Drill sharpening

[me3@neuralfibre.com]

A couple of years ago I bought a 12mm Sutton Viper drill bit. It was my first split point drill. To say the least I was impressed. As someone who often has to drill thicker steel not in a drill-press, anything that makes life easier is a boon.

Since then I've been looking into sharpening

http://www.mmsonline.com/articles/choos ... t-geometry

http://www.cnczone.com/forums/showthrea ... 760&page=1

http://www.drilldoctor.com/group.asp?grp=6

Anyway - Tradetools looks to have a ripoff of the drill doctor for $99.
And it says it can do split point tips.

a) Has anyone bought / tried on yet?

b) Does anyone know any other way of doign multi-angle drill sharpening?

By hand is only an acceptable answer if you can show how to use an angle gauge to prove you got it right. I can sharpen by hand, but not to a high degree of accuracy.

Thanx
Paul

[BlueSuzy]

You don't use a pilot 1st? Makes life easier

I guess you want less time consuming if running a bussiness etc..

[wrksux]

I dont have photo's

All our drills at work are sharpened by hand on a grinder from 3mm-45mm drills, either on a bench grinder or a tool and cutter grinder.

Any toolmaker or fitter worth his salt can consistantly sharpen drills and get them almost ifnot perfect. To learn my boss told me to bring in all the blunt drills from home and then gave me a box of old drills. 4 days of doing drills you get better at it.

Pilot drill, Thin the web on drills and hold it square will reduce nearly all your problems

[Struth]

Very few auto drill sharpeners actually work well.
Best off to learn how to do it by hand. That way you can learn different sharpening techniques for different drilling applications.

Cheers

[PJ.zook]

I eventually learnt to sharpen drills with the belt sander, but i found using pilot drills helps greatly, as the pilot drills are cheap and a bastard to sharpen, the big ones are expensive but easy to sharpen.

[jet-6]

I can sharpen drills ro 2mm up by hand, no worries, BUT i had a spare wad of cash one day and bought a drill doctor to try out, its a mid range version and was like $300 with some freebies

I will NEVER hand sharpen a drill bit ever again, it does split point on all bits from 2mm to 16mm, its so damn good

[nastytroll]

1.2mm drill is the smallest I have sharpened by hand. Thinning the web gives somewhere for the swarf to go and releives tip pressure. There is about 9 main variations of drill tip design for different applications.

Using a belt sander to sharpen drills is not ideal. Belt sanders are flexable and tend to give poor shape to the cutting edge and generally round the cutting edge over and cause the drill point to rub from lack of clearance.

I used to sharpen drill bits to cut 0.05mm oversize by hand. I'm not as good anymore, I don't sharpen drills enough to keep the feel up.

Keys to good sharpening. Not too rough a wheel, good balanced and dressed wheel, centre point is central, flutes are equal length and even distance from drill point, Correct clearance. Some materials need different rake angles and point angles, some need more back clearance too.

[V8Patrol]

..... To learn my boss told me to bring in all the blunt drills from home and then gave me a box of old drills. .....

same
got 10mins of instructions and then left to it


We get locals bringing in boxes of blunt drills all the time ..... first thing I do is run em through the dropsaw so the ends are squared up and the worn sides are cut away.

I dont bother with anything less than 3mm ... they are cheaper when bought in bulk

[KiwiBacon]

Anyone got some tips for sharpening drills in stainless?

I'm drilling some 304 angle (3mm thick) with a 9mm, running ~650rpm. First hole usually cuts fine, second sometimes it will work, but obviously has lost it's edge a little. Sometimes it heats really fast, burning the drill and the hole.
Drill press doesn't have coolant unfortunately.

Once a drill has been burnt, can it be successfully resharpened or does it need at least 5mm taken off carefully to get back into hard metal?

[PJ.zook]

You just answered youre own question. You need to keep the bit cool when drilling.
Buy a small bottle of cutting fluid, mix it up with water in a $2 spray bottle, then squirt that on what youre drilling as youre drilling it.

[nastytroll]

Anyone got some tips for sharpening drills in stainless?

I'm drilling some 304 angle (3mm thick) with a 9mm, running ~650rpm. First hole usually cuts fine, second sometimes it will work, but obviously has lost it's edge a little. Sometimes it heats really fast, burning the drill and the hole.
Drill press doesn't have coolant unfortunately.

Once a drill has been burnt, can it be successfully resharpened or does it need at least 5mm taken off carefully to get back into hard metal?

Slow your rpm, stainless will glaze very quickly. Sqirt coolant on like P.J said and run your drill speed down low, 300rpm ish. If you have flood coolant the higher recomended speeds are fine but when drilling by hand slow it right down. Cutting fluid or grease will help dramatically too, though messy. Rocol or trefolex or equivellant.

Drill will just sharpen up like normal, check the flutes for wear, stainless will wear hard on the flutes.

[wrksux]

Stainless will workharden quickly lots of coolant

[KiwiBacon]

I'm using aerosol lubes (CRC CDT) but it seems to make little difference.

The problem occurs when the hole is down to the last 0.5mm or so, that thin web pushes into the same conical angle as the drill and heats quickly from the centre to the edge.
I'll try a pilot drill too. That'll remove the centre from the final plug and should let the 9mm drill bite into it.

It's one of those jobs where I'm running low on motivation, I could have drilled them all in the time I've been posting here.

[chimpboy]

It's one of those jobs where I'm running low on motivation, I could have drilled them all in the time I've been posting here.

lol I know those jobs, it's not that they are all THAT hard to do but they just don't seem to go the way you think they should, and it gives you the shits.

I have worked out that if I think a job will take one hour, it will take one hour. If I think it will take four hours, it will take four hours. And if I think it will take five minutes, it will take a day and a half of farking around

[KiwiBacon]

I have worked out that if I think a job will take one hour, it will take one hour. If I think it will take four hours, it will take four hours. And if I think it will take five minutes, it will take a day and a half of farking around

Soo true.
I got all 16 holes done, by the time I finished the 9mm drill bit was a whole inch shorter than it used to be.

[fester2au]

I have worked out that if I think a job will take one hour, it will take one hour. If I think it will take four hours, it will take four hours. And if I think it will take five minutes, it will take a day and a half of farking around

Soo true.
I got all 16 holes done, by the time I finished the 9mm drill bit was a whole inch shorter than it used to be.

What sort of feed rate were you using and the pilot is your friend if you don't have special profiles. The other week I had to drill 16 countersunk 10mm holes and 16 14mm holes in 10mm stainless plates. Whilst it took a fair while i didn't need to resharpen once by piloting first and heaps of trefolex. WE like the paste at work for drill holes and generally only use the CDT for holesaw holes as it's a bit more convenient for more frequent application.

[KiwiBacon]

What sort of feed rate were you using and the pilot is your friend if you don't have special profiles. The other week I had to drill 16 countersunk 10mm holes and 16 14mm holes in 10mm stainless plates. Whilst it took a fair while i didn't need to resharpen once by piloting first and heaps of trefolex. WE like the paste at work for drill holes and generally only use the CDT for holesaw holes as it's a bit more convenient for more frequent application.

I was using a mill-drill as a press, the the feedrate is about half an arms pressure.
I've drilled plenty of stainless before (used to work for an automation company doing lamb processing machinery) but then I had the luxury of large drill presses with coolant.
This stainless angle seems to be further work-hardened than other sections of 304, compounded by the small thickness (3mm) which lets it heat really fast.

[PJ.zook]

You should try drilling thru the thin Volvo truck chassis. Even with constant lube spray, we can only drill around 5-10 holes before the slugger bit is blunt as hell, them sum bitches are hardened well.

[shorty_f0rty]

ive got a heap of 13mm bits that I used on 6-10mm thick stuff and pretty much abused them (lots of pressure, heat and rpms).. blunt as hell.. i use kermit cum (is that cdt?) but with a hand drill on the lowest speed setting..

Now that I'm building some sliders for the 80 I'll need to drill about 12 holes thru 10mm plate. with a bunch of blunt bits I figured instead of buying a new one I'd try out a drill sharpener. I ended up getting the only one at bunnings that would do 13mm bits for around $54. I haven't used it yet but will need to soon so i'll report back if its actually any good.

[me3@neuralfibre.com]

Very few auto drill sharpeners actually work well.
Best off to learn how to do it by hand. That way you can learn different sharpening techniques for different drilling applications.

Cheers

*Straps on flame suit*

I have some doubts (as does [s]industry[/s] "the internet") as to accuracy when done by hand. Trying to grind highly accurate matched angles with 2 or 3 facets (split point) whilst maintaining correct relief angles - hmm.

I know I can sharpen a drill - but I also can't do the above.

If anyone can do so - please post pics with an angle gauge to show accuracy.

I'll keep looking at shapening tools I think.

(before anyone asks "does it matter that it's not right" - yes - it matters to me as it's right when I buy it)

Paul

[nastytroll]

Very few auto drill sharpeners actually work well.
Best off to learn how to do it by hand. That way you can learn different sharpening techniques for different drilling applications.

Cheers

*Straps on flame suit*

I have some doubts (as does industry) as to accuracy when done by hand. Trying to grind highly accurate matched angles with 2 or 3 facets (split point) whilst maintaining correct relief angles - hmm.

I know I can sharpen a drill - but I also can't do the above.

If anyone can do so - please post pics with an angle gauge to show accuracy.

I'll keep looking at shapening tools I think.

(before anyone asks "does it matter that it's not right" - yes - it matters to me as it's right when I buy it)

Paul

What "industry" are you in?

I have sharpened D bits by hand and machined spurr gears with them. Any Toolmaker or good machinist should be able to sharpen a cutting tool to cut within size free hand. I used to re-sharpen masonary bits to drill through 58HRC+ hardened steel.

Most drill sharpeners are shit. I use a good one at work sometimes for a special through coolant twist drill. The drill sharpener cost $25k.

A drill can be sharpened very accurately using a "scratch gauge" to check even flute length and a vernier to check point centre. Once having sharpened a few drills it should be second nature to just do it right with out the gauge.

The point angle and releif is not as important as it may seem, and it should be varied to suit different types of materiarls. There are also point forms that an average drill sharpener cannot sharpen. Also how do you grind in a chip breaker or zero front rake or negative front rake?

This is not new technology, I think the book we used at collage was written in 1954, so information should not be hard to find.

[jet-6]

Just buy a drill doctor, not a cheap knock off and this thread and be done!

[PJ.zook]

Whats with all the big words? All ya do is use the belt sander or grinder, grind away both sides gently until they look sharp and arent missing chunks, and that the cutting edge is highest point on the slope. Then just drill thru shit. Works for me anyways. Angles etc doesnt seem to matter.

[ozhumvee]

Another vote for a Drill Doctor, does them perfectly every time from a couple of mm up to 3/4" /19mm. Can do normal, split point, masonry and left hand.
I bought the 750x from the US for about $AU170 and a 110v to 240v 300watt transformer from a bloke in Wagga for $AU32 and it works really well. I also bought a couple of spare diamond wheels and they shoved them in the box with the Drill Doctor.
Got both on ebay, seller id hardware_sales_inc , great service, really quick shipping 4 days from buying it till it arrived!!!
So far I've done 275 drill bits in all sizes (mostly 8mm up to 13mm)
and the wheel is still working well, doesn't need replacement yet.
What prompted me was the tins of blunt drill bits sitting around because I couldn't sharpen them due to lack of practice (I used to be able to do them years ago) and I had run out of sharp bits, went down to the hardware and figured by the time I bought another good set I'd be well on the way to paying for the Drill Doctor.

[r0ck_m0nkey]

Order Number and off to the wholesaler

[jet-6]

Another vote for a Drill Doctor, does them perfectly every time from a couple of mm up to 3/4" /19mm. Can do normal, split point, masonry and left hand.
I bought the 750x from the US for about $AU170 and a 110v to 240v 300watt transformer from a bloke in Wagga for $AU32 and it works really well. I also bought a couple of spare diamond wheels and they shoved them in the box with the Drill Doctor.
Got both on ebay, seller id hardware_sales_inc , great service, really quick shipping 4 days from buying it till it arrived!!!
So far I've done 275 drill bits in all sizes (mostly 8mm up to 13mm)
and the wheel is still working well, doesn't need replacement yet.
What prompted me was the tins of blunt drill bits sitting around because I couldn't sharpen them due to lack of practice (I used to be able to do them years ago) and I had run out of sharp bits, went down to the hardware and figured by the time I bought another good set I'd be well on the way to paying for the Drill Doctor.

Same reason for me, had way to many bluntish bits and to lazy to do them all, so the doctor was the perfect item, i dont have any blunt bits now, there are hundreds of sharp bits in my tool box now

[Struth]

Very few auto drill sharpeners actually work well.
Best off to learn how to do it by hand. That way you can learn different sharpening techniques for different drilling applications.

Cheers

*Straps on flame suit*

I have some doubts (as does [s]industry[/s] "the internet") as to accuracy when done by hand. Trying to grind highly accurate matched angles with 2 or 3 facets (split point) whilst maintaining correct relief angles - hmm.

I know I can sharpen a drill - but I also can't do the above.

If anyone can do so - please post pics with an angle gauge to show accuracy.

I'll keep looking at shapening tools I think.

(before anyone asks "does it matter that it's not right" - yes - it matters to me as it's right when I buy it)

Paul

No need for a flame suit, not all of us were lucky enough to be taught by tradesmen and learn through on the job experience, so some of us need mechanical aids, like drill sharpeners or laser cutters and CAD systems.........

Because theys missin the skillz

[v840]

http://www.pirate4x4.com/tech/billavist ... index.html

[-Scott-]

I can sharpen a drill to make it cut a hole - but I can't sharpen it to make the hole perfectly round, and to size.

I bought some cheapy sharpener from somewhere (probably Bunnings), which goes on the front of a drill to spin the sharpening stone. Unfortunately, it doesn't fit any of my drills properly, but I did manage to acceptably sharpen a couple of bits after a bit of bodgy business.

[Ice]

group buy time ?

I can sharpen drills, its part of my trade lol, but yeah it is quicker to use a machine setup for it when you have more than a couple to do

unsure how these drill doctors go but for what it promises might make a lot of people happy that are struggling to keep drills sharp