Drilling through 1.5" X 3" box

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Hello all, I am looking for a way to drill through a 1.5" x 3", 3/16" box steel.  I'm trying to drill a 13/16" hole through both ends on the 1.5" side, but the bit wants to walk going through the second hole and I can't get the holes to line up perfectly.  Any suggestions?
Reply:If you are good at layout, mark both sides and drill each from the outside.
Reply:I agree, mark and center drill both sides, then drill out one side and flip it over and do the other side. Another ting you coud do is to drill out one side in steps up to the 13/16' when then advance the 13/16 bit down until it touchs the other side. Its big enough that it shouldnt walk. Let it lightly mark the other side so that when you go to your small bit it should start right into the mark made by the large bit. Another option would be a center cut or plunge cut end mill that has a long enough cutting section to go all the way through the 1.5" material. It wont walk and you can start with a 1/2" hole, or what ever size end mill you can use, that is all the way through and straight.
Reply:Absolutely, drill in from each side.And if there are lots of similar holes in the same material, make yourself up a drilling jig to accurately locate an initial smaller pilot hole, in from each side, and work up to the full final 13/16 in stages.It is possible to get nice round accurately located holes, even with a hand held drill, but it must be done starting with a very small pilot drill and working upwards in size.Cheers,  Tony._________________________________Transmig 310 + Argoshield LightOxy acetyleneOxy propanePrehistoric stick welder_________________________________
Reply:Dont try to drill through the side that has the weld seam.  If you have a lot of holes to do consider using a split point on your drill bit.  A thick web or improper sharpening encourages wandering.  A lot of strucural is being drill with bits sharpened with a "centerpoint"  I have never used one but they are designed to not wander and are used on a lot of beam lines where there is no layout or centerpunch marks.
Reply:Find a Curve O Mark lay out tool and you can draw a line all the way around the tube then use a combination square to mark the other line then drill from both sides.  Like others said use a pilot hole and avoid the flash at the weld seam.Dan
Reply:drill press...or slow speed with a small 'new/sharp' bit as a pilotjust suggestionsHow do you know the blacksmith's dog? When you hollar at him he makes a bolt for the door!
Reply:Just about any small bit used as a pilot that's long enough to reach through 3 inches is going to wander. At least I wouldn't trust it. Marking both sides is the way to go. Be sure to do your layout from the same end for both sides."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:break out the mag drill and call it done, and if the seam is on the side of the tube you are drilling make your first hole on the seam side....i have trashed a few annular bits by not paying attention going through from the wrong (non-seam) side....expensive lesson learned!