Drill Sharpening machines

[Moto]

I guess I learned how to sharpen bits on a grinder by reading The Sensuous Gadgeteer -- one of my all-time favorite books, written in the 1970's, when gadgeteers could also be sensuous, it seems.

I'm still using the same box of Hansen bits I replaced in the early 1990's after the original one was stolen. (I have bought some other special bits along the way.) I just sharpen them by hand, no drama.

Moto

[lrutt]

I like sharpening tools, which is good because I sharpen (mostly carbide) chisels endlessly in studio carving granite.  Same with my chefs knives, all variety of wood tools, chainsaws, etc, etc.  All is done freehand, no jigs or gimmicks.   The only challenge that I didn't overcome was sharpening small drill bits and keeping the point centered, especially now that my eyes are not as young as they used to be.... 

On <1/4" bits, they disappear fast chasing a centered point.  So I bought my drill Doctor about 20 years ago and use it all the time.  Still on the first diamond wheel.  I find better drilling results with the bits if I split the point after sharpening, which is also done on the drill Doctor.  I've bought & acquired a lot of "useless" dull bits for free since getting it, because I know most will sharpen without issues.  I would recommend a drill Doctor without reservations but they are not foolproof....

For people outside the trades, It's important to understand that industrial diamonds cannot tolerate heat extremes.  If you get them hot enough to spark and keep going (on metal or stone) they will fail and no longer cut anything.  at the same time, if you heat your bit until it holds color (blue, straw, whatever) you'll overheat  the tool steel bit and anneal it.  Double fail & 100% user error.  If it's tempered and you cannot hold it with bare hands, it's too hot.  So go slow and don't get either bit or diamonds hot and all is good.  Curiously, if you try to carve ice with diamond tools, that extreme cold also wrecks them. 

In some applications, water is used to help keep the diamonds cool so you can grind more aggressively.  A drill doctor isn't equipped for water cooling.   so if you thermal the diamond wheel during aggressive use and don't slow down the thin layer of diamonds on the wheel will be destroyed very quickly.   It's also not designed for heavy grinding, just for sharpening and minor stock removal.    For best results, shape a badly dulled or broken bit to approx shape in a regular grinder (freehand or otherwise). Appropriate effort when grinding against the drill Doctor wheel will help it last through hundreds if not thousands of sharpening.  I will check my depth and reset the holder during sharpening and that helps a lot to produce a great, sharp bit.  Then, just like any other sharpened tool, I keep it sharp instead of letting it get dangerously dull.  A few seconds in the drill Doctor and all is good.

Splitting points is also best done as a check & reset depth as needed.  Going slow and sneaking up on the split is better for the tool than one step with hard pressure.

As mentioned, ymmv.  Just like some here have stated, Some professional machinist friends have told me it's a Mickey Mouse gimmick.  Everyone has their own opinion.  Keeping a green or carborundum wheel perfectly dressed just to sharpen bits is one more obstacle and expense in the shop.   the diamond wheel in the drill Doctor is not stone. It is metal with surface bonded diamonds, which maintains its shape as long as the diamonds are intact.  Having a stone in there would mean constant dressing to maintain profiles.

Used properly, a drill Doctor works great for me- especially on the little bits.  I would not pass a professional drill bit sharpener if the opportunity arose for low$$.  Until then, I'm very happy with mine.

+1 for me as well. I got one for Xmas that does right and left bits, up to 3/4. I used it once to clean up a ton of old bits and honestly haven't had to use it in a couple years now. Did a great job. I have sharpened bits for others. Just don't press so hard and the bits won't temper and wheel won't wear.

[canuck750]

I like sharpening tools, which is good because I sharpen (mostly carbide) chisels endlessly in studio carving granite.  Same with my chefs knives, all variety of wood tools, chainsaws, etc, etc.  All is done freehand, no jigs or gimmicks.   The only challenge that I didn't overcome was sharpening small drill bits and keeping the point centered, especially now that my eyes are not as young as they used to be.... 

On <1/4" bits, they disappear fast chasing a centered point.  So I bought my drill Doctor about 20 years ago and use it all the time.  Still on the first diamond wheel.  I find better drilling results with the bits if I split the point after sharpening, which is also done on the drill Doctor.  I've bought & acquired a lot of "useless" dull bits for free since getting it, because I know most will sharpen without issues.  I would recommend a drill Doctor without reservations but they are not foolproof....

For people outside the trades, It's important to understand that industrial diamonds cannot tolerate heat extremes.  If you get them hot enough to spark and keep going (on metal or stone) they will fail and no longer cut anything.  at the same time, if you heat your bit until it holds color (blue, straw, whatever) you'll overheat  the tool steel bit and anneal it.  Double fail & 100% user error.  If it's tempered and you cannot hold it with bare hands, it's too hot.  So go slow and don't get either bit or diamonds hot and all is good.  Curiously, if you try to carve ice with diamond tools, that extreme cold also wrecks them. 

In some applications, water is used to help keep the diamonds cool so you can grind more aggressively.  A drill doctor isn't equipped for water cooling.   so if you thermal the diamond wheel during aggressive use and don't slow down the thin layer of diamonds on the wheel will be destroyed very quickly.   It's also not designed for heavy grinding, just for sharpening and minor stock removal.    For best results, shape a badly dulled or broken bit to approx shape in a regular grinder (freehand or otherwise). Appropriate effort when grinding against the drill Doctor wheel will help it last through hundreds if not thousands of sharpening.  I will check my depth and reset the holder during sharpening and that helps a lot to produce a great, sharp bit.  Then, just like any other sharpened tool, I keep it sharp instead of letting it get dangerously dull.  A few seconds in the drill Doctor and all is good.

Splitting points is also best done as a check & reset depth as needed.  Going slow and sneaking up on the split is better for the tool than one step with hard pressure.

As mentioned, ymmv.  Just like some here have stated, Some professional machinist friends have told me it's a Mickey Mouse gimmick.  Everyone has their own opinion.  Keeping a green or carborundum wheel perfectly dressed just to sharpen bits is one more obstacle and expense in the shop.   the diamond wheel in the drill Doctor is not stone. It is metal with surface bonded diamonds, which maintains its shape as long as the diamonds are intact.  Having a stone in there would mean constant dressing to maintain profiles.

Used properly, a drill Doctor works great for me- especially on the little bits.  I would not pass a professional drill bit sharpener if the opportunity arose for low$$.  Until then, I'm very happy with mine.

Thank you for this, great information, I have not been too successful with my Drill Doctor, now I know it's more my lack of understanding than blaming the machine, I will dig out the sharpener and give it another go.

Cheers!

Jim

[Lumpy Idle]

That said, this guy made a great vid about drills and sharpening. It is the "long way around" but it's worth watching as he explains everything in terms the average Joe can comprehend.

https://www.youtube.com/watch?v=r8oORR6jyh8

yes! highly recommended. this old tony does great stuff and really goes a long way toward demystifying the whole machine tool experience. his lathe tool grinding contributions are most worthy. go there.

[Ncdan]

Dan, two hex nuts tacked together flat to flat would give a 120 degree angle.

The commonly ground end angle on commercial drill bits is 118 degrees, so 120 is generally "close enough"

That said, this guy made a great vid about drills and sharpening. It is the "long way around" but it's worth watching as he explains everything in terms the average Joe can comprehend.

https://www.youtube.com/watch?v=r8oORR6jyh8

Thanks, good information, I'm going to weld my nuts together and start sharpening my drill bits😂

[Huzo]

Not drawing my sword to you, Huzo.. pointing it at the Drill Doctor. The *most* important thing about sharpening drills is to get the flutes on center. The DD has a couple of MM  spring steel jaws that can and will put the center off. The cheesy collets that hold the drill.. oh, never mind.

My early errors included failing to relieve the heel such that the cutting edge could not engage and the tip of the drill heated up to a point similar to the centre of the Sun..!

[cliffrod]

Thank you for this, great information, I have not been too successful with my Drill Doctor, now I know it's more my lack of understanding than blaming the machine, I will dig out the sharpener and give it another go.

Cheers!

Jim

Glad it's helpful, Jim.  I owed you something for the tool pouch pattern anyways.... 

Grinding the bevels freehand isn't that tough. Matching the bevels while keeping the point centered is the greater challenge, especially on little bits.   To me, it seems obvious the bit is off center in the DD chuck if it grinds more on one side than the other while turning the chuck. It should be the same- if not, fix it...   That's why I check & realign the bit as needed during sharpening. 

I understand that grinding them freehand benefits from regular checking of bevel angles and lengths.  With enough experience/practice, maybe experts don't need to check.   I never check bevel angles on my knives, chisels, etc but know some do religiously.   I know what I need for the job at hand- usually the job that is providing my paycheck- and just do it.

You can add a back bevel by hand after using the DD, which does help. Use a grinder or do it by hand with a little India stone or diamond stone.   I have no doubts that I could easily & quickly learn to do it all freehand.  That will probably happen when my DD dies or needs a new$$ diamond wheel.  Right now I still have other priorities.

[Muzz]

Dan, two hex nuts tacked together flat to flat would give a 120 degree angle.

The commonly ground end angle on commercial drill bits is 118 degrees, so 120 is generally "close enough"

That said, this guy made a great vid about drills and sharpening. It is the "long way around" but it's worth watching as he explains everything in terms the average Joe can comprehend.

https://www.youtube.com/watch?v=r8oORR6jyh8

Good info and video thanks Rick.

[Rick in WNY]

Glad I could give something back to this group, you all have been very helpful to me.

For my needs, I bought an ancient Craftsman drill sharpening jig. it will handle everything from 1/8" to 3/4" drills.

It was designed to be mounted to the side of a grinding wheel, so it can grind against a mostly flat surface. I set mine up to work off my little belt sander. It may be old and slow, but once you get the hang of how to load drills, there is no question of whether or not the point is centered. It's on center, every bit as good as a factory job.

Just checked on evil-bay and there's more out there. Here's one like mine, old school cast aluminum, not the pressed sheet metal new ones.

https://www.ebay.com/itm/VINTAGE-CRAFTSMAN-6677-DRILL-SHARPENING-GRINDING-FIXTURE-IN-BOX/223424886965?hash=item34052938b5:g:YsEAAOSwzEVcTcGS:sc:USPSPriority!14837!US!-1

Look around and you'll find them with different name plates. Mine is a Craftsman, I've seen MAC Tools and Matco among others. Nice solid units, like I said, not fast, but they put a nice cutting edge on dull drills.