Need to Fill and Redrill Frameless Shower Door Mounting Holes

[jkmason]

Good morning, I'm in the process of mounting a frameless glass shower door. First attempt was off by about 1/8".

My mounting holes are 5/16" wide (4 per mounting bracket) and drilled through 1/2" beige travertine. The holes will be hidden behind the mounting bracket.

I picked up a scrap piece of travertine and drilled a couple of 5/16" holes to practice filling and redrilling.

My first attempt was to fill with Bondo. After the product set, I drilled another adjacent hole, but the drill bit just slid into the softer Bondo.

What would be a good product to use in this situation?

[LLigetfa]

What I've done in the past was to use some stainless steel wool and epoxy to fill the hole. Then, to keep the drill from walking sideways, I use a dremel tool to start the hole or a wood block as a guide hot glued to the tile or stone.

[jimbo]

One idea would be to drill a small hole..say 1/8" ...at the new location, then use a Roto with a sprial bit to "worry" that hole big enough for your anchor or bolt.

[jadnashua]

A diamond core bit has no center point - it's essentially a piece of pipe with diamond dust on the end...it probably wouldn't walk. What's the finish on the door? Could you just make the hole a little bigger? A rotary device like a RotoZip with a carbide bit could probably make the hole bigger fairly easily...travertine isn't all that hard.

[jkmason]

Thanks everyone for the advice and all the great ideas. I love the idea of mixing in the stainless steel wool. That got me to thinking. I decided to mix up some crushed travertine (1/8" average size) along with the bondo. I'm working on a test hole to see how it drills. I'm also going to try the stainless steel wool idea.

I tried the diamond core bit, but really had trouble getting it to stay in one place. Right now I'm using glass/tile bits. I'm going to start out with an 1/8" bit and then move onto my 5/16" bit. I'll let you know how it goes. This HEAVY frameless shower door leaves no room for error or adjustment so I need to drill very accurate holes.

[jadnashua]

The magic on using a core bit is to start it at about a 45-degree angle, get an edge divot, then slowly bring it up so it's vertical. This keeps it from walking around. Another way is to drill a hole through something, double-stick tape it in place, then use it as a guide. If you don't keep it wet, you'll wear it out, though.

[jkmason]

Hey Jim, since I have the bit I'll try your technique and make sure to keep the bit wet. Thanks, Jack.

[jkmason]

Back again. Just tried redrilling the newly hardened mix of broken travertine chips and bondo. Worked like a charm. Drilled spot on with no wandering. Thanks everyone for the help. Jack