It will be on a multi spindle Komo cnc router, so actual tool change times on my machine are very quick as they are already there along for the ride, just have to retract current tool/spindle, then drop new one and turn on. If I am running it at 18K, then it does take a short time to get up to speed, but nothing like swapping tools in a single spindle machine, especially if it is a 12ft bed machine and has to go all the way back home to get it.
If I were to run 3 separate tools like I did on the test, I'd still run all holes with one tool before switching to the next.
To be honest, I will probably do the pilot drill and finish it with a 1/4" router bit. It is just one of those things that if it turns into thousands of holes, it may be worth a custom tool. My test I ran all 3 tools at the same rpm to see what it would do. Good results on all three. The 1/4" drill I used is a carbide tipped spur bit used commonly in pt to pt machines for dowel holes or shelf pin holes. I was able to plunge one shot, no peck at 2500 rpm and 100 ipm. Not sure as to long term use without a peck cycle, but I bet it would be fine. It pulled a nice chip, not alot of dust.
It will be backed up on a spoil board so blow out should be minimized if any.
Richard, there are a few options, I can do the custom tool, make it one shot per hole, or I can use a combination of tools. If I do the pilot drill, I may use the current 1/4" drill, then a 1/2" router bit, then interpolate the 1" with it. Would save a little bit of time by just plunging or drilling the 1/2" step and then it could interpolate in one pass vs a couple for the 1/4" as I am sure it would leave a thread of a burr to get rid of if I only did one pass around the 1" counterbore with the 1/4" bit.