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Sharpening split point drills with Deckel SO

billzweig

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Joined
Jun 4, 2015
Location
BC
Deckel is making a simple drill sharpening attachment(for $950!) to the SO and SOE tool grinder. This is grinding the tip in a conventional way, but in fact the SO and SOE can do a much better job without any accessories. Drills 1mm - 19mm can be easily sharpened with the superior split point.
The only requirement is a a set of collets in each size of the drill. I have a full set of Deckel collets in both inch and metric that I share with my FP1, and for smaller and in between sizes I am using a ER holder that fits in the 12mm Deckel collet.
The procedure is simple.
1. Lock the drill in a collet and set the flutes horizontally. I line it up visually against a straight edge on a surface plate.
2. Mount the index head on the grinder and set the horizontal plane (#1 in the photo) angle to the angle of the drill(let say 59 degrees for 118 point)
3. Set the vertical plane angle (#2) to the first cutting angle, for example 8 degrees)
4. Grind both lips (rotate the index 180 degrees)
5. Set the vertical angle to the secondary angle (for example 12 degrees)and cut the two faces.

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I also tried myself at sharpening drills on the SOE a while ago, using the same technique.

The process is very sensitive about the initial orientation of the drill bit in the collet.
One could get extremely different angles with exactly the same machine settings, just depending about the positionning of the drill (see third pic : sharpening try of two drills of the same size without modifying any setting on the machine).
It's no question why most high end drill grinders feature an optical device to define the starting position of the drill to be ground.

I seem to recall I had the best results setting the corner of the lip to be ground above the horizontal axis. Something like 10° or so. Been a while...
I got very good results but found myself a Tatar meanwhile, hence the end of that research program...

Affûtage forêt Deckel SOE (16).jpgAffûtage forêt Deckel SOE (7).jpgAffûtage forêt Deckel SOE (4).jpg
 
Last edited:
Bill,

Thanks for posting the helpful photos!

I recently got an Asian Deckel SO clone, uses 5C collets, and came with a clone of the Deckel drill grinding attachment. I tried and tried, and ground about 5mm in length off an 8mm drill bit but still didn't get decent geometry on the cutting edge. So I'll try it your way as well.

TNB, the kind of variation you are showing is typical of what I was seeing. I suspect it's just a matter of "need better instructions and more practice".

Cheers,
Bruce
 
I also tried myself at sharpening drills on the SOE a while ago, using the same technique.

The process is very sensitive about the initial orientation of the drill bit in the collet.
One could get extremely different angles with exactly the same machine settings, just depending about the positionning of the drill (see third pic : sharpening try of two drills of the same size without modifying any setting on the machine).
It's no question why most high end drill grinders feature an optical device to define the starting position of the drill to be ground.

I seem to recall I had the best results setting the corner of the lip to be ground above the horizontal axis. Something like 10° or so. Been a while...
I got very good results but found myself a Tatar meanwhile, hence the end of that research program...

I have had problems initially, but getting consistent results now. I am using a low power microscope to align the drill flutes and made a table for the settings for various drill angles. I take small cuts and inspect the scend facet until the point is right. It actually does not take that long.
By the way, I started using the Deckel SO for sharpening drills after having disappointing results with Darex V390 machine. Yes, it takes longer now, but I like the results much better.

Ballen, good luck with your clone. I actually bought one (new, from Alibaba. I wanted to use it as a dedicated endmill grinder)) and it was so bad that after spending a couple of days trying to fix it (including machining the out-of-round parts and making new bushings, re-boring the casting, etc ) I throw it in a garbage. Maybe I had a really bad specimen.
 
Ballen, good luck with your clone. I actually bought one (new, from Alibaba. I wanted to use it as a dedicated endmill grinder)) and it was so bad that after spending a couple of days trying to fix it (including machining the out-of-round parts and making new bushings, re-boring the casting, etc ) I throw it in a garbage.

Mine seems to be a good one, I got it through a German company which told me that they have not had any complaints. I had to touch up a couple of things, ie the pin that aligns the 5C collets was a bit too big for my collets, easily fixed. But the spindle/drive is quiet and balanced and the controls are smooth. The 5C collet holder is a nice design that uses 2 preloaded sealed bearings. I love using it for lathe tools, because I can tune the angles and geometry with a lot of control. It's really handy for lots of little stuff, a few days ago I needed to put a bit of a chamfer/taper on the end of a hardened dowel pin, 60 seconds later its done.

Mine came with a long hollow cylindrical grinding stone, and a aluminum cup wheel with a resin-bonded diamond strip. What other kinds of grinding wheels/disks/plates are generally useful?

Cheers,
Bruce
 
Mine came with a long hollow cylindrical grinding stone, and a aluminum cup wheel with a resin-bonded diamond strip. What other kinds of grinding wheels/disks/plates are generally useful?

Cheers,
Bruce

Bruce, I am using the same cup diamond wheel. I have same shape and size vitrified bond grinding wheel I want to use for heavier cuts, but changing the wheel and re balancing and truing every time is too time consuming.
I want to get another SO and keep the wheels on.
Some imports can be good machines, but once burned...
 
I use a cut-off wheel pretty often.
The use of such wheels would be easier with a specific (extended) wheel-holder so as not to be forced to get the spindle all the way out (on an SOE, that is).
Such a wheel holder has been on my to do list for a while (hello Oscar ! :D).

but changing the wheel and re balancing and truing every time is too time consuming.
I want to get another SO and keep the wheels on.

Wouldn't be easier to find some other wheel-holders ?
I have some, and never felt the need to balance and true the wheels on each change.
 
Wouldn't be easier to find some other wheel-holders ?
I have some, and never felt the need to balance and true the wheels on each change.

I don't have an SO here anymore but used a couple daily for years where I used to work. The wheel hubs repeat amazingly well on the spindle, I changed wheels almost each use. There are two types of spindle ends though, one is straight and one is tapered and keyed. I think the taper mount is later and was eyeing better repeatability but the straight mount worked just fine. We had plenty of hubs so never had to buy one, I imagine they aren't cheap but worth it to have the ability to quickly switch from roughing to finishing, or diamond to CBN or normal wheels.
 
The SOE spindle is the tapered/keyed type.
I've never heard of a plain cylindrical spindle on a Deckel. I suppose I haven't come across an SO old enough yet.
But YES : having a few wheelhubs is usefull !
 
Maybe should say sorry for resurrecting a long gone thread - But I won´t, it´s just too good and should rather be Pinned!

I´ve been pondering about getting a SO or better clone for the small tool grinds hence looking around for different uses.

My only 0,02$ would be from my experience with the cuoghi micra 10 drill grinder, a dedicated four-facet machine similar, but not same, as the tatar.
It has, I recall, a 16x illuminated drill point vision / microscope for aligning the drillpoint. Still, different drills with different spiral geometry could be problematic. Looking at the last pic in post #1 the cutting edge is curved, and I´ve seen many worse / stranger geometries. For these I usually made a first pass to get a straight line to align against. Cheap drills (poor geometry) are problems, especially for this drill point geometry - in my experience.
So all in all, I really like the set-up but yes there can be no short-cuts to the aligning however properly addressed it should work like a charm, as it does for Bill. Thanks for sharing Bill!
 
Browsing this thread again makes wonder why Bill choosed an angled mount for the microscope, and how he uses it.
Seems to me that for aligning the tip of the tool to be sharpened or even only to observe the work, the vertical position would be more convenient (vertical position wich is also the route Deckel choosed for the factory setup btw).

mikroskop SOE 2.jpg
 
Title is split point.
Am I missing something in the pictures? I do not see a split.
The "belly" is flute cut geometry to perhaps new tip point angle as this relationship is fixed to give the straight line. Differing point angle need differing flute cuts.
There are uses where this runs better, particularity the curve off on the outside edge helps but inside the arc things go wrong fast .
A lot of margin in that pictured drill. The low clear chisel is doing a lot of work.
Bob
 
Yes, I think the title should simple be "sharpening drills on the SO/ SOE".

I don't even think grinding a split point is feasible on those machines, due to their general layout.
Whatever you dou, it seems impossible to me to feed the drill bit into the wheel in the right position to split point the tip.

Bob, I have really hard time figuring out what you mean with the "belly" thing ! May be a picture would help ?
 
I'm so happy that I found this post. It helped a lot, I own a Deckel clone and the accessories are garbage. Your instructions are very helpful.
Thank you.
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