Sharpening drill bits by hand

[handlewanker]

Astonlee, I've heard of "throw away tips", but draw the line at throw away drills or end mills, and if they're carbide......throw 'em my way and I'll sharpen them and resell them....he He He, money for old rope.

I would agree that if you were able to cost all the consumables to the job total, then at the end of the job the total tool set would be paid for and would actually COST you money to resharpen, hence it would be practical to give the tools to the customer as part of the contract.

I used to do this anyway with press tooling, and the customer always paid for the tooling and it was their's to reuse or refurbish if the contract was renewed after the initial part run.

More often than not a dieset with tooling costing about $2000 got scrapped after the production run, at the discretion of the customer.

Very rarely was a dieset, with all the various dowel and screw holes with all the cut-outs, reused. Just too much messing about trying to find metal to hold the next tooling.

Anyway, if the customer refused to pay the cost of the tooling, it got added to the production run if the run was large enough.

With first time customers it was always policy to get the cost of tooling up front in case the customer cancelled the contract prematurely. BTDT.
Ian.

[cheetahcnc]

A retired tool and die maker taught me to grind drill bits. He handed me a chipped M2 about 3/8", and said "sharpen it". I gave it everything I had, and went back to him with it. He said, "not yet, a little more this way, and a little less of that", etc. After a few times he said it might actually drill OK. So I tried it. It worked pretty good. He said, "let me have that a second". He drove it point first into the grinder, handed it back to me, and said, "If you can make that one cut, you know how to sharpen drill bits". I did, and have been sharpening them ever since! I do agree that replacing small bits is more cost effective, and the sharpened ones end up in the "beater" drill index.

[neilw20]

I re-point my $60 carbide endmills every 5 hours, after they dull on an abrasive job.
http://www.cnczone.com/forums/showth...461#post548461

[venomgrrrl]

Takes alot of practice, but well worth it, most shops ive worked at had the drill shapeners, if my dog had thumbs he could do it! But for one the dont do large drills and well its kinda the lazy way. Had a genius of a jornyman and he sent me back time and time again, till it was perfect. Now for production sake every drill over 1 1/2 is a carbide spade, and we have a shapener, never regret the learning process though!
oh yea...pedistal grinder w 2in wheel

[Motzilla41]

My step father owned a machine shop, and sent me to Benson Polytechnical School in Portland Oregon. They taught drill bit sharpening, lathe tool sharpening, filing and drilling and tapping aluminum. I was 15 years old.
But due to my 15 year old arrogance, I made such a fuss that my folks sent me to the local school that had girls so I could go the easier softer way.
Big mistake.
In the same position I would be firm and not let my son throw away a very good education so he could play hippy.

Now I am going back to relearn the things I lost due to my own stupidity.
Anyone who goes to a technical school should be able to sharpen a drill bit.
It is the same as a guitar player not knowing how to tune his guitar. Just a braggart who talks with his mouth and not with his skill.

[neilw20]

I learned to sharpen all sorts of tools at Technical School. Never looked back.
Did I miss all those horrible subjects and the girls? Girls yes, subjects no.

[Doug_M]

We have 2 drill sharpening machines where I work but IMO they aren't that great . I prefer to hand sharpen but our grinder wheels are always being abused by someone doing a home project or just screwing around until just keeping them dressed is a full time job !!

[edilberto.milan]

Hi all of good people out there a pleasant good afternoon from your new friend ed milan

[handlewanker]

Hello Ed, what's your interest in the CNC or Engineering world?

The forum covers a lot of ground and this thread deals with the aspect of grinding drills by hand, so if you've ever tried to drill a hole and all your drills are blunt, you'll know what I mean.

Are you a tradesman with experience or a newbie? (newcomer).
Ian.

[WA Toolman]

My step father owned a machine shop, and sent me to Benson Polytechnical School in Portland Oregon. They taught drill bit sharpening, lathe tool sharpening, filing and drilling and tapping aluminum. I was 15 years old.
But due to my 15 year old arrogance, I made such a fuss that my folks sent me to the local school that had girls so I could go the easier softer way.
Big mistake.
In the same position I would be firm and not let my son throw away a very good education so he could play hippy.

Now I am going back to relearn the things I lost due to my own stupidity.
Anyone who goes to a technical school should be able to sharpen a drill bit.
It is the same as a guitar player not knowing how to tune his guitar. Just a braggart who talks with his mouth and not with his skill.

Hi Motzilla41... Another one from Benson here. BTW they allow girls now, I'm told.

[Shawn Lucas]

$95/hr? Get out of the cities and get some stuff done without breaking the bank. But even at half that rate, It just makes no sense to stand over at the pedestal grinder and sharpen a drill for more than a few seconds.

[aka.apprentice]

I know this reply is uber-late but I just joined the community and this was one of the first things I've seen!

I wasn't allowed to use a drill bit until I knew how to sharpen one. Same went for lathe tools. Wasn't allowed to use carbide inserts until I could grind my own HSS. =)

[handlewanker]

Hi all, I would go as far as to say that if'n you have a drill bit grinder available, you'd be a fool to grind drills by hand.

It doesn't mean that you should ignore manually attacking the pointy end of a drill bit with a grinder, but the whole idea is to make the tool work.

Being able to grind by hand, using a couple of gauges to indicate progress, is a valuable attribute to your education engineering wise, and anyone who neglects to learn the manual method is taking the short cut to knowledge deprivation.

It's almost as bad as not bothering to learn to read because you have a really cool MP3 player, but it's a competitive field and you'll need everything going for you sometime or other, and not all firms provide drill bit grinders.
Ian.

[christinandavid]

Carbide tooling needs to be ground quite accurately as any deflection is likely to cause it to snap.

The only drill grinder I have used holds the drill bit in an ER16 collet - clamping on the flutes....Unsurprisingly it does not grind the flutes evenly as the drill is never clamped concentric. Looks pretty though.

Regardless of their visual appearance I would always go grind by hand all the HSS/HSCO drill bits for an operation before I start setting up - especially for tight tolerance holes. Drill a bit of inco on CNC and it will soon let you know (horrible scraping sound) if the drill isn't cutting right...you learn quick.

Heck, if I see a bit of wear on the lead of a reamer I will go chop the end off and regrind the chamfer (admittedly a bit more control is required to get new lead concentric - a lap with an adjustable v-block attachment works well - I still back the lead off 'freestyle' though).

Does anyone else cast a shadow over the drill with their hand and examine the drill silhouette with one eye shut to check the drill form? My work colleagues look at me with disbelief when I demonstrate this technique...

DP

[universalfab]

At today labor rate and the fact that you can never really grind a drill point with both flutes cutting at the same time unless you use a comparator. The cost to grind a drill in other than a home shop or to be used in a manual machine is not worth it for a 3/8 drill. As a note I did tool grinding for 10 years and can split point. But unless there is no new drill a regrind will only be use if it the last option.If your a job shop I can see why you would, but a manufactor would not was the time Boston shop rate $95h/60m=$1.58/min x 5min(regrind time)=$7.50 what the cost of new?Buy a dozen at a time and send out for regring when you have many to do The shop we send to charges $2.50/drill under 1/2 and that is with a split point

Manufacture huh, well I have seen the argument on here before about custom made tools "cutters" made by a tool maker for a specific job and the argument that a insert cutter "off the shelf cutters" and a cnc has out dated custom tool grinding. I think that is rediculous, it makes no sense to make a bunch of tiny cuts "adding much longer run times", instead of grinding a custom tool to cut that shape out in a few passes. Manufactures are after speed, and custom tool grinding saves alot of time, electricity, and machine wear & tear when it comes down to it. This is common sense to anyone that knows anything about manufacturing. For 1 off parts if you can get by with a off the shelf tool, then why not add a little longer run time vs. grinding a tool. Now grinding a drill bit I agree a manufacture "most likely" wouldn't regrind little drill bits. It's a valuable skill to have, we and I in our shop re-grind drill bits by hand depending on tolerances of the part and we grind our own lathe and mill tooling along with tool and die making.

[gdgrinder]

I have worked in a machine factory for sell work.As to the used drill bit, if you throw it away and to buy the new drill bit, i think it will wasted money, so it is right to use the drill bit grinder to sharp the used drill bit.it is a wise choose.

[DMF_TomB]

i think your drill bit sharpening poll has more to do with

20% cannot sharpen a drill bit
10% do not want to bother as they don't pay for bits
70% can sharpen and care enough to save money by sharpening bits
.
i wonder what your poll would be for machinist who buy their own drill bits with their own money??
.
when i was an apprentice it was expected for the apprentice to sharpen everybody's drill bits. the better they got at it the sooner they was done with it.

[Dualkit]

Mine have to do with size, I used to be able to sharpen down to 1/32 with a loupe and a diamond wheel. Now with shaky hands and bad eyes, nothing smaller than 5/32. I have found many a time my re-grinds last longer than the drills out of the envelope and I am buying name brand USA made.

[handlewanker]

The fact is everyone, if'n you're in production all the time, that is continuous production, to stop and regrind a drill means you are costing the drill grinding against production output.

In actual fact if the machine is auto working, either CNC or peg board auto or just plain cam auto, the setter usually has enough spare time to do that kind of regrind work.

It takes about 1 minute to hand grind accurately the average drill, say a 9mm (3/8") diam jobber drill, but the machine must be kept running all the time and that means some form of auto control.

In the real world the drill just gets changed, and a $30,000 a year toolroom person operates the drill grinder and puts a point on the drill.

The drill grinding is a hidden cost because the toolroom person is probably a lower skilled worker and serves tools at the store window and grinds drills between time.

In UK in the early 70's we employed a young lad from Trinidad, 16 years old, couldn't read a mike' or a drawing, didn't know the angle of an end mill end face or a slot drill helix, but could serve tools at the store window and operate the drill grinder once shown how....wages then about 800 pounds sterling, or at 2 dollars to the pound, about $1600 a year.

Just before I retired, every drill used in the production process had a tool number backed up by a drawing that stated the max and min length size, and as such were only ground in the tool room on a tool grinder by skilled personnel.

When drills became too short to drawing size, (sometimes only 1mm short), they went into a section of the store for reallocation, and when that box became so large they got periodically obsoleted and sold off to dealers for lack of space to store them.

BTW, I regularly regrind drills as small as 1.0mm diam with a hand drill grinding jig I made, (it was commercially available as the Wishbone Drill Grinder) because nothing cuts like a freshly ground drill especially after you've been pushing it a bit, and 1.0mm drills don't cut if they ain't ground right.
Ian.

[Dualkit]

The fact is everyone, if'n you're in production all the time, that is continuous production, to stop and regrind a drill means you are costing the drill grinding against production output.

In actual fact if the machine is auto working, either CNC or peg board auto or just plain cam auto, the setter usually has enough spare time to do that kind of regrind work.

It takes about 1 minute to hand grind accurately the average drill, say a 9mm (3/8") diam jobber drill, but the machine must be kept running all the time and that means some form of auto control.

In the real world the drill just gets changed, and a $30,000 a year toolroom person operates the drill grinder and puts a point on the drill.

The economics work for me. My dulls go in a box. They are on a "to do" list of things to do when everything is running on automatic. No productive time wasted.