Help With AStuck Collet in Bridgeport

[lafngrvy]

I have a collet stuck in the used Bridgeport mill I just purchased.

Any suggestions on how to get it out?

Thanks,
Steve

[JCHannum]

That doesn't usually happen.
Is it rusted in, as opposed to just stuck? That can happen if it has been in there for a while, especially in an unheated storage area.
Try pouring a good penetrant down the spindle, and let it soak for a while. I prefer Kroil, then Liquid Wrench as opposed to WD40 for this kind of thing.
Be careful when beating it out with a persuader, as you don't want to mushroom the end, and not be able to get that out.

[spope14]

This happens in my shop now and then. Reasons:

1. The keyway is too shallow for the spindle key - does not take much. The key may have been improperly adjusted in a repair or something.

2. The key in the spindle is buggered.

Other reasons occur.

Did the collett come out somewhat/

Here are solutions.
1. When removing the tools in the first place, loosen the drawbar out until just a few threads are engaged in the collett. Hit the top of the drawbar with a soft face (brass) hammer. Threads must still be in the collett. This breaks the taper seal, the collett drops a bit, the tool falls out, then unscrew the collett the rest of the way.

If still stuck - either in the taper or just a bit out:

1. Make a piece longer than the head of the machine - 7/16 diameter, 7/16 - 20 thread on the end for about 1 inch. Remove the drawbar. Screw this new piece in the collett thread. About 8 inches out of the top of the machine head is good for your new bar. Tap out with a brass hammer on top of the bar you made. Do not mash it out. Should take mild to moderate tapping. A penetrent oil also helps at firat, but remember, after adding penetrant, you should oil things back up proper again.

Check the spindle key for buggering, check fit of colletts in the head to begin with, should not have to be forced.

Check your removed collett for buggering on the keyway.

If you need to adjust your keyway back, let me know, I can write this out.

[Stepside]

It is possible that the collet was tightened in place without the pin in the groove. This is a nasty problem as it has now cut itself a new groove. If so I would then want to remove the pin before I removed the collet. If I remember correctly the pin is a 1/4-32 custom set screw. I have seen the pin problem only once in 30+ years of using a B'port mill.

[bpsbtoolman]

When I got my Bridgeport it did not appear to have a key. With my finger I could feel something that felt like a key. Took a piece of model clay and made an impresion of the area. It showed a broken key but also a small piece of the spindle broken out next to the key. ( bummer!!!) Decided then and there to take what was left of the key and throw it away.
It may be your key sheared and is locking your collet. By forcing down you may damage your spindle. Here is what I would do. Lower the spindle a few inches. On the back of the spindle is a set screw that you loosen or take out. Them mark the lower removeable part with a felt marker. You can then make up a pin spanner wrench to remove the right hand threaded lower piece. Now on the back is a set screw you take out and a second set screw that has the key on it. Take it out and I would throw it away. Now put the removed part back and line it up with the felt maked line. Now try a moderate down pressure on the draw bar. If it doesn't come out and you still have an end mill it you may try to rotate it with vice grips to try to aline the collet key with the removed key hole so that it releases the maybe chiped off piece.
Myself and a lot of guys operate their BPs without the key. Remember the key is not ment to stop rotation, only to aid in tightning the drawbar. I have mentioed this several times before but I lever my collets loose and don't hammer them out.
Walt

[backinc]

There are several reasons why a collet may get stuck. Rust is very common if the machine has been sitting for awhile, too much oil on the collet will do the same thing (it causes the collet to have a perfect vaccuum fit) and the third thing that can happen is that the collet spun. Whatever the case the best way to remove it is to get a lon piece of aluminum that is about 3/4" dia and put it in place of the drawbar. Here is where most people get scared. Grab the largest hammer that you have. By this I mean that if you have a 12 or 15 lb sledge then this should be your choice. Give the aluminum one solid whack. Hitting it several times with a small hammer may cause more damage to the spindle than a single hit from a larger weight. Your collet should now be free. At this point in time you should check the spindle to make sure that there are no burrs inside that will cause problems later. If there are just use light sandy-paper to remove them. You will need to remove the key as suggested before and make sure that it is ok. If not check the thread pitch and dia (they vary depending on where your machine was made, and yes not all Bports are made in USA). Do not call and try to order a replacment spindle key. Instead order a box of them from MSC or anothe vender. They are called dog point set screws and they run about $15 for 100 compaired to $9 each for the specific part number from the manufacturer for the mill. I just went through the same procedure and I am sure that it will happen again.

P.S. The key that goes in the spindle IS to stop the collet from spinning in the spindle, not just to help you tighten the collet.

[SGW]

Instead of the "bigger hammer" approach, if the collet greater or equal to 7/16", how about taking a 7/16"-24 threaded rod and a circular disk with a recess that will just fit over the end of the collet, with a 7/16" hole in the middle, thread the rod UP into the collet, put on the disk, put a nut on the rod, and pull the collet out by cranking on the nut?

If the collet is 3/8", you could pass a 3/8" rod with a nut on top right down through the collet and out the bottom, and do the same thing. Smaller than 3/8", the rod might not be strong enough.

[This message has been edited by SGW (edited 06-08-2002).]

[Thrud]

SGW:

A bigger hammer scares me too. Brinelling precision spindle bearings from whacking the drawbar is not a good idea anytime. That is a excellent excuse to have a power drawbar attachment on the B'port.

Dave

[This message has been edited by Thrud (edited 06-09-2002).]

[JCHannum]

I second that. SGW's idea of making a puller sounds good to me.

[bpsbtoolman]

Hi Thurd, where do you get the power drawbar you mentioned. What does it look like.
Walt