Drilling 13/16 holes in rectangle tubing?

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I have a to make 400 pieces of 2by 3 tubing that is 7 5/16s long and has 2  13/16 holes in it through the 3 inch side spaced 1.5 inchs from each end. I have cut them all and drilled them all up to 5/8s but the 13/16s is kicking my butt. I have been using a delta drill press with it on the 250rpm setting. I have used drillco drill bits and fastenal brand and I am only getting about 40 holes per bit using plenty of oil going slow and not pushing. I have had great luck so far with drill bits I only used 1  1/4 , 3/8 and 5/8s to get to this point. I am getting frustrated I have gotten 40 of the 400 drilled and I have burned up 2 13/16s at $35.98 a piece . I am looking at a mag drill any other suggestions?Vantage 300 kubota ,miller 304 xmt ,lincoln ln 25 pro , ranger 305 G, plenty of other tools of the trade to make the sparks fly.
Reply:The drill press I am using is a old delta which is struggling with the job I have broken 2 belts so far in this adventure.Vantage 300 kubota ,miller 304 xmt ,lincoln ln 25 pro , ranger 305 G, plenty of other tools of the trade to make the sparks fly.
Reply:What are you doing to the drills, are they burning from too much speed or are you chipping the edges from too little material to drill?Do the drills grab the work and chip?Too many steps in my opinion, I would have gone from the 1/4 right to the 13/16. No enough material in the hole for thin material and it gets grabby.You need to learn how to sharpen the drills too. Grin
Reply:Originally Posted by Mario428What are you doing to the drills, are they burning from too much speed or are you chipping the edges from too little material to drill?Do the drills grab the work and chip?Too many steps in my opinion, I would have gone from the 1/4 right to the 13/16. No enough material in the hole for thin material and it gets grabby.You need to learn how to sharpen the drills too. Grin
Reply:You should look at getting a carbide tipped hole cutter that looks similar to an an annular cutter for your drillpress.  The center drill bit has a spring to eject the slug as soon as you pass through the steel . It should also save time since you only need to drill one hole instead of taking steps up to reach the final size . They run $40-$50 and depending on the thickness they should last you a while.
Reply:Investing in one of the better Drill Doctors  ( 700X) might be a worthwhile investment. I picked up mine for about what 3 of those bits would run you.I agree your predrilled hole sounds too big. It only needs to be just bigger than the web of the bit..No government ever voluntarily reduces itself in size. Government programs, once launched, never disappear. Actually, a government bureau is the nearest thing to eternal life we'll ever see on this earth! Ronald Reagan
Reply:Hougen RotaCut:http://www.hougen.com/cutters/sheetmetal/Rotacut.html
Reply:What is the wall thickness of the tubing? If it is very thin wall you might try a step drill if you can find one with the proper size.
Reply:You should look at getting a carbide tipped hole cutter that looks similar to an an annular cutter for your drillpress.
Reply:What material is he drilling?   Is there a drill doctor that sharpen larger than 3/4"?
Reply:You're not catching the seam on one side are you?"The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Originally Posted by 7A749Pricey, but most assuredly worth every penny.IMHO of course
Reply:It is 1/4 wall tubing no luckily the seam is on the other side that would be my luck to have to drill the welded seam though lol. I Talked to my rep at fastenal about the drill doctor and he said it wouldn't help me for what I am doing they only go up to 3/4 bits. The bits are chipping it is on a 250 rpm I burnt the first one on 590 before I realized what was up. I have 100 of them already stepped up to 5/8s and the other 300 still at 3/8holes. The chuck on the drill press is 5/8s but It is dieing under this job so that was why I was looking at kickin in the cash and getting a mag drill something more specilized for this .  Fastenal rep said he would have one here on wednesday for me to demo . I was just looking for advice on if I should drop 1k on it or get a beefier drill press.Vantage 300 kubota ,miller 304 xmt ,lincoln ln 25 pro , ranger 305 G, plenty of other tools of the trade to make the sparks fly.
Reply:A mag drill is nice for a lot of applications not sure it will be what you would want for this. The magnet probably will not grab on the tubing as it is too small. You will probably need to make a fixture to clamp the tube in and have an area on it to set the mag drill on.
Reply:All you need is a 1/4" hole to get rid of the "center" which is where a lot of heat will generate... Try that, and post pics of the drill too. What are you using for coolant?HTP Invertig 201Lincoln Idealarc SP250Miller 180 AC StickBy farmall:They should have held the seagull closer to the work, squeezing evenly for best deposition.
Reply:Originally Posted by 7A749Get an Annular bit.
Reply:For the ones that already have a big pilot hole, you could try dubbing the drill bit. http://www.practicalmachinist.com/vb...l-bits-183967/"USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:Originally Posted by 7A749Get an Annular bit. Google it, you'll see what I mean. Your chuck may not be big enough to hold one tho....
Reply:Originally Posted by 7A749DANG!NICE RACK!! Well, rack of Rota Broaches anyways......
Reply:The drill is probably grabbing and chipping/breaking when its breaking through..  After resharpening the drill try dulling the cutting edge slightly with a stone and put a flatter angle on the drill..    also slower rpms would help, I would do no larger than a 1/2" pilot hole. also slower rpms would help..  a cheaper or older worn drill press will have a hard time drilling larger holes simply because of the bearings, or lack of bearings will let the drill walk causing chatter/chipping/breaking. I think a Unibit/Stepdrill would work great if the tubing wall isnt too thick..Last edited by brucer; 12-11-2012 at 02:20 PM.tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:How thick is the rectangular tubing that you are drilling?To minimize chatter, you shouldn't be drilling a pilot hole larger than the web thickness of the larger size drill bit you are using.  I happen to have a 13/16 drill bit (big sucker!), and measured its web thickness at .120, which is a bit under 1/8".  So to make a pilot hole for that, I'd use a pilot drill smaller than 1/8".The 13/16" is going to take a lot of power through thick steel, so you might want to try a unibit on the press you are currently using, because it just removes a small bit at each step and works with much less power.  Otherwise, an annular cutter on a mag drill may be a good option given how many holes you have to do.If you don't need the holes to be precise, you could even make them with a plasma cutter (if you've got one of those.)I am a fan of having a not overly aggressive relief angle on my bits.  This makes them drill slower, (more rotations required) but with less power being required.  Could be helpful for large diameter application.  Be sure to use some appropriate lubricant, like some oil.I sharpened my 13/16" drill bit myself on a diamond wheel on a bench grinder (I use the other side of the diamond wheel to sharpen my tungstens for TIG welding.)  It's too large for my drill doctor to work on it (which maxxes out at 3/4" diameter.) Attached ImagesLast edited by jakeru; 12-11-2012 at 09:55 PM.
Reply:Not pushing kills drill bits.  So do pilot holes.  :Pilot holes increase pressure on the outer edges of the bit causing them to chip.  Not using enough feed pressure causes the bit to pass over material without removing it.  This causes the material to work harden.  Material removed also caries heat away from the bit so not removing material will cause the bit to overheat.  Use only a pilot hole as large as the web of the bit, feed it generous force.  Most professional presses are power feed and will feed so many thousandths every revolution.  Also, learn to sharpen your own bits, it's easy.
Reply:Buy a mag drill, I have a couple and they are great.  Expensive though, and while you're at it you'll need to get some annnular cutters to go with it as others recommended, these are expensive also.However you can drill all those holes with a drill bit and some cutting fluid, no problem.  Your 5/8" pilot is way too big.  This causes excessive heat on the very outside of the cutting edge due to the excessive feed speed causing it to fail.  A 1/4" pilot hole is plenty, drill full size with a little bit of cutting fluid occasionally to keep the bit tip cool and enough feed pressure to keep it cutting.  A nice curly chip from both flutes is ideal.  You already have your drill press running slow enough."The reason we are here is that we are not all there"SA 200Idealarc TM 300 300MM 200MM 25130a SpoolgunPrecision Tig 375Invertec V350 ProSC-32 CS 12 Wire FeederOxweld/Purox O/AArcAirHypertherm Powermax 85LN25
Reply:Built a jig yesterday fastenal rep is coming this morning for me to demo the mad drill and will report back on how it works.Vantage 300 kubota ,miller 304 xmt ,lincoln ln 25 pro , ranger 305 G, plenty of other tools of the trade to make the sparks fly.