To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

wrote in message
...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric


Makes some parts, tap them with a couple different processes and clearances,
then put a bolt in them and twist with a torque wrench to see when the
threads strip. Use the best compromise between machinability and real world
strength requirements.

wrote in message
...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important issue,
you might want to ask your customer to modify the design to use helicoils.

On Sun, 22 Apr 2012 20:20:11 -0700, "Bob La Londe"
wrote:

wrote in message
.. .
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric


Makes some parts, tap them with a couple different processes and clearances,
then put a bolt in them and twist with a torque wrench to see when the
threads strip. Use the best compromise between machinability and real world
strength requirements.


I think that's a great idea. I'll ask the customer today for some of
the pieces cut from the castings and test them.
Thanks,
Eric

On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
.. .
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important issue,
you might want to ask your customer to modify the design to use helicoils.
Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them. I use a tapping head to install them. But
even the parts with thread inserts would benefit from stronger
threads. So I'll be using Bob's idea and measuring the pull out
strength of cut versus formed threads for each particular alloy that
I'm threading.
Eric

On Mon, 23 Apr 2012 06:53:23 -0700, wrote:

On Sun, 22 Apr 2012 20:20:11 -0700, "Bob La Londe"
wrote:

wrote in message
. ..
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric


Makes some parts, tap them with a couple different processes and clearances,
then put a bolt in them and twist with a torque wrench to see when the
threads strip. Use the best compromise between machinability and real world
strength requirements.


I think that's a great idea. I'll ask the customer today for some of
the pieces cut from the castings and test them.
Thanks,
Eric

Because you wanted someone with experience tapping 356, I didn't
respond earlier, but the other issue you mentioned is that there are
some different alloys involved.

I haven't personally tapped aluminum casting alloys but I know you're
going to find some big differences in their ductility and, thus, their
response to form-tapping.

356 is moderately ductile for a casting alloy; A-356 is much better.
Neither of them will be as good in that department as wrought 6061.
The high-silicon casting alloys will be problematic.

In other words, if you're going to run some tests, and you're going to
be dealing with a variety of alloys, they could respond very
differently to form-tapping.

--
Ed Huntress

wrote:
On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
...

To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important issue,
you might want to ask your customer to modify the design to use helicoils.

Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them. I use a tapping head to install them. But
even the parts with thread inserts would benefit from stronger
threads. So I'll be using Bob's idea and measuring the pull out
strength of cut versus formed threads for each particular alloy that
I'm threading.
Eric

Possibly you should look at the likes of Keenserts or Timeserts as I
believe those provide a stronger installed thread than a heli-coil. It
may have been one of those that a company I worked for used in a
magnesium alloy casting for a racing gearbox and as it would be
dismantled regularly a thread insert was a must, IIRC the inserts used
required a more complicated machining than heli-coil and they were
intended to be replaceable if they became damaged, also due to the wall
thickness the thread in the alloy had a greater diameter and so was
stronger.

wrote in message
news
On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
. ..
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important
issue,
you might want to ask your customer to modify the design to use helicoils.
Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them.


*** I use a tapping head to install them. ***

Now that is something to remember. I could make an insert tool to install
them out of drill stock pretty darn quick too.

On Mon, 23 Apr 2012 16:57:13 -0700, "Bob La Londe"
wrote:

wrote in message
news
On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important
issue,
you might want to ask your customer to modify the design to use helicoils.
Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them.


*** I use a tapping head to install them. ***

Now that is something to remember. I could make an insert tool to install
them out of drill stock pretty darn quick too.




I use a Procunier head because it does not self feed. The install
depth of the inserts varies less than .005"
Eric

On Mon, 23 Apr 2012 17:06:06 +0100, David Billington
wrote:

wrote:
On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
...

To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important issue,
you might want to ask your customer to modify the design to use helicoils.

Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them. I use a tapping head to install them. But
even the parts with thread inserts would benefit from stronger
threads. So I'll be using Bob's idea and measuring the pull out
strength of cut versus formed threads for each particular alloy that
I'm threading.
Eric

Possibly you should look at the likes of Keenserts or Timeserts as I
believe those provide a stronger installed thread than a heli-coil. It
may have been one of those that a company I worked for used in a
magnesium alloy casting for a racing gearbox and as it would be
dismantled regularly a thread insert was a must, IIRC the inserts used
required a more complicated machining than heli-coil and they were
intended to be replaceable if they became damaged, also due to the wall
thickness the thread in the alloy had a greater diameter and so was
stronger.
The customer requires helical type screw thread inserts.
Eric

On Mon, 23 Apr 2012 10:04:46 -0400, Ed Huntress
wrote:

On Mon, 23 Apr 2012 06:53:23 -0700, wrote:

On Sun, 22 Apr 2012 20:20:11 -0700, "Bob La Londe"
wrote:

wrote in message
...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric


Makes some parts, tap them with a couple different processes and clearances,
then put a bolt in them and twist with a torque wrench to see when the
threads strip. Use the best compromise between machinability and real world
strength requirements.


I think that's a great idea. I'll ask the customer today for some of
the pieces cut from the castings and test them.
Thanks,
Eric

Because you wanted someone with experience tapping 356, I didn't
respond earlier, but the other issue you mentioned is that there are
some different alloys involved.

I haven't personally tapped aluminum casting alloys but I know you're
going to find some big differences in their ductility and, thus, their
response to form-tapping.

356 is moderately ductile for a casting alloy; A-356 is much better.
Neither of them will be as good in that department as wrought 6061.
The high-silicon casting alloys will be problematic.

In other words, if you're going to run some tests, and you're going to
be dealing with a variety of alloys, they could respond very
differently to form-tapping.
Greetings Ed,
I spoke with the customer yesterday about test pieces. I will be
getting test pieces made from the various alloys I will be tapping.
Some bronze alloys along with the aluminum. I'm pretty sure that the
356 alloy will be better off cut rather than formed but I've been
surprised before. Bob's good idea of actual pull out torque tests will
be put to the test.
Eris

On Tue, 24 Apr 2012 07:13:43 -0700, wrote:

On Mon, 23 Apr 2012 10:04:46 -0400, Ed Huntress
wrote:

On Mon, 23 Apr 2012 06:53:23 -0700, wrote:

On Sun, 22 Apr 2012 20:20:11 -0700, "Bob La Londe"
wrote:

wrote in message
m...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric


Makes some parts, tap them with a couple different processes and clearances,
then put a bolt in them and twist with a torque wrench to see when the
threads strip. Use the best compromise between machinability and real world
strength requirements.


I think that's a great idea. I'll ask the customer today for some of
the pieces cut from the castings and test them.
Thanks,
Eric

Because you wanted someone with experience tapping 356, I didn't
respond earlier, but the other issue you mentioned is that there are
some different alloys involved.

I haven't personally tapped aluminum casting alloys but I know you're
going to find some big differences in their ductility and, thus, their
response to form-tapping.

356 is moderately ductile for a casting alloy; A-356 is much better.
Neither of them will be as good in that department as wrought 6061.
The high-silicon casting alloys will be problematic.

In other words, if you're going to run some tests, and you're going to
be dealing with a variety of alloys, they could respond very
differently to form-tapping.
Greetings Ed,
I spoke with the customer yesterday about test pieces. I will be
getting test pieces made from the various alloys I will be tapping.
Some bronze alloys along with the aluminum. I'm pretty sure that the
356 alloy will be better off cut rather than formed but I've been
surprised before. Bob's good idea of actual pull out torque tests will
be put to the test.
Eris

That kind of practical testing is always a good idea, and there are
enough variables involved that predicting results would be tough in
any case.

It sounds like you have the right plan. BTW, the engineers at Emuge
have been helpful to me in the past (10 years ago) in writing
articles, and they know their stuff. Maybe you'd want to call them to
get some perspective: The testing you're planning sounds like the best
idea, however.

http://www.emuge.com/taps/

--
Ed Huntress

wrote in message
...
On Mon, 23 Apr 2012 16:57:13 -0700, "Bob La Londe"
wrote:

wrote in message
news
On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
m...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important
issue,
you might want to ask your customer to modify the design to use
helicoils.
Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them.


*** I use a tapping head to install them. ***

Now that is something to remember. I could make an insert tool to install
them out of drill stock pretty darn quick too.




I use a Procunier head because it does not self feed. The install
depth of the inserts varies less than .005"


I just have a cheap no name tapping head, and the self feed does cause me
headaches sometimes. I just can't afford a Procunier head. Still, if I
take the time to do a setup properly and set my drill stop with some
experimentation I can eliminate most of my troubles. Not convenient for one
or two holes, but worth it when I have to do 20-30. I read your comment and
thought... a reason to buy another tapping head and another drill press.
LOL.

On Tue, 24 Apr 2012 10:28:26 -0400, Ed Huntress
wrote:

On Tue, 24 Apr 2012 07:13:43 -0700, wrote:

On Mon, 23 Apr 2012 10:04:46 -0400, Ed Huntress
wrote:

On Mon, 23 Apr 2012 06:53:23 -0700, wrote:

On Sun, 22 Apr 2012 20:20:11 -0700, "Bob La Londe"
wrote:

wrote in message
om...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric


Makes some parts, tap them with a couple different processes and clearances,
then put a bolt in them and twist with a torque wrench to see when the
threads strip. Use the best compromise between machinability and real world
strength requirements.


I think that's a great idea. I'll ask the customer today for some of
the pieces cut from the castings and test them.
Thanks,
Eric

Because you wanted someone with experience tapping 356, I didn't
respond earlier, but the other issue you mentioned is that there are
some different alloys involved.

I haven't personally tapped aluminum casting alloys but I know you're
going to find some big differences in their ductility and, thus, their
response to form-tapping.

356 is moderately ductile for a casting alloy; A-356 is much better.
Neither of them will be as good in that department as wrought 6061.
The high-silicon casting alloys will be problematic.

In other words, if you're going to run some tests, and you're going to
be dealing with a variety of alloys, they could respond very
differently to form-tapping.
Greetings Ed,
I spoke with the customer yesterday about test pieces. I will be
getting test pieces made from the various alloys I will be tapping.
Some bronze alloys along with the aluminum. I'm pretty sure that the
356 alloy will be better off cut rather than formed but I've been
surprised before. Bob's good idea of actual pull out torque tests will
be put to the test.
Eris

That kind of practical testing is always a good idea, and there are
enough variables involved that predicting results would be tough in
any case.

It sounds like you have the right plan. BTW, the engineers at Emuge
have been helpful to me in the past (10 years ago) in writing
articles, and they know their stuff. Maybe you'd want to call them to
get some perspective: The testing you're planning sounds like the best
idea, however.

http://www.emuge.com/taps/
Thanks Ed, I'll give them a try. I've used Emuge taps plenty of times
and like them. They do make good taps. Even though I will be relying
on my real world tests I'm sure that getting info from the engineers
at Emuge will help.
Eric

On Tue, 24 Apr 2012 10:01:09 -0700, "Bob La Londe"
wrote:

wrote in message
.. .
On Mon, 23 Apr 2012 16:57:13 -0700, "Bob La Londe"
wrote:

wrote in message
news On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
om...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm doing
a lot more sand cast aluminum parts that are various alloys, 356 being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important
issue,
you might want to ask your customer to modify the design to use
helicoils.
Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them.


*** I use a tapping head to install them. ***

Now that is something to remember. I could make an insert tool to install
them out of drill stock pretty darn quick too.




I use a Procunier head because it does not self feed. The install
depth of the inserts varies less than .005"


I just have a cheap no name tapping head, and the self feed does cause me
headaches sometimes. I just can't afford a Procunier head. Still, if I
take the time to do a setup properly and set my drill stop with some
experimentation I can eliminate most of my troubles. Not convenient for one
or two holes, but worth it when I have to do 20-30. I read your comment and
thought... a reason to buy another tapping head and another drill press.
LOL.

If you try it you'll like it. I have bought all my Procuniers on ebay.
Except the first one I bought. I got that one at a flea market. It was
in pieces in a coffee can. The cork lining for the clutch had come off
of the aluminum hub. I epoxied it back on and it has worked fine for
the last 25 years or so. And the tapping head itself was made before
WW2. I never paid more than 60 bucks for one by the way.
Eric

wrote in message
...
On Tue, 24 Apr 2012 10:01:09 -0700, "Bob La Londe"
wrote:

wrote in message
. ..
On Mon, 23 Apr 2012 16:57:13 -0700, "Bob La Londe"
wrote:

wrote in message
news On Sun, 22 Apr 2012 22:18:09 -0700, "anorton"
wrote:


wrote in message
news:ndc9p7ltge4sidh235bs4d712rnvlhodqi@4ax. com...
To all you folks who are actually making parts from metal,
I use form taps, AKA roll taps, as much as possible. I use them for
not just the easy to tap materials such as 6061 and mild steel. 304
SS, 17-4 SS, 4340 and 4140 steel are metals I have had good luck
with.
Die cast aluminum alloys too, though I don't know what specific
alloys. I have also tapped sand cast aluminum parts but only a few
times and I don't know how well the threads held up. But now I'm
doing
a lot more sand cast aluminum parts that are various alloys, 356
being
one of them. I would like to form tap all the cast parts and I'm
looking for advice from anyone here who hasreal world experience
with
sand cast aluminum parts that have had form tapped holes. I want to
give the customer the best threads and even though formed threads
are
usually better I know that sometimes the formed material can become
brittle from the forming operation leading to weaker threads. I have
contacted a couple tap makers with this question but they have not
given me any information beyond saying that I need to determine
what's
best.
Thanks,
Eric

If thread strength and durability in aluminum is really an important
issue,
you might want to ask your customer to modify the design to use
helicoils.
Many of the castings I machine do get thread inserts. In fact, that's
part of the reason I got some of the jobs. I convinced the customer
that I could install the hundreds of heli-coils faster and cheaper
than they were doing them.


*** I use a tapping head to install them. ***

Now that is something to remember. I could make an insert tool to
install
them out of drill stock pretty darn quick too.




I use a Procunier head because it does not self feed. The install
depth of the inserts varies less than .005"


I just have a cheap no name tapping head, and the self feed does cause me
headaches sometimes. I just can't afford a Procunier head. Still, if I
take the time to do a setup properly and set my drill stop with some
experimentation I can eliminate most of my troubles. Not convenient for
one
or two holes, but worth it when I have to do 20-30. I read your comment
and
thought... a reason to buy another tapping head and another drill press.
LOL.

If you try it you'll like it. I have bought all my Procuniers on ebay.
Except the first one I bought. I got that one at a flea market. It was
in pieces in a coffee can. The cork lining for the clutch had come off
of the aluminum hub. I epoxied it back on and it has worked fine for
the last 25 years or so. And the tapping head itself was made before
WW2. I never paid more than 60 bucks for one by the way.
Eric

You know, my dad has an electronic variable speed reversible drill press he
bought from Sears atleast 35 years ago. I've often thought if I had that I
could make a simple spring centering lockup tapping head without all those
fancy internal gears. I always thought it was "cheap" and light duty, but
when I asked he sais the only thing he ever had to do to it was replace the
speed control pot when I broke off the shaft as a kid.