18 spline input shaft diameter ?
#2447330
02/06/18 12:32 PM
02/06/18 12:32 PM
|
Joined: Sep 2003
Posts: 19,243 north of coder
moparx
OP
"Butt Crack Bob"
|
OP
"Butt Crack Bob"
Joined: Sep 2003
Posts: 19,243
north of coder
|
this is a really stupid question, so please, just consider it from my "old timers" diseased mind ! what is the spline diameter of the 18 spline shaft ? here is the reason for asking. sunday, a buddy showed up with a plastic pilot tool that had 18 splines. however, it was just a tick over 5/8" in diameter, and the pilot was only about 7/16". neither one of us has a transmission, but i said it looked way small, i "thought" it [the spline] should be closer to 1" or so ? i tried the google, but didn't have any luck. so, help this dum old guy out, please ? TIA as always !
|
|
|
Re: 18 spline input shaft diameter ?
[Re: moparx]
#2447519
02/06/18 06:34 PM
02/06/18 06:34 PM
|
Joined: Jan 2003
Posts: 25,618 Rio Linda, CA
John_Kunkel
Too Many Posts
|
Too Many Posts
Joined: Jan 2003
Posts: 25,618
Rio Linda, CA
|
The official input shaft spline dimension is 1-3/16 x 18T.
The INTERNET, the MISinformation superhighway
|
|
|
Re: 18 spline input shaft diameter ?
[Re: moparx]
#2447601
02/06/18 08:36 PM
02/06/18 08:36 PM
|
Joined: Dec 2004
Posts: 350 Houston
it's Bob
enthusiast
|
enthusiast
Joined: Dec 2004
Posts: 350
Houston
|
HemiStan "missed it by that much"....Holding fingers 1/32" apart. Better than I could measure, probably.
Last edited by it's Bob; 02/06/18 08:38 PM.
|
|
|
Re: 18 spline input shaft diameter ?
[Re: it's Bob]
#2447647
02/06/18 09:38 PM
02/06/18 09:38 PM
|
Joined: Jan 2003
Posts: 16,376
dogdays
I Live Here
|
I Live Here
Joined: Jan 2003
Posts: 16,376
|
If the splines are the same diametral pitch then the diameter corresponds to number of splines linearly.
If, however, the diametral pitch is changed then you have things like the larger diameter shaft with fewer splines. A prime example of this is on GM and Ford input shafts. A common style is 10 splines. The Ford is 1 1/16" diameter, the GM is 1 1/8", and there are trucks with 10 splines with input shaft 1 3/8". Each example is using a different diametral pitch when they design the splines.
We're luckier when it comes to axles, because MOST of the popular axles use the same diametral pitch. So in general, we know that a 29 spline axle is stronger than a 27 spline and weaker than a 30. This is disregarding the strength of the axle material, of course. However the strength of the axle in torsion increases by the cube of the increase in diameter, so you can see that increasing from a 27 spline to a 31 spline increases strength by 51%.
Had enough?
R.
|
|
|
Re: 18 spline input shaft diameter ?
[Re: dogdays]
#2447679
02/06/18 10:09 PM
02/06/18 10:09 PM
|
Joined: Jul 2011
Posts: 953 Chicago
PurpleBeeper
super stock
|
super stock
Joined: Jul 2011
Posts: 953
Chicago
|
If the splines are the same diametral pitch then the diameter corresponds to number of splines linearly.
If, however, the diametral pitch is changed then you have things like the larger diameter shaft with fewer splines. A prime example of this is on GM and Ford input shafts. A common style is 10 splines. The Ford is 1 1/16" diameter, the GM is 1 1/8", and there are trucks with 10 splines with input shaft 1 3/8". Each example is using a different diametral pitch when they design the splines.
We're luckier when it comes to axles, because MOST of the popular axles use the same diametral pitch. So in general, we know that a 29 spline axle is stronger than a 27 spline and weaker than a 30. This is disregarding the strength of the axle material, of course. However the strength of the axle in torsion increases by the cube of the increase in diameter, so you can see that increasing from a 27 spline to a 31 spline increases strength by 51%.
Had enough?
R. Or in other words....some of the Centerforce clutch kits & tools have 18 splines & come up in a search for "70 Road Runner" but are the wrong diameter... ask me how I know. Another thing to consider is that my eyes aren't good enough to determine the pitch of splines...so I just count them....stupid non-bionic eyes
70 Roadrunner convt. street car
440+6, NOS, 4-spd, SS springs
'96 Mustang GT convt. street car
'04 4.6 SOHC, NOS, auto, lowered
"Officer, that button is for short on-ramps"
|
|
|
|
|