Gallery, Projects and General > The Design Shop
An idea for drill sharpening jig
sorveltaja:
Joachim Steinke: No worry, you have excellent presentations of the subject. So much information, that it might take some time for me to digest.
Feel free to post more.
sbwhart:
Hi Achim
Very interesting post your quite right about the problems with shop bought drill grinders, not including the drill doctor in this because I have never seen or tried one.
My father taught me many years ago to grind drills by hand, which I'm quite good at, but hand grinding can never be as good as a jig grinding, the action you described is exactly the action, It's easy to demonstrate but difficult to describe.
Sorveltaja
Drill grinding and geometry when you get into it is a complicated subject this is a great thread you've started.
I'll watch progress with interest.
Cheers
:beer:
Stew
Joachim Steinke:
Hallo, only a short message in between,
this may be a little off topic, but as the “Drill Doctor” has already been mentioned above…….
I, similar to Stew have never operated with the relative famous Drill Doctor myself, but I have a friend who works with this Vertex Drill Grinder:
http://www.vertex-tw.com.tw/products/products_list.php?language=_eng&cid=591#pro
I took the chance to test it by myself and the little machine is astonishing well and rigid build (okay, it’s Vertex from Taiwan and not as bad as the most Chinese machinery), very smooth and quiet running and does a really good job on standard drills.
They use special made and inverted mounted ER collets (a clever idea) and axial control curves build in the circumference of a particular collets chuck. This curve is in contact with a corresponding curve in the mounting opening of the machine housing and generates the desired axial movement while rotating the drill in front of the grinding wheel.
Accommodation to the drills diameter is made by using a preset fixture (left side of the machine) where the drill is pre mounted in the collets. As the back rotation angle of the existing cutting edge (relative to the fixtures coordinate systems abscissae) has an effect on the relief characteristic in direct dependency to the tools diameter this single collet chuck can be used to a wide range of drill diameters with one and the same control curve.
This all is very similar to the technique of the Drill Doctor, but Vertex made the wear parts out of hardened steel and hard steel castings, so the well known wear out problems of the Drill Doctor (drill chuck partial made from plastic) should not appear.
As Vertex delivers the machine with a CBN grinding wheel you have a relative constant plane surface on the wheel over a long operation period, dressing the wheel is not necessary.
But this neat little machine is really expensive (just under 900,- Euro here) and you can grind only one type of relief form. It would devinitely do a good job in the commercial shop for daily use, but for unfrequent home grinding it might be a little bit too overshooting….ha ha ha….
Bye from Achim
Bernd:
Joachim,
A bit :offtopic: here. I've been to your web site and find it very interesting. One question. Is the material you use to make all those nice looking tools brass? Thanks.
Bernd
Darren:
Hi Achim, I have a drill doctor and I believe Bernd has one as well. I must say I am very impressed with it. I have sharpened about 200 drills so far with mine and it was second hand when I bought it. The result is without a doubt a better finished point than when purchased new. Nice smooth drill with little or no chatter. If the relief option is used (split point) the effort in drilling is remarkable esp with larger diameters.
Just my take on the tool. A big improvement on my freehand grinding :doh:
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