Drilling 1/2" holes in 1/4" HRS plate

[Wreck™Wreck]

1/2" is a small hole so no pilot drill is required.

1/4" drill depth is only .5 diameters so drill through in one shot, no pecks needed, this should take less then 30 seconds per hole of spindle time.

Do not be afraid to push the drill harder then you think safe, you want it to cut a thick chip at all times, if it just rubs the work it will dull quickly.

One of the problems when using a drill press with an uncontrolled spindle is the tool digging in upon exit so place a piece of scrap material underneath then drill through the part and into the backing material, this will not allow the spindle to jump.

Good Luck

 

[ACHiPo]

1/2" is a small hole so no pilot drill is required.

1/4" drill depth is only .5 diameters so drill through in one shot, no pecks needed, this should take less then 30 seconds per hole of spindle time.

Do not be afraid to push the drill harder then you think safe, you want it to cut a thick chip at all times, if it just rubs the work it will dull quickly.

One of the problems when using a drill press with an uncontrolled spindle is the tool digging in upon exit so place a piece of scrap material underneath then drill through the part and into the backing material, this will not allow the spindle to jump.

Good Luck

Wreck,
Thanks. I was wondering if I might not be pushing hard enough. Will try again with the cobalt drill today.

I don't have much in the way of scrap metal yet--would wood work to back up the part?

Also, given the relative low power and rigidity of my Atlas drill press, I'm assuming I need to drop the speed as low as it will go and feed as high as I can? Even though I don't need to pre-drill, might it better allow the drill motor to keep up with chip making?

Evan

 

[ACHiPo]

Thanks to your advice, things went much faster today. The drill was definitely dull. The cobalt drills were too short (screw machine length), so ended up using a 9/16" Silver and Deming HSS bit and things went much better. Used scrap wood as backing and that helped a lot, although my belt kept slipping which limited how much feed I could give.

Need to get a Drill Doctor!




The finished product--leveling casters for my lathe bench.

 

[Wreck™Wreck]

Wreck,
Thanks. I was wondering if I might not be pushing hard enough. Will try again with the cobalt drill today.

I don't have much in the way of scrap metal yet--would wood work to back up the part?

Evan

Better then nothing, the goal is to control the feed of the drill when it goes through the far side, if a machine with an uncontrolled spindle is used for drilling at a rate that the drill will live through it will auger in like a wood screw when it passes through the now very thin far side. Anything that impedes the drills sudden uncontrolled progress is good.

I believe that you have just learned something, keep at it and it all make perfectly good sense in time.

 

[ACHiPo]

Better then nothing, the goal is to control the feed of the drill when it goes through the far side, if a machine with an uncontrolled spindle is used for drilling at a rate that the drill will live through it will auger in like a wood screw when it passes through the now very thin far side. Anything that impedes the drills sudden uncontrolled progress is good.

I believe that you have just learned something, keep at it and it all make perfectly good sense in time.

Wreck,
I learned quite a bit in the last two days. I've drilled countless holes in my life, never paying much attention. Now that I know a little bit about what's actually happening when the drill is cutting, it's pretty clear what was (or wasn't) happening.

Evan

 

[markba633csi]

I've found that I get better hole placement accuracy when I use at least one and sometimes two pilot drills when drilling 3/8" and larger holes. And the center punch
dimple has to be right on target for a perfect hole.
Mark S.

 

[tq60]

As mentioned before the Web is what matters.

We had wrong information commonly given to step up drill sizes and this may have been likely due to under powered equipment being common.

If drilling through sheet stock or less than 1/16 thick a step drill can't be beat as it is a controlled cut.

Anything else the Web at the tip determines the pilot.

Use a stout center drill to spot your punch mark then through drill pilot size of web.

1/2 drill can go first but 1/8 will work fine as the Web does not cut well.

Sunday we drilled a 1 inch hole in steel with 1/4 pilot with the lathe and we gave it good pressure and it came out fine.

Most important is correct speed and slower better than faster and give it lots of pressure and it will come out fine.

If you need to be sure the hole stays centered on the pilot a step drill is self guiding and can be used to open the hole to size of final size.

Sent from my SAMSUNG-SGH-I337Z using Tapatalk

 

[Downwindtracker2]

Having drilled more than my share of holes in plate, by hand, it comes down to the drill's point. The best millwright I ever worked with taught me that. He was an excellent machinist ,too, but that was only one of his many skills. We would take a drill new out of the package and sharpen it. It made our life so much easier. You can achieve the same ease by using cobalt 135 degree split points stub drills. Don't bother with a drill doctor, the cheap General jig works better for the small stuff.

 

[Silverbullet]

From what I read he has never sharpened a drill bit. The other is he kept using after it was dull. When a drill starts singing and jaming up its done or even ruined.
I have several of the cheap step drills from HF and I've drilled hundreds of holes with the set off hand drill press and mag drill. The set is at least ten years or more old. For the holes you drilled one of those bits would cut from punch dimple to the 1/2" with one bit . There good for up to the 1/4" or 3/8" metal . For my $8.00 they're better then many other brands. Just my opinion and I use angle iron hot plate steel and no grinding just center punch. Even galvanized steel .

 

[JPigg55]

I agree a sharper bit is in order.
Another thing you can try is putting a small piece of cloth between the bit and metal.
It's an old machinist trick I saw on YouTube somewhere. Helped prevent grabbing and made holes rounder on thin material.