Might not be the best place to put this. I might have posted this before, but I don't remember. I've broken too many cheap drill bits over the years and I'm tired of having all my incomplete set laying around. What brand of bits do you like for drilling in metal?
Metal Twist Drill Bits
- Thread starter djg james
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That depends what metal you are drilling and what you are drilling with.
My experience is premium bits work great in a press or mill with things clamped down solid.
If you are drilling with a hand drill a softer bit is better. The premiums will break if they are flexed, and it is easy to flex them with a cordless, they snap like glass. There are a lot of variables to select the best bit for the job.
Both cordless and drill press. I know keeping them sharp and using a lubricant are important. But I thought premium bits wouldn't be as brittle as you're suggesting. Maybe I misunderstood. I drill through Aluminum, which there is no problems, to mild steel mostly. 1/4" thick stuff kills my bits. And recently, I had to drill through a hardened steel bike axle, where I broke two bits.
Good tools aren't cheap and cheap tools can get real expensive.
CL bits are pretty good as are norseman, cleveland twist, triumph and champion.
For drilling in a cordless I have had the best luck with irwin and dewalt.
A good high speed steel drill bit from MSC is going to outperform anything from Irwin and Dewalt. They're not in the same league. I have a nice set that includes the fractions, letters, and numbers. It's great to have every size drill bit on the chart.
Any angle placed on them or if they bind when drilling with them and the premium bits snap like a piece of glass.
The cheaper bits are more forgiving when drilling in less than ideal places.
If we are going to push performance I pull out the hougan carbide annular cutters, its like drillin butta!
There is a wide variety of "High Speed Steel", each alloy having it's advantages and disadvantages. Quality bits will specify the grade. At the bottom end of the scale is T1, which has the advantage of being cheap. Ok for softer metals like aluminium, but won't last long in steels. M2 is a tungsten-molybdenum steel and about as hard as T1, but tougher, so less likely to snap. Good for drilling mild steel by hand and not stupid expensive.
Cobalt can be added to the alloy to improve heat resistance and edge retention. M35 is a 5% cobalt HSS and M42 is 8% cobalt. Both are suitable for drilling medium to hard steels, M35 being preferable for hand-drilling and M42 for machine drilling. This is because M42 is harder and will retain an edge longer, but hardness comes with brittleness, so M42 is not as tolerant of misalignment. And as you might expect, M35 is somewhat pricey but M42 is worse.
At the top end of the hardness and price scales are the solid carbide drill bits. Machine use only, and especially useful for drilling into work-hardening alloys, they are very hard, very heat-tolerant, but very brittle. And very expensive.
Cobalt can be added to the alloy to improve heat resistance and edge retention. M35 is a 5% cobalt HSS and M42 is 8% cobalt. Both are suitable for drilling medium to hard steels, M35 being preferable for hand-drilling and M42 for machine drilling. This is because M42 is harder and will retain an edge longer, but hardness comes with brittleness, so M42 is not as tolerant of misalignment. And as you might expect, M35 is somewhat pricey but M42 is worse.
At the top end of the hardness and price scales are the solid carbide drill bits. Machine use only, and especially useful for drilling into work-hardening alloys, they are very hard, very heat-tolerant, but very brittle. And very expensive.
copen
ArboristSite Member
This guy does a lot of comparison testing
.https://www.youtube.com/watch?v=xgQeSrsAXgE
.https://www.youtube.com/watch?v=xgQeSrsAXgE
I'm not getting notifications so I just saw your replies. Thanks everyone for your input. I'll try to answer everyone's points in this post.
A full set of the Chicago-Latrobe bits like posted is way out of my league.
I have ordered individual bits from McMaster-Carr and Grainger before when I needed them. I believe they were Cle-Line and Chicago Latrobe (I had to look it up). The are relatively expensive compared to Big Box stores. I may end up buying a basic 1/16 - 1/4" set and then fill in with individuals like 5/16, 3/8 and 1/2".
According to the Grainger website, if I understood it correctly, the bright High Speed Steel bits are a little more forgiving (hand drilling) than most. And I'll probably go with the 118 deg point.
As for sharpening, I have a used Drill Doctor which is probably set for standard 118 deg.
I do from time to time, need to drill Stainless Steel. I'll look into one of those specialty hardness mentioned in a specific size.
A full set of the Chicago-Latrobe bits like posted is way out of my league.
I have ordered individual bits from McMaster-Carr and Grainger before when I needed them. I believe they were Cle-Line and Chicago Latrobe (I had to look it up). The are relatively expensive compared to Big Box stores. I may end up buying a basic 1/16 - 1/4" set and then fill in with individuals like 5/16, 3/8 and 1/2".
According to the Grainger website, if I understood it correctly, the bright High Speed Steel bits are a little more forgiving (hand drilling) than most. And I'll probably go with the 118 deg point.
As for sharpening, I have a used Drill Doctor which is probably set for standard 118 deg.
I do from time to time, need to drill Stainless Steel. I'll look into one of those specialty hardness mentioned in a specific size.
You need Norseman drill bits. Union made in the USA! We use these for elevator work, drilling thick steel machine beams.
I drill all kins of crap from plastic to plate steel to broken steel bolts in cast iron. There is a feel you learn when drilling and pre drilling is mandatory in harder metals. The more expensive latrobe, norse etc cut better and longer between sharpenings but they snap off easily. For most jobs i use milwaukee/dewalt/boch etc cheap bit sets since they are softer and shatter less often. Drill small and slow after center punching working your way up, drill dr works good but beware it will ruin a bit just as fast as sharpen it.
They are great in controlled drilling but I find them too brittle in hand drilling. I do a lot of work in odd places. I used Norseman bits for the holes here.
I don't have pics of drilling but here is the threading. 1.25" semi hardened bearing plates for a bridge, tapped to 7/8"-9, done in the snow on site. The machine shop that built the plates screwed up the bolt pattern, so I got to drill and tap 64 holes in the cold.
I’ve seen a mag drill twice in my career lol. Almost every hole I’ve drilled over .5” has been with a corded 1/2” Milwaukee hole shooter. Drilling steel overhead sucks, much more so from a ladder across the 12th floor of a hoist way.
copen
ArboristSite Member
ThyssenKrupp?
I wouldn't want to tackle that one by hand, I had the drill slip when a tap got dull, it broke a 3/4" chuck and bent the arbor. My boy told me no problem, he would tap the holes by hand. Then he tried turning the tap with a 12" adjustable wrench and found out how hard that mag drill was working. Drilling overhead sucks but not as much as welding overhead.
Nope but they’re now called tke.
Haven't seen it mentioned but drill RPM is critical. It's very very common for people to spin a bit way too fast when drilling steel. The larger the bit, the slower it should be turned. A typical cordless drill turns way too fast if you hold the trigger down all the way. Have to feather it. I have my drill press geared down to 230 RPM's, which works well with most size bits drilling carbon steel.
This is true, We did have a 3/4” chuck corded Milwaukee that only turned 550 rpm vs the 850 rpm for the 1/2” setup. The bigger drill was also threaded on top to take a pipe bender handle. You needed that with a bigger bit on thicker steel because you couldn’t stall that sucker.
Preferably 8 percent cobalt USA made HSS drills should be fine.
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