Cheap drill bits vs good once

I have an opportunity to buy high quality drill bits really cheap. But since I already have a bunch of cheap Chinese bits from HF and I am
pretty much satisfied with them so I wonder if I even need these hight quality bits. I remember reading on this forum about big difference between good bits and cheap once.
Can anyone explain what exactly the difference is?
Thanks, Alex
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Alex wrote:

I can tell you what I think the difference is.
With a cheap drill, the first time you drill a hole in steel and let the steel work-harden before you've finished the hole, you've dulled or destroyed the cheap drill.
Quality drills keep going and are far more forgiving of drilling in a work-hardened hole.
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Alex wrote:

Cheap has many different levels..from drill bits that unwind, to bits that snap right off to bits improperly ground. You may find a handful of cheapos that are better than most and actually work, but that is a rarity..even with ever increasing quality from India and China.
The real value of a GOOD set of drill bits is seriously reduced hassle level. A good bit cuts soooooo much better than a bad one that it's like night and day. Where the better end of "bad" may take a couple of minutes, a lot of energy and do a lousy job drilling through a part, the good end of good will cut through like butter in 1/10 the time, still be useful after, and give a better hole.
Better to have a few good bits than a whole set of mediocre bits.
It gets worse with taps and dies, which don't yet seem to have developed a good end of bad...cheap China and India stuff is REALLY bad when it comes to these cutting tools.
Note that there are always exceptions to every rule..someone somewhere here probably swears by cheapies....it's just not me.
Koz
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I was at Sears yesterday and saw some one set of HSS drill bits (little red plastic case) on sale that sade made in the USA. The newer version said made in China. The Cobalt and Titanium ones said made in the USA of USA and import parts. I am hoping it's the case that is made elsewhere.
Thanks for the suggestion, as I was going to buy the $60 set of HSS Steel bits, but no more.
Thanks!!
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They had a lot of the little 10 piece and 13 piece kits before Christmas. The one ten piece set I saw the other day was $8.97. The 13 piece kits around Christmas were about $10, I think. If I had known the difference, I would have just bought the little kits to have SOME decent smaller sized bits. I don't remember seeing anything about HSS on the 21 piece kit I was looking at (newer style, no 29 piece kit in stock, and I am thankful they didn't, or I would have bought it).
I bought one 5/8" cobalt drill bit a little over a year ago. After using POS bits my whole life (and a few single bit Titaanium Craftsman bit purchases in the last couple of years), I finally found out a difference in quality!
I would have bought every set they had at that price, too! You will always need some, and you will never be ableto find them any cheaper, so why not buy them out? :-)
Thanks.
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I
in
always
UPDATE:
I went to Sears and they had the 29 piece (regular) drill bits in stock. The website states that they ARE HSS. They are model number 64083. I looked on the box, and the packaging stated the same thing as the newer style 29 - piece Cobalt and Titanium Nitride kits, that they are made in the USA of US and foreign materials. I hope the box is what is made of foreign materials. The 21 piece (normal) drill bit kit DID say made in China on it.
The local Sears had several sets of the "MADE IN THE USA" red, plastic cased HSS drill bits for sale on the reduced price aisle.
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the quality of the metal. the quality of the grinding / sharpening. accuracy of the size.
A poor quality drill bit may be improperly ground which can give you an eccentric hole of the wrong size.
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Here is a cheap drill bit. I bent with my fingers.
http://www.viatrack.ca/Misc/DRILBIT.jpg
Regards,
Boris Mohar
Got Knock? - see: Viatrack Printed Circuit Designs (among other things) http://www.viatrack.ca
void _-void-_ in the obvious place
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Alex,
If you can get you hands on some tool or alloy steel, you'll see the difference rapidly. Mild steel and many common non-ferrous materials are very forgiving. If you run your cheap bits conservatively in these materials, you probably won't have trouble. Industry however has no time for "conservatively" and we don't get to choose the "forgiving" materials so good bits that don't get dull after one hole in D2 are a requirement.
Regards,
Robin
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for
Great explanation!!
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My experience (not extensive, but, still, it's mine :-) is that chinese tools cut for crap. From drill bits to band saw blades. Now, what I have found is that the chinese caliper, for exqample, is in fact accurate to the stated 0.0005 (used a $125 USA to check the three I purchased for $15 each). Also, as long as your not holding tollerances to 0.0001, most all of the gauge blocke, right angle plates, etc that I have purchased check out to be perfectly fine...left unprotected, they will rust and corrode quicker, but that can be controlled....Just my 2 cents
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No, they're not. calipers by their very design are not accurate to .0005. Yes, that's what the dial reads, but if you're trying to get closer than a couple of thou, you best be using your mikes.
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Hi Dave,
Not following ya here. I have purchased precision Brown and Sharp 1-2-3 blocks, they all read, 1-2-3 to the 1.000 with the last +/- 0.0005 stuck on zero. I have found that the secret to using calipers is to wiggle them into the product you are measuring while you apply a bit of pressure (light) on it, take the smallest reading you get, and that is the diameter. Now, i am not a machinist, won't be for 20 more years I imagine, so no argument intended here, just don't follow ya. Wouldn't I expect to get variance from 1.000 on any of the "Chinese" calipers if they weren't as accurate as they are stated to be? Not talking tenths here, just the stated "round to the nearest 0.0005".
My initial statements were more geared towards a comparison of dollars spent for unit of quality...very high for Chinese cutting tools compared to the same Chinese parallels, squares, calipers etc...
Thoughts? Love to get more edumacated :-)
John
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Replying to the Subject:
Cheap drill bits ARE only good once, if that.
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You actually are talking tenths. If a drawing specifies +/-.001", a measured dimension of +.0011 is out of tolerance. Obviously if your calipers read to only five tenths, they'd probably tell you +.001" which would be wrong.
Ideally, your measuring instrument should be ten times more accurate than the tolerance it's evaluating. Sometimes this will drop to between two and five, depending on the actual tolerance, method of measurement, speed, etc., etc., etc.
Regards,
Robin
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