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All Springer/NP/PCP Air Gun Discussion General => Machine Shop Talk & AG Parts Machining => Share Your Simple Home Projects (TRICKS-N-TIPS) => Topic started by: MultimediaMan on September 13, 2013, 12:58:36 AM

Title: Machinist's riddle...
Post by: MultimediaMan on September 13, 2013, 12:58:36 AM
I am a lowly screw. A mere two digits is my size and of a very common pitch am I.  I have a slightly larger, more popular, cousin who shares all of my numbers but not my size, larger by a fraction yet his name is a fraction of mine. So close are we that one is often are mistaken for the other. Our better halves know better. I have another close cousin on the metric side of the family who is every bit as common as my larger cousin, but we don't get along at all; about my size, but his pitch is much too far off.

What am I?
Title: Re: Machinist's riddle...
Post by: Big Bore Bart on September 13, 2013, 01:21:51 AM
#12-28  ;D
Title: Re: Machinist's riddle...
Post by: MultimediaMan on September 13, 2013, 01:33:02 AM
Close, but no cigar.
Title: Re: Machinist's riddle...
Post by: Sundog on September 13, 2013, 04:54:47 PM
#10-32

 8)
Title: Re: Machinist's riddle...
Post by: MultimediaMan on September 13, 2013, 05:45:05 PM
No, and Colder....
Title: Re: Machinist's riddle...
Post by: Motorhead on September 13, 2013, 07:11:53 PM
10-24 sort of fits :P  1/4-20 being larger using the numbers  :P :P larger screw is fraction of original & 6mmX.1 is metric kin with far different pitch.
Title: Re: Machinist's riddle...
Post by: MultimediaMan on September 13, 2013, 07:23:26 PM
Scott is thinking right... there are others, if you look.
Title: Re: Machinist's riddle...
Post by: Motorhead on September 13, 2013, 07:25:15 PM
Scott is thinking right... there are others, if you look.

So that's wrong ? .... My head hurts ... NEXT  ;D
Title: Re: Machinist's riddle...
Post by: MultimediaMan on September 13, 2013, 07:26:49 PM

#14 - 20  ;)

Title: Re: Machinist's riddle...
Post by: Motorhead on September 13, 2013, 07:29:10 PM

#14 - 20  ;)



So reading this ... it's 1/4-20 you were looking for ?
Title: Re: Machinist's riddle...
Post by: MultimediaMan on September 13, 2013, 07:33:29 PM
no... #14 - 20 was the size... 1/4 -20 was the larger cousin. "I have a slightly larger, more popular, cousin who shares all of my numbers but not my size, larger by a fraction yet his name is a fraction of mine." #14 is 0.242"; 1/4" is 0.250"....


Title: Re: Machinist's riddle...
Post by: Motorhead on September 13, 2013, 07:36:40 PM
Been on SAE charts course and fine and no such size as 14 I was able to find ???
Mind sharing what the heck a 14 size is ?
Title: Re: Machinist's riddle...
Post by: MultimediaMan on September 13, 2013, 07:41:38 PM
Depends on what year you look.  ;D One of the prime reasons #14 -20 was retired was that it almost was interchangeable with 1/4" - 20. So it's kind of a sucker question if you're not old enough to remember them or to have ever seen one. Most machinists hardly ever notice #14 screws... but they sure notice a #14 screw HOLE... you see a 1/4" - 20 bolt will break off in them almost every time. ;)
Title: Re: Machinist's riddle...
Post by: Motorhead on September 13, 2013, 08:21:21 PM
Depends on what year you look.  ;D One of the prime reasons #14 -20 was retired was that it almost was interchangeable with 1/4" - 20. So it's kind of a sucker question if you're not old enough to remember them or to have ever seen one. Most machinists hardly ever notice #14 screws... but they sure notice a #14 screw HOLE... you see a 1/4" - 20 bolt will break off in them almost every time. ;)


So a sucker I am ....  and that 10-24 still works that riddle   :'(
Title: Re: Machinist's riddle...
Post by: QVTom on September 13, 2013, 08:28:29 PM
I'm with Scott on the #14-20.  Really? ??? I have lots of old handbooks from various sources and have never seen a #14 listed.  The #12 still pops up now and again but is certainly obsoleted. I admit that I didn't start making screws with a file so there is much I don't know.  Number 14 (mumbling under breath)

Tom
Title: Re: Machinist's riddle...
Post by: sixshootertexan on September 13, 2013, 08:34:56 PM
Gagemaker.
(http://i42.photobucket.com/albums/e330/sixshootertexan/scan0001_zps8ec8e5d4.jpg) (http://s42.photobucket.com/user/sixshootertexan/media/scan0001_zps8ec8e5d4.jpg.html)
Title: Re: Machinist's riddle...
Post by: JJXGRUNT on September 13, 2013, 08:45:53 PM
Tom, the info you need will be found on page 1823 of Machinery's Handbook Twenty Fifth edition it also found it on page 1411 of a very much earlier edition. Ican't give you the date of the earlier publication, as I only have a plastic laminated page over my lathe bench.

John
Title: Re: Machinist's riddle...
Post by: QVTom on September 13, 2013, 08:54:51 PM
Ha ha. I can't argue with the source, I guess you got me. 8)  I will say that Machinery's Handbook could use some thinning out.   
Title: Re: Machinist's riddle...
Post by: JJXGRUNT on September 13, 2013, 09:00:44 PM
All the new technology in the last decade!

John
Title: Re: Machinist's riddle...
Post by: sixshootertexan on September 13, 2013, 09:16:12 PM
We have 3 or 4 different machinist handbooks at work I'll look tomorrow.
Title: Re: Machinist's riddle...
Post by: MultimediaMan on September 14, 2013, 01:18:27 AM
I'll grant you it isn't common anymore, but it used to be quite common as a "trades" screw for certain items, particularly in older tooling and automotive applications (Carburetors, distributors, precision parts of larger machines). In Aerospace, it still has a following among certain aircraft engine manufacturers - Lycoming and Pratt & Whitney.  I remember my dad running across the street to the lumber yard to buy some #14 - 20 taps and dies when announced it's removal from the official SAE series... about 1985, I think...

Anyway, here they are, still in the wrapper, about 30 years later...

(http://img842.imageshack.us/img842/1927/u8di.jpg)

Eventually, the 1/4" - 20 was the preferred standard across "disciplines", leading to the decline of the largest end of the numbered screw series during WWII and after. Most people who use #14 - 20 today do it to prevent common (untraceable) 1/4" - 20 fasteners from being used for a particular reason - so they still have a place, crazy though it may be.
Title: Re: Machinist's riddle...
Post by: willbird on September 14, 2013, 12:18:04 PM
I actually have a 14-20 tap in it's proper drawer (with the number taps) out in the shop :-).
Title: Re: Machinist's riddle...
Post by: JJXGRUNT on September 14, 2013, 09:38:46 PM
Regardless which volume of "Machinery's" you are looking at, the table will be in the chapter regarding tapping.

John
Title: Re: Machinist's riddle...
Post by: HYspd on September 30, 2013, 11:14:53 AM
that's not a riddle that's history or trivia..THIS is a riddle.

how much lead would a lead screw lead if a lead screw could lead screws
Title: Re: Machinist's riddle...
Post by: Roadworthy on September 30, 2013, 01:09:17 PM
That was an interesting bit of trivia.  I did a web search and found there was such a thing and it is still supported, though not very common.  Thanks for sharing.  I am now a wee bit wiser with arcane information and trivia.
Title: Re: Machinist's riddle...
Post by: OleTomCat on September 30, 2013, 05:33:26 PM
8-32, has a larger cousin 10-32, which can be mistaken for an M5 or 6 don't remember which...

5/16-18 can be mistaken for an M8.....

Just some fun facts...