Jump to content

Welcome to eMastercam.com
Register now to gain access to all of our features. Once registered and logged in, you will be able to create topics, post replies to existing threads, give reputation to your fellow members, get your own private messenger, post status updates, manage your profile and so much more. This message will be removed once you have signed in.
Login to Account Create an Account
Photo

FEEDS & SPEEDS FOR 1/8-27 NPT

- - - - -

  • Please log in to reply
14 replies to this topic

#1
Camdude®

Camdude®

    Advanced Member

  • Members
  • PipPipPip
  • 1,977 posts
I have to tap afew holes in 1018 using a 1/8-27 NPT tap. Doesanyone have a good feed and speed range for this tap. normally i would thread mill it but TPTB's don't want to do that so i'm stuck tapping.

#2
Mike Whitten CAD/CAM Contractors

Mike Whitten CAD/CAM Contractors

    Advanced Member

  • Customers
  • PipPipPip
  • 1,748 posts
  • Location:Carson City, NV USA
It depends if you are using oil or coolant (water based) and what type of tap and machine as you must have the power at low rpm. If coolant and standard tap and machine, I usually go slow. Something in the range of 10-15sfm would be fine. It's about 40% of what the book (OSG) would say. By the way, I always recommend tapering the hole using a taper pipe reamer or 1-1/2 deg em. This makes for much easier tapping and less chance of tap failure.

Mike

#3
Plastmo

Plastmo

    Member

  • Members
  • PipPip
  • 103 posts
270 rpm and 10 ipm feed

#4
Mic6

Mic6

    Advanced Member

  • Members
  • PipPipPip
  • 3,252 posts
  • Location:Sunnyvale, Ca

quote:


tap failure

aka...POW!

#5
jeff

jeff

    Advanced Member

  • Members
  • PipPipPip
  • 6,622 posts
As said above, an NPT Reamer helps out alot.
Interrupted tooth taps seem to be better also (just from my own experience).
Try it at about 400 rpm's and see what the threads look like.
But overall, I've never had the best of luck tapping npt's on a cnc for some reason, the threads like to tear about 50% of the time.

#6
K2csq7

K2csq7

    Advanced Member

  • Members
  • PipPipPip
  • 2,362 posts
  • Location:CT
"the threads like to tear about 50% of the time."

1018, 50% may be an understatement... you say just a few holes, I'd just go deep enough to get them started & finish by hand.

cutting oil will be much better than coolant IMO.

#7
jeff

jeff

    Advanced Member

  • Members
  • PipPipPip
  • 6,622 posts

quote:


just go deep enough to get them started & finish by hand.

Another good thing about using an npt reamer is that it's way easier to start the tap by hand, if you don't start it on the cnc, provided that you take the reamer to the correct depth and let it chamfer the hole.

#8
newbeeee

newbeeee

    old but NOT grown up

  • Members
  • PipPipPip
  • 1,711 posts
  • Location:Where the Ind Revolution began
I know you don't want to thread mill, but if you tap by hand, at the point that you stop there will be a vertical line up the flanks because it's cutting on the full engagement of the tap (unlike parallel tapping where it's only at the bottom/start of the tap).
We couldn't get around the line whatever we did (different oils/taps etc), so had to end up thread milling.

#9
RandleXX

RandleXX

    Advanced Member

  • Members
  • PipPipPip
  • 737 posts
+100 on Threadmilling

#10
Odell

Odell

    Member

  • Members
  • PipPip
  • 165 posts
REMEMBER....stop 1/4 turn before it breaks and you'll have no problems. biggrin.gif

#11
CADCAM3D5AXIS

CADCAM3D5AXIS

    Advanced Member

  • eMC Learning Group
  • PipPipPip
  • 402 posts
^^
+1000 cool.gif

#12
Camdude®

Camdude®

    Advanced Member

  • Members
  • PipPipPip
  • 1,977 posts
lol@Odell,
thanks guys gives me a start point,
like i said i WANT to threadmill but the powers that be do not>>>> mad.gif

#13
Cad-Camr

Cad-Camr

    Member

  • Members
  • PipPip
  • 119 posts
Use a good rich mix on your coolant or use tapping fluid if possible and peck tap if you have that capability. graemlins/cheers.gif

#14
lionel 3362

lionel 3362

    Newbie

  • Members
  • Pip
  • 13 posts
We run npts at my shop all the time. On a 1/8-27 i go 300 RPM 11.11 IPM and Z-.350 deep and we use tapping fluid

#15
jhjr

jhjr

    Member

  • Members
  • PipPip
  • 173 posts
Tapping oil +++ , coolant works sometimes depending on what coolant you are using. Using both won't hurt. Definatly use an interrupted tooth tap as others have said.