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Hole saw for 5" holes in 1" thick A36 steel plate?

James Lederer

Hot Rolled
Joined
Mar 19, 2012
Location
Southern Wisconsin
I need to cut some holes in a machine base with a 1" thick top. It's way too big to put on a mill and I want to avoid heat, so torch or plasma cutting is out of the question. I have access to a mag drill. Has anyone used a hole saw to do a job like this? Is there another method I should consider?
 
I need to cut some holes in a machine base with a 1" thick top. It's way too big to put on a mill and I want to avoid heat, so torch or plasma cutting is out of the question. I have access to a mag drill. Has anyone used a hole saw to do a job like this? Is there another method I should consider?

Find someone with a large enough mill.
 
I have a mag base drill and a box full of annular cutters but I have never seen one in the diameter you need and I doubt a typical mag drill could power it, not alone fit it under the arbor. How about a series of smaller holes in a circle to give you a finished hole near what you need. Will these holes be visible? A CNC plasma burning table would make very short work of your holes and the water bath would insure absolutely no warpage...at least that's how I see it!

Stuart
 
It is doable, but slow. One technique that will help immensely is to drill several cleanout holes to allow the chips to get away from the blade. Drill 5/16 (or thereabouts) holes so the OD just touches the outside of the hole saw kerf. Then don your safety glasses and a face shield and grab a blow gun for your air hose. You have to get the chips away from the blade somehow.
 
If you are going to do it with a hole saw(s) I hope you have lots of time and don't forget to bring a lunch, you are going to be a while. Once the cut gets deeper than the teeth things really start to slow down and chip or fine filing start to bind up and you begin to wonder if this was such a good idea. The holes around the inside of the cut help big time, but it's a long and tedious task. Use lots of cutting oil. :codger:
 
Biggest one I have done is 3" with a Milwaukee. cutter on a Milwaukee mag drill on 3" thick plate slow and plenty of cutting oil but this one got carbide teeth on it
I will like to know how you get it done and pics to get ideas
 
Geez you guys whine a lot. I just cut about 10 4" holes in 1/4" treadplate, thru multiple stacked layers with my mag drill, it wasn't fast but it sure didn't take me all day either.

OP, I'd advise you to heed the advise of the poster above who suggested some chip relief holes, I'd go so far as to suggest 4 placed 90* apart rather than 2x 180* apart. I'd also suggest that if you can do this near enough to shop air or a portable compressor, set up a cool mist or some other mist coolant and maybe an additional chunk of loc-line on a mag base for an air blast to help keep it cool.

Also, buy some GOOD hole saws, not the cheap woodworking crap you get at your local hardware store. I've had best luck with Bahco from a nearby industrial supply shop but Morse is pretty good too.

Edit: If you have a real sturdy mag drill and there's a budget for tooling might also consider getting yourself a single point "grooving" tool attached to a pilot bit in the center, like a piloted trepanning tool, might be faster and clear chips quicker.
 
After looking, it seems a magdrill is going to run into issues. I can't seem to find one that will allow a 5 inch tool to clear the base. Maybe a router with a carbide endmill and a speed control? Or maybe I should plan on taking the machine apart and having a water jet shop do it.

Although, this Milwaukee looks like it could swing 5":

http://www.ebay.com/itm/Milwaukee-4...867?pt=LH_DefaultDomain_0&hash=item5662b92763
 
A router with a carbide endmill cutting through 1" plate :crazy: Be sure to take some videos of that operation as "it didn't happen without pictures".

Stuart
 
A router most definitely won't do it. A circle cutting attachment won't either. A hole saw is doubtful and time consuming, even with perimeter relief holes. I'd bite the bullet and opt for the water jet, or the proper size mill.
 
How about the mag/vacuum base drills (Milwaukee makes one) for drilling
concrete (diamond bit) they easily do 5", most I see are 6" and up.
 
If the OP does this himself,,please,please take some video.Also like to see the tooling receipts.
My vote is take apart and have water jetted.
 
I think it could be done with a hole saw and a big old slow drill motor.
About 20 years ago I helped drill four 6" holes in 3/4" thick stainless on a vertical surface on a paper machine. We used a peavy handle to keep the drill from getting away. It was slow and awkward, but it did work.
 
i use big hole saws fairly often but mostly on aluminum and never on anything much thicker than 1".
it is a slow going and painful process that begs to never be repeated but since i cant plasma out a 4" hole in 1" thick 6061 i do what i have to do.
if you MUST do it the hole saw way make sure you buy or make a real hole saw mandrel and not one of those little carpenter ones.
*as suggested, relief holes around the perimeter help a ton.
*go slow and use plenty of coolant
*be prepared to hear noises coming out of your DP like you've never heard before

my vote would be to take the machine apart and plasma those holes then bore to size if needed.
 
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