drilling out lugs from hub, disc brake upgrade
NOTE: Before you drill out lugs, try to punch each lug out from the front side. I got lucky, and two lugs acutally popped out. (They may have been lugs replaced some time after the car left the factory.) It took 2 hours or more to drill out the remaining 8 lugs from 2 hubs. I used a drill press. A hand drill could be used, but you'd have to be pretty careful to keep the drill bit perpendicular to the hub, so as to not cut into the splining (grooves) in the hub that keep the lug tight in the hub. I start the holes with a 1/16 bit and gradually increase bit size to one as wide as the lug threads. You might need to go a bit wider. Use lots of oil, and drill slowly.
Start drilling before you grind off the flange (lip) at the base of the lug. I found this made it easier to center my drill holes. You can then use a grinder to remove as much of the flange as you can. A small ring ( lug on right below) will be left on the lug, because it is lower than the metal of the hub. This ring will crack off when you punch the lug out. If it does not, drill a little wider.
Below, you can see where the lug on the left was drilled a little off center, removing some of the splines and cutting into the hub. You can also see on the splines on the right hand lug are flared out near where the threads begin. This deformation is caused by the swaging process that pressed the lugs in at the factory. This is why you can't punch out the lugs from the front -USUALLY.
NOTE: You do not want to drill too deep, as you may end up punching out the threaded part of the lug, but leaving a ring of the splined (grooved) part of the lug left in the hub. You are only going to drill a hole LESS deep than the thickness of the hub. In fact, you may only need to drill down enough so that you can crack off that ring I mentioned, seen in the first picture. Deeper drilling will probably make the lugs much easier to punch out, which reduces the risk of bending the hub, though.
NOTE: Before you drill out lugs, try to punch each lug out from the front side. I got lucky, and two lugs acutally popped out. (They may have been lugs replaced some time after the car left the factory.) It took 2 hours or more to drill out the remaining 8 lugs from 2 hubs. I used a drill press. A hand drill could be used, but you'd have to be pretty careful to keep the drill bit perpendicular to the hub, so as to not cut into the splining (grooves) in the hub that keep the lug tight in the hub. I start the holes with a 1/16 bit and gradually increase bit size to one as wide as the lug threads. You might need to go a bit wider. Use lots of oil, and drill slowly.
Start drilling before you grind off the flange (lip) at the base of the lug. I found this made it easier to center my drill holes. You can then use a grinder to remove as much of the flange as you can. A small ring ( lug on right below) will be left on the lug, because it is lower than the metal of the hub. This ring will crack off when you punch the lug out. If it does not, drill a little wider.
Below, you can see where the lug on the left was drilled a little off center, removing some of the splines and cutting into the hub. You can also see on the splines on the right hand lug are flared out near where the threads begin. This deformation is caused by the swaging process that pressed the lugs in at the factory. This is why you can't punch out the lugs from the front -USUALLY.
NOTE: You do not want to drill too deep, as you may end up punching out the threaded part of the lug, but leaving a ring of the splined (grooved) part of the lug left in the hub. You are only going to drill a hole LESS deep than the thickness of the hub. In fact, you may only need to drill down enough so that you can crack off that ring I mentioned, seen in the first picture. Deeper drilling will probably make the lugs much easier to punch out, which reduces the risk of bending the hub, though.