pipe thread tapping tips? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**passthebuck** · 02-25-2004, 03:48 PM

Hey all, I need to drill & tap a hole in my castiron thermostat housing in 1/4 pipethread. I've tapped a million holes using regular taps & chasser taps BUT I've never done a pipe thread hole. I know that pipethread is tappered & so I know you cant go too deep or else the hole will be too big. Can anyone give me any other tips? Thanks

*67Fleetsidedream* · 02-25-2004, 03:50 PM

Tap a little then check with what ever is going in the hole. Tap a little then check until it is at the desired depth.

oldsub86 · 02-25-2004, 04:07 PM

An obvious point I guess, but make sure you use a pipe thread tap. Usually comes with the set.

PanelDeland · 02-25-2004, 10:37 PM

Use thread tapping oil. It will help get smoother cut and better thread.

SideStepper · 02-26-2004, 12:00 AM

The most important thing about tapping pipe threads is to keep in mind what fitting is going to be use. If the fitting is a 90 degree elbow for example, it is usually critical on which direction the fitting points (clocked) when is tighten.
Tap the hole until the fitting is clocked in the direction required, it may take as slight re-tap to get it right. Take your time, this kinda effort shows how much of a craftsman you are.

jamesi20 · 02-27-2004, 01:02 PM

do yourself a favor and get the proper drill and a tapered reamer the job will turn out perfect with no problems down the road

gonebad2 · 02-27-2004, 01:50 PM

Don't try and turn the tap in all at once. When you get a full turn, back it off about 1/4 turn then continue. It will cut cleaner threads.

02-25-2004, 03:48 PM	#1
passthebuck Sisyphus was my mentor! Join Date: Sep 2002 Location: Carleton Place, Ontario CANADA Posts: 984	pipe thread tapping tips? Hey all, I need to drill & tap a hole in my castiron thermostat housing in 1/4 pipethread. I've tapped a million holes using regular taps & chasser taps BUT I've never done a pipe thread hole. I know that pipethread is tappered & so I know you cant go too deep or else the hole will be too big. Can anyone give me any other tips? Thanks __________________ passthebuck #5642 -TWO 1967 GMC 910's. One with L6/3-on-the tree and the other with 355 w/435hp & a 700r4. -a 2013 Honda Civic as my "sensible" car

02-25-2004, 04:07 PM	#3
oldsub86 Registered User Join Date: Dec 2002 Location: Canada Posts: 695	An obvious point I guess, but make sure you use a pipe thread tap. Usually comes with the set. __________________ 1968 Chevy - 292 with a powerglide

02-25-2004, 10:37 PM	#4
PanelDeland I am a Referee of life. Join Date: Jun 2000 Location: Greensboro N.C. Posts: 13,992	Use thread tapping oil. It will help get smoother cut and better thread. __________________ The 47-present Chevrolet and GMC Truck Message Board Network,it's owners,moderators,members,and associates of any type should not be held responsible for my opinion. You can't fix stupid,not even with duct tape. "My appearance is due to the fact that "GOD" does punish you for having too much fun!" Barrett-Jackson has perfected alchemy,they make rust into gold! "You can lead a horse to water but you can't saddle a duck" "Cleverly disguised as a 'Responsible Adult' "Sometimes your Knight in shining armor is just a retard in tinfoil"

02-27-2004, 01:02 PM	#6
jamesi20 Senior Member Join Date: May 2002 Location: NORTHEAST OHIO Posts: 494	PIPE THREADS do yourself a favor and get the proper drill and a tapered reamer the job will turn out perfect with no problems down the road

02-27-2004, 01:50 PM	#7
gonebad2 Merciless Butcher Join Date: Oct 2003 Location: CC Nevada Posts: 1,447	Don't try and turn the tap in all at once. When you get a full turn, back it off about 1/4 turn then continue. It will cut cleaner threads. __________________ Your Bought And Sold....I Got Your Soul!

02-25-2004, 03:50 PM	#2
67Fleetsidedream Wiseass secured himself a BAN Join Date: Nov 2000 Location: MOON!!! Posts: 2,282	Tap a little then check with what ever is going in the hole. Tap a little then check until it is at the desired depth.

02-26-2004, 12:00 AM	#5
SideStepper Registered User Join Date: Jun 2002 Location: Southern California U.S.A. Posts: 280	The most important thing about tapping pipe threads is to keep in mind what fitting is going to be use. If the fitting is a 90 degree elbow for example, it is usually critical on which direction the fitting points (clocked) when is tighten. Tap the hole until the fitting is clocked in the direction required, it may take as slight re-tap to get it right. Take your time, this kinda effort shows how much of a craftsman you are.

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