God I'm surprised only one guy told you the right answer... You use a
"step bit", Home Depot has them, they are cone shaped and cut 1/16 or
1/8 inch per step, you stop pushing when you hit the 3/4 inch step.
They cut very fast, clean, and round especially through aluminum, but
set the drill slower for aluminum. They are not cheap bits but well
worth the money for metal fabrication jobs.
Think about it. He wants 3/4" holes. The largest step on the bit I referred to
is 3/4". Also the
bits are made at least as large as 1 3/8". I have several different sizes and
ERRRRRRR!!! Wrong! I have a one inch step bit
in my drill case. It doesn't have a drill point.
I have to drill a 1/2 inch hole first. Large
step bits are very expensive and may only be
available from supply houses that serve more of
a professional clientele. I've been working in
the field of fabrication (not the political kind)
for many years so I know these things. I'm also
a tool junkie. Google before you post. One example:
I don't see how I was in error. The poster wrote
that the bits only go to 1/2 inch. WRONG!
The poster wrote that a 3/4 inch bit will have
lands of less than 1/4 inch. WRONG!
I have step bits in my tool box that have 1/2
steps. I own a half dozen of the Harbor Freight
bits and I have used them to drill through 1/4
inch aluminum without a problem. The only thing
I recommend is using a lubricant and low speed.
I've been using step bits since the things hit
the market around here in the 1970's. The first
bits I bought were marketed by Unibit. My first
bits lasted me 10 years before I broke any of them.
The bits I own have 3/8 and 1/2 inch shanks.
It was just an example of a large bit. It can drill
a large hole. My 3/4 step bits have a 3/8 shank and
I have used them to drill 3/4" holes in 1/4 inch
aluminum without a problem. Comprehend before you
It's no problem, I use my 15 year old B&D 12 volt
cordless drill and a touch of saw wax and it zips
right through it. I've built a lot of aluminum
store fronts and installed manual and automatic doors.
I have designed and built numerous items out of thick
aluminum plate and have no problem drilling holes.
I do have a 1/2 Milwaukee Hole Shooter that will take
your arm off if it gets hung and I only use it for
step bits that have a 1/2 shank. There are times when
I use my drill press for precision work but most of
the time, the 3/8 cordless works just fine.
On Nov 3, 7:39 pm, firstname.lastname@example.org wrote:
First you argue that the bits do not exist, then you argue the link is
then you argue the shank size is wrong, then you argue the bits won't
they exist & they work in standard sized drill chucks & they work in
1/4" alumimum with a 3/8" shank
(even with 1/4" shank) aluminum is soft; even 6063-T6 BTDT
so please stop saying it won't work / cannot be done........it can &
Yeah, using the wrong tool, the wrong technique or the wrong operator.
Drill a 3/4" hole in aluminum with a HSS paddle bit ...not the most
beautiful result with a used bit
but with a new $5 Irwin bit & lube it will be
(back up the aluminum plate with a piece of plywood to save the paddle
on 1/4" aluminum, a typical Unibit(tm) isn't going to help. I have
one in my desk drawer as I type this, I hauled it out and looked at
it, and it won't do more than 1/16" in one pass and 1/8" from both
sides. For a nicely finished hole, unless you have a 1/2" drill
motor, a hole saw is your best choice. Choice #2 would be to buy a
proper 1/2" drill and a 3/4" bit with a 1/2" shank (pref. w/ 3 flats)
but that could easily run close to $200. Most bits that size start at
$20-30 and go up from there for fancier coatings, etc. Of course
depending on the definition of "several" that might be the way to go.
I use step bits all the time in aluminum. My
only suggestion would be to use a lubricant.
I use either a liquid lube made for aluminum
or saw wax. A tube of saw wax looks sort of
like a chap stick on steroids. I've used Tap
Magic cutting fluids for years:
I stick my drill bit into the wax and the wax
will melt from the heat generated by drilling
which will lube the drill bit.
Actually Silver and Deming is simply the name for that type of reduced
shank drill bit (that is, a bit with a 1/2" shank, 6" OAL, and 3"
flutes) unless they are real antiques. I say the latter because I
presume (without any proof) that they must have been originally made by
a company of that name.
replace "roosters" with "cox" to reply.
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