Arrow 750 finish trouble Please help

[overflowmachine]

Hey guys I have just picked up an arrow 750 with a 2100 control. I am having serious finish trouble. I did test cuts before buying this machine and never saw anything like this. The spindle sounds great at all RPM's I have done several tests and believe the cartridge is sound. The belts are nearly new and properly adjusted. Things sound fine until the tool engages the work piece. At this point it vibrates and shows right up in the finishes. While plunging with an end mill, drill or spot drill it chatters. At this point I am thinking my draw bar is not holding tight enough. Any thoughts on this would be appreciated. I know this draw bar uses spring washers. I do not have any assembly drawings. Has anyone replaced these before? How tough is it to do? Were can I get part numbers and replacement washers? Any help would be great. I need to be making chips with this machine now !

[scudzuki]

Check your pull studs?

The symptom chattering when plunging with a drill suggests that something is preventing the taper from seating, as drilling pressure would effectively increase the spring pressure.

Put a toolholder in the spindle with a large diameter long tool and grab the end with your hand. Wiggle it back and forth, is the any slop at all?

I discovered on my Arrow 500 (after changing the drawbar springs) that in its past life someone had worked on the spindle and left the big spanner nut that preloade the bearings loose by a small fraction then bent the tab on the locking washer. It is supposed to be torqued to 80 ft/lbs! I was not having problems drilling, though, just side milling, which leads me to believe the pullstuds you are using may be too long? Forgive me for suggesting this if you've checked already.

I sourced my bellevilles from McMaster, part number 96445k437

McMaster-Carr

You need 18 pcs.

They can also be had from Key Bellevilles, maybe better quality, maybe cheaper. I got them overnight from McMaster for no extra charge so I went that way.

Disc Springs, Belleville Springs & Washers by Key Bellevilles, Inc.™

I have a set of 6000 RPM spindle bearings for sale if you need them, bought 'em from MAG and turns out I didn't need them. $550 shipped.

Joe

[underthetire]

So, it cut ok before you moved it? I'd say it needs to be leveled and trammed. I'd bet some pads aren't on the ground.

[PinnacleMachine]

Are your tools loaded into the TC the correct way - dimple in.

JP