re drilling drums for new pattern?

is there a problem with redrilling the bolt pattern on my drums. they are a chev 5 on 4 3/4 i think. i need to go to 5 on 4 1/2. they are big 11" drums with plenty of room to drill a new pattern. i don't think i would compromise the strength enough to be an issue. just wanted some reassurance.

 

I have done it on rotors before, worked fine. Go for it.

 

Just make sure tou get them lined up perfect before you drill !

 

thats my biggest concern. i made a template out of clear plexi that should be good.

 

Take a straight-edge, and lay it on the drum so one end goes through the center of the lugnut hole on one side of the big center register, the other end of the straight edge goes between two lug holes. Take a sharpie marker and mark a straight line corresponding between the two lug holes.

You can go overkill and do this for all 5 lug holes, but it isn't necessary.
The sharpie line is now where your new lug holes are going to be located.

I did this with a set of new Moser axles on my 8 3/4-rear end, redrilling the drums for a Chevy bolt pattern.
I set the newly marked drum on the ground, set the axle flange on top of it, lined up the empty stud holes in the axle flange with the sharpie marks I made, took a transfer punch and made the dimples. Then drilled.

-Brad

 

I have done this a couple times & have used a wheel adapter as a drill guide

 

You are actually talking about drilling either front hubs or rear axle flanges which is where the wheel studs mount. How feasible it is depends on the back surface of the hub or axle flange. Some have ribs or slanted surfaces on the back side which require some spotfacing or grinding.
Redrilling drums is not a problem.

 

If the register hole in the drums you are using fits the axle flange drum register snugly then you can yuse a 1/2" mill to slot the hole the 1/4" inboard. The wheel will hold it on and it will register on the axle.

Charlie