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Posted by DoN. Nichols on April 15, 2008, 10:08 pm
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> On Tue, 15 Apr 2008 13:20:45 +0700, Bruce in Bangkok
[ ... ]
>>Just out of curiosity, why not learn to sharpen the drill by hand? I
>>learned when I was 14 years old and it couldn't have been that complex
>>if a 14 year old kid with a different type of drilling on his mind
>>could master it -- sure wish I could have mastered some of those girls
>>I was thinking about :-)
[ ... ]
> As the high school shop teacher explained " you put the drill over
> your left index finger resting on the tool rest and bring it up to
> touch the wheel, then you just rock and roll it" (mid '50s)
As long as it isn't the left index finger which you bring up to
touch the wheel. :-)
Enjoy,
DoN.
--
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
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Posted by Gerald Miller on April 16, 2008, 12:16 am
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wrote:
>> On Tue, 15 Apr 2008 13:20:45 +0700, Bruce in Bangkok
>
> [ ... ]
>
>>>Just out of curiosity, why not learn to sharpen the drill by hand? I
>>>learned when I was 14 years old and it couldn't have been that complex
>>>if a 14 year old kid with a different type of drilling on his mind
>>>could master it -- sure wish I could have mastered some of those girls
>>>I was thinking about :-)
>
> [ ... ]
>
>> As the high school shop teacher explained " you put the drill over
>> your left index finger resting on the tool rest and bring it up to
>> touch the wheel, then you just rock and roll it" (mid '50s)
>
> As long as it isn't the left index finger which you bring up to
>touch the wheel. :-)
>
> Enjoy,
> DoN.
BTDT
Gerry :-)}
London, Canada
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Posted by Larry Jaques on April 13, 2008, 11:38 pm
Please log in for more thread options On Sun, 13 Apr 2008 17:29:31 -0700 (PDT), with neither quill nor
>I recently discovered how to fix an issue with drilling that I was
>having... I wanted to drill at a fairly slow speed in certain
>materials and found that one type of bit worked best. Unfortunately,
>they don't make that bit in letter sizes, which I need. Through
>experimenting, I've realized that the reason why just this one bit
>brand/type works so well, is how they designed the angle on the tip.
>Not the point angle that is generally spoken of, such as 118 degrees
>or 135 degrees... but the angle at which the tops are cut at. I'm not
>even sure what you call that part of the bit. But if you look at the
>bit from the side and see the main point, which is typically the
>standard 118 or 135 degrees... then turn the bit to the other side and
>look at the angle that goes along the top of that side... This is the
>angle the controls how much bite the blades (if that what's they're
>referred to) make into the material. I noticed that, that 'blade'
>angle on the bits that work well for me are particularly flat compared
>to most other bits... There's very little angle/bite at all. So... My
>question is, does anybody know of a sharpener that isn't a fortune,
>but can control that angle? Or is it possible to find human-beings
>these days that actually know enough about sharpening to understand
>that? I would like to sharpen numerous bits to that configuration.
If you're saying what I think you might be saying, the angle is called
"lip angle". If you set the bit down on its cutting edge, it's the
clearance angle from the cutting edge to the back of the edge, right?
A high angle there would tend to parallel the twist from the back, so
you want a low angle.
You can sharpen them by hand that way. Never having used a drill bit
sharpening machine, I don't know if that angle can be set or not.
You could also give the point angle less than 118 degrees by holding
it to the grinding wheel at a lesser angle, but I think it's the lip
you're talking about.
--
Save the whales! Trade them for valuable prizes.
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Posted by Dave99 on April 14, 2008, 12:59 am
Please log in for more thread options wrote:
> If you're saying what I think you might be saying, the angle is called
> "lip angle". If you set the bit down on its cutting edge, it's the
> clearance angle from the cutting edge to the back of the edge, right?
Right... I did some searching and I've now seen it referred to as
"Drill Lip Relief Angle". So 'Relief Angle', 'Lip Angle'... I guess
all the same thing, right? All I know is that all the ones I've tried
with a sharp angle there don't do what I want, and the couple I have
that have the very modest angle do... So that must be the difference.
Dave
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Posted by Jim Wilkins on April 14, 2008, 6:07 am
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> Right... I did some searching and I've now seen it referred to as
> "Drill Lip Relief Angle". So 'Relief Angle', 'Lip Angle'......
> Dave
The original Darex Drill Doctor will grind non-standard relief angles
if you don't align the bit correctly in the setting fixture. The angle
of the center ridge to the cutting edge is after-the-fact evidence
that the bit rotated in the collet but there isn't any way to control
it.
I have been thinking about how to make a separate setting fixture with
an adjustable positive stop for the cutting edge. Has anyone else made
one that worked well?
Jim Wilkins
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