional anyhow. Mike