horrible outcome when drilling metal tube

[jscpm]

Put a tight fitting wooden dowel into the pipe before drilling it.

Drill from the outside only.

 

[Limy Sami]

If you're getting burrs that you can't bend with pliers you probably need to sharpen your drill. What speed are you running the drill? If you're going way too fast you will be dulling even a new one almost instantly. If you took 25 minutes to do one hole, something is very very wrong. Drilling that hole should take no more than a minute.

X2 on that, my first thought was a blunt drill being run too fast.

 

[DDoug]

"Horrible Outcome" is a simple burr ?

You've got more problems than that.....

 

[EPAIII]

To me it looks more like you melted your way through those holes instead of drilling. Yes, get a sharp drill bit and use a slower speed.

In the drill press I frequently put a drop of oil in the upper end of each flute and then drill the hole as quickly as possible as the oil drips down to the tip of the drill bit. The 3/8" hole you show should only take a matter of seconds to poke through.

Don't try to feed the bit too fast and, once you start cutting metal, KEEP GOING down at a moderate feed rate until you break through.

If both sides of the tube are drilled in one pass, I would expect somewhat of a burr on break-through, but no where near as much as you are getting.

If you're getting burrs that you can't bend with pliers you probably need to sharpen your drill. What speed are you running the drill? If you're going way too fast you will be dulling even a new one almost instantly. If you took 25 minutes to do one hole, something is very very wrong. Drilling that hole should take no more than a minute.

 

[kb0thn]

If you want perfect holes and have the time and money, you can use a Cogsdrill to deburr inside and outside. I have used the Cogsdrill on the VMC for a while and it has done a nice job deburring the inside of 17/32" holes through stainless steel. I recently used it with a handheld drill to deburr some holes in stainless round tube and it actually worked really well. Could let the hand drill "ride" around a bit and really clean the burrs off.
Burraway | Deburring Tools by Cogsdill
(MSC stocks these in the US)

If you want sharp non-chamfered holes on the inside, you can use a "dingleberry" type hone in take mostly smooth to perfectly smooth.
Object moved

 

[BT Fabrication]

I have been trying to figure out how to drill holes through round 1" ERW (11 gauge). Each time I drill, the hole that comes out the far
side of the tube has 'ridges' (I'm not sure of the term) when the bit exits. I've included some photos of the exit hole.

I am using a drill press. I apply a good amount of drilling coolant/oil and clean off the drilling shavings every 15 or 20 seconds of drilling.

I tried to delete the last photo (on the right). That is the inside of the entrance hole and it didn't get 'cleaned' out. I'll save that issue for later...if I can figure out the exit hole problem.

Would you have any suggestions on how can improve this so the outside of the exit hole is smooth?

Thanks.

all drilling actions in tube do this. its all the nature and geometry of a drill press and always requires cleanup after. metal is like we spaghetti and malleable

most drill presses always run to fast for anything larger then 1/2" but with all the problems, cheap drill bits are not the answer, good drills that are sharp, and pecking isnt your friend, all it does it burn out the drill tip by getting it hot and annealing the drill bit.

i can drill 3/4" holes in steel in less then a minute, something major is wrong...

 

[michiganbuck]

The first photo looks like you are mushing/deforming the material. That might come from the drill edge not being sharp enough, the drill not having proper clearance, or you are pushing too fast/too hard. The cutting edge should be fingernail shaving sharp...and should have little or no at the corner wear land.

Setting up a drill sharpening fixture, even if for your bench grinder would be an asset. you can have a bar to clamp to your bench grinder table for 30* angle, and just facet bump to a straight dressed wheel at 12 x 30*...and then roll the heal round.

Proper drilling should leave a burr that you can almost knock off with your fingernail. We used to make a short 3 corner file scraper to remove the exit burr.

If this is an often run job you might have/make a special/custom vise insert that has a radius pocket to support the tubing OD with a 1/64th larger hole at the exit place...The vise clamped to the table so to retain the position.

Having a TC grinder you might try a 1/64th x 45 x 12* corner bevel on your drill.

For a long run like this have a dozen drills so there is a sharp one at hand...all sharp.

 

[Mtndew]

Would you have any suggestions on how can improve this so the outside of the exit hole is smooth?

Having a smooth exit hole is unavoidable in your situation.
The best way to do this is to only drill through 1 wall at a time, then rotate the part 180 degrees and drill the other side.
This will force the burr into the ID of the tube, leaving the OD having the best possible outcome.

 

[boslab]

Drill from both sides, drill one hole every piece, use the hole to index the part for the next hole the other side, short of expensive press tooling
Use coolant
Just ideas, it’s a gnarly burr, you’d think “ that drill must be as sharp as sun dried dogshite but really crappy tube is an option, try a different length, the tube could be laminated ( ie skin lam in the sheet before tube forming
Mark

 

[GregSY]

Drilling from both sides negates one of life's greatest, and rarest, joys.....drilling two holes without having to re-setup the part.

 

[Illinoyance]

Switch to a Blair hole cutter or an annular cutter.

 

[iowaguy]

I'm the original poster.
I've made a video of me drilling the tube.

Some things to note are:
--the drill press table really starts to wobble as soon as the bit touches the round stock.
--the drill bit stops spinning (gets stuck) when I move up to the 3/8" bit.


Drilling metal tube -- what am I doing wrong? - YouTube

If you have the 8 minutes to watch the video (or parts of it), let me know what I'm doing wrong and/or what I need to do to improve.

Thanks

 

[neanderthal mach]

Uh dumb question along with stating what should be obvious. But with all the previous posts that pretty much covered your issues and possible solutions. Then if you go to the trouble of taking and posting a YT video, why not just do a search there about drilled hole deburring? Between the two sources you'd have just about anything you could want.

 

[iowaguy]

X2 on that, my first thought was a blunt drill being run too fast.

Recently, I've been at 220rpm and getting the burr. I did notice that the center drill bit and the 1/4" bit went through the tube smoother at 830rpm though.

 

[BoscoDrummer]

Ellipti-Bur tool

Perfect for your situation

Ellipti-Bur | Deburring Tools by Cogsdill

 

[GregSY]

Well...your drill press is a POS, or at least something is off with it. It's wobbling even before you start drilling, and the chuck has lots of runout. It's like you have something stuck under one corner of the foot.

It's hard to tell RPM from a video, but it looks that your spot drill is spinning too slowly.

Regardless, even with a good setup you'll have a burr unless you go to extremes. Extremes are for special cases. Just grind/sand off the burr and get on with it.

 

[iowaguy]

Uh dumb question along with stating what should be obvious. But with all the previous posts that pretty much covered your issues and possible solutions. Then if you go to the trouble of taking and posting a YT video, why not just do a search there about drilled hole deburring? Between the two sources you'd have just about anything you could want.

I've been using Titanium Nitride (TiN) Coated 3/8" bits from McMaster-Carr. I don't use them for more than 6 or 7 holes because I always think they're dull.

I have looked up deburring but it may be only part of the problem. I have watched dozens of videos of people drilling 3/8" steel (including stainless) and they don't have a burr that is noticeable. I have no problem doing the task of deburring but I don't want to mar the outside of the tube.

 

[dcsipo]

Recently, I've been at 220rpm and getting the burr. I did notice that the center drill bit and the 1/4" bit went through the tube smoother at 830rpm though.

Drill the first hole with a 3/16" or so bit through then drill the hole with a bit that is 1/64" smaller than the final size then drill to the final size at a higher RPM something like 400 or so. Deburr with one of that s-shaped Noga thingie.

 

[awander]

Wow, that video was almost painful to watch.

First, as was mentioned above, get the drill press itself to stop shaking all over the place. Is it on a sturdy stand? The way it is wiggling, it looks like it is suspended from a cable.....

Then, figure out why your drill is stopping. Is the belt on the drill press slipping? Or is the drill spinning in the chuck? Either way, fix it.

There is no need to worry about the chips when you are drilling something as thin as those tube walls. You are just wasting time with that magnet. Also, you're going to magnetize your vise, so that in the future, chips will stick and be a pain in the ass.

I think you are spinning the drill too slowly, and also feeding way too slowly. You don't need to baby it. You can push it way more than that and will have a better outcome.

 

[dgfoster]

ERW tube---electrical resistance welded. OK. But what alloy? If that is just a low-carbon unhardened tube (which is what it looks like as far as chips are concerned), then your bits are dulling way to quickly and probably because you are not causing/allowing them to cut but rather they are rubbing. Just speed it up some, put a little pressure on the bit until it starts raising chips pretty vigorously. That spotting should take about 5 to ten seconds, maybe. The hole should take maybe 30 seconds or less to cut.

What others have said about your drill press...jeez.

Denis