Tips Drills And Lubricants-Maintenance Cruz
It is amazing how many maintenance people that really do not know how to drill a hole. I generally spring this test on my potential hires to gauge what they know about machine tools and maintenance in general. I asked "what is the hardest working tool in the shop"? I hear welder or grinder a lot and some other strange things that aren't worth mentioning here. The answer is the drill bit.
It's hard to fathom that a simple item like a drill bit would be worthy of such respect but they are. A drill bit is some what a thing of genius when you get down to the engineering of the thing. The geometry of a drill bit is kind-of a thing of beauty. A double helix ground to perfection with relief on a precision hardened piece of steel. All machine tools are pretty amazing for that matter when you look at geometry and the engineering that went into its design.
This is one of those things that makes me cringe. It is when I walk up on a job or into a shop only to find a tech trying to press a smoking drill bit through a piece of steel. Yes you know the one, the tech who has most of his weight pulling down on the drill press quill handle or all his weight down on a hand drill and getting nowhere fast.
I walked in on a person with a pile, and I do mean pile, of burnt drill bits next to the press. I became instantly curious as he was still trying with all his might to get a hole in this material. I asked him what was up and if I could help. He said he has never had this much trouble and all these bits where garbage, I had to bite my tongue right here. I asked what the material was and he said he wasn't sure but it is a alternator bracket for his hot-rod. I told him to stop because he was trying to drill a piece of high grade stainless and would need a special bit, cutting fluid, and different cutting speed. He had wasted every 5/8ths bit in the shop trying to make this hole and it wasn't even work related, I was not happy.
Taking time to enlighten your crew or yourself about drill bits, materials, cutting fluids, and proper techniques is well worth the time. It is so much better when materials are recognized and proper machining speeds, tools, and fluids are used its almost mind boggling. You whip in your cobalt bit, slow your cutting speed, grab the sulfurized cutting fluid and viol-ah, easy drilling.
You give it a rest, that is, pull the tool back and let some of the heat to dissipate before taking another bite. Once you get your head wrapped around the fact that you have two pieces of metal coming into contact with each other under pressure and in motion you start to imagine the friction. The heat build up between a dry drill bit and the material is intense and will destroy a drill bit in the blink of an eye. Funny thing is, is that most burnt drill bits could have been avoided with cutting fluid and giving the tool a rest.
It is also an economic issue when the entire crew thinks that drills are a one use disposable item, I don't see it that way at all and it gets very very expensive. I would regularly get twenty times the life out of a drill bit then my crew and that is no exaggeration. I make it a requirement for the crew to resharpen the shop bits, this usually gets them on board with proper drill use because they do not want to sharpen bits.
Another strange thing I find often is the lack of pilot holes or even spot drilling. Guys just want to get it done and go on break with little or no regard for the waste and how much harder it is on themselves. I can't stand on a pedestal as I am guilty as well but, when I have the opportunity I try to do everything in the proper manner, mostly because it is so much easier on me. Drilling pilots is so much better then trying to force a large bit through a piece of steel not to mention how much better the hole turns out. A pilot hole is your best bet for reducing or eliminating chatter, anyone who has drilled a piece of steel with a large bit knows what chatter is all about.
There are a lot of things that can be slammed together, whooped out, and rigged but most the time the work is poor and the time saved is not worth it. Everything has its place and when production is down and you need a hole now you probably wont care about pilot holes or cutting fluid but you should.
And lastly, its broken bits that bother me the most as they can not be salvaged with sharpening, well they could but it usually is just not worth it. I have broken bits just like everyone else mostly very small ones but with the larger one I just don't get it. Proper drilling practices should keep anyone from breaking larger bits, of course there are strange circumstances but I am talking about a plain hole through mild steel.
It pays in a personal way to study up on drills, drill geometry, drill materials, feed rates, speed rates, and fluids. Knowledge is power and having the knowledge or obtaining the knowledge to make your work better and easier is wise. As with all machine tools eye protection is a must but you also must want it for yourself. There just isn't anything you are working on worth your eyesight. Just imagine the next day after losing your eye because a bit shattered and pierced our eyeball. You wear protection because you are protecting yourself not because the company says so and if the company doesn't require enough, wear more and get the policy changed.