Metalworking (rec.crafts.metalworking) Discuss various aspects of working with metal, such as machining, welding, metal joining, screwing, casting, hardening/tempering, blacksmithing/forging, spinning and hammer work, sheet metal work.

Reply
 
LinkBack Thread Tools Search this Thread Display Modes
  #1   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 2,473
Default Forming tap

I was rummaging through my tap collection and came across a couple of
forming taps. I have no idea how they got there, but there they were.
Now, the question is: where are they better used than cutting taps?
Since they are more particular about the hole size, I won't use them
unless they have some advantage.

Thanks,
Bob
  #2   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 539
Default Forming tap


"Bob Engelhardt" wrote in
message news
I was rummaging through my tap collection and came across a
couple of forming taps. I have no idea how they got there,
but there they were. Now, the question is: where are they
better used than cutting taps? Since they are more
particular about the hole size, I won't use them unless
they have some advantage.

Thanks,
Bob


Stronger threads in aluminum...

  #3   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 2,163
Default Forming tap

On Sun, 19 Mar 2017 18:38:43 -0400, Bob Engelhardt
wrote:

I was rummaging through my tap collection and came across a couple of
forming taps. I have no idea how they got there, but there they were.
Now, the question is: where are they better used than cutting taps?
Since they are more particular about the hole size, I won't use them
unless they have some advantage.

Thanks,
Bob

Greetings Bob,
Form taps make a stronger thread in materials that are fairly ductile.
So for example, wrought aluminum aloys, mild and stainless steels, and
some copper alloys. It's a little scary but I have form tapped
thousands of 10-32 holes in 304 SS. You need to pay attention to how
many holes have been tapped so that the tap can be changed before the
torque gets too high and the tap breaks. Free machining brass is not a
good material to form tap because it is kind of brittle, but silicon
bronze form taps well. When tapping blind holes form taps are nice
because there are no chips to worry about. They are especially good
when the max length thread is needed in a blind hole. I use form taps
as much as possible in my shop.
Eric
  #4   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 3,984
Default Forming tap

On Sunday, March 19, 2017 at 8:05:49 PM UTC-4, wrote:

Greetings Bob,
Form taps make a stronger thread in materials that are fairly ductile......

I use form taps
as much as possible in my shop.
Eric


I have no experience with form taps, but I have the impression that they last longer than cutting taps in some metals. Is that right or am I wrong?

Dan

  #5   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 5,888
Default Forming tap

wrote in message
...
On Sun, 19 Mar 2017 18:38:43 -0400, Bob Engelhardt
wrote:

I was rummaging through my tap collection and came across a couple
of
forming taps. I have no idea how they got there, but there they
were.
Now, the question is: where are they better used than cutting taps?
Since they are more particular about the hole size, I won't use them
unless they have some advantage.

Thanks,
Bob

Greetings Bob,
Form taps make a stronger thread in materials that are fairly
ductile.
So for example, wrought aluminum aloys, mild and stainless steels,
and
some copper alloys. It's a little scary but I have form tapped
thousands of 10-32 holes in 304 SS. You need to pay attention to how
many holes have been tapped so that the tap can be changed before
the
torque gets too high and the tap breaks. Free machining brass is not
a
good material to form tap because it is kind of brittle, but silicon
bronze form taps well. When tapping blind holes form taps are nice
because there are no chips to worry about. They are especially good
when the max length thread is needed in a blind hole. I use form
taps
as much as possible in my shop.
Eric


I got a 6061 aluminum part back that the shop had form tapped in holes
that were apparently too large, so the tap left a second false thread
groove between the real ones that a screw could engage. They were
small screws, #3 or #4 IIRC, and the torque difference wasn't all that
noticeable at first.
-jsw




  #6   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 5,888
Default Forming tap


wrote in message
...
On Sunday, March 19, 2017 at 8:05:49 PM UTC-4,
wrote:

Greetings Bob,
Form taps make a stronger thread in materials that are fairly
ductile......

I use form taps
as much as possible in my shop.
Eric


I have no experience with form taps, but I have the impression that
they last longer than cutting taps in some metals. Is that right or
am I wrong?

Dan


Dunno, but I've retired several #10-32 spiral point taps after 1000
holes tapped freehand with a Milwaukee reversible drill in 12 Ga CRS.
They were the panel mounting holes in custom welded relay-style racks,
~ 60 panel mounting holes per rail so 8 bays per tap.

-jsw


  #7   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 2,584
Default Forming tap

On 2017-03-19, Bob Engelhardt wrote:
I was rummaging through my tap collection and came across a couple of
forming taps. I have no idea how they got there, but there they were.
Now, the question is: where are they better used than cutting taps?


Blind holes is one example, as they don't form chips which need
to be cleared out. Just make sure that the tapping head stops before
they bottom out. :-)

Your workpiece should be a fairly ductile metal, of course.
Forget about tapping hardened tool steel -- but then cutting taps don't
do to well there, either. :-)

I've even used them in Teflon, where the material expands to
grip the screw once it is in place.

Since they are more particular about the hole size, I won't use them
unless they have some advantage.


Be sure that you use the right hole size. You can look it up in
a table in _Machinery's Handbook_, or in certain machinist's
calculators.

Enjoy,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
  #8   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 1,768
Default Forming tap

"Bob Engelhardt" wrote in message
news
I was rummaging through my tap collection and came across a couple of
forming taps. I have no idea how they got there, but there they were. Now,
the question is: where are they better used than cutting taps? Since they
are more particular about the hole size, I won't use them unless they have
some advantage.

Thanks,
Bob


I wonder how forming taps would work in punched holes to maximize the amount
of thread created.



  #9   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 556
Default Forming tap

On Monday, March 20, 2017 at 3:44:35 PM UTC-4, Bob La Londe wrote:
"Bob Engelhardt" wrote in message
news
I was rummaging through my tap collection and came across a couple of
forming taps. I have no idea how they got there, but there they were. Now,
the question is: where are they better used than cutting taps? Since they
are more particular about the hole size, I won't use them unless they have
some advantage.

Thanks,
Bob


I wonder how forming taps would work in punched holes to maximize the amount
of thread created.


In interviews with many tap manufacturers, I've always heard them emphasize the importance of hole accuracy for thread-forming taps. It sounds unlikely that punching holes would be a reliable way to do it.

--
Ed Huntress
  #10   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 2,473
Default Forming tap

Phil, Eric, & DoN -- thanks. I'm curious enough to get the drill I need
(#16 for 10-32) & try it.


  #12   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 2,584
Default Forming tap

On 2017-03-21, Bob Engelhardt wrote:
Phil, Eric, & DoN -- thanks. I'm curious enough to get the drill I need
(#16 for 10-32) & try it.


My lookup shows 4.4mm (usually metric sizes for roll taps for
imperial screws. That works out to 0.1732", while the #16 is 0.1770" so
the thread will be a bit poorly formed.

Good Luck,
DoN.

--
Remove oil spill source from e-mail
Email: | (KV4PH) Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---
  #13   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 2,473
Default Forming tap

On 3/21/2017 12:11 AM, DoN. Nichols wrote:
My lookup shows 4.4mm (usually metric sizes for roll taps for
imperial screws. That works out to 0.1732", while the #16 is 0.1770" so
the thread will be a bit poorly formed.

Good Luck,
DoN.


Ummm ... these are Balax taps and this Balax page shows that a .177
drill will give a 70% thread.
http://balax.com/products/thredfloers/12288-000

I'm not used to thinking about threads in percentage terms, but 70%
sounds pretty good to me.
  #14   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 2,163
Default Forming tap

On Tue, 21 Mar 2017 00:58:18 -0400, Bob Engelhardt
wrote:

On 3/21/2017 12:11 AM, DoN. Nichols wrote:
My lookup shows 4.4mm (usually metric sizes for roll taps for
imperial screws. That works out to 0.1732", while the #16 is 0.1770" so
the thread will be a bit poorly formed.

Good Luck,
DoN.


Ummm ... these are Balax taps and this Balax page shows that a .177
drill will give a 70% thread.
http://balax.com/products/thredfloers/12288-000

I'm not used to thinking about threads in percentage terms, but 70%
sounds pretty good to me.

70% will be plenty strong enough. If tapping punched holes in fairly
thin material you can get away with a slightly undersized hole because
the metal will just extrude away from the material surfaces. Remember
that a high pressure cutting fluid is good to use because the thread
is being formed.
Eric
  #15   Report Post  
Posted to rec.crafts.metalworking
external usenet poster
 
Posts: 600
Default Forming tap

On 3/19/2017 6:38 PM, Bob Engelhardt wrote:
I was rummaging through my tap collection and came across a couple of
forming taps. I have no idea how they got there, but there they were.
Now, the question is: where are they better used than cutting taps?
Since they are more particular about the hole size, I won't use them
unless they have some advantage.

Thanks,
Bob



I used them for threaded arbors on mini-grinder cup brushes. They take
two to three times the horse power but no chips. They always tell you
when they are too dull....SNAP!


Reply
Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules

Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Vacuum Forming Bob La Londe[_7_] Metalworking 11 January 21st 13 08:24 PM
Metal Forming Rob[_14_] Metalworking 2 May 26th 08 08:53 PM
Ice forming in freezer? [email protected] Home Ownership 3 May 14th 07 07:18 PM
forming aluminium Anjali Pandit Metalworking 0 February 15th 06 12:40 PM
Wood Forming ROYNEU Woodworking 20 September 5th 05 04:38 PM


All times are GMT +1. The time now is 12:25 AM.

Powered by vBulletin® Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 DIYbanter.
The comments are property of their posters.
 

About Us

"It's about DIY & home improvement"