Cobalt Drill Bits - Any Recs?

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Tin Man

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I currently have two set of HHS drill bits: Chicago Latrobe 150ASP series HSS black oxide made in USA drill bits and CLE-LINE . I also have a set of CLE-LINE HHS black/gold bits. They are both 135 degree split points. They are good bits. I use my Drill Doctor to keep them sharp.

I use my bits for general projects (boats, stainless steel, aluminum, carbon steel, automotive (chassis/body), etc)

I would like to add a Cobalt set of bits to my drill bit sets.

Any recs on brands made in USA that won't necessitate mortgaging my home!


Thanks!
 
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I found a cobalt set of DeWalt bits in the discount bin a few years ago. They are EXCELLENT, much better than the cheap HF Titanium bits that I buy when they go on sale cheap. I've slowly lost a number of them, but the cobalts are still my favorite when I need to get through something hard. I use them carefully and lubricate them during use.
 
Cobalt is just a better grade of tool steel used in cutting tools. Completely unnecessary for home use unless you just want them. As a toolmaker for over 50 years, I have used all different types, if your going to drill hard material, then get solid carbide drills, otherwise, for the dollar spent just a good ( not chinese) set of bits for home use is all that is needed. Drill doctors are for people that dont know how to sharpen drill bits...no offense intended...but it is quite easy to learn basic drill bit sharpening, and much faster by hand than setting up a drill doctor. I have a decent quality set of high speed drills that have drilled thousands of holes over the past 30 years without need of high priced speciality drills. By just making minor changes to the angle and relief to a regular drill bit can control its ability to drill with ease thru either tough or soft material. My whole point here is dont run out and buy expensive drills unless you have a special need, wasted money....just learn to properly use and sharpen high speed quality drills and you are good to go!!
 
Home Depot sells sets of cobalt drill bits made by CLE-LINE. Q&A I saw on the small set says made in USA (easy enough to verify in the store). The small set (1/16 - 1/4) is under $30. The 15 piece set (1/16 - 1/2) is about $75.
 
I think I paid $10 for the set I got, and I wish I'd bought every one they had. Didn't know at the time what I had.
 
Besides a good drill bit, do this when cutting hard materials. Get a spray bottle full of water and continuously spray the drill whilst drilling. If you need to, have someone else do that if you need both hands on the drill. You'll cut through 3-5 times fater!

Tip for drilling stainless steels - medium to medium-high speed (RPM) and high feed (push) ... else you will work harden SS if turning the RPMs and pushing it to bite. And I can guarantee you ... you will never drill through such a work hardened piece ...
 
I was reading about Cobalt. The Cobalt bits stay cooler, especially when drilling through aluminum (and its lower melt point). I never learned to sharpen bits so the Drill Dr. works great for me. I was really only considering the Cobalt bits for aluminum boats and aluminum projects. Otherwise my HSS USA made bits are used for most projects and the cheaper Chinese bits for non precise holes.
 
Soft material such as aluminum needs a drill with a different angle ground on it, you will do better using a light oil such as kerosene on aluminum. If you have a lot of holes to drill in aluminum then get "made for aluminum" cutting oil at most fastener places like Fastenal as that will greatly increase the life of your drill and allow you to drill much faster. As far as drilling any metal type material, always use a lube/ coolant to let the drill cut faster and cooler !! Water is not a good choice except for plastic, instead a light/ med weight oil and your drill will last much longer and be able to drill much faster. When drilling large holes in metal ( those over 3/8") always drill a pilot hole ( smaller) first, this will relieve cutting pressure on the very tip of the larger drill. When following up with the larger drill, slow down the rpm and allow the drill to do its job, rushing here will cause the material to heat up and glaze which is hard to cut thru
 
"Project Farm" on YouTube has an excellent video on cutting oils. Which ones work and which are not so good. Well worth your time to watch this if you want to take care of your good bits.
Do you know how long ago this video was?
 
About 20 years ago I purchased a Rodman drill bit set at a home show. They will drill through anything, but it is recommended that they turn 2000 RPM or faster. They look like a masonry bit. I watched the guy at the show drill through files and other drill bits with these bits. They are great at drilling holes through grade 8 bolts and other hard materials. They are guaranteed for life. If you break or bend one of them, you can send it to them, and they will replace it. I have sent a couple back that I have bent, and they sent me a new one. They are kind of pricey though.
 

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