gbin

kok328

I really like the new Milwaukee drill w/lithium ion batteries.

Nestor_Kelebay

Gerry:

If I were you, I wouldn't buy a set of drill and driver bits. I would buy separate sets of each item you can use in the chuck of your cordless drill. That is, a set of 1/4 inch drive sockets, a set of drill bits and I'd buy the driver bits separately as you need them.

You can use the sockets you get in a 1/4 inch imperial and metric socket set with your cordless drill if you spend $2 or so on a "hex bit adapter", which looks like this:



You put the hex shank end in your cordless drill and push any size socket you want on the 1/4 inch drive at the other end, and you can effectively use your set of imperial and metric socket wrenches as a full set of imperial and metric nut driver bits.

If you are interested in buying screw driver bits, some of the best on the market are made by Wera and Bondhus. I've used Wera screw driver bits over the past 20 years and they seem to last forever. Bondhaus makes a wide variety of both screw drivers and driver bits. Not only do they make Torx and Allen head driver bits, they also make a special line of screw drivers and driver bits made especially for driving Robertson screws when the driver is at an angle to the screw. This comes in particularily handy when you don't have good access to the screws used in light fixtures and electrical applications (which typically will use Robertson drive screws. Wera also makes a full line of stainless steel driver bits, but any advantage that stainless steel would impart to an already very hard screw driver bit made from high speed steel would be debatable. Rusting has never been a problem with my tools, so I'd be reluctant to pay extra for stainless steel tools.

So, when it comes to driver bits, I'd buy Wera bits for all the common screw heads (Phillips 1, 2 and maybe 3), slot, and if you do a lot of electrical work, Robertson 1, 2 and maybe 3. For all the other drives, like Torx, Allen six sided recess and for turning Robertson head screws when you have poor access to them, I'd look to a Bondhus retailer for a driver bit.

http://www-us.wera.de/
http://www.bondhus.com/

When it comes to buying a good 1/4 inch drive socket set, I particularily like Westward socket sets, but I think they're only available in Canada. Proto is good quality and relatively inexpensive. The advantage in house brand tools like Sears Craftsman hand tools is that they come with a lifetime guarantee (as all the previously named brands do) and getting replacements from Sears isn't like fighting with a bear. Basically, unless you use your hand tools every day like an auto mechanic does, you're probably never going to appreciate the subtle differences in balance and design between the inexpensive house brands and the very expensive professional tools like Snap-On.

Well, I think a comment on the different kinds of drill bits is in order because if you already know the difference between cobalt steel drill bits, titanium nitride coated drill bits and high speed steel drill bits, you're probably ahead of most people in here.

Before buying a set of drill bits, the first thing you need to do is look in your yellow pages phone directory and check to see if the places that offer sharpening services in your area can and will sharpen cobalt steel drill bits.

The first thing to know is that "steel" is nothing more than iron with some carbon in it. Prior to World War 1, steels were made harder simply by increasing their carbon content. Very hard steels (at the time) would have as much as 0.9 percent carbon in them. At the time, machining rates had to be low to prevent the machine tools from overheating and dulling quickly. High speed steel first got it's name prior to WWII (in the 1930's) when steel with a high tungsten content (as high as 7 percent) was first used to make machine tools. The high tungsten content gave the steel a high "red hardness", which meant that it stayed hard at much higher temperatures, and that made much faster machining rates possible without dulling the machine tools. Hence "high speed steel" meant steel that wouldn't loose it's sharp edge at high temperatures, so you could machine metal faster without dulling the tool. Because of shortages of tungsten during WWII, research was directed at finding similar steels that could be used to make high speed steels without tungsten. It was found that both molybdenum and vanadium could be used in place of tungsten to achieve comparable high speed steels, and in some cases BETTER high speed steels at a lower cost than using tungsten. Nowdays, high speed steels for most tools are still made by alloying steel with molybdenum and/or vanadium.

Nowadays, your based drill bit is made of high speed steel. Mild steel has a Rockwell C hardness of about 35 to 45. High speed steels have Rockwell C hardnesses from the high 50's to the low 60's. It's that greater hardness of the high speed steel that allows it to CUT into mild steel without dulling too rapidly.

Cobalt steel drill bits are made from steel alloyed with cobalt to give it a Rockwell C hardness from the mid to high 60's, say 65 to 68. Cobalt steel is not brownish in colour; the brownish colour of cobalt steel drill bits is due to a heat treatment applied to them after manufacture so that they can be easily differentiated from normal high speed steel drill bits. The brownish colour is something that's added merely for easy identification of cobalt steel drill bits; it's not a characteristic of cobalt alloyed steel.

The "bright gold coloured" drill bits that you commonly see sold in home centers and hardware stores are high speed steel drill bits that have been coated with titanium nitride. Titanium nitride is a very hard alloy of titanium with a Rockwell C hardness of about 82.

Thus, the hard coating on titanium nitride drill bits allow them to drill into hard steels (like stainless steels and high speed steels) and so they last longer because of that greater hardness. The trade-off is that once a titanium bit dulls, it can't be resharpened without grinding off that very hard titanium nitride coating on the front of the bit. So, by sharpening a titanium drill bit, you effectively reduce it to a high speed steel drill bit.

By sharpening a cobalt steel drill bit, you effectively have a new cobalt steel drill bit.

So, if you can easily afford the difference in price, my advice is to spend a little more and get a set of cobalt drill bits if there's a grinding service in your area that will sharpen them for you. The few times you have to drill into very hard steels like stainless steel and tool steels, you can always buy a titanium bit or two specifically for those jobs.

And, if it wuz me, I'd look in your yellow pages under "Machine Shop Equipment and Supplies" when shopping for cobalt steel drill bits. My own experience is that the local places that provide tools and equipment to machine shops in my area tend to carry high quality cobalt steel drill bits cheaper than any retail outlets. I don't know why that is, but I suspect it's because machine shops won't buy anything but cobalt steel drill bits, and so places that supply machine shops will only sell high quality brands that their customers are satisfied with. And, maybe they just sell those bits to the general public at the same price they do to their high volume customers. I bought two 1/8 inch cobalt drill bits at Luke's Machinery here in Winnipeg for the same price as Home Depot charged for one; $2.40 each versus $4.80 for one at HD.

http://www.irwin.com/irwin/consumer/....xml&asked=yes

Nestor_Kelebay

I forgot to comment on this quote:

You need to understand that drilling into masonary is a completely different process than drilling into wood or metal. The drill bits used to drill into wood or metal actually CUT their way into the wood or metal, but you can't do that in hard masonary like stone or concrete.

Drilling into stone or concrete involves basically battering a hole into it, and that is why masonary bits have a great big hunk of tungsten carbide at the tip. A "percussion type" hammer drill or a "rotary hammer" will work by both turning the drill bit and moving it forcefully forward and back at the same time. The forward and backward "hammering" motion of the drill bit basically batters the masonary in front of it into rubble, and the flutes of the drill bit carry away that rubble with the rotary motion of the drill bit the same way as with other drill bits. So, even though the flutes carry away the cutting or rubble the same way, it's that battering versus cutting action that differentiates masonary bits from twist drill bits.

That means you need a forward and backward motion of the drill bit to have any success battering a hole in masonary. Without that forward and backward "battering ram" motion of the drill bit, then the best you can hope for is to grind a bit of a hole in your masonary with the tungsten carbide before it dulls. And, that's also why a "dull" masonary bit works almost as well as a sharp one. A dull bit can batter masonary into rubble too. I have a Hilti TE10 rotary hammer and I can batter a hole in concrete at about the same rate as I can drill into hardwood with a sharp HSS bit. However, without a POWERFUL hammering action, drilling into hard concrete is darn near a waste of time.

My Hilti rotates at about 400 rpm and it moves the SDS bit back and forth about 1/8 of an inch on each rotation. The kinds of "hammer drills" sold in home centers fall into the "Percussion type" hammer drill category. These drills turn a little faster, but have hammering rates anywhere from 10,000 to 50,000 blows per minute. They work OK on soft masonary like brick, mortar, ceramic tile, concrete blocks and maybe soft stone like marble or limestone, but they're just not suitable for hard concrete or hard stone like granite. (and, a lot depends on the size and depth of hole you're drilling, too)

If you want to drill into soft masonary with a drill that only rotates, you might try a special kind of drill bit made by a company called Artu:

ARTU USA

I have never used an Artu bit to drill into anything, but I've been answering DIY questions for a while now on the internet, and I have heard more than one person saying that they can use them to drill into ceramic tiles, brick and cinder blocks fairly well with them. So, ideally it would be best to batter a hole in your masonary with a hammer drill of some sort, but if your drill simply can't produce that all important hammering action, then my only suggestion is to try an Artu bit. But, I can't say they work well because I've personally never used one.

gbin

Nestor, I don't know what to say except... you're awesome!

I did know much - but not all - of what you wrote about steel types and treatments (I'm a studious person by nature and profession and so read a lot even in areas I've never worked before, plus I worked as a machinist a few summers in my youth), and I was afraid if I didn't say something like I did then all I would get was a brief tutorial on that subject without the specific recommendations I was actually after. But you both expanded my education on the subject and broke it down into specific recommendations, and I really appreciate it!

I don't know why I didn't think of just buying a hex bit adapter to use with my socket set rather than buying a bunch of nut drivers. I knew those adapters exist, but... well, I guess sometimes I'm just an educated dummy! It was a great catch on your part, in any event.

And I'm sorry I forgot to mention that I plan to pick up a good hammer drill before long, too, with masonry work in mind. But you anticipated my need and began my education on drills for that kind of work, too!

I just can't tell you how thankful I am. I know how long it takes to write such thorough, well-organized posts - they're mini-essays, really - and I won't forget your thoughtful kindness!

Now I'm going to see about putting what you've shared with me to use...

Gerry

Nestor_Kelebay

thanks for the thanks.

I went over the differences between the different kinds of drill bits in that post because I expected that lots of people in this forum would be interested in that and benefit from knowing those differences.

Redwood

Nice Job Nestor!

I share your love of cobalt drills!

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Nestor_Kelebay

Thanks, Redwood.

I probably should also mention that those Artu drill bits that supposedly can drill into soft masonary well might only be doing so because the vibration of the drill itself might be imparting a hammering action at the front of the drill bit. I don't really know what to think of them, but I'm certain that regardless of how well they work in a rotary drill, they'd work very much better in a hammer drill. I've heard good things about them, but I'm still a skeptic cuz there's nothing I can see about them that would explain why they would work better in a strictly rotary drill.

Anyhow, this is a slow moving thread, so hopefully someone with some experience with them will chime in.

When I reread my first post I noticed that I didn't mention that the "percussion type" hammer drills made for the DIY'er market don't have anywhere near the "battering power" that you get from rotary hammers made for the professional market. So, rotary hammers can turn hard masonary into rubble much faster than percussion type drills can. But, I think that's pretty well common knowledge to all but the freshest newbie.