Smooth shaft Keyed PTO backing off / un-hooking????

Dave M7040 · Dec 26, 2015

I once had a blower with the same design you have.
I used a special Loctite product called 620 stud and bearing mount.
It takes up all the slop, however slight which leads to the set screw working loose.
The loctitie is thick and goes between the major parts.
Amazon.com: LOCTITE 38652 620 High Temperature Bearing Mount Bottle - 36 ml: Automotive
Dave M7040

Farmer495 · Dec 26, 2015

If the blower has been run with the shaft loose, it will never stay tight (hence why it walks off)

I'd be carefully drilling a cross bolt with a nice sharp bit and lots of oil.

Barring that, I'd lock tight the screw and tack weld the yoke on the shaft. I'd hate to do that...but sometimes "wrong" repairs are the only one that will work cheaply.

Steave · Dec 26, 2015

Dave M7040 said:
I once had a blower with the same design you have.
I used a special Loctite product called 620 stud and bearing mount.
It takes up all the slop, however slight which leads to the set screw working loose.
The loctitie is thick and goes between the major parts.
Amazon.com: LOCTITE 38652 620 High Temperature Bearing Mount Bottle - 36 ml: Automotive
Dave M7040

Now this would be the ticket if it does everything it says. I see it has a 5 star review rating (if that means anything). Glad to hear from somebody that has used it. How long does it take to set up and be back in operation. We used some sort of stuff (not locktite) on pulleys and shafts that were slightly loose it would hold for a while but would fail again (1-2 months) usually or before. It was mainly used on shafts with a gear or chain sprocket. I would think the forces would be the same as your situation? Never tried the locktite and the stuff we used didn't take 580 degree heat to release. Sounds pretty tough. I'm thinking for mounting a bearing to a shaft this would work great but a collar to a shaft it would have to be real tough. might be worth trying at $27.

ruffdog · Dec 26, 2015

If the shaft is hardened, no set screw will bite into it and hold. Take a small grinder and grind a flat right where the set screw needs to bite the shaft. Use black magic marker to blacken the shaft and then install the yolk and tighten the screw. Then, you should have a mark to locate the small flat. A good file may even be hard enough to cut the hard shaft. You just want a divot so the shaft can't come off without loosening the set screw. You can use a round file or the edge of a large file.

Dave M7040 · Dec 27, 2015

Steave said:
Now this would be the ticket if it does everything it says. I see it has a 5 star review rating (if that means anything). Glad to hear from somebody that has used it. How long does it take to set up and be back in operation. We used some sort of stuff (not locktite) on pulleys and shafts that were slightly loose it would hold for a while but would fail again (1-2 months) usually or before. It was mainly used on shafts with a gear or chain sprocket. I would think the forces would be the same as your situation? Never tried the locktite and the stuff we used didn't take 580 degree heat to release. Sounds pretty tough. I'm thinking for mounting a bearing to a shaft this would work great but a collar to a shaft it would have to be real tough. might be worth trying at $27.

Here is a link to the technical data sheet.
Cure time is a max of 24 hours but if faster cure is desired then an activator product can be applied to the parts first.
http://tds.henkel.com/tds5/docs/620-EN.PDF
I would take the time to clean all rust and crud off the parts before using.
If not using the activator I would wrap electrical tape around both ends of the parts to keep air out since the curing is anerobic.
It can deal with up to a 15 thousand of an inch gap ie. .015 which is a pretty sloppy fit!
I doubt the shaft is hardened but agree grinding or filing a flat spot for the set screw to bear against would be prudent.
Dave M7040

Steave · Dec 27, 2015

NJDiverDan to me it would be worth the chance on using the Locktite that Dave M7040 has provided information on. It's a little pricey and I don't mind helping other people spend their money.

so give it a try and let us know

. Some people get a chuckle when you mention stuff like JB Weld for repairs but I believe all farm repair shops need a room full of JB Weld...Locktite...Gorilla Glue...Duct Tape. Enjoyed reading everybody's idea and I've tried most of them.

NJDiverDan · Dec 28, 2015

Well I am debating on the loc-tite vs drilling a cross bolt. I like the idea of being able to remove the yoke easily but in realality I have never removed the implement side of any of my PTO shafts.

Going to get some on order tomorrow.

Steave · Dec 28, 2015

Know what you mean about trying to decide. One thing it is removable, any propane tank will easily heat it up to temp's necessary for removing it and won't hurt the shaft or the collar. You could protect the seal in the gear box from excess heat while removing but chances are the reason for removing the collar would be to repair the gearbox. . . and you would replace the seal anyway. I'm also going to add the locktite to my arsenal of repair junk. Good luck let us know how it holds up. I'm assuming from your location you'll have the chance to try it out soon.

Fallon · Dec 28, 2015

I unhook both sides of my flail mower PTO when unhooking a lot. PTO shaft has a sheer pin in it too, not that you need it (belts on the flail go before a sheer pin would). Makes unhooking a bit easier, but not much.

Make sure you have a proper 2ndary attachment method and/or sheer pin setup if you cross-drill. My post hole digger has a cross-pin as a connector & sheer pin comming out of the gear box. There is also a grove on the output shaft & a set screw that goes into that grove. So when the sheer pin breaks, the set screw will keep the PTO shaft attached to the gearbox despite the PTO spinning ON the shaft not spinning the shaft. Without that set screw & grove, if things broke it's probable I'd have a 30hp flailing PTO shaft destroying my implement & back of my tractor.

aczlan · Dec 28, 2015

Fallon said:
I unhook both sides of my flail mower PTO when unhooking a lot. PTO shaft has a sheer pin in it too, not that you need it (belts on the flail go before a sheer pin would). Makes unhooking a bit easier, but not much.

Make sure you have a proper 2ndary attachment method and/or sheer pin setup if you cross-drill. My post hole digger has a cross-pin as a connector & sheer pin comming out of the gear box. There is also a grove on the output shaft & a set screw that goes into that grove. So when the sheer pin breaks, the set screw will keep the PTO shaft attached to the gearbox despite the PTO spinning ON the shaft not spinning the shaft. Without that set screw & grove, if things broke it's probable I'd have a 30hp flailing PTO shaft destroying my implement & back of my tractor.

In this case, there is a keyed shaft to handle rotational torque. The cross pin is just a backup to make sure it stays put.

Aaron Z