Drilling 1" Holes

colu41

colu41

Joined
Dec 24, 2014
Messages
1,598
I'm thinking of making a Karambit style knife. But for the "pinky hole", my drill press will not drill that big. Is there other ways other than a mill? Or is that just a lot of filing then?
 
There are so many ways:

Drill a circle of 1/8" hole and cut them out...then file.
Use gradually increasing drill bits - 1/4-1/2-3/4-1"
Use a hole saw ( what most do). A 1" carbide hole saw is a very handy thing to have in the shop.
Drill it out to 1/2" and drift it to 1" ( for those who forge).
Take it to a friend or machine shop with a bigger drill press or mill.
Get twenty or thirty water jet cut with the hole included.
 
Damn, never even thought of a carbide hole saw. That sounds like my choice right there. Thanks Stacy.
 
Just how big of a drill press do you need to use a 1in drill bit? Could using a larger drill bit(with a smaller shank) damage a drill press? I have a larger Delta drill press and used a 3/4in drill bit the other day and the hole it drilled seemed a little off. The part drilled was locked in a xy vise. I slowed speed down to 200rpm and flooded with cutting oil while drilling of course.
 
JG Custom Metal Works said:
Just how big of a drill press do you need to use a 1in drill bit? Could using a larger drill bit(with a smaller shank) damage a drill press? I have a larger Delta drill press and used a 3/4in drill bit the other day and the hole it drilled seemed a little off. The part drilled was locked in a xy vise. I slowed speed down to 200rpm and flooded with cutting oil while drilling of course.
Click to expand...

I have a cheap HF press. I don't trust that thing drilling anything bigger than 1/2". And honestly I realized 1" is too big for what I was looking for. May only need 3/4"
 
Pick up a set of Blair Rotabroach Cutters, I use them at work to drill through 1/4" plate and channel all the time. The set I have is 20 years old and they are still sharp.
 
Chasing a hole with another larger drill can be sketchy.

When drilling a large hole on an industrial machine I'll drill a pilot hole the size of the web of the drill, then follow that with the big drill. I understand that sometimes a smaller machine might not have enough grunt to go directly to 1" so I understand the need to use intermediate sizes, but without the web engaged the drill is going to wander around so you probably won't get a round hole and there is a dangerous tendency for things to bind up. If you go that route you need to find the right amount of feed and back the hole with something. If only the corners of the drill are engaged in the cut it will tend to over feed. A 1" hole would be done at ~200 RPM. This is about as big as I'll drill on a full size mill.


I'm only mentioning this if someone wants to drill, but a hole saw is a better choice. You can drill the pilot hole for the saw separately and install a solid pin in the saw for better results in difficult materials
 
Thanks guys. I think I may just go with a bi-metal hole saw. This is just something different I wanted to make so MIGHT not have a frequent use. So ill start with a $10 hole saw for now.
 
Do they have boring heads that can be chucked into drill presses? I have one for my mill and that thing is just amazing.
 
Hey, Colu41, send me a PM before you buy anything. I've got a number of 25mm hole saws that I ordered by mistake instead of the 28mm and 32mm that I normally use. From experience, you can easily cut 32mm in mild steel, but 25mm in stainless will twist the spindle on the bigger 16 speed HF drill. Also, carbide doesn't work well if there is ANY wobble in the chuck. It will destroy the teeth on the bit if it wobbles, whereas a holesaw will handle it much better.
 
0fdf85c2-3434-40aa-9932-c8e22e23bb71_400.jpg
 
I've drilled countless 1" holes with this carbide-tipped holesaw from McMaster-Carr chucked in a cheap HF drill press. I think it was around $60-70, but if you're drilling lots of 1" holes, especially in high vanadium steels, it's worth its weight in gold! If you only need to make a couple-few holes, the much less expensive bi-metal holesaws may suffice. :)

photo-X2.jpg
 
Nathan the Machinist said:
Chasing a hole with another larger drill can be sketchy.

When drilling a large hole on an industrial machine I'll drill a pilot hole the size of the web of the drill, then follow that with the big drill. I understand that sometimes a smaller machine might not have enough grunt to go directly to 1" so I understand the need to use intermediate sizes, but without the web engaged the drill is going to wander around so you probably won't get a round hole and there is a dangerous tendency for things to bind up. If you go that route you need to find the right amount of feed and back the hole with something. If only the corners of the drill are engaged in the cut it will tend to over feed. A 1" hole would be done at ~200 RPM. This is about as big as I'll drill on a full size mill.


I'm only mentioning this if someone wants to drill, but a hole saw is a better choice. You can drill the pilot hole for the saw separately and install a solid pin in the saw for better results in difficult materials
Click to expand...

What a great answer. Chock full of the pertinent information, as always. Thanks Nathan :)
 
Shawn Hatcher said:
I've drilled countless 1" holes with this carbide-tipped holesaw from McMaster-Carr chucked in a cheap HF drill press. I think it was around $60-70, but if you're drilling lots of 1" holes, especially in high vanadium steels, it's worth its weight in gold! If you only need to make a couple-few holes, the much less expensive bi-metal holesaws may suffice. :)

photo-X2.jpg
Click to expand...

There's a bunch of different models on McMaster-Carr. Do you know which one of these it is?

http://www.mcmaster.com/#carbide-hole-saws/=z5k7v2
 
You must log in or register to reply here.
Back
Top