[RobinDobbie]

I don't know why y'all have such an aversion to modifying metal things. If there were flat, recessed areas on the bars, I wouldn't have to mess with anything else.

 

[ryan50hrl]

It's not that we have an aversion to modifying metal things that need modifying....it's that we tend to use things in the way they were intended to be used. There are thousands of guys that have bought these bars and use them with the tapered holes....and they work great. I think most of us are just against extra work for the sake of extra work.

 

[woodnthings]

modifying ...

I think you are letting the tail wag the dog here. There is no guarantee that the drill you show will self center in the existing hole, rather it probably won't. Wood should be the subject material not the metal. If care is taken to pre-drill the holes into the wood using the bar as the guide, the holes should be aligned properly, and the flat head screws will keep if from shifting afterward.
Feel "free" to do what ever you want, but that's my "free" advice.

I don't know why y'all have such an aversion to modifying metal things. If there were flat, recessed areas on the bars, I wouldn't have to mess with anything else.

I've modified more metal things than you would ever believe. Cut, welded, machined, drilled, countersunk, bent and re-bent... etc. I have a 13" metal lathe, 2 metal cutting bandsaws, 3 sheet metal brakes, a 3 ways to weld metal except TIG. I've drill enough holes in metal to sink a large ship including custom truck bodies, mobile bases for stationary power tools and buidling a 990 lb road scarifier for my tractor. Here's winch mount I just built:

 

[RobinDobbie]

It's not that we have an aversion to modifying metal things that need modifying....it's that we tend to use things in the way they were intended to be used. There are thousands of guys that have bought these bars and use them with the tapered holes....and they work great. I think most of us are just against extra work for the sake of extra work.

I hear ya. But I checked out the reviews on amazon for these miter bars and the first review was expressing my same concern for the coutersink holes. The one comment in response was to the effect that the double stick tape would keep the bars from moving, and ten out of ten people found that comment useful. I must be the only one who's dealt with adhesive in the heat. It likes to get gooey and slide around. I don't have an air conditioned shop. If the doors are closed and the fan's off, I have no idea how freakin hot it must get in there. I just know as much as I've gone through, I'm not going to rely on tape.

And, my miter slots in the table saw certainly weren't intended to be tight in the front and back. Modification was the only remedy, there, if I wanted to take full advantage of adjustable miter bars.

In no way did I mean to imply anyone here wasn't competent with metal. I was sure you were, which is why I asked about it. Does that make sense?

 

[ryan50hrl]

I hear ya. But I checked out the reviews on amazon for these miter bars and the first review was expressing my same concern for the coutersink holes. The one comment in response was to the effect that the double stick tape would keep the bars from moving, and ten out of ten people found that comment useful. I must be the only one who's dealt with adhesive in the heat. It likes to get gooey and slide around. I don't have an air conditioned shop. If the doors are closed and the fan's off, I have no idea how freakin hot it must get in there. I just know as much as I've gone through, I'm not going to rely on tape.

And, my miter slots in the table saw certainly weren't intended to be tight in the front and back. Modification was the only remedy, there, if I wanted to take full advantage of adjustable miter bars.

In no way did I mean to imply anyone here wasn't competent with metal. I was sure you were, which is why I asked about it. Does that make sense?

The sticky tape is to hold the bar while you drill and fasten with screws. I've used that trick before.