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Thread pitch ID (Read 2995 times)

westerner Frequent Elocutionist Offline deleted posts and threads record holder. Posts: 12372 Location: Why, out West of course Joined: May 29^th, 2006	Thread pitch ID Jan 23^rd, 2021 at 6:28am	Print Post
	How do you determine thread pitch in small screw holes? Small like 4 5 6 or 8. Say you have no screw that fits the threaded hole and have no pitch gauge that will fit in the hole.

	A blind squirrel runs into a tree every once in a while.
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MikeT Senior Forum Member Offline Posts: 295 Location: St. Cloud, MN Joined: Sep 7^th, 2005	Re: Thread pitch ID Reply #1 - Jan 23^rd, 2021 at 8:38am	Print Post
	Try to thread a wooden match stick into the hole, then measure the number of threads on the match stick and calculate the threads per inch. Keep on hav'n fun! MikeT


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Dusty Texian Junior Member Offline Posts: 58 Joined: Aug 20^th, 2013	Re: Thread pitch ID Reply #2 - Jan 23^rd, 2021 at 10:30am	Print Post
	To add to what Mike T said , in the past I had to make a screw that was for an early 1700s flintlock . The threads were all hand cut on this old Swedish rifle . I used a round piece of aluminum tapered and slowly turned into the hole and the threaded hole cut a thread on the aluminum rod . Worked fairly easy . DT


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JLouis Frequent Elocutionist Offline Posts: 10625 Joined: Apr 8^th, 2009	Re: Thread pitch ID Reply #3 - Jan 23^rd, 2021 at 11:40am	Print Post
	A piece of turned down Delrin to the below major diameters also threads itself very well. Major diameters for 4-40 and 4-48 are both .1220, 5-40 and 5-44 are both .1250, 6-32, 6-40 and 6-48 are all .1380, 8-32, 8-36 and 8-40 are all .1640.

	" It Is Better To Now Have Been A Has Been Than A Never Was Or A Wanna Be "
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westerner Frequent Elocutionist Offline deleted posts and threads record holder. Posts: 12372 Location: Why, out West of course Joined: May 29^th, 2006	Re: Thread pitch ID Reply #4 - Jan 23^rd, 2021 at 12:30pm	Print Post
	I was thinking there might be a product that could be poured into the hole then unscrewed and measured. Cerrosafe?

	A blind squirrel runs into a tree every once in a while.
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JLouis Frequent Elocutionist Offline Posts: 10625 Joined: Apr 8^th, 2009	Re: Thread pitch ID Reply #5 - Jan 23^rd, 2021 at 1:18pm	Print Post
	Never tried Cerrosafe but I also never had the need I bought a gun screw set several years back from Brownels that goes from 0-80 up to #12 and one of those best money ever spent items for my own use. Was a time I worked on several rifles for friends so I always had what I needed on hand and only had to cut them to the proper length all being 1 inch in length.

	" It Is Better To Now Have Been A Has Been Than A Never Was Or A Wanna Be "
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jfeldman ASSRA Board Member Offline Posts: 1120 Location: Imperial Beach, Ca Joined: Nov 5^th, 2005	Re: Thread pitch ID Reply #6 - Jan 23^rd, 2021 at 3:17pm	Print Post
	Joe, I have used a product from J-B Weld called SteelStik to make external threads in the past but have never tried it for internal threads like a screw. I think it would work, but I'd be afraid of it sticking in the hole. Small hole, it would be hard to be sure the release agent was applied everywhere. Regards, Joe


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westerner Frequent Elocutionist Offline deleted posts and threads record holder. Posts: 12372 Location: Why, out West of course Joined: May 29^th, 2006	Re: Thread pitch ID Reply #7 - Jan 23^rd, 2021 at 4:13pm	Print Post
	We once used it to repair a valve seat in a BBC, Joe. Car ran down the track just fine. Seat was still there when we pulled the heads off. I'd be afriad to use it also. I might just try the Cerrosafe. Save a lot of time messing around tring to get the diametr right in the lathe. John. Rifle is an old Swiss percussion Schuetzen rifle with a ill fitting trigger spring screw. Nothing I have comes close to matching. Going to have to make one on the lathe.

	A blind squirrel runs into a tree every once in a while.
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GT Frequent Elocutionist Offline Posts: 2370 Location: Northeast Wyoming Joined: Jun 28^th, 2015	Re: Thread pitch ID Reply #8 - Jan 23^rd, 2021 at 5:08pm	Print Post
	Joe, Let me know how the cerrosafe works for you, I tried it a couple different times, usually on the smaller holes it just twisted off, then it's the heat gun to melt it back out. Turn a piece of hardwood.025 larger than you measure the inside of the hole with your trusty calipers, dip the hardwood stub in a little candle wax (got to light the candle first) - it's lube, and screw it in the hole. Probably give you a good thread and size. Did this recently on a antique Austrian, came out to about a 5-46 thread. (.123 x 45.5 using the optical comparator.) Greg

	"To invent, you need a good imagination and a pile of junk" T. A. Edison "The trouble ain't that there is too many fools, but that the lightning ain't distributed right" M.T.
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westerner Frequent Elocutionist Offline deleted posts and threads record holder. Posts: 12372 Location: Why, out West of course Joined: May 29^th, 2006	Re: Thread pitch ID Reply #9 - Jan 23^rd, 2021 at 5:44pm	Print Post
	I've used a piece of tapered lead wire. Gives the TPI but not the diameter. I'm always looking for a shortcut.

	A blind squirrel runs into a tree every once in a while.
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GT Frequent Elocutionist Offline Posts: 2370 Location: Northeast Wyoming Joined: Jun 28^th, 2015	Re: Thread pitch ID Reply #10 - Jan 23^rd, 2021 at 7:12pm	Print Post
	That is our nature.

	"To invent, you need a good imagination and a pile of junk" T. A. Edison "The trouble ain't that there is too many fools, but that the lightning ain't distributed right" M.T.
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John Taylor Frequent Elocutionist Offline Posts: 1851 Location: Lewiston, ID Joined: Oct 23^rd, 2006	Re: Thread pitch ID Reply #11 - Jan 24^th, 2021 at 1:51pm	Print Post
	I have used Cerrosafe many times. If it gets stuck a little heat and pore it out.

	John Taylor Machinist/gunsmith
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