Go Back   The Ford Barn > General Discussion > Early V8 (1932-53)

Sponsored Links (Register now to hide all advertisements)

Reply
 
Thread Tools Display Modes
Old 07-19-2020, 10:46 AM   #1
russcc
Senior Member
 
Join Date: May 2010
Posts: 2,380
Default 7/16-14 thread chaser

Did a search on the forum here and found a set of thread chasers for reasonable money. In all my years with cars and as a machinist, I only needed one once for a spark plug hole, and that was MM. So I only need a 7/16-14. I know I can make one, but would prefer to buy it. Any sources a for single thread chaser tap. Have done an internet search and all the comes is regular taps. Thank you Fordbarners
russcc is offline   Reply With Quote
Old 07-19-2020, 11:06 AM   #2
19Fordy
Senior Member
 
19Fordy's Avatar
 
Join Date: May 2010
Location: Coral Springs FL
Posts: 8,119
Default Re: 7/16-14 thread chaser

Here's a good deal.
https://www.summitracing.com/parts/s...yABEgJLAvD_BwE
19Fordy is offline   Reply With Quote
Sponsored Links (Register now to hide all advertisements)
Old 07-19-2020, 11:08 AM   #3
KiWinUS
Senior Member
 
KiWinUS's Avatar
 
Join Date: May 2010
Location: Charlotte NC KiWi-L100 available here
Posts: 2,075
Default Re: 7/16-14 thread chaser

Mac tools. I have a Mac tool thread restoration kit & it is in kit. You can purchase it from them individual.
Cheers
Tony
KiWinUS is online now   Reply With Quote
Old 07-19-2020, 11:15 AM   #4
DavidG
Senior Member
 
DavidG's Avatar
 
Join Date: May 2010
Posts: 6,987
Default Re: 7/16-14 thread chaser

USA-made UNC kits including 7/16-14 on Amazon for $15.50.
DavidG is offline   Reply With Quote
Old 07-19-2020, 12:52 PM   #5
Kube
Senior Member
 
Kube's Avatar
 
Join Date: May 2010
Location: Wisconsin, USA
Posts: 6,219
Default Re: 7/16-14 thread chaser

McMaster-Carr
__________________
"I can explain it for you. However, I can't understand it for you".
Kube is offline   Reply With Quote
Old 07-19-2020, 06:00 PM   #6
JSeery
Senior Member
 
JSeery's Avatar
 
Join Date: Nov 2012
Location: Wichita KS
Posts: 14,795
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by russcc View Post
Did a search on the forum here and found a set of thread chasers for reasonable money. In all my years with cars and as a machinist, I only needed one once for a spark plug hole, and that was MM. So I only need a 7/16-14. I know I can make one, but would prefer to buy it. Any sources a for single thread chaser tap. Have done an internet search and all the comes is regular taps. Thank you Fordbarners
I use them a lot, all different sizes, SAE & Metric. They are very handy to have. If you always work with new stuff, guess you might not need them, but clean/chase all of the bolt holes on any of the blocks I work on.
JSeery is offline   Reply With Quote
Old 07-19-2020, 08:34 PM   #7
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,836
Default Re: 7/16-14 thread chaser

Here are few things to think about for head studs.

A thread to be properly used needs to be CLEAN bare metal.
No corrosion, rust or scale. Any of these will corrupt a torque reading.
A thread chaser is essentially an under size tap which will clean out MAJOR rust and corrosion. This device can not produce a correct size CLEAN thread. Like it or not, the laws of physics apply here.

Head stud holes in a block need to be cleaned with a standard tap which will make the thread size as it came from the factory. This operation needs to be done with a fixture that holds the tap in perfect vertical alignment or a machine such as a mill or large drill press.
If the hole does not clean to bare metal then it is too rusted/corroded to hold proper torque and needs to be repaired.
While sometimes not visible, corrosion can account for up to 20% corrupt torque readings before the thread fails.

A sealer such as high temp. RTV can be used on the dead end but a thread lube absolutely must be used on the fine thread end. The sealer should be allowed to dry for at least an hour before assembly.

Head stud holes in a block can be tested before final assembly of the engine with simple home made tools. A 3 inch diameter by 2 inch thick steel slug (BOTH SIDES PARALLEL) with a 1/2 inch hole in the center, a HEAVY HARD steel 7/16 washer, a HARD high nut and a proper length stud. You install the stud through the slug with the lubed nut and washer on top and torque to 80 for a model A or flathead V8. If the thread is good, the torque wrench will have a solid feel. No “floating” or wanting to keep turning.

Good threads will easily go over 100 if you are wondering.
Pete is offline   Reply With Quote
Old 07-19-2020, 08:48 PM   #8
donald1950
Senior Member
 
Join Date: May 2010
Location: san antonio, texas
Posts: 461
Default Re: 7/16-14 thread chaser

here is an ARP unit on Amazon

https://www.amazon.com/ARP-911-0004-...mg_top?ie=UTF8
donald1950 is offline   Reply With Quote
Old 07-20-2020, 07:57 AM   #9
russcc
Senior Member
 
Join Date: May 2010
Posts: 2,380
Default Re: 7/16-14 thread chaser

Thank you. And thanks to Pete for the insight. I would use #2 non hardening Permatex on the end of the stud. What about "thread lube" for the USS end in the in the block ?
russcc is offline   Reply With Quote
Old 07-20-2020, 08:56 AM   #10
51504bat
Senior Member
 
51504bat's Avatar
 
Join Date: Sep 2013
Location: SoCal-Redlands
Posts: 1,576
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by Pete View Post
Here are few things to think about for head studs.

A thread to be properly used needs to be CLEAN bare metal.
No corrosion, rust or scale. Any of these will corrupt a torque reading.
A thread chaser is essentially an under size tap which will clean out MAJOR rust and corrosion. This device can not produce a correct size CLEAN thread. Like it or not, the laws of physics apply here.

Head stud holes in a block need to be cleaned with a standard tap which will make the thread size as it came from the factory. This operation needs to be done with a fixture that holds the tap in perfect vertical alignment or a machine such as a mill or large drill press.
If the hole does not clean to bare metal then it is too rusted/corroded to hold proper torque and needs to be repaired.
While sometimes not visible, corrosion can account for up to 20% corrupt torque readings before the thread fails.

A sealer such as high temp. RTV can be used on the dead end but a thread lube absolutely must be used on the fine thread end. The sealer should be allowed to dry for at least an hour before assembly.

Head stud holes in a block can be tested before final assembly of the engine with simple home made tools. A 3 inch diameter by 2 inch thick steel slug (BOTH SIDES PARALLEL) with a 1/2 inch hole in the center, a HEAVY HARD steel 7/16 washer, a HARD high nut and a proper length stud. You install the stud through the slug with the lubed nut and washer on top and torque to 80 for a model A or flathead V8. If the thread is good, the torque wrench will have a solid feel. No “floating” or wanting to keep turning.

Good threads will easily go over 100 if you are wondering.

Just wondering your thoughts on head BOLTS on an 8ba? I always heard never to clean the holes with a tap only to use a cleaner tap. Also per the machinist very experienced with flatheads use number 2 Permatex to seal the threads.
__________________
Making the simple complicated for over 30 years.
51504bat is offline   Reply With Quote
Old 07-20-2020, 08:58 AM   #11
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 3,773
Default Re: 7/16-14 thread chaser

Can we circle back to the idea of using a tap and not a chaser? I understand the difference and get the physics aspect of this in regards to cleaning out all the rust and scale.

Caveat: This is what I've read, but have not actually compared. I thought the thread pitch Ford used for their head stud holes is not the same standard pitch we use today. That's why some say to make a chaser out of a an old head bolt by cutting flutes into the side.

I'd really like to know is this fact or fiction.
Tim Ayers is offline   Reply With Quote
Old 07-20-2020, 09:01 AM   #12
GOSFAST
Senior Member
 
GOSFAST's Avatar
 
Join Date: May 2010
Location: Long Island, NY
Posts: 1,039
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by Pete View Post
Here are few things to think about for head studs.

A thread to be properly used needs to be CLEAN bare metal.
No corrosion, rust or scale. Any of these will corrupt a torque reading.
A thread chaser is essentially an under size tap which will clean out MAJOR rust and corrosion. This device can not produce a correct size CLEAN thread. Like it or not, the laws of physics apply here.

Head stud holes in a block need to be cleaned with a standard tap which will make the thread size as it came from the factory. This operation needs to be done with a fixture that holds the tap in perfect vertical alignment or a machine such as a mill or large drill press.
If the hole does not clean to bare metal then it is too rusted/corroded to hold proper torque and needs to be repaired.
While sometimes not visible, corrosion can account for up to 20% corrupt torque readings before the thread fails.

A sealer such as high temp. RTV can be used on the dead end but a thread lube absolutely must be used on the fine thread end. The sealer should be allowed to dry for at least an hour before assembly.

Head stud holes in a block can be tested before final assembly of the engine with simple home made tools. A 3 inch diameter by 2 inch thick steel slug (BOTH SIDES PARALLEL) with a 1/2 inch hole in the center, a HEAVY HARD steel 7/16 washer, a HARD high nut and a proper length stud. You install the stud through the slug with the lubed nut and washer on top and torque to 80 for a model A or flathead V8. If the thread is good, the torque wrench will have a solid feel. No “floating” or wanting to keep turning.

Good threads will easily go over 100 if you are wondering.
Some excellent info here, especially that last sentence in red?

Thanks, Gary in N.Y.

P.S. We actually test ALL the head bolt holes when we mount the block plate either during a pressure test session or for finish honing the bores, but they ALWAYS get checked way before the final assembly time! Occasionally we'll do singles also (photo below).
Attached Images
File Type: jpg Flathead Ford Head Bolt Torque-90.JPG (87.4 KB, 54 views)
GOSFAST is offline   Reply With Quote
Old 07-20-2020, 09:07 AM   #13
Mart
Senior Member
 
Mart's Avatar
 
Join Date: May 2010
Location: Solihull, England.
Posts: 6,661
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by Tim Ayers View Post
Can we circle back to the idea of using a tap and not a chaser? I understand the difference and get the physics aspect of this in regards to cleaning out all the rust and scale.

Caveat: This is what I've read, but have not actually compared. I thought the thread pitch Ford used for their head stud holes is not the same standard pitch we use today. That's why some say to make a chaser out of a an old head bolt by cutting flutes into the side.

I'd really like to know is this fact or fiction.
Sort of true, but "pitch" is not the correct term.

It's just the diameter that ford held tight. You can buy taps that are correct to match the ford thread spec, but a general purpose one bought willy nilly will probably not be to that tighter spec. Someone did post the correct spec once on this forum but I can't remember who it was or the title of the thread.
I use a set of blue point thread chasers. They have proved invaluable over the years.
Mart is offline   Reply With Quote
Old 07-20-2020, 09:54 AM   #14
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 3,773
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by Mart View Post
Sort of true, but "pitch" is not the correct term.

It's just the diameter that ford held tight. You can buy taps that are correct to match the ford thread spec, but a general purpose one bought willy nilly will probably not be to that tighter spec. Someone did post the correct spec once on this forum but I can't remember who it was or the title of the thread.
I use a set of blue point thread chasers. They have proved invaluable over the years.
Thank you for the clarification.

Agreed on the thread chasers. I got mine from Sears, but they are made by Apex. My friend is a Snap On dealer and he confirmed they are the same as Snap On/Blue Point, just a different sticker on the plastic case. Exactly the same.
Tim Ayers is offline   Reply With Quote
Old 07-20-2020, 10:16 AM   #15
glennpm
Senior Member
 
glennpm's Avatar
 
Join Date: Sep 2014
Location: Wiscasset, Maine
Posts: 878
Default Re: 7/16-14 thread chaser

I would not use a tap in fear of removing parent material, BTDT. Use a thread chaser.

This article explains it well.

http://https://www.autoserviceprofes...stener-threads

Last edited by glennpm; 07-23-2020 at 07:16 PM.
glennpm is offline   Reply With Quote
Old 07-20-2020, 07:16 PM   #16
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,836
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by 51504bat View Post
Just wondering your thoughts on head BOLTS on an 8ba? I always heard never to clean the holes with a tap only to use a cleaner tap. Also per the machinist very experienced with flatheads use number 2 Permatex to seal the threads.
Bolts are good, IF, both the male and female threads are clean and lubed properly. Hard washers should be used also. Lube the washer also.
A problem with bolts is, you sometimes have them seep water with no sealer on the thread. If you use sealer instead of lube, the torque readings will be off.
Pete is offline   Reply With Quote
Old 07-20-2020, 07:29 PM   #17
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,836
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by glennpm View Post
I would not use a tap in fear of removing parent material, BTDT. Use a thread chaser.
It is physically IMPOSSIBLE for a standard tap to remove parent metal unless the thread is damaged.
Pete is offline   Reply With Quote
Old 07-20-2020, 07:42 PM   #18
Tim Ayers
Senior Member
 
Join Date: May 2010
Location: NJ
Posts: 3,773
Default Re: 7/16-14 thread chaser

Quote:
Originally Posted by Pete View Post
It is physically IMPOSSIBLE for a standard tap to remove parent metal unless the thread is damaged.
Pete,

Is the comment above accurate about the tolerance factor in regards to tap? If not, how did that myth get started?
Tim Ayers is offline   Reply With Quote
Old 07-20-2020, 08:42 PM   #19
Pete
Senior Member
 
Pete's Avatar
 
Join Date: May 2010
Location: Wa.
Posts: 3,836
Default Re: 7/16-14 thread chaser

Most threads in the parts we are talking about (flathead Ford engines) are "standard" class 2 threads as used in assembly line production.This is normally a 77% thread. A class 2 tap will not remove metal from a class 2 threaded hole unless the the female thread is damaged.

Myths get started by very intelligent people "creatively" answering a question rather than spending the time to look up the correct answer. Once a myth gets started, it is hard to dispell.
Pete is offline   Reply With Quote
Old 07-20-2020, 08:44 PM   #20
Ol' Ron
Senior Member
 
Ol' Ron's Avatar
 
Join Date: May 2010
Location: Chester Vt
Posts: 7,544
Default Re: 7/16-14 thread chaser

I find that the internet, especially Amazon to have most everything I need at a reasonable price and quick delivery, Even to Vt
Ol' Ron is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Sponsored Links (Register now to hide all advertisements)


All times are GMT -5. The time now is 11:31 AM.