I'd like to drill a 1.25" hole in 1.75" aluminum round bar, about 10" deep, blind hole. Hard to find drills that long, I guess gun drilling would be the classic approach but I don't have that set up. Prototrak lathe or Deckel mill is what I have. Are there long bits available, or some easy way to do this? Tolerances are unimportant.
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Cheap way to drill a deep hole in aluminum?
- Thread starter swarf_rat
- Start date
- Replies 30
- Views 2,668
CORONA VIRUS
Banned
- Joined
- Feb 25, 2020
Amec spade drill.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
Yeah, if you really want to keep it cheap, buy a spade drill insert and make your own quik-n-dirty body for it.
If you have coolant on the lathe, you could buy some heavy-wall 1" tubing for the drill body, mill a press-in (or welded) head, then plumb coolant through the center.
If you have coolant on the lathe, you could buy some heavy-wall 1" tubing for the drill body, mill a press-in (or welded) head, then plumb coolant through the center.
RJT
Titanium
- Joined
- Aug 24, 2006
- Location
- greensboro,northcarolina
Dan from Oakland
Titanium
- Joined
- Sep 15, 2005
- Location
- Oakland, CA
Ya don't need a spade drill to do that. Buy a Silver and Demming 1/2" shank twist drill and make a cheapo extension out of some 7/8" or 1" diameter rod. A 1/2" hole in the end for the drill shank and a few set screws and your good to go.
david n
Diamond
- Joined
- Apr 13, 2007
- Location
- Pillager, MN
How many holes? 1? 1000?.................for a couple and I was really on a really limited budget and only need a few holes.............^^^^^^what Dan said^^^^^^....................
gustafson
Diamond
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- Sep 4, 2002
- Location
- People's Republic
And I would mount it to the carriage so once you get past the flutes you can rapid it out o the hole quick
CORONA VIRUS
Banned
- Joined
- Feb 25, 2020
While you're at it, hand make all of the screws, make your own S&D drill, forge a rod out of some old horse shoes laying around the back yard. In manufacturing, time is money.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
This reminds me of the guy who posted here a year or two back about wanting to buy his own screw machine so he could save time and money by not having to go to the hardware store for bolts and such.
I wonder how that worked out for him?
Finegrain
Diamond
- Joined
- Sep 6, 2007
- Location
- Seattle, Washington
No gundrill outfits in Napa?
Regards.
Mike
Regards.
Mike
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
The man said "cheap".
Alright, thanks for the suggestions. I only need to do two holes (plus the ones I screw up). There isn't much of any machine industry in Napa - I probably am the second best equipped shop in town 
.
I'd searched on MSC which didn't produce the spade bit results for some reason (that reason being the MSC website sucks). The spade bits would be in budget, I do have coolant, and I might try the S&D with extension idea though I imagine it will require about a million pecks.
On a 1 1/4 hole with the spade do you just drill it in one shot? or pilot drill?
. I'd searched on MSC which didn't produce the spade bit results for some reason (that reason being the MSC website sucks). The spade bits would be in budget, I do have coolant, and I might try the S&D with extension idea though I imagine it will require about a million pecks.
On a 1 1/4 hole with the spade do you just drill it in one shot? or pilot drill?
jptech
Aluminum
- Joined
- Jun 4, 2009
- Location
- NE Ohio, USA
Contact Allied Machine. I just drilled 56 - 1.562 dia. x 9.7 deep holes. 6061 Alum, coolant through drill in a VMC. G81 for 1st hole. Spindle load went up to 80% around .5" from final depth. It stayed at 35% until then, I'm thinking chips not evacuating. The rest of the job was with a G73, Q of .100". Horizontal drilling will be much better. No pilot, just spot drill. ------------ John 
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
If you use a spade, you might be able to power feed with the carriage if you plumb coolant to the drill body. Even low PSI may be enough if you play with the feed to get the right chip formation.
Pete Deal
Titanium
- Joined
- Apr 10, 2007
- Location
- Morgantown, WV
Figuring out affordable tooling for small jobs is a challenge I can relate to.
Yg1 spade drill components are more affordable. I’m no spade drill expert but I believe no pilot and no pecking is preferable. But you need the coolant pressure to get the chips out. If coolant pressure isn’t quite enough then peck. And if it’s not breaking chips it’s better to peck.
I had a few deep holes in stainless. Not quite enough coolant pressure couldn’t get it to break chips with what I had. Got through by pecking. Very small pecks.
Yg1 spade drill components are more affordable. I’m no spade drill expert but I believe no pilot and no pecking is preferable. But you need the coolant pressure to get the chips out. If coolant pressure isn’t quite enough then peck. And if it’s not breaking chips it’s better to peck.
I had a few deep holes in stainless. Not quite enough coolant pressure couldn’t get it to break chips with what I had. Got through by pecking. Very small pecks.
Milland
Diamond
- Joined
- Jul 6, 2006
- Location
- Hillsboro, New Hampshire
If you have the option of which Al to use, you might try 7075 rather than 6061. It's harder, cuts more cleanly, and you should get actual chips rather than strings or clumps coming off the drill.
The other thing you might look for are the types of spade inserts with the slots at the edge that act as chip breakers. Especially as you'll have low coolant pressure from a regular pump, the slotted cutting edge should help generate smaller chips (even if you have to use 6061).
The other thing you might look for are the types of spade inserts with the slots at the edge that act as chip breakers. Especially as you'll have low coolant pressure from a regular pump, the slotted cutting edge should help generate smaller chips (even if you have to use 6061).
Bobw
Diamond
- Joined
- Feb 8, 2005
- Location
- Hatch, NM Chile capital of the WORLD
Or 2024.
I've never had a melt down with either 2024 or 7075, and I've tried.
Double the price, but a lot easier to machine. I prefer 2024, it doesn't
stain as easy as 7075. You look at that stuff wrong and it changes color,
don't ever leave it in the vise overnight wet with coolant.
LKeithR
Stainless
- Joined
- Sep 1, 2011
- Location
- Langley, B.C.
Seems like a lot of fuss for a couple 10" deep holes. Why not use a plain morse taper socket extension?
An 1-1/4 MT3 drill should get you 7"-8" of depth and a MT3 to MT3 extension should get at least another
3"--there's your 10" depth. Extensions are 25-30 bucks and I'm pretty sure they'd be less than 1-1/4"
in diameter so there would be clearance down the hole. For a bunch of holes I can see some more
"elegant" solutions but we're only talkin' two holes here...
An 1-1/4 MT3 drill should get you 7"-8" of depth and a MT3 to MT3 extension should get at least another
3"--there's your 10" depth. Extensions are 25-30 bucks and I'm pretty sure they'd be less than 1-1/4"
in diameter so there would be clearance down the hole. For a bunch of holes I can see some more
"elegant" solutions but we're only talkin' two holes here...
gregormarwick
Diamond
- Joined
- Feb 7, 2007
- Location
- Aberdeen, UK
Honestly, Korean spade drill bodies are so cheap I'd have to be really desperate to save money and have lots of spare time before I'd do that.
I realize the question was how to drill, not how to make the end product, but I have to ask - can't you start with a tube? I did a quick search and see that extruded tubes are available in 1.75"OD 0.25" wall size, then either weld a cap or thread in or on a plug, making a tube out of solid seems like a waste of resources, especially since ready made tool will be expensive and making custom one still will take time and a drill to start with...
edit, in absence of TIG or other welding method, even propane torch with aluminum brazing rod would do
edit, in absence of TIG or other welding method, even propane torch with aluminum brazing rod would do
