I need all the info I can get for hand tapping a metric 6 x .5
thread(these are very fine threads about a 1/4 inch in diameter) in
..104 inch thick galvanized steel. What is the best tap or taps? taper,
plug or bottoming? The drill I use is a .218.

On 3 Sep 2005 06:31:08 -0700, wrote:

I need all the info I can get for hand tapping a metric 6 x .5
thread(these are very fine threads about a 1/4 inch in diameter) in
.104 inch thick galvanized steel. What is the best tap or taps? taper,
plug or bottoming? The drill I use is a .218.

Since you're obviously tapping through, If you only had one tap I'd
choose the taper tap to aid in starting the thread then just keep
turning until full threads are cut. A bottoming tap is out of the
question since your hole doesn't have a bottom.
Randy

Thank you for the reply. Before I started on this project I contacted a
well known tap maker, I can't remember the company name. The tech
helped me figure out the threads from a bolt I had. Seemed very smart.
He told me to use a bottoming tap. Now, after sucessfully using the
bottoming tap, I read in two different books the same info you just
gave me. I wonder why the tech told me to use the bottoming tap.
And yes, it is a thru hole.

Taper tap since you can go all the way through. No great torque needed,
this is a small tap and thin material. Be sure to figure out how to keep
the tap straight as you start it.

wrote:
I need all the info I can get for hand tapping a metric 6 x .5
thread(these are very fine threads about a 1/4 inch in diameter) in
.104 inch thick galvanized steel. What is the best tap or taps? taper,
plug or bottoming? The drill I use is a .218.

In article 1125761509.264329.180150
@g14g2000cwa.googlegroups.com, says...
Thank you for the reply. Before I started on this project I contacted a
well known tap maker, I can't remember the company name. The tech
helped me figure out the threads from a bolt I had. Seemed very smart.
He told me to use a bottoming tap. Now, after sucessfully using the
bottoming tap, I read in two different books the same info you just
gave me. I wonder why the tech told me to use the bottoming tap.
And yes, it is a thru hole.


Since it's a thru hole, a spiral point tap, AKA gun tap, is
the best choice. If availability is a problem, a taper tap
would be the next best choice, followed by plug.

Ned Simmons

In article ,
Ned Simmons wrote:
:In article 1125761509.264329.180150
, says...
: Thank you for the reply. Before I started on this project I contacted a
: well known tap maker, I can't remember the company name. The tech
: helped me figure out the threads from a bolt I had. Seemed very smart.
: He told me to use a bottoming tap. Now, after sucessfully using the
: bottoming tap, I read in two different books the same info you just
: gave me. I wonder why the tech told me to use the bottoming tap.
: And yes, it is a thru hole.
:
:
:Since it's a thru hole, a spiral point tap, AKA gun tap, is
:the best choice. If availability is a problem, a taper tap
:would be the next best choice, followed by plug.

Unless he's hand tapping. Spiral point taps can be a bit trickier to
get started, and thus aren't recommended for hand tapping.

--
Bob Nichols AT comcast.net I am "rnichols42"

In article ,
lid says...
In article ,
Ned Simmons wrote:

:Since it's a thru hole, a spiral point tap, AKA gun tap, is
:the best choice. If availability is a problem, a taper tap
:would be the next best choice, followed by plug.

Unless he's hand tapping. Spiral point taps can be a bit trickier to
get started, and thus aren't recommended for hand tapping.


I've never heard this, nor have I ever had a problem
starting spiral pointed taps by hand. Who recommends
against it?

Ned Simmons

In thin material, the bottoming tap may do a better job of forming the
threads as it will tend to cut deep faster than the taper shape. The
bottoming tap will not only cut the threads but will also tend to force some
of the material asize like a forming tap and thus make a better hole.

--
Why do penguins walk so far to get to their nesting grounds?

In article ,
Ned Simmons wrote:
:In article ,
says...
: In article ,
: Ned Simmons wrote:
:
: :Since it's a thru hole, a spiral point tap, AKA gun tap, is
: :the best choice. If availability is a problem, a taper tap
: :would be the next best choice, followed by plug.
:
: Unless he's hand tapping. Spiral point taps can be a bit trickier to
: get started, and thus aren't recommended for hand tapping.
:
:
:I've never heard this, nor have I ever had a problem
:starting spiral pointed taps by hand. Who recommends
:against it?

When I flip through the "Taps" section of my J&L catalog, I find
the following note:

+================================================= =======+
| F.Y.I |
| |
| In hand tapping the use of spiral point taps is not |
| recommended because it is difficult to obtain a true |
| start. Usually a 3 or 4 flute tap with proper lead is |
| preferred. |
+================================================= =======+

Like you, I've used spiral point taps for hand tapping with no real
problem, but I do take greater care when starting them.

--
Bob Nichols AT comcast.net I am "rnichols42"

"Ned Simmons" wrote in message
...
In article ,
lid says...
In article ,
Ned Simmons wrote:

:Since it's a thru hole, a spiral point tap, AKA gun tap, is
:the best choice. If availability is a problem, a taper tap
:would be the next best choice, followed by plug.

Unless he's hand tapping. Spiral point taps can be a bit trickier to
get started, and thus aren't recommended for hand tapping.


I've never heard this, nor have I ever had a problem
starting spiral pointed taps by hand. Who recommends
against it?

Ned Simmons

I, for one, do. Spiral point taps are intended to be power driven and are
not easy to start by hand. They're prone to damaging the starting threads
because they don't self align well, the way a taper tap does. . There's
no better tap on the market as far as I'm concerned, but I also have a
Procunier tapping head.

Likewise, four flute "hand taps" should *not* be power driven, but you can
get away with it if the material is thin enough. The chips that accumulate
in the straight flutes tend to load the tap, often breaking it.

Harold

In article , Harold and Susan Vordos says...

I, for one, do. Spiral point taps are intended to be power driven and are
not easy to start by hand. They're prone to damaging the starting threads
because they don't self align well, the way a taper tap does. . There's
no better tap on the market as far as I'm concerned, but I also have a
Procunier tapping head.

Spiral point taps and two- or three- flute gun taps are not the same
thing however. Spiral point taps are designed to extract the chips
backwards out the hole in a continous cut. The gun taps are ground
to sling the chips forwards in the hole, and as such are best used
in through holes.

I would not shy away from power tapping a hole like the OP mentioned
using a two flute gun tap. I've done stuff like that with nothing
more than a reversible, variable speed milwaukee hand drill.

With a procunier head, it's dead easy.

I prefer two flute gun taps over regular hand taps any day, even
when tapping stuff by hand. The need to stop and clean out small
holes as the chips accumulate (if they cannot be through holes) is
not a terribly big deal as most of the stuff I do is not production,
it's one off.

I think most of the gun taps are simply higher quality than the
hand taps I see.

Jim


--
==================================================
please reply to:
JRR(zero) at pkmfgvm4 (dot) vnet (dot) ibm (dot) com
==================================================

On 5 Sep 2005 07:57:06 -0700, jim rozen
wrote:

In article , Harold and Susan Vordos says...

I, for one, do. Spiral point taps are intended to be power driven and are
not easy to start by hand. They're prone to damaging the starting threads
because they don't self align well, the way a taper tap does. . There's
no better tap on the market as far as I'm concerned, but I also have a
Procunier tapping head.

Spiral point taps and two- or three- flute gun taps are not the same
thing however. Spiral point taps are designed to extract the chips
backwards out the hole in a continous cut. The gun taps are ground
to sling the chips forwards in the hole, and as such are best used
in through holes.

Umm one little nit pick. Spiral point taps are gun taps. Spiral
"flute" taps are the ones that bring the chip out of the hole.


Wayne Cook
Shamrock, TX
http://members.dslextreme.com/users/waynecook/index.htm

"jim rozen" wrote in message
...
In article , Harold and Susan Vordos
says...

I, for one, do. Spiral point taps are intended to be power driven and
are
not easy to start by hand. They're prone to damaging the starting
threads
because they don't self align well, the way a taper tap does. .
There's
no better tap on the market as far as I'm concerned, but I also have a
Procunier tapping head.

Spiral point taps and two- or three- flute gun taps are not the same
thing however. Spiral point taps are designed to extract the chips
backwards out the hole in a continous cut. The gun taps are ground
to sling the chips forwards in the hole, and as such are best used
in through holes.

See Wayne's post. His comments are on the money.


I would not shy away from power tapping a hole like the OP mentioned
using a two flute gun tap. I've done stuff like that with nothing
more than a reversible, variable speed milwaukee hand drill.

That was my point. I suggested not power tapping with *hand* taps,
although I may not have made it clear. Straight flute taps without the
spiral point don't drive the chips in either direction, permitting them,
instead, to accumulate at the point of origin. If you don't back the tap
at least every half turn, quarter turn being preferred, they don't fall
away, eventually packing up enough to jamb the tap. Thin material
presents the same problem, buy you're usually through the hole before the
tap has accumulated enough chips to jamb.


With a procunier head, it's dead easy.

But not with a *hand* tap.


I prefer two flute gun taps over regular hand taps any day, even
when tapping stuff by hand. The need to stop and clean out small
holes as the chips accumulate (if they cannot be through holes) is
not a terribly big deal as most of the stuff I do is not production,
it's one off.

I do too, but not when starting the tap. It's a no brainer once the tap
is started----I don't like fighting with the chips any more than anyone else
does. I use the typical gun tap for even blind hole tapping. It's easy
enough to remove the accumulated chips from the holes with a needle air
hose, which I keep at the ready. Rarely do I have problems removing them
unless I've tapped into them to the point of full compaction. Do keep in
mind that I've run parts in production, not just tooling.

I think most of the gun taps are simply higher quality than the
hand taps I see.

Very good observation. I have hand taps that are not ground threads, which,
today, boggles the mind. The process of making such tools is so easy by
grinding that I can't even imagine milling them, yet that was common
practice at one point in time. Good name brands, too-----such as
Greenfield.

I don't like hand taps, but I have them.

Harold