another Morbark question

[Altissimus]

...what do you torque the knife bolts to ?? ... Manual provides a torque table but also says to find a good spec through trial and error. 3/4" Fine Thread Grade 8...table says a bit above 400 lbs. ...seems ridiculous and a problem in the making. Guys at Morbark said tight enough so they don't come loose. Right. Been tightening to 150 ft. lbs...

 

[sotc]

Mine are 385 ft pounds of torque but I think they are 1 in coarse. Maybe 7/8

 

[squisher]

That seems incredibly high to me. I think my bandit was 175? Anyone?

 

[BIGTWIG]

Pretty sure my bandit calls for 170-180 as well. There may be different torque specs for drum and disk chippers.

 

[sotc]

Your bandit probably had counter sunk bolts? I had to buy a $500 torque wrench when I got this chipper

 

[Al Smith]

I can't remember if it's fine or coarse thread .I can remember drilling the things out twice on Tom's machine becuse he omitted using never seeze though .That's a job .

 

[Cobleskill]

Never seize sure can save some headaches down the road.

 

[Altissimus]

...around 150 now ... Some time and use will tell
Highly doubt bolts will loosen and back out of the drum.

 

[Altissimus]

I can't remember if it's fine or coarse thread .I can remember drilling the things out twice on Tom's machine becuse he omitted using never seeze though .That's a job .

...EXACTLY what I wish to avoid

 

[Mick!]

Probably not relevant but the book for my 55hp disc chipper is 150.

 

[sotc]

Yeah, hp makes a difference, ours is 135-140 horse.

 

[Altissimus]

When new I actually had them way too tight , then went conservative. Problem is I was using flex bar w cheater and guessing the ft. lbs. Must a guessed wrong. Now accurately torqued with a loaner click type wrench. Will buy my own shortly w a six point impact quality head.

 

[sotc]

I like the click, ezpz

 

[NickfromWI]

Ours are tightened to 180. It's an 8" disc Morbark.


love
nick

 

[GrappleYarder]

...what do you torque the knife bolts to ?? ... ...table says a bit above 400 lbs.

There's a reason that they are 3/4" grade-8, because that's the torque they want. We torque the 420lb as per the table for our 2400xl. Knife failures are not nice...

 

[sotc]

Looks like bearing failure caused knife failure?

 

[Cobleskill]

Ugly.

 

[treebilly]

Looks like bearing failure caused knife failure?

Either way that's not pretty. Looks expensive also

 

[Merle Nelson]

No place to hide, no place to run.

Probably all over before most people could react.

 

[sotc]

Yeah, Morbark is proud of those drums!

 

[CurSedVoyce]

Bad... very very bad

 

[GrappleYarder]

This is a parts chipper I bought thinking I might rebuild it. I'd say a knife holder broke loose, knife meet anvil and things went south from there. Blew the pillow bearing caps on both sides and the top guarding was gone. Must have been the scariest thing ever...

 

[sotc]

I bet

 

[Altissimus]

...I wonder if a big piece of Quartzite or mebbee a piece of chain found it's way into the infeed...