First post so I hope this is clear. I'm looking for a way to "hollow" out an 8" od piece of 6061 aluminum. It's 13" long,with a 2.66 hole all the way thru. we need to open the center up to 3.900, 1" from both ends. Is there any tooling that would make this easier? Thanks for the help.
Follow along with the video below to see how to install our site as a web app on your home screen.
Note: This feature may not be available in some browsers.
Largest Manufacturing Technology Community on the Web
Stay Connected:
How to "hollow" out aluminum blank
- Thread starter kms1
- Start date
- Replies 20
- Views 3,915
plastikdreams
Diamond
- Joined
- May 31, 2011
- Location
- upstate nj
Big lathe big drills big, solid boring bar
Larry Dickman
Titanium
- Joined
- Jan 30, 2014
- Location
- Temecula, Ca
trepan it...
bore to 3.9" inches but only 1" deep?
Large lathe or slightly smaller lathe and steady rest. Horizontal boring machine.
Or line boring if you are really adventurous.
rcoope
Stainless
- Joined
- Sep 25, 2010
- Location
- Vancouver Canada
You need a nice strong boring bar with a tool that sticks out at least .625, preferably more, but with an overall width of less than 2.66. Then you can increase the ID by .620 to get to 3.9.
This is a strange problem. That is an enormous amount of left over aluminum on the wall and ends. Can you describe the application at all so we can suggest ways of redesigning it using much less material? That's the best part of unusual projects on PM. I want to guess this is for a cyclotron experiment.
This is a strange problem. That is an enormous amount of left over aluminum on the wall and ends. Can you describe the application at all so we can suggest ways of redesigning it using much less material? That's the best part of unusual projects on PM. I want to guess this is for a cyclotron experiment.
PDW
Diamond
- Joined
- Jul 24, 2006
- Location
- Australia (Hobart)
The question is a bit ambiguous - the usual problem with people who don't post a drawing or at least a sketch.
What I *think* he wants is to leave 1" depth at each end at the 2.66" hole size and open up the centre between these ends to the larger dimension. Which meand working through the 2.66" holes to make the 3.9" cavity.
So drills, trepanning etc won't work. Probably need a boring bar with an adjustable/retractable cutting tip. I can't be bothered doing the math to check for clearances. I expect chip extraction would be interesting though.
If I'm wrong and it's basically a 3.9" bore 1" deep both ends then the problem is so trivially simple that the answers are obvious.
PDW
What I *think* he wants is to leave 1" depth at each end at the 2.66" hole size and open up the centre between these ends to the larger dimension. Which meand working through the 2.66" holes to make the 3.9" cavity.
So drills, trepanning etc won't work. Probably need a boring bar with an adjustable/retractable cutting tip. I can't be bothered doing the math to check for clearances. I expect chip extraction would be interesting though.
If I'm wrong and it's basically a 3.9" bore 1" deep both ends then the problem is so trivially simple that the answers are obvious.
PDW
npolanosky
Cast Iron
- Joined
- Apr 9, 2016
- Location
- USA, FL
At that point,could the part be redesigned so you could machine a tube to size and two "caps", weld the caps on, and finish machine as needed? I know it would take a huge welder, but might still be cheaper than specialty tooling like that.
<Not a welder though, so maybe there's not enough preheat in the world for that.
<Not a welder though, so maybe there's not enough preheat in the world for that.
Limy Sami
Diamond
- Joined
- Jan 7, 2007
- Location
- Norfolk, UK
If it is hollowed out like a bottle, - which I have done several times (and assuming my maths are correct 
) an old school 1.75'' dia boring bar with an inserted HSS cutter projecting 0.7'' will do the trick.
From then on it's a case of patience - with probably light DOC and high feed rates, …….and IME the hardest part is getting the chips out.
) an old school 1.75'' dia boring bar with an inserted HSS cutter projecting 0.7'' will do the trick.From then on it's a case of patience - with probably light DOC and high feed rates, …….and IME the hardest part is getting the chips out.
Bill D
Diamond
- Joined
- Apr 1, 2004
- Location
- Modesto, CA USA
Bore to full diameter full length. thread the ends and screw in plugs or loctite in unthreaded plugs. How accurate/smooth does the bore and transition need to be. Why Al and not steel or brass for easier soldering/welding. Can you use external tie rods like a hydraulic cylinder.
Bill D
Diamond
- Joined
- Apr 1, 2004
- Location
- Modesto, CA USA
I wonder if this even has to be water tight or can it leak like a sieve? Do you care if lock tite insulates the endcaps from the main body. What temperatures and chemicals will it have to withstand. Is outgassing an issue.
The young folks would say 3d print it. Older ones would says lost wax casting.
The young folks would say 3d print it. Older ones would says lost wax casting.
I agree, he wants to open the ID to 3.9" and leave 1" at either end at 2.66". This is generally a pain in the ass to do....and I'd guess there is no good reason to make anything that way. After all, the ends will still be open to the tune of 2.66" so it's not gonna hold anything from leaking out.
ISCAR Cutting Tools - Metal Working Tools - TGIR/L-C
The largest of these will do it off the shelf. Barely.
The largest of these will do it off the shelf. Barely.
SteveBausch
Stainless
- Joined
- Jan 11, 2010
- Location
- Indianapolis
They are making a silencer for something.
Legal(for engine) or illegal (for firearm), I can’t determine.
A welding shop would suspect that, or pressure vessel, so they won’t be going to a welding shop.
Or it’s intended for some mystical energy device.
Legal(for engine) or illegal (for firearm), I can’t determine.
A welding shop would suspect that, or pressure vessel, so they won’t be going to a welding shop.
Or it’s intended for some mystical energy device.
Illinoyance
Stainless
- Joined
- Aug 24, 2015
Drill through and bore to 2.66. Bore 3.9" to 1" from the far end. Press in a bushing 3.9 OD x 2.66 ID x 1" long.
Alternatively use tubing. Bore through to 3.9" . Press a bushing in each end.
Alternatively use tubing. Bore through to 3.9" . Press a bushing in each end.
Singtoe
Plastic
- Joined
- Jul 27, 2014
- Location
- United States
An 8" od silencer for a firearm would be enormous. I'm guessing that it is a mystical energy device.
plastikdreams
Diamond
- Joined
- May 31, 2011
- Location
- upstate nj
Maybe it's for a tank...every time someone asks about boring a cylindrical part at least one genius has to make a silencer comment...
Bill D
Diamond
- Joined
- Apr 1, 2004
- Location
- Modesto, CA USA
Probably a trump design to take it up the rear end.
Bil lD
