Chipper anvil bolt shearing

[lbj]

I have a bandit 90 and the bolts are shearing or snapping it looks like the blade is hitting the anvil . Did adjust anvil with more clearance and the bearings are only about 1 year old had a friend do them . The previous owner had a blade come loose and they repaired it is it possible that it is no longer balanced ? When changing blades the holes are a little egg shaded but i torque them down and they do not appear to be moving . It seems like this happening more often .Any advise is appreciated

 

[Eq Broker]

To check the balance of the disc, spin the disc by hand and then let go. If it comes to a complete stop, you should be ok. If it rocks back and forth, it could be out of balance. You can also run the chipper and see if there's a lot of vibration. Simply put your hand on the chipper and feel for vibration and I would recommend doing this at low, medium, and high RPM's. You'll more than likely feel it at low and medium RPM's. You may need to take the chipper, a new set of knives and bolts to a machine shop and they may have to fill and redrill the oblonged holes.

Hope this helps!

Dave
Global Equipment Exporters
770-420-6400

 

[cookies]

is there play in the shaft the blades attach too? Im thinking you have damaged bearings that allow deflection under a load when material gets behind the head putting a load on the back side that then the shaft is pushing forward enough to contact the anvil. im just throwing out a guess here but are the ejected chips larger than they used to be? I understand a friend replaced the bearings but sometimes $hlT happens even to good people!

 

[lbj]

Thanks for the reply’s since it is a direct drive have not taken belts off to check disc for play but did take the bearing cover off and ran machine it definitely has a wobble in the shaft and the pervious owner had a blade come loose the disc is in rough shape and when the machine is tuned off the disc does rock back and forth before stopping . Been thinking about upgrading vs fixing machine . Did some Leyland pruning and some of the chips were 2 feet long

 

[lbj]

To check the balance of the disc, spin the disc by hand and then let go. If it comes to a complete stop, you should be ok. If it rocks back and forth, it could be out of balance. You can also run the chipper and see if there's a lot of vibration. Simply put your hand on the chipper and feel for vibration and I would recommend doing this at low, medium, and high RPM's. You'll more than likely feel it at low and medium RPM's. You may need to take the chipper, a new set of knives and bolts to a machine shop and they may have to fill and redrill the oblonged holes.

Hope this helps!

Dave
Global Equipment Exporters
770-420-6400

I’m looking at another chipper i spun the disc it almost stoped then went backwards and stopped should I do anything else to check balance ? It’s just over 900 hours and clean also the disc is not scared up

 

[mrhemihead]

I used the method that Eq Broker suggested.

Spin up the disk/drum to operating rpm, disengage the clutch with a hand resting near the disk/drum bearings.
Any vibration while it spins down to a stop is a red flag in my book. Also listen for growling or binding from the bearings.

Worn bearings would not be a deal breaker, but they are not cheap and can be a PITA to replace. $1K off the price for this maintenance item.

 

[Huskybill]

What grade bolts? In shear what size bolts? In the machinists handbook there’s a section for the bolts in shear.