Damaged R8 spindle key(?)

So one of my employees (while I was away) was trying to get the boring head off an R8 adapter. So he had the brilliant idea to load it in the mill (very loosely, just a couple turns of the draw bar), and then use a 15" crescent wrench to try and unscrew the head. Well he twisted it the wrong way (tightening it) and ended up breaking that little key off inside the spindle. I came in the next day, he didn't bring it up and I had no idea, I then went to load a collet in the mill and noticed that it just spun inside. I asked him about it, he got all nervous and said it broke while he was milling, so I was suspicious and checked my security camera and saw what he did. He doesn't work for me anymore. If you're going to be an idiot and make stupid decisions, that's one thing. But I can't tolerate lying. At least be honest.

Anyway, is that little key inside important? I can't imagine it does that much considering how small it was. The only thing I can think of is that little key is just for holding the collet in place while being tightened. Is there any critical application to this piece that I need to get fixed, or can I just deal with the nuisance for now?

I always take those keys out and many others do too. They're a pain in the ass and slow you down loading collets.

I'd inspect the taper pretty close. It might have deformed the area around the key from when it broke.

The feeling around here is mostly ya don't need the dumb thing. As it can cause a burr to be formed in the spindle when it fails and a collet spins. Easy to replace or remove but do check for and damage in the spindle. Personally my BPs both have the key but I'm the only one that uses them.

Along with inspecting the spindle You might want to remove the stub left in the spindle..
Just to prevent it coming out on its own and causing some other havoc..

I was always preached to about not removing the key because it would cause issues while heavy milling. I did all kinds of heavy milling with a B.P. that didn't have a key and never had an issue.

Can't remember the last time I ran a BP with the key in it. Maybe back in tech school a couple decades ago.

Rockwell did not even drill a hole for a key in the R-8 spindle of my mill. I have been using it for 40 years and never had any tooling spin in the spindle and never had a problem removing tooling.

Larry

Gentlemen, the key isn't there so you can pull a heavy cut. It's there to keep the collet from spinning while you screw in the draw bar.

That's good to know. I'm kinda glad he broke it now!

The key helps when R-8 threads are damaged. This happens when the drawbar is backed off to where only a couple of threads are engaged. Then the operator whacks the drawbar. The draw bar and collet threads are then distorted.
My fix was to pull the drawbar, engage the collet/jacobs, tap the nut end on the floor till engagement loosened up. The 'three life drawbar'

Except for the new Bridgeport, there were eight total, there were no keys in the spindle.
John

It's pretty easy to change or remove.
loosen or remove the setscrew on the back of th quill housing that locks the nose piece into th e quill housing.
use a spanner and unscrew the nose piece.
using a ball ended Allen or one ground short enough to fit between the housing threads and the spindle, remove the key.
reinstall the nose piece, realign the set screw dimple, don't over tighten the setscrew in the quill.
run it!

I advocate removing the index key for these reasons:

1 tool changes go quicker when the tool and drawbar are spun when changing tools

2 the index key has no significant torque capacity and shears when to tool slps on the taper.

3 high torque tooling (flycutters , face mills, larger shell mills, larger drill) WILL slip sooner or later)

4 when the tool slips and shears the key the tool shank and the upper tooling register will be damaged by the failed stup scoring the bore often the to point of making tool removal difficult.

5 there is no reason for precise tool indexing on a manual mill spindle

Thus, I conclude the existance of a dog point screw as a tooling index feature in an R8 spindle is all negative with no meaningful positive attributes. Therefore, I advocate the complete removal of the index key dog point setsecre andlocking screw and storing it in an envelope with the machine's spares against the day the machine is sold.

The R8 spindle taper desparately needs a keyed anti-rotation feature like that found on ASA 5.18 #30, 40 and 50 spindles but none was provided. The R8 spindle is the design legacy of a machine originally intended for light detail milling smaller cutters held with a collet; a machine re-purposed to suit present day needs for general milling.

Econdron said:

So one of my employees (while I was away) was trying to get the boring head off an R8 adapter. So he had the brilliant idea to load it in the mill (very loosely, just a couple turns of the draw bar), and then use a 15" crescent wrench to try and unscrew the head. Well he twisted it the wrong way (tightening it) and ended up breaking that little key off inside the spindle. I came in the next day, he didn't bring it up and I had no idea, I then went to load a collet in the mill and noticed that it just spun inside. I asked him about it, he got all nervous and said it broke while he was milling, so I was suspicious and checked my security camera and saw what he did. He doesn't work for me anymore. If you're going to be an idiot and make stupid decisions, that's one thing. But I can't tolerate lying. At least be honest.

Anyway, is that little key inside important? I can't imagine it does that much considering how small it was. The only thing I can think of is that little key is just for holding the collet in place while being tightened. Is there any critical application to this piece that I need to get fixed, or can I just deal with the nuisance for now?

Click to expand...

It doesn't help your problem but I would lie to you too if termination was the end result of something so petty. If fucking up key way was the worst problem I walked into I'd buy my employees dinner.

Teach a person its ok to tell the truth is far more important that teaching a liar they should become a better one so they still have their job.


I agree with not tolerating a liar and you can fire who ever you like.

If the former employee would lie about something so small, what would he say if he crashed your mill and bent the spindle? Oh, I know, he'd just say what the criminals say on CSI when the detectives are trying to get them to confess. That would be SODDIT i.e. "some other dude did it". I would have fired him too.

As to the index key, as mentioned above, it's not really necessary. I leave the one in my mill, well, just because.

countryboy1966 said:

It doesn't help your problem but I would lie to you too if termination was the end result of something so petty. If fucking up key way was the worst problem I walked into I'd buy my employees dinner.

Teach a person its ok to tell the truth is far more important that teaching a liar they should become a better one so they still have their job.


I agree with not tolerating a liar and you can fire who ever you like.

Click to expand...

Breaking the key was not the cause of termination. And I agree 100% about teaching someone not to lie. I'm a firm believe that once a liar, always a liar (same with a thief), unless you are changed by a life-changing event. In my first job I was caught stealing a bottle of soap of all things and I then lied about it. My boss sat me down and had a very stern conversation with me that lying and stealing were unacceptable and would cause much more problems down the road if I continued on this path. He let me know if he caught me again he would fire me. That talk changed my life and taught me what integrity really was. Back to my employee, this wasn't the first time he lied to me. This was the second. The first time I sat him down and had the same conversation. Hopefully termination was enough to teach him something that a talk wouldn't. Even if he crashed the mill and destroyed it, if it was an honest accident and he was honest about it, he would still have his job. Like I said before, I don't tolerate lying (or stealing), but I'm much more understanding on everything else. I need people I can trust working for me.