Drill bits

[Scott91370]

I am abut to take on the task of drilling out lug stud holes - 9 holes total - and need some help on picking the right drill bit. The current hole is .555" and I am going up to .609" or 39/64. I had a Bosch Black Oxide bit here in the right size so I gave it a try. First hole was great. Cut through with no issues. Went to start the second hole and it wouldn't even scratch the surface. I was only going about 400rpm to try and keep heat down but I did not use any oil or coolant on the bit. As easy as it went through it didn't seem like it needed it.

So, what type and brand of drill bits do you guys recommend? And what kind of coolant/lube/cutting oil so I can do all of these in one shot?

 

[sparky 1971]

I was on a job trying to drill a 3/8 hole in something, don't remember what it was. I do know that my brand new Bosch black oxide bit was barely making a scratch. A buddy pulled out his Drillco bit and blew through like it was nothing. I have Drillco bits in my Ebay watchlist but so far. I am too cheap to pull the trigger. I have also heard good things about Irwin Cobalt, but have no experience with them.

 

[Legion Prime]

Pretty much anything made in the US is going to be a good bet. Norseman, Chicago Latrobe, Viking, Atlas Cutting Tools, Cleveland Twist, CleLine, Morse, Ohio Drill & Tool, ICS Cutting Tools, Midwest Cutting Tools, MA Ford, Triumph Twist Drill etc. Keep an eye out sometimes there will be a group buy here from Norseman and I've even found good deals on Amazon. Just do your due dilligence, for example Precision Twist once a quality manufacturer is now made in Brazil and as always, caveat emptor.
For cutting fluid, pretty much anything labeled as such should get the job done, everyone will have their preferred flavor but if you're only drilling a couple holes even 3 in 1 will probably do.

 

[Ign]

Legion nailed it. Any US-made HSS. You can go cobalt if you want, but meh whatever.

Truthfully ya gotta learn to sharpen them. Otherwise it's like asking for magical tires that never need to be rotated. Learn to rotate your tires - empower yourself

 

[Bubba Fett]

Most of the drill bits you find in stores are only good for light duty. Even the high end (titanium coated, etc.) don't hold a candle to industrial-grade bits. Any of the ones Legion mentioned should be able to handle that. Be prepared to spend some money, though.

Legion nailed it.

Or did he drill it?

 

[Scott91370]

Most of the drill bits you find in stores are only good for light duty. Even the high end (titanium coated, etc.) don't hold a candle to industrial-grade bits. Any of the ones Legion mentioned should be able to handle that. Be prepared to spend some money, though.



Or did he drill it?

Smooth!!!

 

[ez-duzit]

I am abut to take on the task of drilling out lug stud holes...The current hole is .555" and I am going up to .609" or 39/64...I was only going about 400rpm...did not use any oil or coolant on the bit...

RPM is too high and you need to lube it.

 

[anndel]

Legion nailed it. Any US-made HSS. You can go cobalt if you want, but meh whatever.

Truthfully ya gotta learn to sharpen them. Otherwise it's like asking for magical tires that never need to be rotated. Learn to rotate your tires - empower yourself

I've used the Drill Doctor with great success.

 

[2ndGearRubber]

FWIW you are.going to thrash any bit in that application. You're drilling almost exclusively with the outer edge of the flute. The bit will be fighting to grab, and after break through will want to aggressively self feed.

American made is the best I've found. Buy them and enjoy bits that actually drill. Tap magic or boelube lubricant, drill doctor to fix up the larger size bits.

 

[Scott91370]

Thanks for all the input.

I bought some cutting oil, turned the drill to the lowest rpm and used a Celine bit. Did the remaining 9 holes without any problems. The bit barely got warm to the touch at the end of each hole. I would drill one adding a drop or two or cutting fluid every so often then let the bit sit about 5 minutes before moving to the next one. Each hole only took about a minute to get through.
The right tool for the job always makes it easier!

Thanks again!

 

[nbpt100]

Industrial drill bits are the way to go for any kind of steel drilling. I have learned the hard way. Most of the stuff at Ace, Lowes and Home depot are fine for soft materials. But you need industrial HSS or harder for serious drilling.

I have considered a Drill Doctor but keep getting side tracked. When I researched it I heard the pros and cons. I think those who do not like it eather got a lemon or do not know how to set it up. Set up it critical for any precission type of work and that is what drill sharpening is.

 

[kelpaso1]

I have considered a Drill Doctor but keep getting side tracked. When I researched it I heard the pros and cons. I think those who do not like it eather got a lemon or do not know how to set it up. Set up it critical for any precission type of work and that is what drill sharpening is.

Agreed. I have one and it sharpens bits just fine. Almost even too good as the bit wants to grab a lot.

 

[Crabman]

Some GJ folks like the Norseman vortex moly bits

 

[Rinspeed]

I've had such great luck with Norseman over the years I've never thought to look elsewhere.

 

[Legion Prime]

Industrial drill bits are the way to go for any kind of steel drilling. I have learned the hard way. Most of the stuff at Ace, Lowes and Home depot are fine for soft materials. But you need industrial HSS or harder for serious drilling.

I have considered a Drill Doctor but keep getting side tracked. When I researched it I heard the pros and cons. I think those who do not like it eather got a lemon or do not know how to set it up. Set up it critical for any precission type of work and that is what drill sharpening is.

Dude I worked with back in the 20th century bought one when they first came out. I had a drill bit I must have taken a half inch off of from resharpening I used it so much. It isn't hard to get set up and as long as you pay attention and get it set up correctly they work AWESOME! I can't even begin to imagine how many bumpers I drilled through with that one drill and giving him 50 cents each time I used it was a real bargain.

 

[Rinspeed]

At the shop we have a SPG sharpener and what a work of art it is. Not cheap at all but it makes getting the perfect angle a lot easier.



https://www.travers.com/tdrsrd-drill-grinder/p/87-145-075/