Jinma Chipper Feed Roller Connection Problems

[Smalljobs]

Last year I had trouble with the male square on the end of the feed roller shaft. It rounded off so, rather then replace the roller, I welded the drive shaft knuckle square socket right to end of the feed roller. So far so good until this year when the same drive knuckle itself rounded inside its own connection - the one held together with the C-ring.

I just bought a heavy duty driveshaft from Tommy and now have to make another decision:

1) I can cut off the old knuckle connector and replace it with a high strength impact male 1/2" drive. It would be welded to the old feed roller and I realize it is once again a one way street. I might have to slightly shorten Tommy's shaft so that it doesn't bottom out like a "too long" PTO shaft. I think it's all doable.

2) The alternative is to buy another feed roller and just swap out the parts. I'm worried the new feed roller male drive might repeat the same rounding off problem I had with the existing feed roller.

For those of you who have not seen Tommy's high strength shaft it's really robust! FYI, the male female telescoping parts are larger than the old shafts and are therefore not interchangeable. I still have the male part welded to the feed roller and it just spins around inside the new heavy duty one.

Any recommendations?

 

[RonMar]

Option 1 would probably work OK, providing that socket extension will fit properly thru the bearing inner race. If it didn't workout, you always have option 2 to fall back on. I find it unusual that the squared end of the roller shaft would round-off That would imply that it was VERY loose in the first place and able to wear enough that the torque could twist the outer part past the corners of the squared part. The only way I see this hapening is if that end of the Ujoint, like a broken socket, is split allowing it to expand under high torque and rotate around the squared portion. Allowed to continue this would turn both squared parts round pretty quickly

I just got done going thru all of my parts while I re-designed the safety mechanism, as the slider assembly just never would release with the roller under load, which will be exactly when you need it the most. I added a spring loaded belt tensioner idler pully and a kicker mechanism that loosens and then derails the belt and kicks it off the drive pully when the safety bar is pressed all the way down. All my driveshaft parts are still tight with no appreciable wear. In fact, the only issue I have had with the driveshaft is one of the Ujoint pins came out and the drivechaft disassembled itself. But I found all the parts including the pin and it all went right back together. I welded the head of the pins in place. So I wonder what caused yours to round off?

 

[Smalljobs]

Hi Ron,
My driveshaft is the older style with no pins. It's the telescopic shaft with the C-clip retained knuckles (not yokes) at each end. See photo. The first failure was at the roller shaft and it was the roller male that rounded off. I would never have taken the drastic step to weld it if I could have just replaced one end of the telescopic shaft. Since the roller male end was ruined, it made sense to weld it. Yep, see photo where the welded knuckle can no longer pass through the bearing block.

The failure last week was at the other end of the shaft, in fact, it was the knuckle joint on the female half of the shaft. The male drive on the worm gear output is OK but now it's inside that C-clip retained joint.

The new shaft from Tommy has robust yoke "universals" on each end.

The welded half of the old drive shaft will not pass through the bearing. If I cut it off and weld on an impact socket 1/2" male drive, I'll still have the same problem where it cannot pass through the bearing. I don't want to mess up the bearing and the welded coupler is right up against it now.

The more I think about it, I may buy another roller and then I'll have OEM stuff from start to finish and maybe some sort of warranty backup. This way, I'll have the improved driveshaft, new roller, and basically all stock parts from the roller to the worm drive. I'm not hard on this chipper and have no explanation why the roller male failed unless it had poor or no heat treatment right from the factory.

 

[RonMar]

Got it... Mine came with the ujoint shaft... I wasn't aware there was another driveshaft in use...

 

[Smalljobs]

Problem solved: Bought myself two new feed rollers along with pair of new flanged bearings for same as part of May China business trip. Now, I've got plenty of spares.

 

[Brad_Blazer]

Nice. Hopefully some spare knives too.

 

[Smalljobs]

When I imported the chipper I ordered and received spare knives, spare anvil, and spare bolts! I have a lifetime supply of those parts now.

 

[5030]

Who the heck is Tommy and what does his driveshaft look like? I'm having issues with mine (Jinma 8" chipper).

 

[Smalljobs]

Tommy is "Affordable Tractor" and you can easily find them online. The driveshaft is shown along with other Jinma chipper parts.

 

[5030]

Been contemplating taking the old (but still works) drive shaft, lopping off the ends and putting on real greasable u joints with alemite fittings, utilizing the square broached ends to engage the roller and the clutch. In as much as I own a machine shop, it's very doable. I see ther is a u-tube video where someone did just that but there isn't a link to who, what or where.

Mine is the new style with crude U joints already.

BTW. for an FYI, the drive belt is a 3L 40, available at any auto parts store for a couple bucks.

The infeed drive is the weak link far as I can see.

Been running mine behind my M9000 Kubota with 87 PTO ponies. 8" hardwood logs, no issue. I did add a Weasler 3 plate fricton clutch btween the input shaft and the PTO on the tractor and had to add an additional 8" to the base to get the driveshaft to run level, my Kubota is a Class 2 3 point.

I also added air holes to the knife access plate to allow more air into the cutter disc. No need to run it at 540 PTO, I run about half that. ven with an 8" knot, I can't get the tractor up on boost.....