Farm Equipment - Allis T80 mower

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Allis T80 mower

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Category: Allis Chalmers
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=34735
Printed Date: 30 Oct 2025 at 10:52pm
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Topic: Allis T80 mower

Posted By: KansasOrange
Subject: Allis T80 mower
Date Posted: 30 Jul 2011 at 6:06pm

Ive got an Allis T80 trail mower that is driving me crazy! Any help or advice from any who have ran one would be greatly appreciated. This little 7' sickle mower would be just the ticket for the little bit of horse hay I mow each summer. The trouble is the sickle head bushing. A few weeks ago I hooked onto the mower, greased it up, replaced a couple sections and went to work. I mowed about 2 acres when the mower quit cutting and found that the mower had sheared the bolt holding the sickle head bushing and the sickle head together. I replaced the bolt with another grade 8 1/2 bolt and went back to work, this time I only made it about 100' and the nut worked loose, I have repeated this process over and over trying different things each time to try and keep it tight. Ive used lock washers, double nut, even bought a brand new bushing for $145.00! I am thinking maybe I should just give up and hire my hay mowed. Ive spent a total of 25 hours and several hundred bucks trying to get this thing to mow and all I can get cut is 20 or 30 feet at a time until the nut and bolt work loose.

I am putting the bolt up through the bottom of the sickle bar at the sickle head, through the sickle head bushing and sucking everything up as tight as I can. Ive greesed the bushing well at the zerk. Im just about had it with this thing, but thought maybe somebody out there might be able to fill me in on something simple I have wrong. I bought the allis manual for this mower and cant see anything obvious according to it that should be changed. Thanks in advance for any replies.

-Rob McDonald

Replies:

Posted By: Chalmersbob
Date Posted: 30 Jul 2011 at 10:17pm

Have you tried a self locking nut? It will have a nylon bushing it and is only good for 1 use. Bob

Posted By: Adam Stratton
Date Posted: 30 Jul 2011 at 10:19pm

I am not familiar with the problem you are having, but do you have room to run another nut on as a lock nut? Do you have a lock washer in place? Maybe one of those self-locking nuts? Put the bolt in, drill a hole through and a safety wire or pin? Touch it with a welder after it is tightened down to lock the nut? We have 2 nuts on most of the sickles on our combines to keep from vibrating out.

Posted By: Adam Stratton
Date Posted: 30 Jul 2011 at 10:20pm

Took the words right out of my mouth Bob!

Posted By: Tracy Martin TN
Date Posted: 30 Jul 2011 at 10:27pm

We have mowed a gazillion acres with a 80r mower. Never had a problem as that. The bushing was made for a bolt to run through it into the sickle head, no nut required. I am not sure if there is enough room for a nut on the bottom of sickle head at the far throw of sickle blade.Might be, just ain't standing at the mower .You probably need a new sickle head. I think it is a 1/2 -20 nf thread on the bolt. HTH Tracy Martin

Posted By: Brian G. NY
Date Posted: 31 Jul 2011 at 7:58am

I had that problem with my 82S.

Turned out the threads in the head were pretty well worn out.

My solution; welded a Gr 8 nut on the underside of the head.

I had to just slightly grind the nut for clearance.

Installed a new Gr 8 bolt and have not had a problem since; about 5 years.

If the threads are still good in your head, I think I would try Adam's suggestion.

Posted By: GregLawlerMinn
Date Posted: 31 Jul 2011 at 8:14am

Same as Tracy, my 80R has 1/2" NF threads in the sickle knife head and the bolt goes down thru the serrated bushing into the sickle knife head (I applied some medium locktite to the bolt threads). I also placew washers under the bolt head so only a few threads show under the knife head. Sounds like the threads are shot in your knife head.

You can still obtain parts (and new sickles) for the 80/82 series mowers from Webb's Sickle Service: http://www.sickleservice.com/ - http://www.sickleservice.com/

-------------
What this country needs is more unemployed politicians-and lawyers.
Currently have: 1 D14 and a D15S2.
With new owners: 2Bs,9CAs,1WD,2 D12s,5D14s,3D15S2s, 2D17SIVs,D17D,1D19D;1 Unstyled WC

Posted By: KansasOrange
Date Posted: 31 Jul 2011 at 8:40am

Thaks guys for all the help. I think my problem is now pretty obvious, there are no threads at all in my sickle head. Im guessing now that there must have been threads in the head from the factory but that they are just shot. Looks like Im going to have to replace the sickle bar or weld a 1/2" nut into my existing head to accept the bushing bolt. Thanks again guys for all the replies, its good to know Im not crazy.

Thanks - Rob

Posted By: Bill Long
Date Posted: 31 Jul 2011 at 11:25am

You might want to try Sandy Lake. They are great at working with you to solve a problem. I know they will get the right part or parts to complete the job.
Let us know how it goes.
Good Luck!
Bill Long

Posted By: Tracy Martin TN
Date Posted: 31 Jul 2011 at 3:47pm

Sickle Service is as cheap on entire blade and knife head as anyone. HTH Tracy Martin

Posted By: Brian G. NY
Date Posted: 31 Jul 2011 at 7:37pm

A new complete knifehead and cutbar sure would be nice wouldn't it?

Not that I couldn't afford to do it, I guess I'm just too cheap.....and.....

maybe "practical".

Good luck to you on whichever road you choose to travel!

Posted By: Ray
Date Posted: 01 Aug 2011 at 2:11pm

Hi: I live here in Kansas also (near marysville) I have 3 new sickles ($120.00) each plus other mower parts new and used. 785-353-2392