Alright what am I doing wrong: drilling hot rolled steel

[Jeff in Pa]

Originally Posted by ford4150

Select the slowest speed your drill press can turn. Feed slowly.
The best bits I have found are made by "Ridgid", sold at my local Home Depot.

Originally Posted by Yosemite Sam

There is nothing special about hot rolled, are you drilling a pilot hole first?
And yeah, get yourself a Drill Doctor.

Slow speed and a constant feed rate. Motor oil is much better than WD-40 as a cutting fluid. Start small and step your way up to the size you need.

Have a grinder with a smooth face on the wheel? ( not all hacked up ) Drill bits are easier to hand sharpen if you touch them up when they just start to lose their cutting edge than pushing them to far and having to grind back the cutting edge.

Here's a youtube video of how to hand sharpen a drill bit. I don't move back and forth but the process is the same
https://www.youtube.com/watch?v=ZlqrddCRqNM

[olds45512]

Originally Posted by jimbob200521

Slowest speed? Thought metal wanted speed?

When it comes to metal slower is always better, going fast just heats up the bit and makes it dull.

[Sam Mac]

Google

https://www.google.com/?gws_rd=ssl#q...hardened+steel

[mrmiller]

I typically use a 3/16" stubby drill bit for a pilot hole and then you could step up to 3/8" You don't necessarily want speed it all depends on your material and drill bits. Certain bits are made for "high speeds" others are not. The best drill bits I have ever used were Precision Twist brand bits which are for high speed mild steel material like what you are drilling.

[Jeff in Pa]

Originally Posted by jimbob200521

Slowest speed? Thought metal wanted speed?

There is a thing called "surface footage". You need to match the cutting tool diameter with the material you are cutting to figure out the correct rpm.

Instead of the formula I use at work, here's a chart of surface footage for materials
http://img.photobucket.com/albums/v7...1.jpg~original

Match the surface footage to the drill diameter
http://img.photobucket.com/albums/v7...9.jpg~original

[john hall]

A good quality 3/8 drill (ordinary, not a high production grade/design) in a machine shop in a rigid setup will run at 900 RPM's with plenty of coolant. In a CNC mill with flood coolant you could push it up to about 1050. On a manual mill probably more like 700. I assume you are on a drill press or hand drill, I'd keep it at around 450-600 and use a heavy oil--at least motor oil. WD-40 is too light for much of anything, maybe aluminum but it will still get you in trouble there. If your chips are blue, you are running too fast. Carbide can tolerate blue chips, HSS tools can't.

If you must buy more drills to finish the project, try to get something made in the USA if it is available local without paying a fortune. I would stay away from China and certainly no crap from India.

You shouldn't need a pilot hole, at least we wouldn't even think about it at work unless we are using a hand drill. I assume the tool is turning reasonable true in the chuck? That could cause some serious premature wear on the corners. As was suggested, try re-sharpening the drill as soon as it becomes dull. The best way to do that if no one is around to teach you is to watch a couple videos and then start grinding one that is burnt up until it looks just like a new one. Keep the angles the same, both the point and the clearance angles. Too little/no clearance and it won't cut at all. Too much and it will try to pull itself into the work causing the drill to stall or the point to break.

If you have time, order some drill bits from MSC. You don't need anything fancy, a good set of no-name made in USA will work fine, jobber length would be best for around the house. Unfinished or black oxide will work just fine, no need to pay extra for TIN coatings (gold).Trust me on this one, I purchase all the tooling for a 25 man machine shop and we just use mid grade tooling unless I have need of something more high performance for a large CNC run. FWIW, most of what we work with is tool steel.

[Billy-O]

You're not drilling in reverse?????????? I've seen this sh happened before!!!!!!!!

[jimbob200521]

Wow thanks for all the advice guys! Got a fresh day ahead of me with some new knowledge so I'm anxious to sharpen some bits and see what kinda damage I can cause

[Jumper]

Originally Posted by Billy-O

You're not drilling in reverse?????????? I've seen this sh happened before!!!!!!!!

That's hilarious but true ! Production line techs would borrow the magnetic base drill press and drill bits for mounting guards and such to machine bases. The defective drill bit would come back with the bit web looking like the end of a used welding rod...... Those wiz kids were amazing with key boards, ladder logic and electronics, they just needed to ask for help once in a while.
Hot and cold rolled steel is not the same now as it was back in the 70's and 80's, most now is made off shore and loaded with anything that will stick to a magnet. If you do go to some place like McMaster Carr or Fastenal for drill bits, also buy a number 2 and 3 center drill. They are accurate hole starters and give your drill bit a fighting chance at the start.

[green 4 acres]

You need to drill a pilot hole over 3/16"
They make bits that have them built in
I like the 1/8" production bits H F Sells for the pilot hole they drill 4130 like mild steel
I did not see the post above