Key missing in bridgeport spindle?

Well, I've finally got the shop in the shape where I can actually start making some chips. Today I went to cut some flats on the end of 13"x1.485" shaft for a microscope boom stand. When I went to change collets, I noticed that there doesn't seem to be any locating pin or key up in the spindle to locate the collet! I'm not sure how I missed this before, but it seems I did. Any clues as to how to replace this missing pin/key?

John

I am no expert, but I don't think the key does all that much. I use a mill all the time and it doesn't have one. I wouldn't worry about replacing it, more trouble than its worth. I remember there was a discussion on this very subject not to long ago on the HSM site.

Scott

The key is a PITA. It has no significant torque capacity and it interferes with quick tool changes. If for some reason you spin a tool, the key shears off and hangs up sideways making it difficult to extract the tooling.

Many shops remove the spindle key from their R-8 turret mills permanently. There aint one in mine.

the only thing I like about the key is if a chip gets cought in the collet threads. There is no way to hold collet if draw bar gets jammed up.

John,

This was covered in the BP section not more that 2 months ago.

JR

My secondhand Excello 602 is also missing this key. I was thinking I should replace it, but now I guess I won't.

-Gord

One more vote for not replacing the key.

Paul G

The key is there to keep the collet from spinning when it is tightened up.

It has the same purpose as the key on a 5C collet holder. It allows the collet to pull up without spinning.Fortunatley, most mills have enough friction when the collet is being tightended that it pulls up anyway without spinning.

On my Series 2 the key is a small allen head with a tip on it.Its like an 1/8 setcrew or something like that. Its been awhile since I've had to change it so my memory fails me for the exact size.

My other mill has been running a couple of years without one. Never seemed to be a problem as you simply hold the collet with one hand and use the other to tighten up the drawbar.

The Series 2 has a powerdraw on it. A key may be a bit more cirtical on it as the drawbar pulls it up in several seconds.

If you can tighten up the collet without it, I cant see worrying too much about it...

Thanks for the feedback guys. As always, good information here. I had scanned the BP forum and didn't see it mentioned, but I haven't read every thread. It looks as though I won't worry about it as it didn't seem to slip when I was cutting some 300 series stainless yesterday with a 1" endmill. I wansn't taking a huge bite, but just a slow, steady feed. I was getting a bit of noise out of the head though (in back gear) that's not there under no load conditions. Is this normal, or are there perhaps bearing issues I wasn't aware of?

Thanks again.

John

My BPT mill spindle key seemes to have worn down. I have been using the mill for months now with no key and its MUCH less of a hassle because I don't have to worry about aligning the collets and even better - collets don't get jammed any more.

Its not as though we have 25HP and 10,000rpm.