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 Post subject: Drill bits
PostPosted: November 8, 2013, 6:10 pm 
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I am looking for recommendations for larger drill bits specifically the 1/2" drill but which is one of the most common that I need for my car. I have tried the DeWalt ones that are $17xx from lowes http://www.lowes.com/pd_71208-70-DW1232 ... Id=3382658 and really not impressed. I have destroyed 3 already and last night I took one out of the packet. It got stuck immediately and chipped both cutting edges making it useless. It did not even manage to bore any steel.
I tried one from Seat(Irwin maybe) the best they had which was a similar price but that also only managed about 10 holes before it was useless.

I have recently bough a second drill press which might help drill bit life. Any suggestions/recommendations on a good drill bits to use?

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 Post subject: Re: Drill bits
PostPosted: November 8, 2013, 6:25 pm 
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Location: Vancouver, BC
First off i would check your speeds and feeds, secondly dont drill the full 1/2" right away. Start with a smaller pilot hole, then work up in increments to the 1/2" bit. And use lots of coolant (oil). If you dont have a copy already, i would suggest getting a Machinists Handbook, its a very handy book to have on your shelf.


As for bits, I typically grab what ever is relatively cheap (stay away from the very very cheap ones).


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 Post subject: Re: Drill bits
PostPosted: November 8, 2013, 6:48 pm 
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I usually get mine from fastenal or mcmastercarr. Not the cheapest but last a lot longer. Like said above, the right speeds and coolant is a must.

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 Post subject: Re: Drill bits
PostPosted: November 8, 2013, 7:40 pm 
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Joined: April 8, 2012, 7:05 pm
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Location: Warrens WI
I also just use the ones that are relatively cheep(haven't bought one for years) but I also sharpen mine when they get dull. I sharpen mine by hand with a bench grinder but have also used sharpeners to some success. Also when you are stepping up drill sises don't make the steeps to small.


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 Post subject: Re: Drill bits
PostPosted: November 8, 2013, 8:00 pm 
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cs3tcr wrote:
First off i would check your speeds and feeds, secondly dont drill the full 1/2" right away. Start with a smaller pilot hole, then work up in increments to the 1/2" bit...

^ This.

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 Post subject: Re: Drill bits
PostPosted: November 8, 2013, 8:57 pm 
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If you are drilling into the thinner metals (~14 ga or less) get one of those stepped drills. They work great and make nice round holes. They don't catch and break your wrist either. I always thought they were a gimmick. Then I got one from my Dad's tools. Boy was I wrong all those years!

For drilling into the thicker materials, what all the others said! Creep up to the final hole in steps and use the right speed/pressure.

I really don't understand how a second drill press might help drill bit life though.

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 Post subject: Re: Drill bits
PostPosted: November 8, 2013, 11:39 pm 
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I'll second/third/whatever McMaster for bits (high speed steel, titanium nitride coated only), making sure the speeds are correct, stepping up in 1/16" increments, and using some sort of coolant. For anything that needs to be precise I'll use the step drill up to the size that is one step below where I want to be then finish it with a normal drill. The hole diameter tolerance on the step drills is a little sloppier than that of a normal bit but it makes drilling quicker.

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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 1:03 am 
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Joined: December 7, 2012, 8:28 am
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Location: Sarasota
rx7locost wrote:
I really don't understand how a second drill press might help drill bit life though.

I guess that statement is a little misleading. I previously owned a drill press but returned it. I have since purchased another one (a second drill press) which is better for drilling then the hand held electric drill.

Thanks for all the info form everyone, I guess I will do more research. I do have a step drill bit but it is still in the packaging so I will give that a try next time.

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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 1:40 am 
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send me your old drill bits instead of throwing them away, i learned to sharpen drill bit over 50 years ago and i'll take anything free.

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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 7:57 am 
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Joined: August 28, 2010, 7:53 am
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if you are using the drill press, get the 135* point drills (from Mcmaster) Get the stubby ones, if you are not drilling deep holes, b/c they dont flex. They require much more pressure than a standard 118* bit, but they are a lot tougher and drill holes which are more accurate, both in location (they dont walk) and diameter.
As mentioned, use coolant. I like Boelube paste (Enco sells it..AWESOME stuff, no mess) regular drillingcutting oil is good too (NAPA sells it)
Learn how to sharpen, its not a big deal. There are probably lots of good youtube how to videos.


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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 8:03 am 
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More of the same.

I sharpen mine with a small file when I'm in a hurry. I recieved a "Drill Doctor" for Christmas a few years ago and it works great when you have a pile that need sharpening. I've probably drilled hundreds of thousands of holes as an aircraft mechanic for various airlines, aircraft manufacturers, and military. All these places reuse bits over and over again by resharpening them. I prefer HSS bits, bang for buck. I use at least 3 bits starting at 1/8 to get to 1/2 when drilling material up to .125" thick.

If it is chipping/snagging, step it down a couple sizes and gently engage the burr to slowly remove it.

Too fast and/or dull: blueing, smoking, squealing, tiny particles being removed.

Ideally, for mild steel, the cutting comes off as a continuous ribbon or at least large chips.

Lower rpm and more pressure tend to work better for most everything. HSS doesn't have anything to do with the correct cutting speed and pressure to use for a material.

I suggest the unibit step drill and a tree shaped, [Fatherless Child] cut, carbide rotary file with about 1/2 od for removing casting flash, deburring inside corners, porting, etc. They cost about $20 but last a lifetime.

Clear plastic boxes for fishing lures with adjustable dividers work great for keeping your bits organized.


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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 8:29 am 
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Joined: February 28, 2009, 11:09 pm
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Location: Connersville, Indiana
Sharpen a drill with a file? Really??

Bill


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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 8:45 am 
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A completely dull bit and a fine small file with the curved side? Absolutely! Ideal? No! Did I mention that I was in a hurry?

I'm talking about the two corners that provide the initial bite. Down in the flutes, not the tip.


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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 12:09 pm 
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Joined: February 28, 2009, 11:09 pm
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Location: Connersville, Indiana
Just tried filing a Craftsman 1/2" drill bit with a Nicholson file. Results: Drill bit 1, file 0. While this might work with a wood bit, have you ever done it with a decent HSS bit?

Anyone doubting this, try it. Select a small portion of the file you never use, such as the edge at either extreme of the file. It will be ruined.

Bill


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 Post subject: Re: Drill bits
PostPosted: November 9, 2013, 3:15 pm 
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Joined: July 4, 2006, 5:40 pm
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Location: Novato, CA
You can sharpen drill bits?


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