Shopsmith Forums

I do not recall the who or the when but I got this idea from somewhere. Wish I could give credit.

Let start with what is happening. You have a nice 3/4" hole. Thing is you wished it were say 20mm. As you may know 3/4" is smaller then 20mm so it clearly can be done, right?

Say this is your hole:
The bit you want to use looks like this compared to the hole.
You could take various routes to do the drilling but today we will look at using a step drill. In this case I happen to have a 20mm spiral groove version.
By design the bit is self centering and has a chamber to help get it started. As a result you can get a hole that looks like this:
Now the bit has a nice place to start as shown here:
This is of course not the only way to do this but it sure works slick.

Ed

Nice. That is much easier than anything I've used so far.
I almost want to drill too small of a hole just to try it out.

I depend a lot on my step drills but now I need to go get another one. I want to have a metric in my tool box.

Thanks Ed.

Great tip.