Yesterday's Tractor Co.
Shop Now View Cart
   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver
Classified Ads
Photo Ads
Tractor Parts

Discussion Forums
Project Journals
Tractor Town
Your Stories
Show & Pull Guide
Events Calendar
Hauling Schedule

Tractor Photos
Implement Photos
Vintage Photos
Help Identify
Parts & Pieces
Stuck & Troubled
Vintage Ads
Community Album
Photo Ad Archives

Research & Info
Tractor Registry
Tip of the Day
Safety Cartoons
Tractor Values
Serial Numbers
Tune-Up Guide
Paint Codes
List Prices
Production Nbrs
Tune-Up Specs
Torque Values
3-Point Specs

Tractor Games
Just For Kids
Virtual Show
Museum Guide
Memorial Page
Feedback Form

Yesterday's Tractors Facebook Page

Related Sites
Tractor Shed
Ford 8N/9N Club
Today's Tractors
Garden Tractors
Classic Trucks
Kountry Life
John Deere Tractors Discussion Forum
Show Parts for Model:

Why 540 rpm pto?

Welcome Guest, Log in or Register
Author  [Modern View]

05-26-2013 04:06:27

Report to Moderator

Does anyone know the history of pto on the first tractors and why 540 rpm and not 600, 500, 530 etc?

[Log in to Reply]   [No Email]

05-27-2013 12:16:03

Report to Moderator
 Re: Why 540 rpm pto? in reply to bernieinva, 05-26-2013 04:06:27  
As Brendon mentioned below, the actual value of 540 RPM was a result of a consensus agreement and the difficulty getting one of those is about the same difficulty as herding cats.

The first PTOs were for mowers, grain binders, and similar equipment that utilized sickle bar cutters for which operating speeds were in the 500-600 RPM range for the average traveling speeds at that time.

The initial push for standardization of this feature was made in the 1920's by the Farm Equipment Institute (now part of the Association of Equipment Manufacturers) because of the variances in diameters, spline details, locations, and speeds of PTOs. There was a desire to try to standardize PTO details so implements and tractors could be interchanged more easily. (A study in 1929 of 35 popular tractors showed PTO speeds varying from 515 to 745 RPM.)

The original draft of the standard made by the FEI was adapted by ASAE (American Society of Agricultural Engineers, now called ASABE) in April 1927 and specified a 1 3/8" shaft, 6 splines, clockwise rotation, and 536 +/- 10 RPM, located on the centerline of the tractor, and was to be 14" ahead of the drawbar pinhole. By 1958, the standard had been rounded off to 540 RPM.

By the way, this standard (ASAE S203) was their longest-running and was only discontinued in 2011 since a similar world-wide ISO standard was adapted by ASABE.

Although ASAE S203 was adapted in 1927, it wasn't mandatory and not all tractor manufacturers changed their configurations at that time. John Deere, for example, in Field Service Bulletin 148-S dated 15 June 1944, introduces a number of "bundles" of available parts to modify tractors built earlier to make them compatible with ASAE standards.

[Log in to Reply]  [No Email]

05-26-2013 15:12:40

Report to Moderator
 Re: Why 540 rpm pto? in reply to bernieinva, 05-26-2013 04:06:27  
A few years ago there was a short article in the ASABE (the society formally known as ASAE) magazine about the history of the 540 rpm speed of the standard PTO. The article mentioned that most early binders had a shaft that rotated about this speed and since this was one of the first applications of the tractor PTO this was standardized.

[Log in to Reply]  [No Email]
coonie minnie

05-26-2013 17:49:56

Report to Moderator
 Re: Why 540 rpm pto? in reply to Brendon-KS, 05-26-2013 15:12:40  
Well, that would make sense...

[Log in to Reply]  [No Email]
coonie minnie

05-26-2013 10:20:11

Report to Moderator
 Re: Why 540 rpm pto? in reply to bernieinva, 05-26-2013 04:06:27  
It does seem goofy to use such an unusual number...

I'm guessing ASAE adopted something that the first manufacturer had already come up with, and that was probably just how the proposed gearing matched to engine speed. Think about it... there was no implement already designed so you had free reign. Is this the specs for the first IH stuff?

Same with the 3 pt hitch. What is now standard was first invented and then patented by Harry Ferguson. Is was much later that it became a "standard".

It took a while for early PTOs to have a common size, too. Early Bs and I believe F12s had a 1 1/8 shaft, and most Gs had a larger than standard shaft.

And then came positioning with the drawbar as far as height and distance from hitch pin hole.

[Log in to Reply]  [No Email]

05-26-2013 09:45:09

Report to Moderator
 Re: Why 540 rpm pto? in reply to bernieinva, 05-26-2013 04:06:27  
NOT really an answer to your question but interesting anyhow...

"The first industry standard for PTO design was adopted by ASAE (the American Society of Agricultural Engineers) in April 1927.

The PTO rotational speed was specified as 536 10 rpm; the direction was clockwise.

The speed was later changed to 540 rpm.

[Log in to Reply]  [No Email]
[Options]  [Printer Friendly]  [Posting Help]  [Return to Forum]   [Log in to Reply]

Hop to:

Fast Shipping!  Most of our stocked parts ship within 24 hours (M-Th). Expedited shipping available, just call! Most prices for parts and manuals are below our competitors. Compare our super low shipping rates! We have the parts you need to repair your tractor. We are a company you can trust and have generous return policies. Shop Online Today or call our friendly sales staff toll free (800) 853-2651. [ About Us ]

Home  |  Forums

Copyright © 1997-2016 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy

TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters