Technical Drill preference

Hey everyone, Just a quick question about your choice of good quality drills for metal. I've bought a few sets that were supposed to be good quality drill bits but turned out useless for drilling metal. So what are you guy's using ? Thanks !!

 

I was curious about this as well, so a couple of years ago, I looked this in depth, and this was the result : https://www.jalopyjournal.com/forum/threads/drill-bit-recommendation.1134851/#post-12893939.

 

I have a set of Norsemen (made in USA) stainless and they are awesome. Around $90 on Amazon for 29 piece set. Well worth the cost

 

X2....good bits for the money. Also have the 12 piece quick release set for my impact drill.
https://smile.amazon.com/gp/product/B0077P8ZRQ/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
https://smile.amazon.com/Viking-Norseman-66480-Premium-Mechanical/dp/B001C92C04/ref=sr_1_5?crid=F4SOE1LG560Q&dchild=1&keywords=norseman+drill+bits&qid=1613843500&s=hi&sprefix=norseman,tools,1014&sr=1-5

 

Drill Hog set. I use their cobalt M42 bits, and love them.

 

I use a relatively inexpensive set of titanium coated high speed steel bits for mild steel and aluminum. For tough (stainless steel) or hard materials (tool steels), I have a too expensive set of solid carbide bits (US made ~$700 for a 115 pc set). They don't get used much so they've lasted for many years. And don't lend them to anyone else to use. I hate replacing one at a time, because the cost is even more ridiculous.

 

A steady hand and drill bit lube goes a LONG way in bit life. Even when drilling softer materials.

Mike

 

As well as speed , speed kills drills !

 

I use Greenfield Industries HS bits for most softer metals. 118 degree point, and sharpens easily in my sharpener. For hard metals, I use Partsmaster Cryobits. Keeping the bits sharp, Running them at the right speed for the metal, and as Mike says using lubricant makes all the difference.

 

Yes indeed! Aluminum-Windex, sounds goofy but works really good, parafin-cast iron, rub on the bit before and during drilling (learned those 2 from a friend years and years ago don't ask how many...). Mild steel-Tap Magic or chain oil for a chain saw (discovered that one by mistake one day, grabbed the wrong bottle of oil to fill an oil can, and wow it worked good, so...serendipity). Don't work with many other materials much so no practical experience recommendations.

 

I’ve seen people dull good bits using high speed drills, I keep telling them make a pilot hole first. I have a bunch of cheap bits I use in my drill press, steady pressure and proper speed with water/soluble (sp) oil to keep the bit cool. I rarely have to sharpen them.
The larger the bit, the slower the speed you need. Somewhere I have a chart I got from when I took a JC machine shop class.

 

Feed and speed rates are the key. I see a lot of dulled/broken drill bits by people who think faster is better. My favorite was a guy who was drilling 3/4" holes in square tubing; had the drill press at 6000 rpm and a cheater pipe to reef the bit through. Most of it got scrapped because they were to be fitted with bushings and a part to slide inside, but the material was bell-mouthed.

 

my dept at pratt whitney jet engines tested everything(imagine drill/tap over 1k holes a day) and wrote the machining specs for aircraft material. some nasty stuff out there you will never see in our toys. minimum spec for drill, mills, taps and dies is cobalt m42. carbide only used if used in a machine where part doesnt move. correct feed /speed and the tool will last a long time.

 

As stated above, too high of rpm will kill a drill bit.
An easy way to determine the rpm for drilling in mild steel is this formula:

350 / Diameter of drill bit.

Example: 3/8” drill bit is 350/.375= 930 rpm.

That’s a little conservative, so if the chips aren’t blue, you could go faster. If you use coolant, you could go faster.

I would recommend getting split point drill bits.

I also like the short length drill bits. Unless your drilling deep holes, jobber length isn’t necessary.
I’ve had good luck with these black oxide coated short length.

https://www.mcmaster.com/catalog/127/2628?SrchEntryWebPart_InpBox=drill+bits




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That's all great information from some very knowledge people. Thank you all, I learned alot

 

Bought a drill set off the Snap-On truck in 71 or 72. I've drilled a lot of holes with them in steel and aluminum. I keep them sharp and I've only had to replace a couple of the smallest bits that I broke (my fault). About 8 years ago I bought a Drill Doctor and they are much easier to sharpen now. When a bit stops cutting it only takes a couple of minutes to sharpen it instead of carrying on with a dull bit.

I also inherited my dad's drills and bits. I did find one or two that were actually sharp. He bought cheap, (a child of the depression), and wasn't good at sharpening them. He bought a Black & Decker drill bit sharpener which I also inherited. I followed the instructions but was never able to sharpen a single bit with it.

 

It's a great skill to learn to sharpen drills by hand on any old grinding wheel.
The drill "inventory" at one repair shop I worked at was a big bin full of dull drills, the boss was pretty impressed when I took one of the right size and sharpened it in a few seconds on the pedestal grinder.

But then I was rewarded by being allowed to spend most of the day sharpening the big ol' pile of wrecked drills. Not fun, after a couple hours.

 

We also use a drill doctor at work to sharpen drills...

 

I've used different sharpeners, or as some of the old ones were called, "Drill Pointers", but never had luck with the Drill Doctors.

 

A good variable speed drill is a worthy investment also. One speed doesn't work with many drill bits....

 

I had a guy give me a Drill Dr a few years ago, I think that pile of junk is under one of my benches someplace. When I was young, I worked in factory maintenance. They sent me to a guy in the machine shop to have him teach me how to sharpen drill bits on a bench grinder. It was one of the best things I ever learned.

I've drilled a lot of holes in a lot of materials over the years in my welding shop. Breaking small drill bits is sort of an expected end result of drilling through one piece of metal and catching the one under it at an angle. I usually get about 5 years out of the set of a 21 piece $40 index drill set, usually using nothing but water as a coolant, if I use anything at all. Usually cutting oil in a welding shop causes a lot of problems.

Split point drill bits and a variably speed drill are a must. A pilot hole nearly always helps with larger diameter holes in thicker material. Gene

 

I use baby oil for lube. It also takes the grease right off my hands and makes putting gloves on easy..