Video: How to Change a Collet Alignment Screw

Welcome to MSC, this is Larry the Machinery Guy. The purpose of this video is to show you how to change the collet alignment screw in your milling machine. It's a real simple process, it could save you a lot of money by calling in a service tech. Watch the video we're gonna make it as simple as possible for you.

The tools you're going to need: you're going to need a spanner wrench. A set of feeler gauges, allen key, and an R8 collet. The purpose of that collet alignment screw is to keep the collet from turning when you hit the draw bar that's on top of the machine. So sometimes they get smashed, they need adjustment, whatever happens. So, what we're going to do is take you through that process of how to change that.

First thing we're going to do, is there's a set screw all the way in the back of the quill, you've got to remove that because if you try not to remove that and remove this nose cap that holds the spindle in place, you're going to mess up those threads and that's not a good thing.

Next what we're going to do, is going to take our spanner wrench and just loosen that cap up, remove the cap, be careful very fine thread you may struggle a little bit putting it back on, but just take your time. Patience is always nice. So we have the cap off there and that exposes our collet alignment screw on the spindle itself. Now, be advised when I remove that screw, most of the time they're right-handed threads sometimes they're left, so just be careful when you start that process.

Then we’re going to move these two set screws that are in here, and the reason you have two is one is a collet alignment screw the other one is just the backup. Then we'll move that collet alignment screw and what happens is, this collet alignment screw you see, I know it's real tiny, but has a shoulder on, it has it turn down diameter, and that fits in that slot in that R8 collet.

So now what we're going to do, is just reverse the process. I'm going to put that little set screw back in, make sure everything's nice and clean. Now I'm going to put my hand up in the spindle get the collet alignment screw started in here, I'm just going to let that protrude a little bit before I set the exact positioning of that. And you can feel it coming through or protruding out on the inside. We’re going to take that collet again and slip in there and it's holding everything in there nice and tight.

Now we're going to do, is put that backup pin in, the same thing. Once I get it started, I can run in there with that allen key, you don't have to worry about stripping anything out. And you want to make sure that's nice and tight.

Last thing we have to do, reverse the process. Go in there and we're going to put this retainer cap in, tighten that up. Get our spanner wrench; make sure that's tight. Check our clearance; make sure we have at least six thousandths or a little more, or a little less. Then we're going to put that other set screw that holds everything together. There you go.

Thank you again for watching the MSC video, we appreciate your business, and you have a great day.