Farm Equipment - F3 question

Print Page | Close Window

F3 question

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=133342
Printed Date: 13 Jun 2025 at 8:17pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: F3 question

Posted By: Ben (MI)
Subject: F3 question
Date Posted: 03 Jan 2017 at 9:17am

On my F3, the left side cleaning shoe drive gear/hub was not running true. I found the shaft key was damaged. My problem is I don't know if the hub that the drive gear attached to is damaged or not. It has a notch for the shaft key that turns into a bigger notch further inside the hub. Is this correct? Also, what should the inner diameter be of the hub? I don't know what a new one should look like so I don't have anything to compare to. I was going to buy a new one but the cost is outrageous. Thank you.

-------------
Part time farming with a 1980 7060 and 1984 F3 hydro.

Replies:

Posted By: SteveM C/IL
Date Posted: 03 Jan 2017 at 1:01pm

Think F3 is different than older F2 there but hub has straight bore with keyway that "fits".The bore should just fit over the shaft.Not an interference fit.I would bet your shaft is sub-par there too.Spend the money and fix it right.You'll never have to do it again.

Posted By: tbran
Date Posted: 03 Jan 2017 at 5:55pm

correct - more than likely the walkers clogged up at some point and twisted the eccentric shaft. The damage was probably done then. Do not just repair the shaft w/o looking at the chopper knives. If they do not have the 120 degree sharp non rounded leading edge -reverse them or replace them. IF one walks up to the back of the shoe while the combine is at an idle and with the separator clutch engaged and observes that the shoe moves perfectly back and forth with no side to side movement then the eccentric shaft is fine, otherwise the shaft is bad.

-------------
When told "it's not the money,it's the principle", remember, it's always the money..

Posted By: SteveM C/IL
Date Posted: 03 Jan 2017 at 9:01pm

What Tbran is saying is that shaft can get twisted causeing bad things with the shoe.

Posted By: Ben (MI)
Date Posted: 04 Jan 2017 at 6:11am

What happened was the set bolt fell out of the hub and the assembly wobbled on the shaft, there was no plugging anywhere in the combine. I will check it out as suggested though.

The shaft is fine, it is not bent and is 1" diameter, even where the hub wobbled.

I didn't do a good job of describing the notch on the inside of the hub. It is notched all the way front to back for the keyway. The notch widens in the center then narrows back down, front and back are key width, interior is two key widths making me think it is supposed to be pushed on and twisted so the key fits in the wide notch, then tighten the set screw.

I also want to know what the inside diameter of the hub is supposed to be because if it is ok I won't need to spend $400+ on a new hub.

Thanks all.

-------------
Part time farming with a 1980 7060 and 1984 F3 hydro.

Posted By: DrAllis
Date Posted: 04 Jan 2017 at 9:10am

That keyway is wallered out. No such thing as a narrow then wide keyway. The setscrew got loose causing the failure. Get setscrew tight and check it every day for a week to be SURE it stays tight.

Posted By: SteveM C/IL
Date Posted: 04 Jan 2017 at 10:16am

I would try this,new key,Loctite on shaft&hub.Anti-sieze on set screw and tighten really tight.The Loctite will pull the load with the set screw TIGHT.The key probably won't be doing anything if it lands where the wollowed spot is.The set screw sits on a flat so it might work.You will only know by trying.What is there to loose?

Posted By: Ben (MI)
Date Posted: 04 Jan 2017 at 10:19am

Thanks Steve-I will give it a try and make sure the shoe runs true.

-------------
Part time farming with a 1980 7060 and 1984 F3 hydro.

Posted By: Bret (OH)
Date Posted: 04 Jan 2017 at 10:43am

You might consider broaching a new keyway into the hub in a new location. I use Minute Man Broaches for this kind of work. Might try a machine shop to see if they can do it for you.

http://www.mscdirect.com/product/details/00309112?cid=ppc-google-New+-+Holemaking+-+PLA_s6wvMu6ez&cid=PLA-Google-PLA+-+Test___164124449507_c_S&mkwid=s6wvMu6ez&cid=PLA-Google-PLA+-+Test|dc&pcrid=164124449507&gclid=CMak57H3qNECFVc2gQodCYMLjQ

Just google Minute Man Broaches

Posted By: Ben (MI)
Date Posted: 04 Jan 2017 at 11:20am

Great idea Bret, I have a great shop nearby. I had thought of having them just make a whole new hub but I will talk to them about a new keyway instead-thanks! Another "why didn't I think of that" moment for me.

What do you think the interior diameter should be of the hub for the 1" shaft it mounts to, please? My guess would be no more than 10-20 thousands over 1". I want to figure out if I have ruined the entire hub or not.

-------------
Part time farming with a 1980 7060 and 1984 F3 hydro.

Posted By: Lonn
Date Posted: 04 Jan 2017 at 11:30am

I'm not a machinist but 10-20 thousandths would be too big in my book. Maybe 1 thousandths, a slip fit for that application.

-------------
-- --- .... .- -- -- .- -.. / .-- .- ... / .- / -- ..- .-. -.. . .-. .. -. --. / -.-. .... .. .-.. -.. / .-. .- .--. .. ... -
Wink
I am a Russian Bot

Posted By: tbran
Date Posted: 04 Jan 2017 at 1:49pm

keep in mind the sprockets and eccentrics are TIMED!

left to right!!!!!!!!!!!!

-------------
When told "it's not the money,it's the principle", remember, it's always the money..

Posted By: Ben (MI)
Date Posted: 04 Jan 2017 at 2:23pm

Good reminders Lonn and tbran!!!

-------------
Part time farming with a 1980 7060 and 1984 F3 hydro.

Posted By: MACK
Date Posted: 05 Jan 2017 at 10:20pm

Save your self a lot of time and money later BUY A NEW SHAFT AND SPROCKET. The shaft is 1" And sprocket is 1". 0 interference fit. MACK

Posted By: shameless (ne)
Date Posted: 06 Jan 2017 at 1:20am

X2 what MACK says!

Posted By: Ben (MI)
Date Posted: 06 Jan 2017 at 6:13am

Thanks all!

-------------
Part time farming with a 1980 7060 and 1984 F3 hydro.