On Sat, 3 Dec 2016 08:55:41 -0500, "Jim Wilkins"
<
murat...@gmail.com> wrote:
>"Larry Jaques" <
lja...@invalid.diversifycomm.com> wrote in message
>news:q8n44clpk4j78jc0i...@4ax.com...
>> On Fri, 2 Dec 2016 09:02:06 -0500, "Jim Wilkins"
>> <
murat...@gmail.com> wrote:
>>
>>>
>>>Yep, push down, let it rise, push down...., while steadying the top
>>>end with the other hand. It's less awkward and tiring than a bow
>>>drill. Since it spins both ways a blunt spear point with flats on
>>>the
>>>edges works well for the drill bit, and is easy to resharpen. You
>>>could drill your first counterweight with a bow drill that doesn't
>>>need one.
>>
>> I wondered about the bit end. Dual flats, eh? Spoon bits are
>> interestingly shape, too.
>
>Like smaller spade bits. Reducing the rake angle decreases the depth
>of cut and the power absorbed.
Yeah, I see how that would be self-limiting.
>
https://en.wikipedia.org/wiki/Drill_bit
>"The twist drill bit was invented by Steven A. Morse of East
>Bridgewater, Massachusetts in 1861.The original method of manufacture
>was to cut two grooves in opposite sides of a round bar, then to twist
>the bar (giving the tool its name) to produce the helical flutes.
>Nowadays, the drill bit is usually made by rotating the bar while
>moving it past a grinding wheel to cut the flutes in the same manner
>as cutting helical gears."
Funny you should mention that.
http://diversifycomm.com/listenup/1960sJapaneseDrillbit.jpg
This happened with a powerful B&D 3/8" VSR hand-drilling through an 18
or 20ga piece of sheetmetal. It surprised me.
And I just remembered to replace the little gimlet set which was
stolen. They're very handy camping/on a hike, and well worth the
money.
http://tinyurl.com/jn7tuk7
The only thing on that page which I don't have and use is the mag core
drill, but I have some large core bits, toothed and diamond.
>
http://wiki.vintagemachinery.org/Milling-Machines-in-the-United-States.ashx
>See Fig. 19. "English and American Tool Builders" claims on page 196
>that the first one (Fig 16) was made to machine twist drills. The
>rotary index head is geared to the table feed and the table swivels on
>its circular base, allowing the mill to cut a spiral groove as the
>slowly rotating work passes under the cutter. See fig 29.
>
>The text states but the engraving doesn't clearly show that the table
>of Fig 16 swivels.
No, but you can see it in fig 29. Different machine, tho.
All you need are a couple of power feeds and you, too, can grind your
own billdrits!
>> As a Neanderthal wooddorker, I have either used, and/or made, dozens
>> and dozens of old tools like that, but never a pump drill. I made
>> fire with a bow drill just once, then immediately declared the end
>> of
>> my enthusiasm for them. They're a lot of work. Those pipe augers
>> look
>> like a whole lot more of the same. Ugh! Breast drills are a joy to
>> use, compared to pumps, bows, braces, Yankees, and little
>> egg-beaters.
>> Ditto post drills.
>
>> And now, with metal, I'm finding much more ease with a drill press.
>> Who'd have guessed? A mill is a pain to set up, comparatively, but
>> is
>> sure is accurate. Having come from a woodworking past, my time with
>> Glenn in his metalworking shop was a real eye opener on most fronts.
>> That's why I'm here: to continue learning with all you good
>> teachers.
>
>I normally leave the mill set up for drilling and use the tops of the
>vise jaws as the table.
Whatever works for you.
--