Jump to content

Sharpening Drill Bits

Recommended Posts

Hi folks,  I learned a "bit" about this skill from a machinist I worked with.  I've messed up a few drill bits in my career (15 years as a Wood Model/Pattern Maker).  I don't use this skill much, and recently I decided I couldn't see the grinder and bit as well as I would like so I went shopping for a drill bit sharpener online.

After seeing the prices, I have decided to buy a bright light and a magnifier.  And maybe a new set of bits.  The price of a sharpener would justify it.

I found this video and picked up a few tips I didn't know.  I can add my own tips;  Eyeball the angle.  It's hard to tell if your grind is lopsided by eye but hold it up to the light and look anyway.  The Web break should be roughly 45º to the cutting edges.  Bit Wear. Check how your bit is wearing.  If it's vibrating or if the relief is rubbing grind more off the shiny side.  Shiny Spots.  That's the side that's touching the work.

Hand Sharpen Drill Bits - Youtube - 8+ minutes

Link to comment
Share on other sites

I have a Drill Doctor, medium priced bit sharpener.  I too was taught how to sharpen them early my career.  I find that with lesser eyesight and skill set(out of practice), I do a better job more times than the Drill Doctor.  Perhaps like medical doctors, who PRACTICE medicine, this Doctor does too.

Link to comment
Share on other sites

Regardless if you do it manually or use a drill doctor, its been my experience once you have to remove/grind material much deeper then where the factory original tip was (Say after a few sharpens) THEY NEVER PERFORM AS WELL OR LAST QUITE AS LONG BEFORE DULLING. I'm NOT saying they cant be sharpened and that it doesn't "help" if done properly, heck maybe a machinist or expert can make them work as good as factory original by proper sharpening ????????? 

John T  NOT a machinist or materials person, this is ONLY my personal observation over many years or sharpening drill bits, manually or drill doctors. 

Edited by oldjohnt
Link to comment
Share on other sites

Being a former tool and die maker, I will state drill bits may be resharpened to cut as good as, or better than(depending on material) a new bit. The tool crib had a bit sharpener that worked for most standard bits and materials, but drilling thick (2") copper is unique, and a new standard bit would not stay sharp very long. It took lots of experimenting with different grind designs to find the solution. Drilling thin material often causes the bit to grab in the hole as it pierces the bottom side, this calls for a negative angle on the cutting edge; however it specializes the bit to where it's nearly useless for anything else(drilling glass is OK) unless the negative grind is eliminated.

FLJoe, the only way to learn is to ruin some bits in the learning curve. You can purchase a drill-bit sharpening guide that sets the angle of each cutting edge while displaying if the length of each cutting edge is the same. The heel of the flute must be lower than the cutting edge, but too much angle results in short life.


Edited by Ray,IN
Link to comment
Share on other sites

I have often bought the cheap gold colored HF bits.  When sharpened these cut pretty good, better than new.  They don't stay sharp very long but the DD brings the cutting edge right back.  I just wish the DD worked for bits larger than 3/4".  When using a hand drill I really like sharp bits.  When the drill press is doing the work, I am a little more tolerant of less than perfect drill bits.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...