If I wanted to calculate the pressure needed to punch a 5/8 inch hole in stainless steel tubing, is there a formula for that? The stainless tubing is 0.028 inch thick, but I'm not sure what grade stainless it is. I can find the info about shear strength of stainless online, but I would imagine tubing would be stronger because of its geometry? I couldn't find info on that.
Through both walls of the tube, or just one? Drilling holes would probably be more effective, IMHO. Punching leads to severe distortion around the punched hole, unless it is fully supported against the punching action. And if it IS through both walls simultaneously, you won't be able to support the tube internally. More inforequired Nick
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03:49 PM
2.5 Member
Posts: 43235 From: Southern MN Registered: May 2007
As stated earlier, if you are only doing one or two then drilling is much better. If you are doing thousands you will need to have a support that goes inside the tube and the od matches the id of the tube. You say the thickness is .028, but what is the diameter of the tube? If it is a large diameter and you are supporting it then you can assume it is nearly the same as flat sheet.
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06:15 PM
doublec4 Member
Posts: 8289 From: Oakville, Ontario, Canada Registered: Jun 2003
If you are talking about using a punch press, you have problems. The punch is only 1/2 the tool. The underside has to be supported by a die with an id just a few thousandths bigger than the od size of the punch.
Trying to just 'punch' thru the wall with nothing to support the underside will likely destroy the punch and will certainly distort the pipe--not to mention resulting in a non-gage hole--if you even get a hole thru it. Non-gage meaning incorrect size.
I sell stainless steel for a living. Punching through that tube is not going to happen without a proper punch setup. .028 is a thin wall. What is the OD of the tubing? Also, we are talking about tubing here and not pipe, correct? Best way to go through it would be a drill press, unless you have the proper setup for a a punch machine, would is rather expensive and you probably wouldn't be asking us this question if you did. What size whole are you trying to make? A little help here please.
He wants to punch a .625 hole--he didn't mention +/- tolerances.
quote
.028 is thinwall
That's an understatement!! Less than 1/32" wall thickness. Drilling stainless that thin is going to take a very high spindle speed if you want any kind of nice looking hole.
[This message has been edited by maryjane (edited 12-30-2009).]
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07:55 PM
PFF
System Bot
lurker Member
Posts: 12355 From: salisbury nc usa Registered: Feb 2002
He wants to punch a .625 hole--he didn't mention +/- tolerances.
That's an understatement!! Less than 1/32" wall thickness. Drilling stainless that thin is going to take a very high spindle speed if you want any kind of nice looking hole.
While .028 is a thin wall, in it's 1/2" form it still has an allowable working pressure of over 1000psi. Tubing is instrumentation grade stuff and built for high pressure applications. Problem is that it isn't made as a structural. Anyway, was it said what the OD of the tubing is?
no, but obviosly somewhat larger than 5/8 od, since that is his target hole size.
Well .028 wall only goes up to 1", so that only leave 3/4, 7/8 and 1". Really need some more information to help him out here, best (cheapest) bet is probably a drill press and a nice bit.
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12:04 AM
Jan 2nd, 2010
MidEngineManiac Member
Posts: 29566 From: Some unacceptable view Registered: Feb 2007
He wants to punch a .625 hole--he didn't mention +/- tolerances.
That's an understatement!! Less than 1/32" wall thickness. Drilling stainless that thin is going to take a very high spindle speed if you want any kind of nice looking hole.
Hit it with this.......
then use a reamer to clean up the edges and get the size you want.
