Remove many material from drill-bit

[keesh]

Hi all!

Merry Christmas in the first place! 

I have a question about using the DBS-22 with a Tormek sharpener (in my case the T4). At some drill bits, I have to remove a lot of material. Some drills are abused and some drills are 'sharpened' by hand, so that the geometry is totally out of shape. I used the TT-50 for the first time (removed a couple of tenth's), while there were some light grooves in the stone (I sharpened about 25 drill-bits I guess).

But for now, I feel that I have to be a little careful to save my stone when I have to remove a lot of material. I don't have a workbench grinder for now (I can buy one of course  ).

What do you use to grind a lot of material from the drill-bits? A workbench grinder? An angle grinder? Or a diamond stone?

I had an idea to make a drill bit diameter 20 to 22 (with a 13 mm shaft) as a countersunk drill (I know that it only has 2 cutting sides instead of 3). Therefore, I need to change the top-corner from 118 deg to 90 deg (and remove a lot of material). I guess I don't want to do that on the SG-200..

Kind regards,

Kees

[RickKrung]

Have you read much of the historical posts in this forum?  There has been quite a bit of discussion on this.  First off, the SG stone is not great for sharpening drill bits, which is part of the reason for the SB stone.  Drill bits are typically High Speed Steel, which the SB stone is designed to do a better job of grinding.  But, my experience has been that even the SB stone is not adequate.  I went through a wide range of possible solutions for more aggressive metal removal for some of the reasons you have. 

1) traditional high speed bench grinder,
2) traditional high speed grinding wheel fitted for the Tormek shaft,
3) belt grinder (I outfitted it to work with Tormek jigs, but not necessary),
4) slow speed bench grinder with white matrix grinding wheels,
5) Tormek diamond wheels (all three),
6) 180 grit CBN wheel on a Tormek (10" wheel for my T87),
7) 80 grit CBN wheel on the slow speed bench grinder. 

#1 works quite well except one had to be careful about heat management

#2 works very well and preserves the dust free, water grinding system of the Tormek.  A bushing with a 12mm bore must be bought or made to mate the traditional grinding wheel with the Tormek shaft.  This is a bit slower than the higher speed alternatives, but is one of the easiest and least expensive alternatives. 

#3 works well and belt grinders are very useful around a shop for a variety of task. 

#4 works well and the white matrix wheels are better for heat management.  I outfitted mine with the Tormek BGM-100 for use with Tormek jigs, but found that the dry grinding grit gets in the sliding surfaces of the drill jig and I no longer use it this way.

#5 is better than the SB but even with the DC (coarse) wheel, I found it still too slow,

#6 is much faster and I use this in nearly all sharpening tasks

#7 still has the problem of throwing dry grinding grit into the DBS-22 sliding surfaces and I no longer us this method for drills in that jig.  I do use it for most non-Tormek grinding tasks. 

Good luck.  Do some reading on the forum. 

Rick

[Ken S]

Kees,

As I was getting ready topost this, I noticed Rick's reply. Rick, he has a T4, so no SB option is possible. However, keep reading:

Here is what I did to solve a very similar problem: (It works very well with the T4) You need a Norton 3X grinding wheel, either 46 or 80 grit. It costs around $60US. For heavy drill bit grinding, I might favor the 46 grit, although either grit will work. You will want the eight inch diameter. It comes with a one inch bore and step down reducers to 5/8". I used a short piece of 5/8" OD plastic pipe.
The ID is 7/16". You need to bore this out with either a 12mm or 31/64" drill bit.You may have to enlarge the hole slightly by drilling slightly off straight. Get a three pack of fender washers with 12mm inside diameter. (The 3X wheel in only one inch thick.

This is a somewhat primitive, but adequate fix. Rick Kruger had a much more elegant fix. He machined a bushing. You might want to talk with a local machinist. This neither complicated nor time consuming.

Use the 3X wheel with water. I used a diamond T dressing tool. Rick has used his TT-50.

Two untried ideas: You might try a dremel with a carbide cut off cutter. I would think a 3D printed bushing might work well.

Keep us posted.

Ken

[keesh]

Have you read much of the historical posts in this forum?  There has been quite a bit of discussion on this.  First off, the SG stone is not great for sharpening drill bits, which is part of the reason for the SB stone.  Drill bits are typically High Speed Steel, which the SB stone is designed to do a better job of grinding.  But, my experience has been that even the SB stone is not adequate.  I went through a wide range of possible solutions for more aggressive metal removal for some of the reasons you have. 

1) traditional high speed bench grinder,
2) traditional high speed grinding wheel fitted for the Tormek shaft,
3) belt grinder (I outfitted it to work with Tormek jigs, but not necessary),
4) slow speed bench grinder with white matrix grinding wheels,
5) Tormek diamond wheels (all three),
6) 180 grit CBN wheel on a Tormek (10" wheel for my T87),
7) 80 grit CBN wheel on the slow speed bench grinder. 

#1 works quite well except one had to be careful about heat management

#2 works very well and preserves the dust free, water grinding system of the Tormek.  A bushing with a 12mm bore must be bought or made to mate the traditional grinding wheel with the Tormek shaft.  This is a bit slower than the higher speed alternatives, but is one of the easiest and least expensive alternatives. 

#3 works well and belt grinders are very useful around a shop for a variety of task. 

#4 works well and the white matrix wheels are better for heat management.  I outfitted mine with the Tormek BGM-100 for use with Tormek jigs, but found that the dry grinding grit gets in the sliding surfaces of the drill jig and I no longer use it this way.

#5 is better than the SB but even with the DC (coarse) wheel, I found it still too slow,

#6 is much faster and I use this in nearly all sharpening tasks

#7 still has the problem of throwing dry grinding grit into the DBS-22 sliding surfaces and I no longer us this method for drills in that jig.  I do use it for most non-Tormek grinding tasks. 

Good luck.  Do some reading on the forum. 

Rick

Hi Rick,

Thank you for your reply. I scrolled through the list with topics regarding drill-bit grinding, but unfortunately, didn't find anything interesting..

I have a T4. The backside of a Tormek are the costs.. especially as a hobby user. I don't want to buy many Tormek grinding wheels for the quantity of drill bits that I have to grind.

I don't own a workbench grinder yet (instead I bought a T4 )... but I can do if that's the way. But in the very cheap options I won't be happy about the quality of the grinders.
I read also a topic of someone who used the DBS-22 with a bench grinder and got some scratch marks on the DBS while the rotating direction is opposite to the Tormek... pity. That's definately not the way to go!

I mounted my angle-grinder in the vise with a flat deburr-disk, maybe that's an option as well to grind very roughly (like free-handed grinding on a workbench grinder).

Your second option sounds most interesting to me. I'm a machine designer, so I can make a model/drawing of a spacer to fit a 'normal' grinding wheel to the T4. I guess that the wheel has to be resistant to use in water (maybe they are all?).

The Tormek Diamond wheels (DC) are not so good for this job? (grinding much material). SB wheels are not available for the T4..

CBN-wheels can be interesting as well, but I think they are expensive too..

[keesh]

Kees,

As I was getting ready topost this, I noticed Rick's reply. Rick, he has a T4, so no SB option is possible. However, keep reading:

Here is what I did to solve a very similar problem: (It works very well with the T4) You need a Norton 3X grinding wheel, either 46 or 80 grit. It costs around $60US. For heavy drill bit grinding, I might favor the 46 grit, although either grit will work. You will want the eight inch diameter. It comes with a one inch bore and step down reducers to 5/8". I used a short piece of 5/8" OD plastic pipe.
The ID is 7/16". You need to bore this out with either a 12mm or 31/64" drill bit.You may have to enlarge the hole slightly by drilling slightly off straight. Get a three pack of fender washers with 12mm inside diameter. (The 3X wheel in only one inch thick.

This is a somewhat primitive, but adequate fix. Rick Kruger had a much more elegant fix. He machined a bushing. You might want to talk with a local machinist. This neither complicated nor time consuming.

Use the 3X wheel with water. I used a diamond T dressing tool. Rick has used his TT-50.

Two untried ideas: You might try a dremel with a carbide cut off cutter. I would think a 3D printed bushing might work well.

Keep us posted.

Ken

Hi Ken,

Thanks for your help. The Norton wheel is 'just' a normal workbench grinder wheel? And you keep it flat with a truing-tool?

I don't know what the material of the core in a Norton grinding wheel is, but I prefer to leave it as it is and design a spacer..

Cheers!

[RickKrung]

Hi Ken,

Thanks for your help. The Norton wheel is 'just' a normal workbench grinder wheel? And you keep it flat with a truing-tool?

I don't know what the material of the core in a Norton grinding wheel is, but I prefer to leave it as it is and design a spacer..

Cheers!

Thank Ken for clarifying that the SB wheel is not available for the T4 and for providing more detail about using a Norton 3X grinding wheel.  I don't know if all traditional grinding wheels are water resistant/proof, but the Norton 3X and the no-name ones I used in water on my T8 had to be as they never degraded or fell apart after years of use. 

I think you're on to a good solution for the bushing.  You will also need some wide flange washers to make up the difference in wheel width, as the Norton 3X are 1" wide.  I machined my bushing from stainless steel and flange washers from aluminum.  Most grinding wheels in the US come with a 1" bore, which needs to be filled with bushings.  Many come with several nested sleeves for mating with different diameters of grinder shafts, just not 12mm. 

Rick