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miamicuse 01-12-2012 10:20 AM

Tough Drill Bits
 
I am running into some REALLY HARD wood doing some truss repair.

I think it's southern yellow pine, but I am not sure.

More often I have to sister a notched piece of bottom chord, and I will drive a 3-1/2" screw into the new sister wood, the drill cuts through the new wood like butter. But when it hits the old wood, it's like it slams into a concrete wall.

I then tried predrilling these holes. That works better definitely, but so far I have broken two drill bits predrilling.

However, even with predrilling, sometimes (about 1 out of 4) when I get the screws to about 3" deep, it just won't go any deeper. I'd had to back out the screw and try again. Of course, part of it is being on the ladder, working at a tight angle, sometimes just doesn't have the leverage to really lean into the drill to get that in.

But another thing is, my philip drill bits would get chewed up and spin. The screw heads are OK, but the bit is ruined. I like the long 3" bits, works better in tight angles. I now wonder if the problem might be my bits. I got the bits from Harbor Freight, I am thinking may be those are cheap junk bits? Are there really tough bits that would last longer against these really hard wood?

titanoman 01-12-2012 10:34 AM

You can't chew up a Philips bit unless you allow it to spin.
You either need more pressure, or you have the wrong size bit.
Try the square drive bits and screws, or the Torex.

Sent from a Samsung Galaxy S2

Ironlight 01-12-2012 10:52 AM

Two words for you: impact driver.

Nothing better for driving screws into old slow growth pine.

And I'm going to wager that those bits from HF are trash. It's a cheap and easy experiment to compare them to something of better quality. But as mentioned, if the bit spins, it's going to get destroyed no matter where you got it from.

user1007 01-12-2012 11:13 AM

I worked almost exclusively on old houses and some of that aged pine and fir is like drilling into cast iron or steel. You are on the right track with the concept of pre-drilling.

Make sure you are using nice, quality, and sharp drill bits. Not sure you can find them at box stores. I most certainly know they do not exist at HF. You get what you pay for and is your frustration worth the surface cost savings? Pay the piper and buy nice ones from a tool store. My tool supplier has nice ones. Sears still has nice, quality drill bits. If one breaks in normal use, take it back for a new one. Not saying they will not snap on you either but life will be easier to start.

As for driver tips? They can take a beating but do not try to make a fastener head stripped work. Once you loose the grip and especially if they are box store fasterners? You have lost it. Pull it out, say a prayer to the Devil or at least use his words, and try another one. Get good fasteners at a fastener or real hardware store. Not a box store or HF.

Here is one trick taught me that really can help give GOOD fasteners a chance. Carry old candles or even a block of wax as used to be used for canning. Roll the screw threads in the wax, and try again. Amazing hugh and a $.03 solution?

Daniel Holzman 01-12-2012 11:30 AM

The hardest wood on the planet is generally considered to be ipe. I built an entire deck out of ipe, and I can tell you that ipe is easily drilled using titanium nitride coated drill bits, which are readily available from big box stores, or woodworker supply shops. If you are having trouble driving screws into old growth softwood, you definitely need to predrill, using a sharp bit as previously noted. The correct predrill size is the diameter of the root of the screw, and of course you need to predrill the full length of the screw. You should have no trouble driving screws into any wood if it is correctly predrilled.

miamicuse 01-12-2012 12:32 PM

I think there are several issues here now that I got some comments.

It is true that I did not predrill the full depth. Reason being the drill bit I have does not run the full 3.5". I could not find a drill bit for that diameter that is that long. I suppose one way to go deeper is to drill a larger hole on the face of the sister so I can predrill further.

I don't mind getting a high quality bit, just that I don't know if there is a difference. Seems bits from HF, Home Depot, Sears are all made in China, so I don't know if one I spend $5 is actually better than one that's $1.79. Anyone has a specific brand/model they recommend?

Also I am using the quick change bits. I put in the drill bit into the hex bit holder, drill and switch to the actual philip bit. May be the hex bit holder allows a bit of wobble which is part of the problem of it spinning? But without using the bit holder it takes much longer to change between drill bit and driver bit.

Daniel Holzman 01-12-2012 01:06 PM

I have a few drill bits that are designed to fit into the hex head holder. All of those bits are black metal oxide, which is not particularly hard, and not particularly durable. The harder the bit, the longer they last, and usually the more expensive they are. In terms of hardness, from least hard to hardest, you have steel, black metal oxide, cobalt tipped, titanium nitride, diamond. There are other types in between as well.

Diamond is a specialty bit, not used in wood. If the bit is titanium nitride, it is going to last a long time, at least if you keep the bit lubricated while you drill (oil if drilling metal, for wood I don't usually bother lubricating the bit).

It is certainly possible to get long drill bits, they are commonly called jobber bits, and the really long ones are called aircraft bits. You may not be able to get them at the big box store, there is a hardware store near me that has a wide variety of bits, including long bits. I have several 18 inch bits I use for specialized work.

As for value, well I can't speak to brands, I know most of them are made in China, most important is the material on the tip, that is where all the cutting action occurs.

joecaption 01-12-2012 01:08 PM

Cobalt bits, impact driver, use ceramic coated decking screws, buy bits that say right on the package, impact ready.

Knauer 01-12-2012 01:21 PM

Use spax framing screws they use a t20 bit. They are strong and bend not break like nails. Drill bits from dewalt, Milwaukee, Mikita, are usually pretty good quality for the most part you get what you pay for. And always use impact rated bit so you don't break them, torx star etc bits are better than philips because they are designed to be driven hard. The philips are designed to let the bit slip out so the screw isn't stripped or over torqued.

user1007 01-14-2012 04:27 AM

Quote:

Originally Posted by Daniel Holzman (Post 820471)
The hardest wood on the planet is generally considered to be ipe. I built an entire deck out of ipe, and I can tell you that ipe is easily drilled using titanium nitride coated drill bits, which are readily available from big box stores, or woodworker supply shops. If you are having trouble driving screws into old growth softwood, you definitely need to predrill, using a sharp bit as previously noted. The correct predrill size is the diameter of the root of the screw, and of course you need to predrill the full length of the screw. You should have no trouble driving screws into any wood if it is correctly predrilled.

I have worked with Brazillian and Indonesian hardwoods. Of course teaks helping people with boat decks. I have not heard of ipe. Is this an abbreviation for something? I am guessing it looks nice. Can you PM pictures if you do not want to post publically. Kapur out of South America was wicked stuff too and used for staking trees in California. It played fair and nice when wet but once dry? No way you could get a nail or screw into it easily.

I shift from the post though. The other thing I forgot to mention from my experience is that once you find a quality drill bit, you have to learn the drill speed that matches the material. This is like metal drill press 101 but people forget, especially with hard or cured woods discussed, the same is true with wood. If you continually overheat the drill bit, it has to fail on you. Even the best of them. And remember, dull tools are dangerous tools.

Daniel Holzman 01-14-2012 07:54 AM

Ipe is the name of the wood, it is a Brazilian hardwood. google it, you will find dozens of references, since it is sold commercially throughout the world. Used a lot for decks, since it is naturally insect resistant, and is so oily it does not need to be stained, varnished or oiled in any way to resist decay. My posts are cumaru, an Indonesian hardwood. Ipe requires predrilling of all holes, as otherwise the wood will split, or you will not be able to drive the screws. I predrilled my entire deck using tapered drills with an incorporated countersink, they cost about $8 each, I went through 3 of them I think, which isn't bad for about 10,000 screws.

user1007 01-14-2012 11:09 AM

Quote:

Originally Posted by Daniel Holzman (Post 822134)
Ipe is the name of the wood, it is a Brazilian hardwood. google it, you will find dozens of references, since it is sold commercially throughout the world. Used a lot for decks, since it is naturally insect resistant, and is so oily it does not need to be stained, varnished or oiled in any way to resist decay. My posts are cumaru, an Indonesian hardwood. Ipe requires predrilling of all holes, as otherwise the wood will split, or you will not be able to drive the screws. I predrilled my entire deck using tapered drills with an incorporated countersink, they cost about $8 each, I went through 3 of them I think, which isn't bad for about 10,000 screws.

Perfect boat deck next time asked. Thanks. :thumbsup:

woodworkbykirk 01-14-2012 05:40 PM

trying to figure out if the original poster is referring to drill bits or driver tips...

if your talking about driver tips. dont buy cheap drivers that the shank and tip are two separate pieces.. if your using them in an impact driver they are far more prone to break than a one piece driver bit. your best bet is to get the bits that are directly at the contractors desk or sold at electrical wholesalers.. they may cost more money but they will last 100 x longer.. ive bought packs of cheap driver bits only to have them burn up within the first 25 screws, 5 years ago i started buying the expensive bits and im more prone to need to replace them do to losing them instead of having them wear out


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