Cincinnati Arrow 750 Spindle Removal

Hello all,

My buddy just bought a Arrow 750 for cheap, screws seem awesome, can move 0.0001 and back and watch indicator move the same, pretty sweet. But the Spindle bearings sound horrible and have about 0.001 runout. I believe a crash took out the bearings. I have the drawings but not sure exactly how to get the spindle out. Seems like you have to remove the bearing retainer plate on the bottom then get the pulley off to slide everything out the bottom. Not sure how to remove the pulley. Does the belleville retainer at the top unscrew? Held in with set screws? roll pin? All my speculations are by looking at the drawing only. If some one could give me the basic procedure that would be great.

Thanks all

Dear TurboStew,

We have just removed the spindle from our machine (Arrow 500, Acramatic A2100 control) about 2 weeks ago. Procedure is the same for the arrow 1000- I'll upload some photos on this tomorrow for your reference. Its pretty straight forward (steps may not be 100% accurate- this is as i remember)-

1. Remove Z axis cover
2. Remove drawbar actuating cylinder assembly from on top (should be a triple cylinder with three incoming hoses, or a manifold at the cylinders). This is held on a plate, which is bolted onto the Z axis casting with 4 bolts- remove these 4 bolts and the full plate with cylinder assembly comes off (along with proximities if i remember correctly) note: we disconnected the proximities and removed the full assembly.
3. loosen/remove spindle motor bolts to release the belt tension (4 bolts, then slide the motor towards the spindle). Note: I removed the full motor, as I was cleaning up everything and also changing all the linear guides on all axes
4. remove the bolts from below and jack the spindle down.

From what I understand, step 2 is optional. We removed it anyway as we are rebuilding the full machine. Changing all guides, cleaning up the mess and putting it back together. Our screws were good too. My spindle cone was in bad condition and have sent it for a regrind at the same time bearing replacement.

I bought this machine recently and it reached my factory about 4 weeks ago. We powered it up and got it running, and then decided on a full rebuild as the axes were noisy.

Best of luck!

Thanks jaideepshinh,

I think your instructions might be for the cartridge spindle. Ours is not. I'm pretty sure the pulley has to come off. Ours has the Emerson Control Techniques FNC control. Here is a drawing of our spindle:

We have the cover off and can see what is going on now. Seems the spindle pulley is loose, like the pulley nut is loose. We can rock the pulley a little and it runs out enough to easily see with the eye. Seems the nut has been loose for a while and wore out the pulley ID. Anyone seen this? Does the belleville retainer at the top unscrew? Or just held in with the set screws? Hoping spindle is hardened and pulley is soft!

It looks like a 2 piece spindle, I have not seen Cinci use this type of spindle. Do you have the service manual, it should tell you how to take it apart. I think the center nut has backed off and the key is bad. Did you make the check for the bearing preload that we talked about? What did you find??

Mike CNC Machine Services INC | Cincinnati Milacron MachinesCNC Machine Services

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Originally Posted by meckardt55

It looks like a 2 piece spindle, I have not seen Cinci use this type of spindle. Do you have the service manual, it should tell you how to take it apart. I think the center nut has backed off and the key is bad. Did you make the check for the bearing preload that we talked about? What did you find??

Mike CNC Machine Services INC | Cincinnati Milacron MachinesCNC Machine Services

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So we made some special tools to compress spring stack for removal and tightened the pulley nut to spec. So much better now. A little hum from the belts I believe. No radial runout at all measured inside the tool holder taper. We did the spindle axial play check with an indicator on the spindle snout and hit the tool release button. We got 0.005 inches (5 thou). Sound excessive? Can we preload the bearings more? How? We don't have a service manual. We have operators manual and a parts manual.