brad points for steel ?

[worth]

Where can I find brad point bits for 20ga. steel ?

[sluckey]

Go to Lowes and look at this Dewalt 18 piece 'Pilot Point' bit set.

http://www.lowes.com/pd_196676-70-DW1958++G_0__?productId=3393310&Ntt=brad+point+drill&pl=1&currentURL=%2Fpl__0__s%3FNtt%3Dbrad%2Bpoint%2Bdrill&facetInfo=

[Willabe]

I bought these at Menards. Milescraft Stubby Bit set. HSS, 6 sizes, 3/32"-- 3/8" with hex shank. I like them in alu. but i tried to drill an 1/8" hole in a Mojo stand alone reverb steel chassis the other day and the bit snapped in two. It was a brand new bit, in a bench top drill press and I had made a nice center punch hole with a sharp center punch.   

They also sell a 6 pc. standard length set from DeWalt, 1/8" -- 1/2". I've used them in alu. and seem to work fine. I have not tried them in steel yet.


         Brad,         


 

[DummyLoad]

if you want ALL bit sizes to be pilot point of the Dewalt set, get the 29 piece set or buy them individually.

model # DW1969 is a 29 pc. set that has all sizes that are pilot point. the 18 piece set does not - look closely; sizes 3/16 and below are conventional bits.

lowe's stocks the 29 pc. set - it runs about 60.00. best 60.00 i've ever spent on tooling.

you probably already know this; when drilling steel drill slow and use a lubricant, otherwise you burn the bit up in a hurry. cut with tap oil or flood tool coolant.

--DL

[Willabe]

you probably already know this; when drilling steel drill slow and use a lubricant, otherwise you burn the bit up in a hurry. cut with tap oil or flood tool coolant.
--DL

Doh! Had the drill press on it's highest speed.   


           Thanks,    Brad

[G._Hoffman]

NEVER use brad point bits for steel.  The tips are too delicate.  You want to use a standard twist bit.


Gabriel

[stingray_65]

I believe what DL is suggesting is DeWalts "Pilot Point" drill bits.

They have a nub on the end that resembles a center drill and a common rake on the cutting lip like a standard twist drill.

http://www.google.com/imgres?q=pilot+point+drill&um=1&hl=en&safe=off&tbm=isch&tbnid=5EbK6Yy5YITDkM:&imgrefurl=http://www.micro-machine-shop.com/drill_bits_countersinks_reamers_counter_bores.htm&docid=LbVeevs67FllrM&w=640&h=472&ei=PgpmTs2aFYjpgQfKhayWCg&zoom=1&iact=rc&dur=618&page=1&tbnh=126&tbnw=176&start=0&ndsp=21&ved=1t:429,r:9,s:0&tx=108&ty=85&biw=1024&bih=707

Brad points have an inverted rake like so:

http://www.google.com/imgres?q=brad+point+drill&um=1&hl=en&safe=off&tbm=isch&tbnid=Qw4TRVRnxQPALM:&imgrefurl=http://xiushunjie.en.made-in-china.com/product/cqyxTGvEbiVO/China-Brad-Point-Bit-Wood-Brad-Drill-Bit.html&docid=6za_1UP5cqdkvM&w=400&h=284&ei=LAtmTsjmH5LrgQfY3cmTCg&zoom=1&iact=hc&vpx=717&vpy=238&dur=32&hovh=189&hovw=267&tx=187&ty=85&page=1&tbnh=135&tbnw=192&start=0&ndsp=22&ved=1t:429,r:10,s:0&biw=1024&bih=707

Gabriel is correct in saying that brad points are NOT for steel, aluminum either!

DL is also correct in suggesting a cutting fluid when drilling steel.

I'm going out on a limb and am guessing that you want to use a "Brad Point" to through steel because you are getting out of round holes.

Triangular shaped holes are caused MOSTLY because drill diameter is so much larger than the material thickness.

What happens is the cutting tip breaks through the material well before the outer cutting lip is engaged. This then relies on the cutting lip to keep centered on the material that it is cutting. (doesn't give great results).

The relatively small diameter of the pilot point pierces though the sheet metal first and engages into your backing material while the relatively shallow grind of the cutting lip stays in the material.

The other 2 factors contributing to this are too fast speed and insufficient clamping or rigidity.

To get nice round holes in sheet metal you need a follow a few guides.

Back your workpiece with a nice hard dense material, NOT OAK. Maple, MDF, aluminum etc. (Oak's grain changes density so much it will actually force the drill bit to follow the less dense pulp)

Make sure your table (drill press) is clamped very tight and your workpiece and backer are flat and held firmly. (if you are hand drilling you'll never get perfect holes, but you can get acceptably round holes following the rest of the suggestions)

Use cutting fluid

If you still get triangular or oblong holes, reduce cutting speed, if you are getting chatter (saw toothed edge where cut) reduce cutting pressure.

There is a book called "The Machinery's Handbook" This is THE bible for machining almost ANY material, it will give you speeds, feed rates, correct cutting tip angles and so much more!.

I have a PDF version I keep on my shop computer.

Ray

[Willabe]

In a post I started asking for help with drilling chassis, jjasilli posted this company's website on drill bits.

Data sheet says brad point bits and lists sheet metals as one of the materials they will cut.      

 http://www.wlfuller.com/html/short_length_brad.html

Here's the link to the thread, good info from a number of members on drilling chassis and types of bits. The info they gave has helped me greatly.

http://www.el34world.com/Forum/index.php?topic=11297.0


            Brad          

[kagliostro]

FANTASTIC LINK

http://www.micro-machine-shop.com/drill_bits_countersinks_reamers_counter_bores.htm

Many thanks you posted it

there are a couple of articles that I've never seen in my 45 year of DIY career

Kagliostro