Finish mower options

[North Idaho Wolfman]

To me it doesn't look that bad.
But if you think it's bad, one trick is try spinning the shaft 180° on the shaft.

 

[Paul Allwood]

To me it doesn't look that bad.
But if you think it's bad, one trick is try spinning the shaft 180° on the shaft.

Ok, thanks. I thought the third video shows it looking pretty bad. I'll try spinning it 180 degrees and see what that does. I was also going to try it again this morning with grease as the splines were pretty dry from cleaning and handling. Unfortunately it wouldn't start - it turned over but was really sluggish. I tried a second battery and a jump start with the same result. I've now got a battery on charge overnight and will try again tomorrow. I kicked it and headed inside to watch the Aussies play Paraguay in the world cup - I'm not a soccer fan, but don't mind watching these games.

Could the sluggish to turn over also be caused by a starter motor on the way out....worn brushes, high resistance ?

 

[chim]

Good morning Paul. The experience I have with drivelines is connecting and disconnecting implements, so I'm far from knowledgeable. If your pictures were all taken without moving anything between shots, I wonder if your joints are out of phase.

EDIT TO ADD: I posted the above before seeing the most recent posts. It appears the joints are close to 45° out. Shafts I'm familiar with have joints at both ends and a sliding shaft that is automatically indexed via odd-shaped lobes or something like that. A shaft with a u-joint on one end and spline on the other can be assembled in perhaps 32 different relationships, with most being off. I don't know how much each spline would count. Maybe a shaft made in a joint-x-spline configuration would need both intended joints in the right rotation before welding the spline to the shaft?

 

[Paul Allwood]

Thanks Chim.

The yokes at the green and red arrows are aligned - I think this is how the original shaft was, but now you've got me guessing. Not sure if that means they are in phase or out of phase.





EDIT: I just asked Google - looks like I have them in phase.

 

[chim]

Pardon my incorrect observation. In the pictures it looked to me as though the two joints were at different angles (rotation wise).

 

[Paul Allwood]

Pardon my incorrect observation. In the pictures it looked to me as though the two joints were at different angles (rotation wise).

I may have bumped it between photos, or it may be the angle of the camera ? I didn't really pay attention.

 

[North Idaho Wolfman]

Make sure the hydraulic system isn't being loaded while trying to start it.
I've had this happen on my B7100 and it will 100% act like a dead battery.

 

[Donystoy]

Just for comparison this is how I attached a blower to the B7200 that I previously had. I set up a similar drive train under the axle but mounted to the support frame that attached to the rear mower supports. Not sure what type of framework you are intending for the front mower. Likely just fasten it to the frame that you already added. At least you will not have to raise and lower it like a blower.

 

[Paul Allwood]

Make sure the hydraulic system isn't being loaded while trying to start it.
I've had this happen on my B7100 and it will 100% act like a dead battery.

I left a battery on charge overnight, wiggled the hydraulic valve lever and it started easily this morning.

 

[Paul Allwood]

Just for comparison this is how I attached a blower to the B7200 that I previously had. I set up a similar drive train under the axle but mounted to the support frame that attached to the rear mower supports. Not sure what type of framework you are intending for the front mower. Likely just fasten it to the frame that you already added. At least you will not have to raise and lower it like a blower.

Thanks for sharing that - looks great. I noticed you don't have a slip joint in the shaft, I guess because you are running straight from the mid PTO shaft to a rigidly mounted bearing block, or do you allow the yoke to slide on the mid PTO shaft splines ?

EDIT: Just looking at the pic of your drive shaft again. Is it a single piece of square tube, or a smaller square inside a larger square tube to provide a long slip joint ?

 

[Paul Allwood]

Good morning Paul. The experience I have with drivelines is connecting and disconnecting implements, so I'm far from knowledgeable. If your pictures were all taken without moving anything between shots, I wonder if your joints are out of phase.

EDIT TO ADD: I posted the above before seeing the most recent posts. It appears the joints are close to 45° out. Shafts I'm familiar with have joints at both ends and a sliding shaft that is automatically indexed via odd-shaped lobes or something like that. A shaft with a u-joint on one end and spline on the other can be assembled in perhaps 32 different relationships, with most being off. I don't know how much each spline would count. Maybe a shaft made in a joint-x-spline configuration would need both intended joints in the right rotation before welding the spline to the shaft?

It must be my bad photography. Here's a shot showing the whole shaft which shows the uni joints in phase.



Here's another of the slip joint splines. It can only fit together in one spot.

 

[chim]

I should have known that you had it under control. I reached as they would say at work an "optical confusion"

 

[Paul Allwood]

I should have known that you had it under control. I reached as they would say at work an "optical confusion"

It's a big step to assume I have it under control.

 

[Paul Allwood]

Last attempt before I give up for now and just make a mower to go at the back.

I cut the drive shaft apart and started again. This time I eliminated the long splined slip joint. Instead I've left the pin out of the bit that slides onto the mid PTO shaft so it can slide as the axle pivots - it only needs about 7-8 mm. I'll have to re-check this when it's back on the ground - might be more movement than this when the drive at the front axle changes from forwards to reverse, drive to overrun etc....not sure how easy this will be to check or measure.

Anyway, for now this change appears to have fixed the wobble at the mid PTO end of the drive shaft - much better than it was.

Here it is at idle - approximately 600 rpm.

Again at full speed - 2500 rpm.

Looking straight up at the mid PTO connection with the front axle pivoted fully both ways. This shows how far the fitting slides on the PTO shaft.

 

[Paul Allwood]

One more idea before I give up on the idea of a front drive shaft....if I need more movement than I can get with the fitting sliding on the mid PTO shaft, maybe I can use square inside square. I think if the overlap is almost the length of the shaft a small clearance between the inner and outer square tubes should result in negligible wobble.

I had forgotten about the hydraulic drive option suggested by @North Idaho Wolfman - maybe I pushed it aside on purpose because I'm more familiar with and therefore more comfortable fiddling with mechanical stuff.

 

[Paul Allwood]

Has anyone run a standard PTO shaft at 2500 rpm ? Does it work ?

 

[PoTreeBoy]

Has anyone run a standard PTO shaft at 2500 rpm ? Does it work ?

Rear wheel drive cars and trucks have used drive shafts, with u-joints larger than you're using, for years. They regularly exceed 3000 rpm, and some have 2 piece drive shafts with 3 u-joints.

 

[Paul Allwood]

To me it doesn't look that bad.
But if you think it's bad, one trick is try spinning the shaft 180° on the shaft.

I reckon this looks better. This is a second version without the slip joint at 2500 rpm. The length variation is taken up by the fitting on the PTO shaft.

It's still a work in progress.