Cutting a nice hole in aluminum plate - having problems

admin

Its about 3/8" thick.  Need to make a lot of holes.I clamp it down on drill press and got to town with 2 1/16" hole saw (an older Starret bi-metal).1) The hole saw seems out of round.  I double check the quill and its OK.  It has to be the saw.  Bottom line, its a sloppy hole.2) Once I get about 1/8" deep, the saw has a tendancy to bind up (and by 1.5HP drill press the belts just slip).I buy a new, Milwaukee 2 1/8" hole saw (nobody locally stocks 2 1/16" and the first couple holes were so sloppy...)So...Should I be doing this with a hole saw in the first place? Is there a better brand for aluminum?  The Starret loaded up the teeth, the Milwaukee didn't.BTW, this was all done at 250rpm.  Would higher or lower help?  The big issue being the binding up of the hole saw.What about those circle cutters?Thanks,Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Originally Posted by con_fuse9Its about 3/8" thick.  Need to make a lot of holes.I clamp it down on drill press and got to town with 2 1/16" hole saw (an older Starret bi-metal).1) The hole saw seems out of round.  I double check the quill and its OK.  It has to be the saw.  Bottom line, its a sloppy hole.2) Once I get about 1/8" deep, the saw has a tendancy to bind up (and by 1.5HP drill press the belts just slip).I buy a new, Milwaukee 2 1/8" hole saw (nobody locally stocks 2 1/16" and the first couple holes were so sloppy...)So...Should I be doing this with a hole saw in the first place? Is there a better brand for aluminum?  The Starret loaded up the teeth, the Milwaukee didn't.BTW, this was all done at 250rpm.  Would higher or lower help?  The big issue being the binding up of the hole saw.What about those circle cutters?Thanks,
Reply:lube  wd -40 works great on alum.  pilot bit.   maybe try jig .  cut a hole in a wood 2x4 or something and clamp that on top of your work peice ,for a guide.    It don't sound like this will work,but I'll throw it out there.  drill a 1/4'' pilot hole where the hole is going to cut . this give the chips a place to go no cloggging or bindding. this work awsome in counter tops and pressed woodsDaye
Reply:Everything that dave said X2.If you have a lathe, turn the OD of the holesaw down a bit,  I do this for cleaner cuts on thin gauge 4130.  You have to cut slower (you just chopped off the outbound teeth) but it'll give you a cleaner hole.If you cannot do this, use a 2" hole saw & a sanding drum (in the drillpress)to clean it up.Set the drill press speed as slow as it'll go, & get some acculube(or even a bar of soap) .  the stuff works great with alum.Make a hole guide with a piece of plywood, it'll hold it a bit more.Drill a 1/4" pilot hole, & then put a 1/4" pin into the hole saw.  it'll run a little truer than a drill bit.Buy American, or don't whine when you end up on the bread line.
Reply:If the hole has to be dead on rough it in with a 2" hole saw and finish it with a fly cutter preset to your final size.Miller XMT 304 CC/CVSyncrowave 180 SDLincoln PowerMig 255XTTermalDynamics 52Lincoln 305GComlpete machine shop to back it up
Reply:Originally Posted by dave powelson1-How many is "a lot" of holes?2-What is the finished hole size tolerance?3-Concerning hole saws:-Do not use the quick change feature on the mandrel to hold the saw---thoseinduce lots of wobble. Hand tighten the hole saw against a flat washer on the mandrel.Dis-able the quick change pins if necessary.-Lenox Vari-tooth hole saws have more chip clearance in the tooth set than'normal' hole saws do. They hold size better, as well.-Hole saws will cut over size. The Lenox style-above only cuts about .020 oversized.4-Hole saws have trouble getting rid of the chips. This is causing the binding that you mention.Using pre-drilled chip relief holes, thru the plate, at least 2, setting the outside theoretical dia. of those holes, slightly less than the finished cut sizes5-Other option that works fairly well is to blow out the chip swarf periodically, with the holesaw retracted6-Presumably you are using cutting oil, preferably one that is recommended for AL.7-A fly cutter is more hassle than a hole saw....and they scare me.8-Hougen roto broaches on drill press adapter mandrel are really the way to fly,if you can justify the cost.
Reply:Originally Posted by dunemetalX2 on number four.IMO a flycutter is for producing flat surfaces, a boring head is more in tune with producing a finished dimension on a roughed in hole. It's much easier to control cut adjustment and less tool overhang (depending on model and make).
Reply:Larry: Agreed, I have used a flycutter in the past for milling a portion of a circle, an arc, from the edge of a work piece. Or, rounding out the ends of a slot cut in the middle of a work piece. In this business, you can never have too many tools but you can run short on funds or time, so you are right, you have to find a way to skin the many cats.
Reply:Get some laquer thinner or acetone and remove the paint from the hole saw. This can also cause binding because the paint melts and glues the hot chips to the saw.
Reply:Kerosene on aluminum cutting tools works very well.I hole saw is not as good as machining.AWS certified welding inspectorAWS certified welder
Reply:A nice clean hole in 10mm Ally can be achieved with a Tungsten tipped hole saw.3/8 to 1/2" is about the max depth the ones I have used. The holes we do are 50.8mmA clean sharp hole that wont chatter like the Bi metals ones.Speed drill press to max and plenty of fluid, its not that important what fluid you use really.BrettA good guess is better than a bad measurement
Reply:Can you take it to someone with a water jet?  Does it have a tolerance to it, or is that open and just needs to have a hole in it?---No good deed goes unpunished---
Reply:i think a rotabroach might be in your future..  http://www.hougen.com/cutters/indust...ndustrial.html  i think the pilot is seperate.hole saws suckLast edited by brucer; 01-29-2011 at 04:56 AM.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:nozzle gel, you know the anti-spatter stuff, works amazing at keeping the aluminum from gumming up in the teeth and flutes of the tooling. Even when using a flap disc for shaping, put a lil gel on it and grind away, it keeps the disc lubed allowing it to clear the waste metal... if you dont have a rotobroach, then the pin pilot idea for the hole saw really works. if you have time3, but need very clean holes, then a spiral upcut bit in a plunge router will also work very well... http://www.homedepot.com/Tools-Hardw...atalogId=10053 <---- like thatmigweld 250parcmate 205weldall 250piforcecut 80i plasma'07 pro 300 miller'08 trailblazer 302mm350pdynasty 700dynasty 200deltaweld 452xr-a 50ft push pull feeders and gooseneck