removing drive gear in chain-driven tiller

[scattleberry]

Hi,
I've got a 42" chain driven tiller for my tractor. I'm trying to remove the upper cog that is on the shaft that connects to the PTO. The previous owner had replaced the stock cog with a smaller one so the tiller could be operated at 1000 rpm PTO speed. I'd like to replace the existing cog with the larger stock one so that I can operate the tiller at 540 rpm.

My problem is removing the cog. I removed the clamp ring, but I can't get a puller on the cog because the chain runs around it right now, and the puller would have to engage the chain, which I don't think is a good idea. I can't break the chain, because the link with the removable pin slides back and hits the back of the case before it disengages the link. There isn't enough play in the chain to move it forward so I can move the pin far enough back to break the link.

Any clever ideas? Right now I've got penetrating oil on the shaft at the cog. Should I forgo the puller and just use a prybar to try to lever out cog, turning the cog (by turning the pto shaft) as I apply the pressure?

I can't help but think there is an easy solution to this, but I sure can't see it!

thanks,
chris

 

[jimmysisson]

Is there room to drill the chain guard so you can drive the pin out the hole? Then plug it after.
Jim

 

[scattleberry]

Jim,
Interesting idea. What's the best way to plug the hole later?
chris

 

[uniqman]

hi, the best way to make room is to pull aout at the same time the top and bottom sprocket along with chain. Do not drill the chaincase...

 

[uniqman]

This is the way i split chains when i repair howards E60 E70 tillers.

 

[scattleberry]

hi, the best way to make room is to pull aout at the same time the top and bottom sprocket along with chain. Do not drill the chaincase...

How would you pull the sprockets, then? I'm not too excited about pulling on the chain that's in the way....

 

[Wayne_Freeman]

Take a look at the attachment to see what the link looks like. There is no pin and it comes out together!

 

[dfkrug]

hi, the best way to make room is to pull aout at the same time the top and bottom sprocket
along with chain.

Yeah, that is how I would do it and that seems to be the way they were put on, too.

I restored 5 JD 550 (Howard) tillers a few years ago and they used massive #100 chain. I still saw broken
links. The master link SHOULD go on with the big part on the outside and plate inward.

 

[Stimw]

He is taking the chain apart at a "Half Link" not the master link.
You might have better luck with the master link because the outside link will come completely off.
Looking at the pic the Key is about half sheared. That will make it harder to get off.
You can try prying but make sure that you don't break what you are prying on.

 

[whis]

Does it have an idler sprocket? If so loosen the chain, turn master link to the middle of sprockets and see if you can pry it out enough to remove it

 

[Tx Jim]

He is taking the chain apart at a "Half Link" not the master link.
You might have better luck with the master link because the outside link will come completely off.

I agree on correct way is separating chain at the master link instead of the offset link aka 1/2 link. Then use a 3 jaw puller to remove sprocket. If you think about it there is no such thing as a 1/2 link as it's actually same length as a link see attached photo.

 

[Stimw]

I agree on correct way is separating chain at the master link instead of the offset link aka 1/2 link. Then use a 3 jaw puller to remove sprocket. If you think about it there is no such thing as a 1/2 link as it's actually same length as a link see attached photo.

BUT, a half link lengthens the chain one link. When two links is too much!
A Master Link will lengthen the chain two links because it requires two of the inside links to attach!
Half link is my term, there is probably an official name for it. ???

 

[Tx Jim]

BUT, a half link lengthens the chain one link. When two links is too much!
A Master Link will lengthen the chain two links because it requires two of the inside links to attach!
Half link is my term, there is probably an official name for it. ???

The official name for link in question is "offset link" but is known in industry as 1/2 link. I understand an offset lengthens chain one link and a master link with roller link is two links so how did offset get the name of 1/2 link if it's actually the same length as the other links?

 

[Egon]

Angle grinder and cut the connecting link if there is no tensioning sprocket.

 

[scattleberry]

I agree on correct way is separating chain at the master link instead of the offset link aka 1/2 link. Then use a 3 jaw puller to remove sprocket. If you think about it there is no such thing as a 1/2 link as it's actually same length as a link see attached photo.

Thanks for all the responses so far.

Unfortunately, there is no master link, only the half link that is pictured in my original post. Apparently the master link was removed by the original owner when the chain was shortened to accommodate the smaller sprocket. Also no tensioner sprocket on this unit. Is it crazy to drill out the case so I can slip the pin out, and then plug it with a bolt?

chris

 

[Baby Grand]

I'd do like Egon suggests and cut out a full link, which I'd then replace with a master link, like it should have had in the first place. This would make any future disassembly/reassembly much easier and not require plugging any holes.

 

[uniqman]

Hi, even if released the whole thread of chain tensioner still won't be possible to take it out off the sprockets. The link that connects any chain can't be placed facing the cotter pin towards the machine as the two shafts of the link are longer essentially to accept the cotter pin and won't have the necessary clearance, where as if facing the chain case there is no problem...
I have opened seven howard tillers and renovated them and all had the link the way i mentioned, at least for the howards this is the way it is

 

[jimmysisson]

Maybe drill the case the size of a firewall grommet. Then a small through bolt with a nylock nut will hold the grommet in place. Or, simpler, just a bolt and nylock with a dab of silicone around it. I could imagine that case seeing some internal pressure when hot.
Jim

 

[jimmysisson]

I would drill the case, then, and stick with the half link as its easier to get out one pin than a master link. Dab silicone on a small bolt and add a nylock nut inside or out where it fits best.
Jim

 

[Tx Jim]

Thanks for all the responses so far.

Unfortunately, there is no master link, only the half link that is pictured in my original post.
chris

From your photo this looks similar to a master link to me. I'll bet with a die grinder I could have that chain off the sprockets in short order.