Author Topic: Unable to sharpen drill bit. At a complete loss!  (Read 778 times)

Offline Dr Spin

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Unable to sharpen drill bit. At a complete loss!
« on: June 21, 2020, 01:21:22 pm »
hello all. Please see attached picture of a 8mm drill bit with my attempts to sharpen it with my T8. The primary facet comes out wedge shaped and the secondary starts some way around the circumference and not at the bottom! I have done several bits successfully with my new T8 and also previously with the BGM-100 but a few previously unsharpened bits end up like this. I have tried all the variables with no luck so at a complete loss. Any help would be much appreciated regards John

Offline micha

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #1 on: June 21, 2020, 01:49:46 pm »
Hi John,
first of all, after having sharpened several hundreds of drill bits, I had a handful of those which I couldn't sharpen, too. One of these had very strange flutes, which left a curved edge, or were simply bent, which made sharpening them quite pointless (pun intended :))

In case of your drill bit I think you should start by simply grinding it down further, at least until the primary facet is completely clean. The wedge shape should be gone by then. I think that results from an slightly different point angle, but usually is not a problem.

Make sure the edge is still parallel to the markings on the jigs after grinding the primary facet.

Keep us posted
Mike



Offline Dr Spin

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #2 on: June 21, 2020, 01:55:42 pm »
Thank you Mike. Will give that a try. The bits that are doing it all look similar so I might have bought them as a job lot? Cheers John

Offline micha

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #3 on: June 21, 2020, 02:05:56 pm »
John,
as the edge looks straight, I think it's just the point angle not exactly matching with the jig's setting. Grinding the fist facet completely should cure that, as far as I can tell from the picture.
Don't think it's a general problem with all these bits.

Mike


Offline RichColvin

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #4 on: June 21, 2020, 02:12:57 pm »
John,

The wedge shape is entirely due to the rotation of the bit’s cutting edge.  This is outlined in the manual for the DBS-22 on pg. 14.  Here is a link to the online version :  https://www.tormek.com/media/105148/instruction_dbs22_en.pdf

I have found that when removing a lot of metal for badly mis-shapened bits, the location of the cutting edge needs to be adjusted.  What happens is that, as the metal is removed, the edge is rotating around due to the rotation of the flute on the drilling bit’s shaft.  There is discussion about this on pg. 13.  This can also happen when significantly changing the point angle (see also, pg. 6).

So, the solution is to grind away the badly mangled edge, and then re-check the alignment.  I find that using the magnifier as discussed on pg. 7 to be useful.  I do this even on larger bits as it is a bit easier for me to see the alignment.

More guidance is here :  https://www.sharpeninghandbook.info/GT-DrillBits-Twist.html

Good luck.

Kind regards,
Rich
---------------------------
Rich Colvin
www.SharpeningHandbook.info - a reference guide for sharpening
www.ColvinTools.com

You are born weak & frail, and you die weak & frail.  What you do between those is up to you.

Offline Ken S

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #5 on: June 21, 2020, 04:59:44 pm »
John,

The DBS-22 has always impressed me as Tormek's most advanced, sophisticated jig. Borrowing a term from Alan Holtham, who did the excellent Tormek video on it, it can also be Tormek's most "fiddly" jig. It is certainly not automatic, and requires patience and skill. I hope Tormek will dedicate an online class to it.

Please share your experiences.

Ken

Offline Dr Spin

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #6 on: June 21, 2020, 05:20:27 pm »
Thanks to Mike, Rich and Ken for their very helpful information. The edge was parallel to the markings and when it isn't or has been sharpened past that point it does create a wedge on the primary facet but not like the one I received which appeared wider and longer. I even tried varying the edge angle anticlockwise and clockwise and the wedge was replaced with a wider parallel sided edge when the edge lined up with those extra diagonal lines on the jig. The point angle was about 120 deg and I tried that and 118 to no avail. Increasing it towards 130 deg actually made it improve.
  Following the advice I set it at 120 deg and tried a 7 deg jig angle as this seemed to involve removing the least metal. I sharpened the whole tip into a primary facet first then changed to the secondary.  I did get a 4 facet point as in my photo not as good as usual but still satisfactory. A valuable lesson and I will experiment with the other drill bits.
Cheers John
« Last Edit: June 21, 2020, 05:23:58 pm by Dr Spin »

Offline micha

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #7 on: June 21, 2020, 05:54:35 pm »
John,
congrats, that looks like a good result now.
I've found that once you have a good understanding of the jig's principles sharpening drill bits can be quite fun - and working with sharp drill bits is fun, anyway.
The only downside is, you'll never again be satisfied with one of those brand new standard bits. :)
Regards
Mike

Offline courierdog

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #8 on: September 25, 2020, 09:12:20 pm »
My First Attempt, turned out reasonable on the Primary Facet. When I reset for the Secondary I found I did not have a full grasp of not just the concept but the total setup and grinding process.
When I started the Secondary Facet grind, I found the Primary Facet totally disappeared.
Where did I go wrong.
I spoke with Ken and Mats at Tormek, I obtained a pdf copy of the DBS-22 Instructions.
I then spent 2 days and edited the Instruction Manual to give me One Process One Drawing per Page.
OK So I now have an 89 Page Instruction Manual, SO What!!
I started Over Square One, Using the New One Page, One Process Instruction Manual, No other illustrations to confuse my thought process.
Tormek has done an excellent job in the Design and Illustration/Documentation process, It just does not work for me. Why?
I need to be forced into the one Step, One Process, One Drawing, One write up way of Thinking/Working.
OK So What!
The Point here is I am no different than most other people.
What I need is to follow the Illustrated Manual Exactly as Illustrated and Written.
When I started Over and Followed the Intent of the Original Instruction Manual Every thing worked.
Each and Every Step, in the Process, saw exactly as is illustrated in the Instruction Manual.
The Primary Facet when ground was exactly as depicted in the Illustrated Instruction Manual.
Next, this is where I ran right of the rails on my first attempt.
Using the New One Step, One Illustration, One Write Up Process.
The Secondary Facet started to show progress with the first pass across the grinding wheel. My initial grind was the reverse of what I thought. The Initial grind was coming from the Heel. and working toward the Primary Facet.
Caution if you see the developing Facet looking uneven, this is corrected by ensuring the Cutting Edge is aligned using the magnifier with the centre mark on the Drill Bit Holder.
I did follow Ken's reminder to "Sneak" up on the Secondary Facet.
As The Secondary was beginning to form it did not have that two step overlapping look.
So I took it even slower,
This paid off as the Secondary Facet slowly began to form and I saw after each pass, the development of the multi Faceted Drill Bit.
Wow, as I slowed down and took my time and paid careful attention to each pass the Secondary Facet just began to form and as it crept up on the point and I began to see the two distinct facets over lap as in the Illustrations in the Instruction Manual it became exciting to achieve the Factory like finish right before my eyes on my machine in my shop, in my hands.
Thank You Tormek
« Last Edit: September 25, 2020, 10:03:33 pm by courierdog »
Retired Engineer

Offline micha

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #9 on: September 25, 2020, 09:55:11 pm »
Dave,

thank you for the interesting field report. I'm glad it works for you now.
And finally working with drill bits ground in such a way is the other really satisfying part. ;)

Mike

Offline courierdog

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Re: Unable to sharpen drill bit. At a complete loss!
« Reply #10 on: September 25, 2020, 10:24:17 pm »
The key for me, was sticking to the process as illustrated and written. I had difficulty, with the Instruction Manual as written, really only because there was to much on one page. The Manual is well written, very very few intensional mistakes. I did point out some to Mats at Tormek, who replied I was correct and that the Swedish version did not word it in the manner expressed in English.
The Key for me is, SLOW DOWN, ONE STEP, ONE STEP, ONE STEP.
Initially this may seem like you are just plodding along.
Believe Me, IF You Follow Exactly As The Manual Says, You Are Making Good Progress.
The End Results Will Show All your Adherence To Detail.
The Jig IS Simple, The Process Is Simple, Learning to Follow The Exact Process Can At First Seem Tedious, However When You See Your First Drill Bit With 4 Perfect Facets, You Will Forget All The Drudgery of the Process.
You will Want to turn on the Drill Press and Start Drilling Holes.
I have a Lathe project which requires an extensive amount of Hole drilling which have to be very precise.
So My First Thought Was How Or Where to Find Sharp Accurate Drill Bits.
Purchasing New Drill Bits Is Pricey, What About Sharpening My 40 year Old Premium Grade Drill Bits.
I did not what a Single Purpose Drill Bit Sharpening Device that gathers dust when not in use.
I began hearing good Things about the Tormek Drill Bit Sharpener.
Since I Already Owned a Much Upgraded Tormek 2000 Machine, Look at the DBS-22 Jig.
I watched several YouTube Videos. I was hooked.
When it arrived and I opened the box. I knew I had made the right choice.
No Second Rate attachment, This is a Real No Holds Bared Jig designed to sharpen Drill Bits.
Yes, I struggled to learn how.
With the help of forum Members and Factory Support, I attacked the process as an opportunity to learn and grow. As I am now retired at 79 I guess it is time for me to learn something right.
The DBS-22 Is a First Rate Accessory which compliments the Tormek Sharpening System and now has a permanent place in my shop.
Thanks for Listening
Retired Engineer