How to remove collets from a SB Vertical Mill?
I recently purchased a 9x42" South Bend vertical mill. It has the standard quill that has the two set screws on opposite sides to hold your tool holder in.
First off, how do I easily remove a tool from that? Also the machine came with an adapter that mounts into the quill and lets me use a bunch of different sized collets that came with the machine. The adapter uses a big nut to secure the collet up into the adapter. Looks just like an Erickson quick change adapter.
My question is how do you get the damn collets out of the adapter once you take the nut off. I have been using a brass punch and slowly tapping the collet from the side while rotating the spindle around and eventually the collet pops out. Most of the time the tool is also stuck in the collet or I was thinking I could put a hook type tool up into the collet hole and tap straight down. There just is not good way that I can see to hit the collet in a downward direction to make it release, so little of it shows.
I feel stupid doing it this way, there must be a better way. I learned on a drawbar machine and am used to just taping the drawbar and having the collet pop out nice and easy with one light hit.
What am I missing?
Answer to first Q; loosen the set screws (2 total, one on each side). Then stick a straight blade screw driver between the flange of the holder and the spindle face and pry. Be ready to catch it because the holder will pop right out. National taper is barely self holding, not like a MT.
Second Q: You would have to verify which kind of collet chuck. I'm not familiar with Erickson QC. If, OTOH, it is the original SB chuck like in the top of this photo, there isn't much to do but what you describe.
My suggestion would be to get an NMTB 30 taper shank ER collet chuck and adapt it to your machine. I use an ER40/max size 1" collet. ER32 is also a good size with less bulk, largest shank being 3/4" (same as orignal SB). ER collets have a pulling ring in the nose that pulls the collet when unscrewed a few more turns after loosening. (ETM chuck in photo above). How to adapt it, and any other NMTB30 tooling, as below. Use a 1/2" carbide end mill with the corners dubbed off a little.
I bored a 5c E collet to 30 taper. Then use a 1/2 - 13 bolt as a drawbar to retain the toolholder being worked on in the collet. See bolt head at base of DH in photo below.
Yes, my collet attachment looks the the rusty one on the top-right of your photo. I was not sure if it was original to the machine. Interesting to know that it was an original SB part.
I hate to junk it, it works great, has every size collet that I could ever want and a few extras. My only complaint is that the collets can be a pain to get out. Also this is a hobby for me and I hate to put any extra money into the machine to fix something that is not really a big problem. I would rather spend the money on more end mills.
I just could not believe that SB would not have a better way to remove the collets from the machine. I figured I was missing some sort of trick.
And thank you for the photos of modifying standard holders for this machine. I may end up having to do that to make a 1" holder for some of my huge end mills that I inherited.
Stephen Thomas, nice work. When we need to modify a holder for our SB we just grind a new step with a cutoff wheel on the pedestal grinder.
Jacksonpollack, to get around the sticky collet not coming out we smear anti-seize on the collet.
Is there anyway to pop it out with a soft rod from the top? (I am not familiar with the SB Mill, so don't know if this is an option)
or come at if from the bottom with a device like a slide hammer with a "hook" that will go inside the collet grab the top of the collet and gently "pull" it out?
Sadly there is no way to get to the top side. The motor is directly over the collet, no draw bar on these machines.
I would put a hook type tool up into the collet, but my problem is that the tool is normally tightly held in the collet. Everything is very tightly cinched up into the adapter. Perhaps I am over tightening the nut on the adapter when I put the tooling in. I have no idea how tight to go. My wrenches are about 14" long and I put ~20-30 lbs of force on them to tighten everything up when I put the tool in.
The nut comes off easily enough, just the collet can be tough to get to "pop" out of the adapter.
Thank you everyone for the ideas.
I don't have a SB original collet setup in my SB mill, I have an ER40 modified by Stephen, but I don't put anywhere near that much force on the collet nut. It only has a ~7" long wrench that came with it and I put at most 20 lbs on that and don't have any trouble at all.
I have the same collet setup (original) on my South Bend mill. I would hazard a guess that the inside of the taper is scored, and/or you are tightening it too tight. I have a hard time convincing my other users not to crank down with all their might. (Also with the motor, quill, and table locking levers.) Just snug is good enough. I do have a few tool/collet combinations that are harder to separate than others, but a light tap with a brass hammer brings it out.
Last edited by KMoffett; 11-15-2010 at 03:30 PM.