Welcome! Please use the navigational links to explore our website.
PartsASAP LogoCompany Logo Auction Link (800) 853-2651

Shop Now

   Allis Chalmers Case Farmall IH Ford 8N,9N,2N Ford
   Ferguson John Deere Massey Ferguson Minn. Moline Oliver

Discussion Forum
:

H/M Steering Wedges (Narrow Front)

Welcome Guest, Log in or Register
Author 
Red Mist

04-22-2008 10:16:01




Report to Moderator

Howdy, boys. You know those steering wedges they made for the H and the M, that you put between the lower bolster and the upper bolster shaft? I always thought they were installed with the narrow edge to the front so that it would give the steering geometry more POSITIVE caster, thus making the tractor track in a straight line better - and with less tendency to "flutter wheel". That would also tend to cause the steering to return to "center" after making a turn.

Now, a fellow told me the other day that they were made to install with the thick edge to the front so that it would give the steering geometry more NEGATIVE caster and thus make it easier to steer. That would also take away any tendency the tractor might have to return to center.

I realize that the wedge will tend to do either, depending upon how it is installed, but my question is: What was the intended (original) purpose for IH to offer the wedges? Straighter steering and less flutter wheel (positive caster), or easier steering effort (negative caster)?

Thanks. mike

[Log in to Reply]   [No Email]
Janicholson

04-22-2008 14:19:05




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to Red Mist, 04-22-2008 10:16:01  
Mike,
The positive and negative caster idea can be confusing. The location of the contact patch of the tire on the road compared to the orientation of the axis on which the steering wheel turns is the basis for positive caster. Take a caster wheel on a shopping cart. The pivot on which it turns is vertical. the contact patch is an inch behind the point on the floor through which the pivot would project (its axis). This is positive caster. and is just the same on the Farmall.
On a Motorcycle, the rake angle of the steering head is tilted toward the back on top. This gives positive caster by projecting that axis out in front of the tire contact patch (causing self centering, with differing amounts for different rake angles. all the way to the rediculous angles found on extreme choppers that do not steer well)
So positive caster is more distance between the point of axis and the contact patch, and less happens until there is none, at which point the axis and contact patch are on the same center. Negative caster would be if the contact patch was in front of the axis, then the wheel would want to turn around and follow (like on a shopping cart) Though narrow fronts have two wheels, the effect is the same as though it had one. (think of a chair caster with two wheels).
In cars we adjust the ball joint location (to the front to lessen, and the rear to increase caster). I hope this makes sense out of it. JimN

[Log in to Reply]  [No Email]
RustyFarmall

04-22-2008 14:49:46




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to Janicholson, 04-22-2008 14:19:05  
I did a quick google search, and it is just as I was taught in auto mechanics. Positive caster is with the tire contact patch in front of the steering axis.



[Log in to Reply]  [No Email]
Red Mist

04-22-2008 15:06:58




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to RustyFarmall, 04-22-2008 14:49:46  

RustyFarmall said: (quoted from post at 14:49:46 04/22/08) I did a quick google search, and it is just as I was taught in auto mechanics. Positive caster is with the tire contact patch in front of the steering axis.
Caster



Rusty: Hmmm! Thanks, Rusty. mike

[Log in to Reply]  [No Email]
Red Mist

04-22-2008 14:39:53




Report to Moderator
 Re: H/M Steering Wedges - BobM and Janicholson in reply to Janicholson, 04-22-2008 14:19:05  
Jim: Thanks to both you and BobM. Yes, I do understand positive caster as it pertains to an automobile front spindle with an upper and lower ball joint - lower ball joint forward of the upper. Also, I understand positive caster as it pertains to a "chopper". In both those cases I can see where the pivot axis is ahead of the tire patch vertical.

The shopping cart example is more difficult for me to comprehend, but I think I have it. Now, the tractor wedge I am wrestling with. It seems to me that tractor wedge, properly installed, in effect, changes the angle of the steering source to where the pivot axis would be ahead of the tire vertical axis, i.e., positive caster. But yet, the shopping cart example would be like installing the tractor wedge backwards??? So, I guess I'm going to have to work my already over-taxed brain with it some more. Regardless, I'm going to go with what you and BobM have told me. Thanks. mike

[Log in to Reply]  [No Email]
Bob M

04-22-2008 19:27:27




Report to Moderator
 Re: H/M Steering Wedges - BobM and Janicholson in reply to Red Mist, 04-22-2008 14:39:53  
Mike - You pretty much got it!

Just keep in mind the stock H/Mlower bolster is configured to provide a small positive caster (tire patch is behind the pivot shaft axis). The wedge correctly installed reduces - but does eliminate - this positive caster.

Nor does the wedge change the angle enough to result in negative caster (tire patch ahead of the pivot shaft axist). Negative caster gives unstable steering action ("flop" steering): Let go of the steering wheel while going straight ahead and the steering will immediately flop either full left or full right.

[Log in to Reply]  [No Email]
Janicholson

04-22-2008 14:59:52




Report to Moderator
 Re: H/M Steering Wedges - BobM and Janicholson in reply to Red Mist, 04-22-2008 14:39:53  
Good!
Added content.
The intention of the wedge is to make the tractor easier to steer. The wedge takes caster out, making turning easier by reducing the amount the tractor would react to the wheel movement. Example: If the tractor were on a flat slab of ice, and not moving, and the steering had "original" caster", when turning from straight ahead to full left, the tractor would move to the left (as much as an inch or two) If we took out all the caster, the wheels would turn left, but the tractor would stay still, and not move left. The force to move the tractor left when moving is proportional to speed. as cornering forces are applied to the wheels they try to straighten back out. This causes increased force to be applied to the wheel. Putting the plate you have on in the direction you are supposed to will reduce forces on the wheel, but not reduce shimmy. Putting it on the other way might reduce shimmy, but will make it much harder to steer. It will not hurt to try it. Just be prepared to change it back. Make sure to get the limit bolt in the correct hole to prevent over steering the gears. Changing its length might be needed. Look under the top of the upper bolster mounting flange to find the recess the bolt goes into.
Wobble is best cured by tight gears, tight U joints and couplers, and wheel centering and ballance (yes ballance ing the fronts helps dramatically at 18mph. JimN

[Log in to Reply]  [No Email]
randy hall

04-22-2008 13:16:11




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to Red Mist, 04-22-2008 10:16:01  
from my general sales bulletin no. 5, feb.22, 1952 on the introduction of the super m. front end improvements. the amount of caster on the bolster used with regular equipment front wheels has been decreased from 1 1/2 to 7/8 inches. this reduces the effort required to turn the front wheels yet sufficient caster remains to induce "self recovery" after the turn is completed. this change has been in effect for approximately one year. the wedge you are talking about did this to the eariler tractors. it was sold by tractor supply, not international harvester as far as i know.

[Log in to Reply]  [No Email]
Bob M

04-22-2008 10:46:51




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to Red Mist, 04-22-2008 10:16:01  
Mike - The correct orientation for that wedge is with the THIN edge to the front. (Punch below for a photo of the one on my Super H - notice how "FRONT" is cast into thinner side the part...)

Original intent for the wedge is to lessen caster and thus reduce steering effort - sort of a "poor man's power steering". However this reduced caster makes the steering less self-centering. And if there's any slop in the steering mechanism it'll make a wobbly front end even wobblier when running on a hard surface.

[Log in to Reply]  [No Email]
gene bender

04-22-2008 12:18:31




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to Bob M, 04-22-2008 10:46:51  
So why did they move the pedestal back on the B tractor to improve steering.



[Log in to Reply]  [No Email]
Red Mist

04-22-2008 12:30:23




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to gene bender, 04-22-2008 12:18:31  

gene bender said: (quoted from post at 12:18:31 04/22/08) So why did they move the pedestal back on the B tractor to improve steering.


I would have to assume it was to make less steering effort. mike



[Log in to Reply]  [No Email]
Red Mist

04-22-2008 11:19:35




Report to Moderator
 Re: H/M Steering Wedges (Narrow Front) in reply to Bob M, 04-22-2008 10:46:51  

Bob M said: (quoted from post at 10:46:51 04/22/08) Original intent for the wedge is to lessen caster and thus reduce steering effort - sort of a "poor man's power steering". However this reduced caster makes the steering less self-centering. And if there's any slop in the steering mechanism it'll make a wobbly front end even wobblier when running on a hard surface.
Super H steering wedge



BobM.: Thanks. I follow you - sort of.....

That orientation for wedge installation is what I thought. However, that installation gives more POSITIVE caster - making turning somewhat more difficult, but tracking more true. On an automobile positive caster is when the lower ball joint is further forward of the upper ball joint - or, when the bottom of the king pin is further forward than the top - thus placing the spindle with a forward pitch at the bottom. For example, a "chopper" custom motorcycle has extreme POSITIVE caster, and should give more straight line stability but more difficult steering. Do a web search on Positive Caster.

Placing the narrow end of the wedge at the front of the farmall bolster has the same effect on the lower bolster (bottom more forward than top). That is POSITIVE caster. So, I must conclude that the purpose of the wedge was steering stability, or better tracking.

Anyway, you have answered my question by showing me the "forward" orientation in the photo, and that is what I wanted to confirm. Thanks. mike

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

Hop to:


TRACTOR PARTS TRACTOR MANUALS
We sell tractor parts!  We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]

Home  |  Forums


Copyright © 1997-2023 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

Website Accessibility Policy