Had to go look it up. Enjoy if you don't know this post.
Glad to hear it, last thing I want is, for what should be a
discussion to get out of hand and start to spoil anyone's day!
Then I apologise Jim!!
SOMBODY said that and, in the convolutions of this thread I had come
it was you!
(trust me..if it gets any more convoluted I will be writing nasty
myself..and so will you!)
No disagreement..unless you HAVE to! My point is that a lot of people
list have only the option of tackling it with no help, no aids, no
skill and no
practice...or NOT DOING IT! What a tragic waste!
I can't be there to help them..but at least I can give them the
TRY..knowing that it CAN be done, It has been done, and by golly, if
fart teenut can do it SO CAN I!!
(Forgive me Jim..I am not SHOUTing..just putting emphasis on the key
I believe I learned on a 3/4" taper shank drill..it is a lot easier to
the angles and begin to understand how they work and interact.
By the way..we had a handy little dohickey to help get the drill lips
have never heard it described before..
For the morse taper shank drills from 1/4" up to about 1" diameter, we
piece of 2" by 1/8" hot rolled steel strap..about 14" long. One end
was bent at
right angles, about 2" from the end to form an L shape with one 12"
a 2" horizontal. In the geometric center of this short leg was afixed
center..not a lathe tailstock center!!...more like a 1/2" bolt, 1/2"
turned or ground to a 60 deg point (Approx...no great precision
screwed in from the under side. Thats IT..toolmaking over!
In use the inner face of the upright was coated with whitewash (Never
marking blue 'til I got in the toolroom!) The drill was ground,
the FACE of the wheel (not the flat side)...care being taken to keep
angle as equal as possible on both sides..I'll tell you how to do THAT
Lets do that now in fact..
Jim, You are dead right about not being able to grind a drill without
help! Well here's how you create your own "6 Million Dollar Bionic
Let's assume we are going to sharpen a 3/8" diameter, 2MT shank
about 8" long (these figures are arbitrary..I just want every one to
same mental picture of what I am describing.) We approach the wheel,
been dressed on its face, dead straight across with no grooves..(Ve
ve catch putting grooves in ze drill wheel!!..No Pity..No
The drill shank is held firmly in the RIGHT hand...ALL the movement
is imparted by the RIGHT hand. For the purposes of drill grinding, the
could be...with benefit..a LUMP OF CLAY!!
It is from this "lump of clay" that we fashion the Bionic Darex".
Place your left hand thumb and finger tips LIGHTLY together..Relax the
three fingers aand let them naturally curl against the palm of your
the drill flute drop into the vee between thumb and fore finger and
let the tip
of the finger "Find" the curve of the flute where it fits comfortably.
of the thumb rests on the sharp junction ot the land and the flute,
inch back from the drill tip.
Now...SQUEEZE HARD!!! YOUCH!...I said it would be easier if it were
Lift the drill from your fingers...see the GROOVE?...Drop the drill
locates within a thou or two! Magic?..Bionic at least! Squeeze again
to set the
groove. You have created a customised drill guide that fits better
that that on
any machine ever built! You can relax your grip now..feel how
drill will ride back and forth, guided by the groove you have created
Place the knuckles of your left hand, LIGHTLY on the ginding wheel
and swing the drill shank, from left to right (using ONLY your right
push the drill lengthways though that groove in your fingers back or
the groove to make the drill twist or "rifle" in your fingers. Do NOT
left hand in any way..it is made of clay remember!
A) The drill axis is "eyeballed" to be at half the required point
angle to the
wheel face...You can scribe or chalk reference lines on your grinder
help you line this up..at least untill it become almost second nature.
B) The drill axis is dropped JUUUst below horizontal. This will
your soon to be ground drill lip will start with a "smidgin" of
(Ideally, and certainly for a beginner, the grinder rest should be
radially to the wheel center and about half the drill diameter below
center of the wheel)
C) The two cutting edges of the drill..the straight, sharp bits,
formed by the
junction of the flute and the back face (the only bit you grind),
horizontally disposed..with the edge uppermost on the side closest to
hand..the othe sharp bit of course, pointing downwards (Jeeze this
would be a
lot easier with a sketch pad)
This I will call the SET or START position!
NOW, move your left hand for the first, last, and ONLY time during th
exercise. GENTLY ease the cutting edge towards the spinning wheel,
maintaining all the angles and orientations of the SET position..until
cutting edge is JUST shy of touching the wheel. If you listen
will hear the tone of the entrained air, whistling through the
You will hear a subtle but distinct change of tone JUST, I mean
tenths of a thou BEFORE the edge touches the wheel. STOP!!! FREEZE!!
Now, press the knuckles of your lump of clay..sorry, your left hand
onto, into and around the grinding rest..establish a "Groove" on the
your hand as well as between your fingers.
We are now ready to grind, Your left hand locked to the drill and
is otherwise quite relaxed..letting the drill slide, twist and tilt
your right hand and the groove in your fingers tell it to go.
The actual grinding is a bit of an anticlimax.
You have previously studied a new drill point, you have read about
and cutting angles, and rakes and......
With the RIGHT hand in control, gently, kinda, lean forward... bending
squeezing your arms hands and body..rather than actually moving
take up that last couple of tenths and the wheel begins to cut. Let
cut..don't force it, and dont' rush it..it really won't hurt anything
take a full minute Per pass per face. YOU and your "Bionic Darex" are
in control of that drill and the wheel..Forget the times when, close
you swung the drill wildly past the wheel, hoping to get "the dirty
with as quickly as possible.
Take your time, enjoy the moment, THINK about the shape you are trying
generate. Just the one face is left to "Interpretation"...every other
aspect,angle, facet, what have you...Has ALREADY BEEN TAKEN CARE OF!!
locked in place under your control!
The right hand should perform a "Lower Quadrant sweep" for want of a
term..An observer behind you would see your hand move from about 17
the hour on a clock face, to roughly 25 minutes past. But it isn't a
of a circle, more a sector of an elipse..You see, as your hand starts
slowly, you are also rotating the drill in "the groove"..the first
third of the
turn needs to maintain that very slight clearance angle on the cutting
not increase it too rapidly.
You need the clearance to cut..But too much at that point will WEAKEN
and cause the drill to snatch and chip...So the first part of the
ALMOST but not quite, just as though you were grinding a straight cone
the end of your drill. Only as you approach the second third, does
hand start to noticably drop..kinda "Catching Up" on the rotary
motion...increasing the clearance as it does.
In the last third of the rotaion the right hand drops quite
enough to catch the OTHER drill lip on the wheel..that lip is coming
quite rapidly by now.
Above all, take your time, if it helps, move the drill one degree at a
think ahead what shape or angle the next degree of cutting face
needs...Remember, you have control, and IT ain't going nowhere 'til
After a pass on one face, flip the drill in your "Bionic Darex" DO
THAT LEFT HAND!!, return to SET position and repeat, the pass on the
Having done a couple of passes on each face..it is now time to check
on our homemade "Optical Comparator"
(Sorry Jim I couldn't resist!!) ;^)
Rest the center hole in back end of the drill shank, on the center
point of the
"Comparator" and use, first one and then the other drill lip to scribe
line on your whitewashed (OK Blue or red dyed) surface.
You will readily see if the lines coincide..if the lips are even..or
not, as the
case may be.
Lets assume they are..Now look directly DOWN on the end of the drill
the clearances. HUH? How can you check radial clearance by looking it
in the face? Surely you need to look at it sideways?
Well no you don't...for once all thos interacting and confusing angle
and clearances are going to work together in YOUR favor and make what
could be a
tricky bit of metrology..quite simple. While we are looking at the
end of the
drill, we will also check that the POINT ANGLE is correct too!!!
(Ok guys, leave quietly..teenut has finally lost it!!)
No really, trust me. IF you look straight down on the point of a well
sharpened, standard drill, you will see
the two cutting edges, joined by the CHISEL edge which crosses over
the web of
the drill The angle fromed by the chisel edge to each cutting edge,
ABOUT 50 deg...anywhere between 40 and sixty is ok for a first
attempt. (I can
hear the purists and theorists screaming and lighting up their flame
But believe me, get it in that ball park and your drill will CUT. If
is too steep..you don't have enough clearance...negative clearance
will give you
an angle event greater than 90 deg. Too MUCH clerance and the angle
While looking at the end, check the point angle, How? Look down
the axis of
the drill at the cutting edges. Are they straight? If so, your point
close to the right angle (As designed for that drill, by its
he set the helix angle and the cross section of the flute) If the
CONCAVE the point is too flat and if they appear CONVEX, the point is
If your drill passes all these tests, which take but a second or two
THEN IT WILL CUT..pretty close to size, without chattering, chipping,
overheating, wandering or seizing. I guarantee it!
Hey, thats a pretty good start for the first drill you ever ground!
takes now is a bit of practice for it to become second nature and
almost as easy
with a little 'un or a big 'un!
My apologies for "goin'on" but If it helps just one person to pluck up
couragre and go hand sharpen his (or Her) first drill, by hand...
Then I hope you will bear with me.
It is late, I am tired and I am not even going to proof or spell check
-- - - - - - - - - - -
I didn't either. . . Something funny here, I thought Robert (Tee-Nut) passed in 2001. The
TubalCane youtube was posted in 2010.
Janna, Roberts daugnter, posted on 1/11/2011 the following. . .
"Thanks to you all for remembering teenut again this year. He
obviously made a big impact on a lot of lives with his contributions
here, and it means so much to me to see that he's not been forgotten,
10 years on.
I recently stumbled upon the archive of all of his posts that someone
here took the time to compile, and realised that he'd interspersed his
technical posts on metalworking with A LOT of sage advice and humour.
I wish I'd read it all earlier, but it really gave me some insights
into who my father was."
The above posting dates lead me to question Tee-Nut as TubalCane.
Wouldn't mind at all if someone proves me wrong though. I enjoy TubalCane's videos. :)
OK , it appears that the Logan Lathe QCGB repair videos I watched were NOT
by Tee Nut . I was afraid to criticize those because Tee Nut is held in such
high esteem here ... and I was not impressed . He had the usual crashed
carraige syndrome where the last 16/32 gear pair (left side) had stripped
the 16t section . Logan wants a handsome price for replacements , and
they're worth it - to someone who can't make them in their own shop (I can
and have) . He ended up buying a gear that needed modification but did work
in the end , but bitched and whined thru the whole project .
Not at all what I'd have expected from Tee Nut , based on what I've read
here about him .
On Wednesday, January 13, 2016 at 6:02:08 PM UTC-5, firstname.lastname@example.org
It really means having a business that provides a wage, but the business do
es not make any money above the amount to pay the owners wages and pay on
the capital invested.
Owning a business is having a business that makes money over and above just
In my case I worked with a guy building houses, but he did not really want
to grow. He talked of growing the business, but really just wanted to buil
d one house at a time and have a job where he could control everything. He
went bankrupt. I lost money.
The other one was a guy making fishing rod blanks. He interviewed my son a
nd was going to hire him, but the Sunday evening before the Monday when my
son was to start work, he called me and asked me to break the news to my so
n that he had changed his mind. He never employed anyone other than his wif
e. He had a government pension and just wanted to have job where he did n
ot have any pressure.
Tee Nut on the other hand bought a machine shop, bought some up to date ma
chines, and was developing a rifle as a product. He was working at having
a machine shop , but not a shop where he worked as a machinist.
Yes. And the question was -> what's wrong with that?
Even if the only employee is the owner it
still counts as a business as far as the law
Are you saying that making money off of the labor
of someone else should be regarded as morally
superior to making money exclusively off your
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.