This for sure. I didnt know about this and about wore myself out trying to drill a few small holes and hacksaw through some stainless once.
If I can get stainless hot enough to work harden with a hacksaw, I am sure you could do it quite easily with a power saw/drill.
I would literally go only a few seconds at a slow speed and then stop to see how warm the hole saw and stainless is. If its more than barely warm, wait a bit for it to cool before hitting it another few seconds. You DO NOT want to work harden that stainless.
A brand new hole saw, some good cutting oil, and taking it REALLY slow are worth their weight in gold for this DIY operation.
Using a holesaw in a handheld power drill, without first making a pilot hole risks several adverse outcomes:
[ul]
[li]On a metal surface, the possibility that the inbuilt pilot drill will skip or drift[/li][li]Preventing said drift/skip by initially steadying the drill point with your fingertips puts your fingers at risk of injury from the saw parts[/li][li]When the inbuilt pilot breaks through the material, it the sudden give may result in the saw slamming against the workpiece[/li][li]Without a pilot hole, it’s harder to concentrate on keeping the axis of the holesaw perpendicular to the surface, which can cause the saw to bite or bind, which at worst may shear off the pilot drill or skip it out of the hole, sending it skipping over the material, or it may just result in the hole being cut at an angle (even in thin material, this means it’s non-circular)[/li][/ul]
I’m not sure about this. I had to drill a large number of holes in stainless a couple of years ago. Many recommended lube, keep cool, go slow to me and it didn’t work really. It worked to some degree but one false move and the stainless just work hardened anyway. Then I found a comment on a website by a guy who had done a lot of stainless drilling and his tip was to do exactly the opposite: no lube, medium speed on a powerful drill (I have a drill press) and be absolutely freakin’ brutal. His theory was that if you make sure the drill is biting deep into fresh steel on each revolution then you won’t get work hardening but if you pussyfoot about then you will.
His theory worked a charm. The only catch was that with a lot of pressure on the drill I snapped off a couple of bits, but then I had over a hundred to do.
IFFFFFF when you drill, you have the pressure and speed just so such that nice spiral shavings that look something like fancy pasta noodles are coming out then that theory probably works.
If you don’t get those fancy noodles right off the bat, IMO you better change you game plan fast.
And thats probably only valid for a DRILL bit. I highly suspect you won’t get fancy noodles with a HOLE saw.
FWIW, I am certainly no stainless steel expert. But I can certainly tell you work hardened stainless is a bitch. Its like chipping through a diamond with a toothpick.
Maybe a real expert machinist/stainless dude will chime in here at some point.
Its 3 am and my allergies are killing me so take all this with a barrel of salt.
If you don’t want to unhinge the door, you’ll want to use something like this. These are typically available at tool-rental companies for reasonable fees. Locally, we rent from K&K Tools when we need stuff like that; the last time I rented a drill press, I got the 1/2" for $60/day, + tax. They also rent/sell bits there, but I won’t cut into hardened metals with used tools.
Use cutting oil, sharp cutting implements, and keep the speed down and the pressure moderate. A good cut will deliver a long “corkscrew” shaped metal wire.
Do NOT use a hole saw to cut through hardened metal; use drill bits, and work up from a small pilot hole to the desired size. Do NOT get impatient and jump up in drill size too quickly; you just get broken drill bits.
ETA: wear appropriate clothing and eye protection: that wire/ribbon is sharp!
I lived in an apartment once where someone botched a deadbolt installation. Dunno if it was the landlord or a previous tenant, but the hole wasn’t drilled perfectly straight. I put in a new deadbolt (not knowing the problem was the hole), still didn’t work right.
If you don’t know what you’re doing, ask a professional or someone that has experience installing locks/deadbolts. If you screw it up, your door is ruined and your deadbolt won’t work right.
Good point. New doors, particularly good one are not cheap. At the very least get some advice from someone who knows how to do it and be careful if you do it yourself.
Locksmiths or carpenters that specialize in hanging doors use a jig that clamps to the door and guides the bits for drilling.
I custom build doors and install them. I own this jig: http://www.templaco.com/html/product.asp?id=225&mode=Bore_Master_Kits
For metal doors an adapter for a pilot hole is used to bore from both sides before removing the jig to finish drilling the hole with the proper hole saw.
[drilling hardened steel] These, straight flute solid carbide bits will go through up to Rc 60 hardened steel (they do need the right speed and lube!).
[/drilling hardened steel]
Yes. More times than you can imagine. My father is a contractor and I started working on construction sites when I was 4 (sweeping). A good hole saw will have 1/2"-1" of pilot bite into the material. That’s more than enough to center the drill. Spiral scratch marks are caused by weak wrists and jumping is caused by forcing the drill too much. Neither problem is solved by drilling a pilot hole.