As the thread title states I need to drill / cut a lot of holes for m16 bolts in 3 thicknesses of 3 mm steel for a total cut depth of 9mm, as quickly and as easily as possible (approx 450 holes). The material is Armco galvanised barriers being used to fabricate a cattle handling yard. I have access to 220v 16 amp power plus several dewalt battery drills for zero cost and minimum effort (setting up extension leads). Options currently on the table are; 1, Standard drill bits, 3, 6, 9, 12 and 16mm but I fully expect this to be slow and expensive in the drill bits. 2, Use a Step drill, I expect to have to drill from both sides and again to go through lots of drill bits. 3, Use my plasma cutter, means sourcing the cable and making a 100m 32 amp extension lead plus buying 100m of air hose. Is there any other way anyone can suggest of quickly cutting these holes, currently I'm leaning towards the plasma cutter and long extension lead. Thanks for taking the time to read this, any suggestions appreciated. Mike
You have to weight up cost of drill bits vs cost of 100m air hose, along with the time to drill vs time to plasma cut. How fast can you make the hole with plasma cutter? Also, can you layer them so that you can attack a few barriers at once?
Hole saw? even if you have to buy 10 or so of them it will be cheaper than getting extension cord/hose for plasma or even twist drills,
Step drill, or the plasma. You shouldn't need to drill through both sides with the step drill but will need to tidy the back face up some, but if you're thinking of blasting them through with a plasma you'll need to do the same with that. How about an oxy torch with a cutting head to blast a quick hole through?
I'd be tempted to make a jig to run the plasma cutter round, something that can be slid along and "stencilled", but you'd need to test it first to make sure you can get a cut clean and accurate enough to do the job. Hole cutter would be my second choice, again I'd get my hands on one and try it, see if it's acceptable. You have to be careful with galv. though, the fumes aren't just bad for you, they will kill you if not managed properly.
This sounds like the job for a mag drill. Position it, activate the mag base, activeate the power feed, hole is drilled, retract drill head, deactivate the mag base, and move onto the next hole. Even better if you have flat enough ground for a small hoist to take the weight, or can lay the metal down flat. Rent one for the job rather than buying one so you are working with a quality tool rather than the cheapest available.
Hadn't considered a mag drill with annular bits, will look into hiring one but around here (rural France) I won't hold my breath, I may have come up with a different attachment method I'll try tomorrow if its not wet (forecast is for a lot of rain). Its to weld one end of each piece of ARMCO into place and then bolt the other end to the next welded section, should allow for some expansion and contraction with weather and be strong enough. Got a respirator and spare filters for the welding / cutting fumes, plus I'm working outside.
Thanks for the heads up, always worth mentioning as it is missed a lot. My background before starting farming is marine engineering with an oil major so i'm familiar with most of the risks (although certainly not all of them). I do find it's always worth asking for advice from different sources as there are always different ways of doing a job that I won't have thought of and some things, including risks that someone else will. I'm still enjoying the "luxury" of being able to use non intrinsically safe tools outside plus getting tools without having to wait months for delivery.
That could work, slight issue sorting a backstop for that calibre plus I gave up my FAC when i left the UK and haven't gotten around to getting a French one. The .300 WM I had in the UK made very neat holes in 10mm hardened steel (AR500) targets much to the annoyance of the owner who assured me it was fine to shoot.
I agree Lube is always good when drilling holes, cutting / tapping fat is often overlooked and highly recommended for a smooth easy drilling.
