Chinese bits bite seal killer

Topics include, Machine Tools & Tooling, Precision Measuring, Materials and their Properties, Electrical discussions related to machine tools, setups, fixtures and jigs and other general discussion related to amateur machining.

Moderators: GlennW, Harold_V

User avatar
seal killer
Posts: 4696
Joined: Sat Aug 18, 2007 10:58 pm
Location: Ozark Mountains

Chinese bits bite seal killer

Post by seal killer »

All--

Like many entering this endeavor, my first drill bits were Chinese (from Grizzly). They are TiN coated HSS. I have three 129 piece sets, one is almost unused and the other is brand new. My "go to" set has served me well for years . . . until today.

I needed two through-holes (2" DOC) in a round piece of 1018. The first being a reamed, 0.374" hole. To make this hole, I mounted the 2.125" diameter workpiece in the lathe and spun it up to 74 SFM, center-drilled and then step drilled twice without problem on the way to 23/64". I inserted a 23/64" jobber length bit in the drill chuck and attacked the last step drilled 15/64" hole. When the 23/64" bit engaged the hole, there was something like a 1/4" deflection in the end of the drill bit. Hmmm. I went to the first backup set and got an unused 23/64" bit. Same thing, maybe a little less. Second backup set. It engaged without deflection and I through-drilled the 2" DOC needed and reamed the hole to 0.374". (I will chop the 2" piece up into 3/8" pieces and press a 0.375" rod in them.)

Next, I needed a hole into which I will eventually press a 1/4" rod. I went to the mill, clamped the workpiece in the D675 using dual v-blocks, set 110 SFM, center-drilled, step drilled 11/64", then inserted a 15/64" (0.234") bit. (All this time I have been very generously lubricating with Viper's Venom, a heavy sulfur cutting fluid.) The bit drilled down to its full diameter and then immediately lost its cutting ability. Bit number two did the same thing. Bit number three did, as well. Now, I'm out of bits.

Wrong. I forgot I had a set of millimeter bits I bought from McMaster-Carr long ago. They are sitting in a cabinet, unused. I grabbed a 6mm (0.2362") and chucked it up. It zipped right through two inches of 1018 without problem. (I ALSO forgot I had a 29 piece set of Precision Twist Drills and another 29 piece set of no-name bits from McMaster-Carr, as well. I had forgotten about them, too, hidden away in a cabinet.)

The Grizzly HSS TiN bits that have served me so well for so long suddenly turned to mush. The only thing I can come up with regarding the deflection problem on the first hole when using the lathe is that the bits are not straight. (I was afraid the 2" DOC would cause the bit to snap after so much initial deflection.) But, I don't have an explanation for why the 15/64" bits immediately died when encountering the 1018 on the mill other than the obvious: Cheap Chinese bits. (In my defense, I replace individual bits as they wear out with American made bits. And, I had those three hidden 29 piece sets that I bought long ago, so my intentions are good, although my memory could use some improvement.)

Has anything I've said given you a clue as to operator error? Or, do you think that after seven years of good drilling results (but very little step drilling, I admit), I've found the problem with Chinese bits?

--Bill
You are what you write.
J. Randall
Posts: 144
Joined: Fri Aug 17, 2007 6:34 am

Re: Chinese bits bite seal killer

Post by J. Randall »

Any chance the problem was in the material, and not the drills? Some steel can have inclusions of much harder material that can wreck a drill.
James
Inspector
Posts: 721
Joined: Mon Feb 23, 2009 4:25 am
Location: Saskatoon, SK, Canada

Re: Chinese bits bite seal killer

Post by Inspector »

They are past their "best before date". :wink:

Pete
Torch
Posts: 1684
Joined: Wed Mar 17, 2010 7:58 am
Location: Muskoka

Re: Chinese bits bite seal killer

Post by Torch »

seal killer wrote:When the 23/64" bit engaged the hole, there was something like a 1/4" deflection in the end of the drill bit. Hmmm. I went to the first backup set and got an unused 23/64" bit. Same thing, maybe a little less. Second backup set. It engaged without deflection
Any chance there was a chip stuck to one of the chuck jaws? It might have angled the first two bits, then been dislodged by the third?

Easy to find out if the bits are bent -- just roll them on a surface plate.
OddDuck
Posts: 434
Joined: Fri Dec 16, 2011 1:00 am
Location: Somewhere south of Mt. Katahdin
Contact:

Re: Chinese bits bite seal killer

Post by OddDuck »

If Grizzly gets theirs at the same Chinese flea market stall that Harbor Freight gets theirs, it could be the drill bit. I bought a fractional set with a number of bits in it (1/2"to 1/16" in 1/64th increments...) and they wouldn't even start to drill into aluminum. Took a closer look at them and on just about every one one flute was fine, and the other flute was ground exactly backwards, with negative rake instead of positive rake. I'm going to have to hand regrind every one to make them useable. Good thing they were like $11 with the coupon.
"If you took the bones out they wouldn't be crunchy!" -Monty Python's Flying Circus
User avatar
warmstrong1955
Posts: 3568
Joined: Thu Mar 18, 2010 2:05 pm
Location: Northern Nevada

Re: Chinese bits bite seal killer

Post by warmstrong1955 »

In case there's any question on my opinion on cheap drill bits?
(I think I posted this before)
Drill Bit.jpg
Due to their peanut butter flexibility, it takes very little for the drill to deflect & bend, especially when starting the hole, even with a spot prior to drilling. Add a tip that's not quite sharp, or straight, or like Torch says, a chip in the jaw, or a chip in the taper, and they wander easily.

I drill a lot of 3/16" holes in 4140QT & 1045 for grease passages in pins, for equipment. I buy 3/16" bits by the dozens, jobber, and long-boys. I bought some cheapy jobbers from Enco once, (Interstate I believe) and experienced the same thing you're talking about. Emphasis on 'once'. Back to Clevelands and Hertels, and other USA brands, no more problem, other than my own if I don't quite hand grind one well.

Bill
Today's solutions are tomorrow's problems.
User avatar
GlennW
Posts: 7284
Joined: Sun Apr 15, 2007 9:23 am
Location: Florida

Re: Chinese bits bite seal killer

Post by GlennW »

The best money I've spent in a while was for a 115 pc. set of Chicago Latrobe bright HSS drills.

Sharp, durable, and drill on size.
Glenn

Operating machines is perfectly safe......until you forget how dangerous it really is!
chief
Posts: 236
Joined: Sat Jan 04, 2003 5:51 pm

Re: Chinese bits bite seal killer

Post by chief »

Hey Glenn,

Just out of curiosity I checked MSC and Graingers for a set like you mentioned. I knew they wouldn't be cheap, but !!!!

The reason I'm posting is that they want 5 or 6 hundred, but Amazon claims they will sell it for a 250, but the listing says "usually ships in 1 4 months"??? Ever heard of such a thing?

Terry
User avatar
seal killer
Posts: 4696
Joined: Sat Aug 18, 2007 10:58 pm
Location: Ozark Mountains

Re: Chinese bits bite seal killer

Post by seal killer »

James--

When the second bit bit the dust, I immediately thought of an inclusion. But, what are the odds? I've heard they exist, but I don't know if I encountered one or not.

--BIll
You are what you write.
User avatar
seal killer
Posts: 4696
Joined: Sat Aug 18, 2007 10:58 pm
Location: Ozark Mountains

Re: Chinese bits bite seal killer

Post by seal killer »

OddDuck and Glenn and Bill and chief and All--

McMaster-Carr sells Viking drill bits. They are manufactured in St. Paul, Minnesota. Have you used their drill bits? What is your opinion?

EDIT: Gee. I HAVE a 29 piece set of Viking bits I bought from McMaster long ago. They are unused. Still, before I launch off to buy the master set, what is your opinion?

--Bill
Last edited by seal killer on Thu Jul 24, 2014 10:53 am, edited 1 time in total.
You are what you write.
User avatar
warmstrong1955
Posts: 3568
Joined: Thu Mar 18, 2010 2:05 pm
Location: Northern Nevada

Re: Chinese bits bite seal killer

Post by warmstrong1955 »

I've bought and used lots of standard jobber bits from McMaster, and they were good bits, but I never noticed who made them.
It's been several years ago too, so no telling if they were Viking, as they change vendors quite often. That said, McMaster usually supplies quality stuff.

Bill
Today's solutions are tomorrow's problems.
User avatar
SteveHGraham
Posts: 7788
Joined: Sat Jan 17, 2009 7:55 pm
Location: Florida

Re: Chinese bits bite seal killer

Post by SteveHGraham »

Still no issues with the Harbor Freight 115-piece set I bought. Their main purpose is to serve as a buffer between my work and my USA bits.
Every hard-fried egg began life sunny-side up.
Post Reply