Converting a 2-pt hitch tiller to 3-pt?

[davesisk]

Hi folks:

There's a yanmar tiller for sale at a dirt-cheap price not too far from me. It's 2-pt, but I'm thinking it probably wouldn't be too difficult to convert it to 3-pt. I've got a question in to the current owner to make sure the input shaft is standard 6-spline 540 rpm.

So two questions. Has anyone converted a 2-pt to 3-pt? It almost seems like it might be easier to just make a 3-pt frame and bolt or weld the 2-pt tiller to it rather than modifying what's already there. Any thoughts on this? I can cut-n-weld, so I don't think this would be too difficult to pull off.

On the PTO input shaft, if it's not standard 6-spline 540 rpm, is this still a candidate? If the splines are different, isn't there an adapter to mate them (assuming it's the Japanese standard spline, whatever that actually is), and how much does it cost? If the speed isn't 540 rpm, it's probably 2000 rpm, and I'd imagine it would turn way too slow to be useful. Thoughts on this?

Thanks in advance!
Dave

 

[larso1]

Dave,

I bought a Yanmar 2-pt with the same intentions as you in converting it. I found that my particular Yanmar 2-pt tiller has a 16-spline 30mm shaft which no one seems to have an adapter for. Fortunately mine did come with the short double jointed u-joint that adapts it to a std. 1-3/8" 6-spline. I have a welded-up std. 3-pt triangle with vertical 2" angles each side that will attach to both the 3-pt (on one side) and the 2-pt (on the other side). Haven't tried it yet but am hopeful....this way I won't have to modify the tiller and it can still be used as a 2-pt. The only challenge now is that I need some way to lock the splined metric adapter to the tiller input shaft since it has no circumferential groove cut into it for that method of securing it.....not needed on a 2-pt I guess.

Bill

 

[davesisk]

Thanks for the reply. So even though the input shaft on the tiller is 16-spline 30mm, is it still designed to turn at 540rpm?

By the way, do you have any pics of the 2pt to 3pt adapter that you made?

Thx,
Dave

 

[larso1]

Dave,
Sorry but I don't know what the optimum PTO speed is for these tillers is, but my Iseki tractor has a 4 speed PTO so I wasn't concerned about that. Maybe someone else can answer that.

I layed out the hitch interface/adapter in AutoCad and that's how I came up with the design and hitch pin locations. See attachments of hitch and tiller. Sorry about the picture quality....it was late.

Bill

 

[larso1]

Pic #2

 

[larso1]

Pic #3

 

[Slamfire]

Some tillers with the odd splines turn the opposite direction also. /forums/images/graemlins/tongue.gif

 

[larso1]

Pic #4

 

[davesisk]

So, it turns out this tiller does indeed have a 16-spline presumably 30mm input shaft. Does anyone know if there's an adapter to mate it to a standard 6-spline PTO shaft?

I've asked to seller to now tell me if, when you turn the tines by hand in the direction they are supposed to turn, the input shaft turns clockwise or counter-clockwise.

Someone check me here: a standard PTO turns clockwise looking at the tractor, right? This would mean that a standard input shaft would be turned counter-clockwise if you're standing on the hitch side of the tiller looking at the input shaft, correct?

Thx,
Dave

 

[larso1]

I went out and checked my tiller and tractor (with standard PTO) and they do indeed both turn correctly.....that is, tractor turns CW looking at PTO from rear of tractor, and tiller turns CCW looking at the tiller input shaft. Whew! But good luck finding a splined adapter. I searched all over the WWW and looked at the site for the mfr of the coupling, but no luck. If the tiller in question does not come with a splined coupling for that input shaft, I would leave the tiller where it sits ....... unless you can get one of these couplers from a grey market dealer.

 

[gbirky]

Actually, you don't really even need a splined end on the pto shaft at the gearbox input. In fact, you may NOT want one. My Japanese tiller doesn't have a slip clutch or a shear pin. You could simply get a u-joint pto shaft end that fits snugly over the gearbox input shaft. If you can't find one the right size, get one for a smaller shaft and have a machine shop turn it on a lathe to get the right diameter. Then drill a cross hole in the gearbox input shaft and the pto shaft for a shear pin. That way you get the tiller working, and provide some mechanical protection for the tiller and tractor.

 

[larso1]

That sounds like a very good solution to the problem Greg. And, it would be a good means of locking on the tiller end of the drive shaft so that it doesn't slip off when lifting the tiller up and down.

Bill

 

[Cord]

Don't worry so much about the direction of rotation. Tillers will work if they are rotating with or against the direction of travel. I know that the better home owner grade tillers are reverse cut (against the direction of travel). Troy-Built would be one example. I believe the Yanmar tillers are not a reverse cut.

If you need to adapt the pto consider splitting the shaft apart and just replacing the section that doesn't match up.