I've been slowly retrofitting a MaxNC mini mill that was all clapped out and
had V screws over to acme screws with anti-backlash nuts. Of course nothing
is easy about it. I just finished milling the Z axis slide for a mounting
block for the nut and making the mounting block. Due to limited space I
find myself having to use 6-32 cap screws for a couple things. I just
happen to have a box of 6-32 stainless screws leftover from another project.
Some of the holes tapped perfectly the first time, but that nice little
mounting block I spent most of the day figuring out how to make and cutting
between real work grabbed ahold of the tap and snapped it over its
proverbial knee like a pretzel stick.

It only took me an hour to make another mounting block.

Now I'm paranoid about snapping another tap. I know 6-32 is tough to do by
hand so I was wondering about options. Maybe going with a forming tap
instead of a cutting tap. I looked up a table or two and there is a big
difference. #36 drill bit for a regular cutting tap at .1065" diameter vs
..125" according to one table when using a forming tap. That's a lot more
material removal. I know. I know. Its just aluminum threads, but what
kind of difference in strength are we talking about for the finished
threads?

The holes that mount the block to the slide are done, now I need to tap the
holes that mount the nut to the block.

On Nov 1, 8:17*pm, "Bob La Londe" wrote:
I've been slowly retrofitting a MaxNC mini mill that was all clapped out and
had V screws over to acme screws with anti-backlash nuts. *Of course nothing
is easy about it. *I just finished milling the Z axis slide for a mounting
block for the nut and making the mounting block. *Due to limited space I
find myself having to use 6-32 cap screws for a couple things. *I just
happen to have a box of 6-32 stainless screws leftover from another project.
Some of the holes tapped perfectly the first time, but that nice little
mounting block I spent most of the day figuring out how to make and cutting
between real work grabbed ahold of the tap and snapped it over its
proverbial knee like a pretzel stick.

It only took me an hour to make another mounting block.

Now I'm paranoid about snapping another tap. *I know 6-32 is tough to do by
hand so I was wondering about options. *Maybe going with a forming tap
instead of a cutting tap. *I looked up a table or two and there is a big
difference. *#36 drill bit for a regular cutting tap at .1065" diameter vs
.125" according to one table when using a forming tap. *That's a lot more
material removal. *I know. *I know. *Its just aluminum threads, but what
kind of difference in strength are we talking about for the finished
threads?

The holes that mount the block to the slide are done, now I need to tap the
holes that mount the nut to the block.

I've found that you've got to be really selective as to what you use
for tapping fluid when doing aluminum, that stuff can weld to a
cutting edge in an instant. Grade of aluminum makes a huge difference
as well. 6-32 purely sucks for tapping, I've heard it called one of
the weakest threads, too. Best aluminum tapping fluid I've got is
called Alumicut, don't know what's in it or if it's even still
available, but leaves polished threads instead of bubblegum on
extruded material. A tapping block helps, too.

Stan

On Nov 1, 10:17*pm, "Bob La Londe" wrote:
I've been slowly retrofitting a MaxNC mini mill that was all clapped out and
had V screws over to acme screws with anti-backlash nuts. *Of course nothing
is easy about it. *I just finished milling the Z axis slide for a mounting
block for the nut and making the mounting block. *Due to limited space I
find myself having to use 6-32 cap screws for a couple things. *I just
happen to have a box of 6-32 stainless screws leftover from another project.
Some of the holes tapped perfectly the first time, but that nice little
mounting block I spent most of the day figuring out how to make and cutting
between real work grabbed ahold of the tap and snapped it over its
proverbial knee like a pretzel stick.

It only took me an hour to make another mounting block.

Now I'm paranoid about snapping another tap. *I know 6-32 is tough to do by
hand so I was wondering about options. *Maybe going with a forming tap
instead of a cutting tap. *I looked up a table or two and there is a big
difference. *#36 drill bit for a regular cutting tap at .1065" diameter vs
.125" according to one table when using a forming tap. *That's a lot more
material removal. *I know. *I know. *Its just aluminum threads, but what
kind of difference in strength are we talking about for the finished
threads?

The holes that mount the block to the slide are done, now I need to tap the
holes that mount the nut to the block.

One of these: http://www.use-enco.com/CGI/INSRIT will greatly improve
your results over doing it entirely by hand. Last week, I busted a
6-32 in a piece because I was too lazy to pull out the tapping machine
for just one hole. Then I got to make the widget* over from scratch.
Tapped it with the machine, no problem.

* said widget is an adapter for my Pace desoldering station to hold
the smaller tips. Pace wants $70 bucks (+ shipping) for something that
took me maybe 15 minutes (the second time) and a couple of inches of
7/16" drill rod. It's very nice to be able to make this stuff.

rangerssuck wrote:
One of these: http://www.use-enco.com/CGI/INSRIT ...

"The Enco Model Number that you entered could not be located."

"Bob Engelhardt" wrote in message
...
rangerssuck wrote:
One of these: http://www.use-enco.com/CGI/INSRIT ...

"The Enco Model Number that you entered could not be located."

Yeah, but I suspect he was pointing me towards a hand tapping
machine/fixture. Basically looks like a c-clamp on a pedestal. Hmmm.... I
think I just figured out how to make one.

On Nov 1, 11:59*pm, Bob Engelhardt wrote:
rangerssuck wrote:
One of these:http://www.use-enco.com/CGI/INSRIT...

"The Enco Model Number that you entered could not be located."

Try this: Model #318-0007

It is, indeed a hand tapping machine. The one listed is over $200, but
I'm sure I paid something less than $100 for the identical machine.

rangerssuck writes:

Try this: Model #318-0007

http://www.use-enco.com/CGI/INSRIT?PMAKA=318-0007

DoN. Nichols writes:

For a thread-forming tap, I'll let others
suggest the proper lube.

I form 1/4-20 and 10-32 holes every day in 6061, using perfumed kerosene
(aka WD-40).

Formed threads have a very poor quality. The crests look like little
opposing bulldozers pushed snowbanks together, with a thin gap where the
tops of the flow meet, so you have a potential false thread engagement
halfway out of "phase" with the true thread. For some cursed reason this
false thread start is the one that most easily engages when you casually
insert and start a screw. They are OK if you are doing the assembly (it
takes a certain feel to get a screw started, getting the false start, and
then backing up a half turn with a little pressure), but I avoid
presenting them to customers who have to start screws into them. But
forming certainly is faster and less prone to breakage in soft gummy
material like aluminum. The lube is important because if the metal
starts galling onto the surface of the tap, which it will after a few dry
holes, the tap will seize up and break.

One of these days I want to mill apart a cross section of a formed thread
and post some photomicrographs explaining this low quality.

On Mon, 1 Nov 2010 21:40:16 -0700, "Bob La Londe"
wrote:



"Bob Engelhardt" wrote in message
...
rangerssuck wrote:
One of these: http://www.use-enco.com/CGI/INSRIT ...

"The Enco Model Number that you entered could not be located."

Yeah, but I suspect he was pointing me towards a hand tapping
machine/fixture. Basically looks like a c-clamp on a pedestal. Hmmm.... I
think I just figured out how to make one.

You might make mine. Take a T handle tap wrench and remove the cross
bar. Find a 3/8 socket that just quite won't fit on the top of the tap
wrench and press it on. IIRC, it was 12MM on mine. Then use a speed
wrench for your new tap handle. This lets you hold the tap from moving
side to side way out and the speed wrench lets you go back and forth
really fast. I must have done 50 6-32s just this week in AL.

I use the speed wrench tap handle for nearly all my hand tapping.

Karl

On Nov 2, 7:28*am, Karl Townsend
wrote:
On Mon, 1 Nov 2010 21:40:16 -0700, "Bob La Londe"

wrote:

"Bob Engelhardt" wrote in message
...
rangerssuck wrote:
One of these:http://www.use-enco.com/CGI/INSRIT...

"The Enco Model Number that you entered could not be located."

Yeah, but I suspect he was pointing me towards a hand tapping
machine/fixture. *Basically looks like a c-clamp on a pedestal. *Hmmm.... *I
think I just figured out how to make one.

You might make mine. Take a T handle tap wrench and remove the cross
bar. Find a 3/8 socket that just quite won't fit on the top of the tap
wrench and press it on. IIRC, it was 12MM on mine. Then use a speed
wrench for your new tap handle. This lets you hold the tap from moving
side to side *way out and the speed wrench lets you go back and forth
really fast. *I must have done 50 6-32s just this week in AL.

I use the speed wrench tap handle for nearly all my hand tapping.

Karl

That's good, but the machine has some very nice features. It is
counterbalanced, so you don't have a lot of external forces pushing on
the tap, and you have a very good feel for your progress. It also
keeps the work from spinning without holding it so tightly as to
prevent the tap from aligning with the hole.

You could come pretty close to this by holding a tap in a drill press,
hanging a weight on the handle to make the quill pretty close to
balanced, and holding the work loosely in a vise or between blocks
bolted to the table. You could fashion a long handle that clamps to
the chuck.

That would be very close to this machine, and would probably work
great.

Another hand tapper tool.

http://www.harborfreight.com/hand-tapper-46502.html

I don't think I would buy this one over the internet as it looks like it
could have some issues with the rear clamp on the rod, but that's ok. Its
listed as in store purchase only. LOL. Now if only the local Harbor Fright
store actually stocked much...

I like the Speed Wrench idea. Even with a tapping tool the speed wrench
might be a good modification.

On Tue, 2 Nov 2010 05:55:56 -0700 (PDT), rangerssuck
wrote:

On Nov 2, 7:28*am, Karl Townsend
wrote:
On Mon, 1 Nov 2010 21:40:16 -0700, "Bob La Londe"

wrote:

"Bob Engelhardt" wrote in message
...
rangerssuck wrote:
One of these:http://www.use-enco.com/CGI/INSRIT...

"The Enco Model Number that you entered could not be located."

Yeah, but I suspect he was pointing me towards a hand tapping
machine/fixture. *Basically looks like a c-clamp on a pedestal. *Hmmm.... *I
think I just figured out how to make one.

You might make mine. Take a T handle tap wrench and remove the cross
bar. Find a 3/8 socket that just quite won't fit on the top of the tap
wrench and press it on. IIRC, it was 12MM on mine. Then use a speed
wrench for your new tap handle. This lets you hold the tap from moving
side to side *way out and the speed wrench lets you go back and forth
really fast. *I must have done 50 6-32s just this week in AL.

I use the speed wrench tap handle for nearly all my hand tapping.

Karl

That's good, but the machine has some very nice features. It is
counterbalanced, so you don't have a lot of external forces pushing on
the tap, and you have a very good feel for your progress. It also
keeps the work from spinning without holding it so tightly as to
prevent the tap from aligning with the hole.

You could come pretty close to this by holding a tap in a drill press,
hanging a weight on the handle to make the quill pretty close to
balanced, and holding the work loosely in a vise or between blocks
bolted to the table. You could fashion a long handle that clamps to
the chuck.

That would be very close to this machine, and would probably work
great.

yea, I also have tap wrenches with a guide rod going up from the
handles. Drill a hole in the press or mill. Put this in the chuck
loosely to tap. works a treat.

I don't like breaking taps

karl

rangerssuck wrote in news:f5790449-94f8-4cd7-
:

On Nov 1, 11:59*pm, Bob Engelhardt wrote:
rangerssuck wrote:
One of these:http://www.use-enco.com/CGI/INSRIT...

"The Enco Model Number that you entered could not be located."

Try this: Model #318-0007

It is, indeed a hand tapping machine. The one listed is over $200, but
I'm sure I paid something less than $100 for the identical machine.

If you don't want to spend anywhere near that much, here's a great
alternative:

http://www.brownells.com/1/1/40674-t...e-taprite-kit-
brownells.html

I don't think I've busted a tap in the 35 years I've owned one. I got it
after breaking a couple 4-40 taps trying to do stuff by hand. It's the
best $27 you'll on a tool.

Brownells stopped carrying theses for a while, and I'm really glad they
have them again. I need to buy several for the technicians at work.

Doug White

"Bob La Londe" wrote in
:

Another hand tapper tool.

http://www.harborfreight.com/hand-tapper-46502.html

I don't think I would buy this one over the internet as it looks like
it could have some issues with the rear clamp on the rod, but that's
ok. Its listed as in store purchase only. LOL. Now if only the
local Harbor Fright store actually stocked much...

I like the Speed Wrench idea. Even with a tapping tool the speed
wrench might be a good modification.

I've had a US made one of these for years. It works well if you have a
lot of holes. The speed wrench handle is a help, but if you use it, you
want to bolt it on. It slips off pretty easily.

http://www1.mscdirect.com/CGI/NNSRIT...MT4NO=97045824

Just a bit more spendy than the Harbor Fright version...

I still tend to use my $27 Brownells tapping guide for most stuff (see
earlier post).

Doug White

On Tue, 02 Nov 2010 23:02:10 GMT, Doug White
wrote:

rangerssuck wrote in news:f5790449-94f8-4cd7-
:

On Nov 1, 11:59*pm, Bob Engelhardt wrote:
rangerssuck wrote:
One of these:http://www.use-enco.com/CGI/INSRIT...

"The Enco Model Number that you entered could not be located."

Try this: Model #318-0007

It is, indeed a hand tapping machine. The one listed is over $200, but
I'm sure I paid something less than $100 for the identical machine.

If you don't want to spend anywhere near that much, here's a great
alternative:

http://www.brownells.com/1/1/40674-t...e-taprite-kit-
brownells.html

I don't think I've busted a tap in the 35 years I've owned one. I got it
after breaking a couple 4-40 taps trying to do stuff by hand. It's the
best $27 you'll on a tool.

Brownells stopped carrying theses for a while, and I'm really glad they
have them again. I need to buy several for the technicians at work.

Doug White

A body with an interchangable bushing. That cant be very hard to make.
Maybe 30 minutes to turn and drill and another 5-8 minutes to make
various bushings (each)

This includes locating the stock, lathe and knurling etc etc

Gunner

"Confiscating wealth from those who have earned it, inherited it,
or got lucky is never going to help 'the poor.' Poverty isn't
caused by some people having more money than others, just as obesity
isn't caused by McDonald's serving super-sized orders of French fries
Poverty, like obesity, is caused by the life choices that dictate
results." - John Tucci,

"Doug White" wrote in message
...
"Bob La Londe" wrote in
:

Another hand tapper tool.

http://www.harborfreight.com/hand-tapper-46502.html

I don't think I would buy this one over the internet as it looks like
it could have some issues with the rear clamp on the rod, but that's
ok. Its listed as in store purchase only. LOL. Now if only the
local Harbor Fright store actually stocked much...

I like the Speed Wrench idea. Even with a tapping tool the speed
wrench might be a good modification.

I've had a US made one of these for years. It works well if you have a
lot of holes. The speed wrench handle is a help, but if you use it, you
want to bolt it on. It slips off pretty easily.

http://www1.mscdirect.com/CGI/NNSRIT...MT4NO=97045824

Just a bit more spendy than the Harbor Fright version...

I still tend to use my $27 Brownells tapping guide for most stuff (see
earlier post).

Well, Harbor Fright came through again. Listed as store purchase only
on-line, and deleted from their inventory in the local store. I wonder if
they are going to survive. The have less selection on-line and less
inventory in the store. I'm beginning to think the old man was right. I
hope he wins his lawsuit.

Gunner Asch wrote in
:

On Tue, 02 Nov 2010 23:02:10 GMT, Doug White
wrote:

rangerssuck wrote in news:f5790449-94f8-4cd7-
:

On Nov 1, 11:59*pm, Bob Engelhardt
wrote:
rangerssuck wrote:
One of these:http://www.use-enco.com/CGI/INSRIT...

"The Enco Model Number that you entered could not be located."

Try this: Model #318-0007

It is, indeed a hand tapping machine. The one listed is over $200,
but I'm sure I paid something less than $100 for the identical
machine.

If you don't want to spend anywhere near that much, here's a great
alternative:

http://www.brownells.com/1/1/40674-t...e-taprite-kit-
brownells.html

I don't think I've busted a tap in the 35 years I've owned one. I got
it after breaking a couple 4-40 taps trying to do stuff by hand. It's
the best $27 you'll on a tool.

Brownells stopped carrying theses for a while, and I'm really glad
they have them again. I need to buy several for the technicians at
work.

Doug White

A body with an interchangable bushing. That cant be very hard to make.
Maybe 30 minutes to turn and drill and another 5-8 minutes to make
various bushings (each)

This includes locating the stock, lathe and knurling etc etc

True, but these are nicely blued, come with a wood block to hold
everything, and the body has a shallow V-groove to center the tap on
round objects. I haven't taken a file to them, but they may also be
hardened a bit.

I'd rather spend my time in the shop making stuff I can't buy,
particularly when the price is reasonable.

Doug White