Chaning table bearing/rails on Arrow 750

[laka]

I think our Arrow 750 is slowly dying. The machine shakes pretty bad when it is interpolating a circle. One quadrant of the circle will have very bad chatter.

Anyway, has anyone changed the bearings or linear way bearings on these machines before? Any help would be great.

Thanks
Jason

[Rick Kight]

Jason

I would first look at the angular contact (thrust) bearings on the motor end of the x axis ball screw. These are not protected very well and tend to get coolant and other nasties in them which in turn causes them to go bad which in turn gives you back lash / noise / vibration etc. We replace these on a regular basis as we have 6 machines. The y-axis is better protected and we have not had much issue with them. We have replaced the rails on a few machines also, they are made by THK and you can buy them direct from THK. The lengths will be different, but just get the closest next longest length. We have found we don't even need to cut them off to the original length. We grease our machines every morning as we run composite material in 4 of our machines and by greasing every day it helps flush the composite (glass) out of the THK bearings. If you decide to get new rails and blocks don't forget to get the rail screw hole plugs. I would look at the x-axis thrust bearing before you do anything with the rails. Also one other note. The x-axis motors are suspect to strange things happening due to the same reason as the thrust bearing, they get coolant in them etc.

Rick

[PinnacleMachine]

Thanks Rick, I too have an Arrow 750 and have similar issues. I'm sure I have to do the Z thrust bearing. Where are you sourcing the thrust bearings from? MAG wants something like $370 for the Z bearing.

JP

[Rick Kight]

JP

Never had to replace the z axis bearing. I don't know if it is different than the x and y due to the fact it carries the weight of the splindle / carrier. We have been getting our bearings frrom MAG also, priced them against some bearing houses and they were competitive, really competitive on spindle bearings

Rick

[laka]

Does anyone have any non-Cincinnati part numbers for these bearings?