The 3 Minute Drill

LOL Something I dream of. The dozen that is. GeoffH Norfolk - UK

"Basic research is what I'm doing when I don't know what I'm doing" Werner von Braun

"Dean" wrote in news:bp21hm$7oc$ snipped-for-privacy@enyo.uwa.edu.au:

To me tools are like girls - I'd rather have one

Neither is cheap.

No such thing as 'free'.....when it comes to women.

"Anthony"

A rather nice lady at work says with a laugh " I might be easy, but I aint cheap ! "

Dean.

I've seen some CHEAP drills and similar tools, including the HF items. We buy some for our university engineering and science students to 'beat on'. They can kill most anything ... especially expensive electronics! They busted a sizeable bench vise, and ran our tensile test machine past it's travel limits, doing $4K damage (OUCH!). While running our TABLE saw, they even managed to saw their own cord in two. That's not hard to do with a portable saw, but a TABLE saw? Very creative. At least it's job security for me.

While nobody will claim the cheap import tools as good as the better grade 'brand name' imports, let alone USA produced stuff, I've never seen one fail in '3 minutes'. Even our ham handed students haven't killed one nearly THAT fast (yet).

They've beat the crap out of several, including a couple HF $16.95 right angle 4" grinders for over a year now, and all are still running.

Dan Mitchell ==========

Dean wrote:

And these are "university engineering and science students"! Good luck for the future. Mike in BC

On Fri, 14 Nov 2003 10:13:50 -0500, "Daniel A. Mitchell"

snip

Daniel A. Mitchell wrote: (clip) They've beat the crap out of several, including a couple HF $16.95 right angle 4" grinders for over a year now, and all are still running. ^^^^^^^^^^^^^ If any of the cheap HF right-angle grinders I have ever fail, I will replace them with more of the same. They do the job, and that's all that counts.

I don't know whether that three-minute life-expectancy for cheap drills was meant to be taken seriously, but I, for one, doubt it. Where did the figure come from? The designer? The manufacturer?

3 minutes isnt so big a stretch.. however, had i wagered a guess, i would've put those cheap import drills at/around 10 minutes.

roughly speaking, top quality tools have a tool life of about 30minutes. this can range, probably, from 15mins for a good milling cutter (HSS) to

40 or so minutes for drilling and turning (with coolant)

tool life, if i remember my college days correctly, is the time it takes a tool edge to wear a predetermined amount. whether the tool still "cuts" or not is up to the user.

cutt-off wheels (abrasive), if i'm not mistaken, are in the 2.5 - 3 minute range.

had i a list of important things i've learned over the years, somewhere in there would be:

1. buying good drill bits (and tools, in general)
2. learning to sharpen them by hand

-tony

Tony sez: " had i a list of important things i've learned over the years,

Tony's comments:

#1 belabors the obvious

#2 is impossible (no disrespect to the dear departed T-nut)

Bob Swinney

I bought 3 cheap ($15 on sale) 4" angle grinders with the intention of having one with a wire brush, one with an abrasive wheel, and one with a sanding disk all ready to go at any time. The first one worked fine, ran it for about 5 minutes continuously with the abrasive wheel to clean up some welds... no problems. The second one literally got too hot to hold and went up in cloud of smoke in about 1 minute. It was running continuously, but only working intermittently as I cleaned powder-coat off an oven rack. The guy holding the rack burst out laughing... he watched me take it out of the package, attach the wire wheel, and smoke the thing in less than 3 minutes! lol In hindsight, I have no idea why buying this cheap junk sounded like such a good idea when I read it here... one $50 grinder would have been a much better investment. Live & learn... again, and again, and again! >;-} David

"Daniel A. Mitchell" wrote in message news: snipped-for-privacy@umflint.edu...

But then you don't have any tool snob bragging rights.

Dick

Yeh, that's what's SCARY ... and these are the better examples. I'm appalled by the lack of the most basic skill among even our brighter students. They're not DUMB, they've just never DONE anything! It's like they were raised in a vacuum. Then again, maybe they were. :-(

Sure, there ARE exceptions, but they seem to get fewer and fewer. Even after they're educated, they still don't have any fundamental (hit your thumb with a hammer) understanding of what they're working with. No wonder we get Challengers, Hubbles, and Columbias.

Dan Mitchell ==========

Michael Gray wrote:

Define your terms.

Are we talking CONTINUOUS use at full rated load?

or CONTINUOUS use at or near stall?

or intermittent but frequent use at for a prolonged TOTAL time of 3 (or

10) minutes?

Many light duty power tools arenot even RATED for truly c>

Or, near-to impossible. I sharpen drills at home all the time, and they cut within a thou or so of the listed size.

I only do this on drills bigger than 1/8 inch or so.

Jim

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"tony" wrote in news:k78tb.28014$hV.1028177 @news2.tin.it:

In my humble experience, and testing in a high volume manufacturing facility, 100% designed tool life == 20% tool design + 80% environmental factors.

No tool will last in undesireable conditions. The biggest single enemy is heat.

"Daniel A. Mitchell" wrote in news: snipped-for-privacy@umflint.edu:

Dan, I feel your pain. I too instructed in a machine shop for several years. I taught adult night classes. What's the scariest part..is when they 1) leave the chuck wrench in the lathe, or 2), run the sled into the jaws, or 3) fail to properly secure the workpiece on a horizontal grinder.

Jim sez: "Or, near-to impossible. I sharpen drills at home

Forget it, Jim. The T-nut award has already been passed out to someone that can sharpen *all* sizes of drills by hand.

Bob Sw>

Oh well.

BTW could you give me that person's name, I've got some no. 60 drills that need a touchup!

Jim

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NASA probably has good engineers, but politicians demand that they get told what they want to hear (or else) and bean counters accommodate the politicians.

I agree. There are tables in the Machinery's Handbook that specify speed and feeds to give a certain tool lifetime.

If I drill aluminium at 100 SFPM, my drill could last hours of continuous use. If I drill at 500, all bets are off. Coolant or no? Rigid machine? Anything preventing the drill from getting pulled when it breaks through the rear face of the part?

In some instances, 3 minutes continuous is a long cutting life for a tool.

Regards,

Robin