Rigid Tapping - Thread Question
Moderator: cnckeith
-
- Posts: 483
- Joined: Tue Oct 20, 2020 8:41 pm
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: No
- Oak CNC controller: No
- CNC Control System Serial Number: none
- DC3IOB: No
- CNC12: Yes
- CNC11: No
- CPU10 or CPU7: No
- Location: Arizona
Rigid Tapping - Thread Question
I started on my first project that requires tapping a total of thirty 1/4 x 20 holes in 6061 aluminum (see attached). I completed rigid tapping fifteen of them today and have one question. When you tap a hole, should the screw thread into the hole easily, or should you have to work it a bit. I found that once I got the screw started, I could easily turn it in with an allen wrench, but when turning it by hand, there was a bit of resistance.
Notes:
The tap I used has an H3 pitch diameter limit: https://www.mcmaster.com/catalog/130/2923/2529A18.
I tapped these threads at 700 rpm.
Is the fact that the screw fits tightly in the threaded hole because of the H3 pitch diameter rating of the tap, or do I need to tweak one of the rigid tapping parameters somewhat?
Best... Richard
Notes:
The tap I used has an H3 pitch diameter limit: https://www.mcmaster.com/catalog/130/2923/2529A18.
I tapped these threads at 700 rpm.
Is the fact that the screw fits tightly in the threaded hole because of the H3 pitch diameter rating of the tap, or do I need to tweak one of the rigid tapping parameters somewhat?
Best... Richard
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
Re: Rigid Tapping - Thread Question
I am not a machinist, so I am sure others here will have ideas better grounded in reality. But my take is:
1) In tapping (as opposed to thread milling or lathe threading) the fit is determined almost entirely by the size and shape of the tap.
2) You might get a slightly looser fit if you tap each hole twice (which you can do, with rigid tapping).
1) In tapping (as opposed to thread milling or lathe threading) the fit is determined almost entirely by the size and shape of the tap.
2) You might get a slightly looser fit if you tap each hole twice (which you can do, with rigid tapping).
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
-
- Posts: 483
- Joined: Tue Oct 20, 2020 8:41 pm
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: No
- Oak CNC controller: No
- CNC Control System Serial Number: none
- DC3IOB: No
- CNC12: Yes
- CNC11: No
- CPU10 or CPU7: No
- Location: Arizona
Re: Rigid Tapping - Thread Question
Thanks. These holes .75" deep. I tapped them once at .375 and again at .75 and they feel better. I do think the H3 pitch diameter also makes for a tight thread.
Best... Richard
Best... Richard
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
-
- Posts: 3255
- Joined: Tue Mar 22, 2016 10:03 am
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: Yes
- Oak CNC controller: Yes
- CNC Control System Serial Number: 100505
100327
102696
103432
7804732B977B-0624192192 - DC3IOB: No
- CNC12: Yes
- CNC11: No
- CPU10 or CPU7: No
- Location: Boston, MA
- Contact:
Re: Rigid Tapping - Thread Question
I'm sure you've checked, but have you tested in wax? If there are any inconsistencies in pitch from an incorrect encoder setup, you could be "pulling" the last couple of threads.
Cheers,
Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
Tom
Confidence is the feeling you have before you fully understand the situation.
I have CDO. It's like OCD, but the letters are where they should be.
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
-
- Posts: 483
- Joined: Tue Oct 20, 2020 8:41 pm
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: No
- Oak CNC controller: No
- CNC Control System Serial Number: none
- DC3IOB: No
- CNC12: Yes
- CNC11: No
- CPU10 or CPU7: No
- Location: Arizona
Re: Rigid Tapping - Thread Question
Thanks Tom. I did indeed test in wax and all looks good. I have some other holes to tap in on my next project and the taps I will be using have a more "relaxed" fit. I think that is the culprit.
Have a great day... Richard
Have a great day... Richard
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
-
- Posts: 2541
- Joined: Thu Sep 23, 2021 3:49 pm
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: No
- Oak CNC controller: No
- CNC Control System Serial Number: 6433DB0446C1-08115074
- DC3IOB: No
- CNC12: Yes
- CNC11: No
- CPU10 or CPU7: No
- Location: Germany
Re: Rigid Tapping - Thread Question
I would also use another tap for a looser fit.
On soft metals, I prefer thread forming.
Uwe
On soft metals, I prefer thread forming.
Uwe
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
-
- Posts: 483
- Joined: Tue Oct 20, 2020 8:41 pm
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: No
- Oak CNC controller: No
- CNC Control System Serial Number: none
- DC3IOB: No
- CNC12: Yes
- CNC11: No
- CPU10 or CPU7: No
- Location: Arizona
Re: Rigid Tapping - Thread Question
Hello Uwe,
I will be using another tap for my next project. I have been using the GWizard to get a starting point for the speeds & feeds. With aluminum, I am beginning to get an idea as to what is in the ballpark. But when I work with some new material that I have never done before, I have no idea. For example, the attached is a set of jaws for talon grips I am making from 1018 steel. I used GWizard to estimate the feeds and speeds... but some look a little aggressive to me. We will find out in the next few days!
Jaws for talon grips: https://www.dropbox.com/scl/fi/6s8gmfjp ... wr56q&dl=0
Thanks... Richard
I will be using another tap for my next project. I have been using the GWizard to get a starting point for the speeds & feeds. With aluminum, I am beginning to get an idea as to what is in the ballpark. But when I work with some new material that I have never done before, I have no idea. For example, the attached is a set of jaws for talon grips I am making from 1018 steel. I used GWizard to estimate the feeds and speeds... but some look a little aggressive to me. We will find out in the next few days!
Jaws for talon grips: https://www.dropbox.com/scl/fi/6s8gmfjp ... wr56q&dl=0
Thanks... Richard
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
-
- Posts: 7881
- Joined: Wed Mar 03, 2010 4:23 pm
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: Yes
- Oak CNC controller: Yes
- CNC Control System Serial Number: none
- DC3IOB: Yes
- CNC11: Yes
- CPU10 or CPU7: Yes
- Contact:
Re: Rigid Tapping - Thread Question
i moved this post into the machining strategies forum!
Need support? READ THIS POST first. http://centroidcncforum.com/viewtopic.php?f=60&t=1043
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
All Acorn Documentation is located here: viewtopic.php?f=60&t=3397
Answers to common questions: viewforum.php?f=63
and here viewforum.php?f=61
Gear we use but don't sell. https://www.centroidcnc.com/centroid_di ... _gear.html
(Note: Liking will "up vote" a post in the search results helping others find good information faster)
-
- Posts: 483
- Joined: Tue Oct 20, 2020 8:41 pm
- Acorn CNC Controller: Yes
- Allin1DC CNC Controller: No
- Oak CNC controller: No
- CNC Control System Serial Number: none
- DC3IOB: No
- CNC12: Yes
- CNC11: No
- CPU10 or CPU7: No
- Location: Arizona
Re: Rigid Tapping - Thread Question
Thanks Keith.
(Note: Liking will "up vote" a post in the search results helping others find good information faster)