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
Today in the shop "Making 3/4" holes in to 20mm"
Moderators: HopefulSSer, admin
Today in the shop "Making 3/4" holes in to 20mm"
{Knight of the Shopsmith} [Hero's don't wear capes, they wear dog tags]
-
- Gold Member
- Posts: 109
- Joined: Sat Sep 12, 2020 9:41 pm
- Location: Spring Creek, NV (by Elko) Northern Nevada
Re: Today in the shop "Making 3/4" holes in to 20mm"
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 almost want to drill too small of a hole just to try it out.
- dusty
- Platinum Member
- Posts: 21371
- Joined: Wed Nov 22, 2006 6:52 am
- Location: Tucson (Wildcat Country), Arizona
Re: Today in the shop "Making 3/4" holes in to 20mm"
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.
Thanks Ed.
"Making Sawdust Safely"
Dusty
Sent from my Dell XPS using Firefox.
Dusty
Sent from my Dell XPS using Firefox.