What makes drill bit sets different?

Bill Kahn said:
My small HF bandsaw is doing well. I have destroyed many blades in trying to learn to cut lead bricks. (But have something that is working now for that too.). But for most of my work I have been using https://www.amazon.com/gp/product/B010BOLYP4/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1 at high speed. It has cut through hard stuff, like these railroad spikes, that HSS bits have been destroyed by. Not fast but nice thing about a bandsaw is it is largely launch and forget until the noise stops.
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That is great news. I just ordered from them. Thanks
 
Bill Kahn said:
I have see bits labels as M42 (seems like these are good for drilling hard steel). I also see M35 advertised. Are these I gather are also good, but not quite as good as M42. But is M35 good in some other way, like less brittle or something? And I see the M7 label too. Apparently also very good. Is there a list somewhere of the standard material drill bits are made out of what each material is good, and not so good, for?
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M7, M35, M42, they are all Cobalt based tool steel. And for the H-M, they will drill just about anything you want them to do. As for one shattering, M42 are pretty tough. I have a few that are M7 material and with the sound they make when bumped I think they would shatter just from dropping. Haven't tried. I've bought several used sets of HSS and Cobalt drill sets off of ebay over the last few years. It's hit and miss on what you are bidding on. You can study the pictures and after a while determine what is good and what is junk.

BTW: They only have one of these left in stock! Don't sneeze! Someone may buy it! "And for $945 https://www.amazon.com/Cleveland-C7...83604&sr=1-1&keywords=115+piece+drill+bit+set ":D
 
4gsr said:
M7, M35, M42, they are all Cobalt based tool steel. And for the H-M, they will drill just about anything you want them to do. As for one shattering, M42 are pretty tough. I have a few that are M7 material and with the sound they make when bumped I think they would shatter just from dropping. Haven't tried. I've bought several used sets of HSS and Cobalt drill sets off of ebay over the last few years. It's hit and miss on what you are bidding on. You can study the pictures and after a while determine what is good and what is junk.

BTW: They only have one of these left in stock! Don't sneeze! Someone may buy it! "And for $945 https://www.amazon.com/Cleveland-C7...83604&sr=1-1&keywords=115+piece+drill+bit+set ":D
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I would always check the price on amazon Canada, guess what, the one you linked is only $687.93 on amazon.ca, and that is in Canadian dollar so in fact it is around $600 USD:
https://www.amazon.ca/Cleveland-C70...int,+1/16"+to+1/2",+A+to+Z+and+#1+to+#60+Size
 
The M35 grade is more than likely the Chinese destination for their "Cobalt tool steel" they are used to using. Their steel numbers generally follow the DIN/Germany destinations. Why doesn't the rest of the World not follow the AISI system? Oh well! Can't change it now.
 
I think a good strategy is to get good quality HSS sets for general work and buy individual cobalt drills only as needed. I have some letter and wire size drills I have never used in 30 years, yes its reassuring to know I have em "just incase" but no need to buy all those sizes in cobalt.
 
About ten years back I thought I was being smart by purchasing one of those 115 piece drill bit sets from Enco. They weren't bad, but not great, fine for general purpose work. Life was good until the one day when I knocked the entire drill index off of the bench and onto the floor. Spent the next couple of hours measuring most of the drill bits with a micrometer to get each one back into its correct spot.

Now here I am years later, some of the bits are broken, some are lost, but a fair number need replacing. Instead of purchasing another set of the cheap ones, I have decided to purchase separate letter and number bit sets in separate Huot indexes, and purchase higher quality bits while I am at it. I don't think I will regret my decision. At least if I spill an index I know where all of the bits belong much more easily.

As for cobalt bits and end mills, I do have a few of them, purchased individually for specific projects. They all reside in their cardboard or plastic sleeves and are used only as necessary. My cheap bits are the ones that I leave where my adult children can find and use them. The good stuff is hidden away... if anybody is going to break or lose the expensive stuff, it's going to be ME! That way I don't grumble about the replacement expense.
 
Bill Kahn said:
Beginner's question...
I have a cheap 115 piece HSS drill bit set. Works fine on softer materials. But there are steels it does not work on. (I do not know how to evaluate steel--but I am working on old railroad spikes now. Carbide end mill works on it. My cheaper HSS end mills do not.)
My drills bits do not drill the railroad spikes.
So, how do I figure out what drill bit set to buy that can work on such harder steel?
I look at HF say and see https://t.harborfreight.com/115-pc-cobalt-drill-bit-set-61886.html?utm_referrer=https://www.google.com/ for $110. (Yeah 20% coupon is available).
But also I see https://t.harborfreight.com/115-pc-high-speed-steel-drill-bit-set-with-index-61620.html?utm_referrer=https://www.google.com/ for $40. There must be a real difference. How can I tell what each can drill? And how about http://littlemachineshop.com/products/product_view.php?ProductID=3418&category=-456343308 for $500. So, how is that different?

And for $945 https://www.amazon.com/Cleveland-C7...83604&sr=1-1&keywords=115+piece+drill+bit+set

Are there carbide sets too?

So, I need to select length (Jobber seems good for my PM25 mill).
I need to select tip angle (why 118 and why 135?)
I need to select material/brand/grade. How does one make this selection?

And, in particular, if I want to drill holes in hard steel what should I buy? (I have given up on drilling into ball bearings. But as my carbide end mill does well on the rail road spikes that suggests it is doable.)

Drill bit selection must have been covered before. Any pointer to some such old thread much appreciated--my search did not turn anything up.

-Bill
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Just checking back in here and letting folks know what I did..

I purchased Shars 415-7655, 415-7656, and 415-7657

http://www.shars.com/ms26c-a-z-26-pc-cobalt-straw-finish-jobber-drill-set
http://www.shars.com/ms29c-1-16-1-2-x-64ths-29pc-cobalt-straw-finish-jobber-drill-set
http://www.shars.com/ms60c-1-60-60-pc-cobalt-straw-finish-jobber-drill-set

USA cobalt M-42 135 degree split point jobber

I could not find the stub length I really wanted at anything approaching the price I could swing. As it was, these were a bit on the high end for me--like $350 altogether.

BUT--wow, they are way way better than my cheap set. Way better. I mean, for wood probably makes no difference. But I have some steel (railroad spikes, for free along abandoned tracks) that only my carbide endmill can handle. And these bits drill right through it. No problem at all. My cheap bits can't do a thing to that steel.

So, I can drill steel now. A big step up. Pretty silly to have a lathe and a mill, with carbide tooling, and not be able to drill holes. Now I can. Yippee.

-Bill
 
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I have and am enjoying that 115 cobalt HF set.

They drill through everything I want drilled, and I have only broken 1 of them in the 6 months I have owned them (#43 4-40 thread tap hole size). Have not had to sharpen any of them either.
 
I also have the large HF cobalt set, 135 degree, on sale and then used a 25% off coupon, so got set for well under a hundred. They compare favorably to a no name USA made set I got from Enco a dozen or so years ago. Unlike other HF bits they do not appear to be ground by drunken monkeys. It looks like HF is selectively raising their game, importing some pretty nice tools. I hope they start selling quality screw drivers soon, so far it looks like the drunken monkeys still have the contract to produce their screwdrivers.
 
Bill Kahn said:
Just checking back in here and letting folks know what I did..

I purchased Shars 415-7655, 415-7656, and 415-7657

http://www.shars.com/ms26c-a-z-26-pc-cobalt-straw-finish-jobber-drill-set
http://www.shars.com/ms29c-1-16-1-2-x-64ths-29pc-cobalt-straw-finish-jobber-drill-set
http://www.shars.com/ms60c-1-60-60-pc-cobalt-straw-finish-jobber-drill-set

USA cobalt M-42 135 degree split point jobber

I could not find the stub length I really wanted at anything approaching the price I could swing. As it was, these were a bit on the high end for me--like $350 altogether.

BUT--wow, they are way way better than my cheap set. Way better. I mean, for wood probably makes no difference. But I have some steel (railroad spikes, for free along abandoned tracks) that only my carbide endmill can handle. And these bits drill right through it. No problem at all. My cheap bits can't do a thing to that steel.

So, I can drill steel now. A big step up. Pretty silly to have a lathe and a mill, with carbide tooling, and not be able to drill holes. Now I can. Yippee.

-Bill
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Oh, just a heads up. As fancy as Cobalt M42 bits might be, they still can't drill a ball bearing. I guess someone who understands hardness and stuff would theoretically know, like duh, of course not. Me, without the understanding, figured it out by trying. -Bill
 
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