Announcement

Collapse
No announcement yet.

concentric brand live center

Collapse
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • concentric brand live center

    I picked up a Concentric live center on e bay. From what I gather, maintenance consists of pumping grease in the tailstock end. This is threaded, maybe I can find a zirc fitting that fits. Will a grease gun push the old grease out the other end? There doesn't appear any hole or path for the grease to come out, unless it just oozes out around the circumference of the rotating center? thanks for any advice!

  • #2
    Hi,

    I can't say about that specific brand, but yeah, the excess grease will push out from around point and seal. Just be careful and don't over grease the thing. They will over heat during use. And slow to medium speeds are recommended. No 3000+ rpms please.
    If you think you understand what is going on, you haven't been paying attention.

    Comment


    • #3
      hi dalee, thanks for the caution on overgreasing. I have a Logan 200, top speed as I recall is near 1500 rpm.

      Comment


      • #4
        Over greasing will likely make it run hotter. It should be greased from factory I would think..

        Comment


        • #5
          Originally posted by dalee100 View Post
          Just be careful and don't over grease the thing.
          Not a chance if it's anything like mine. I've wasted more grease on that thing than I've managed to get into it. It's almost impossible to get any grease to come out of the front by pumping, but some excess will ooze out the front when you next use it. You can tell if you managed to get some in. Push the ball bearing at the back in, and the new grease you just put in will shoot back out. Now you have to put some new grease in again I haven't used mine a lot, so it's still fairly tight. A more used one might be easier to grease. Someone on PM said they remove the front circlip to grease it, but my pliers wouldn't grab it.

          I've tried three different grease guns with it, including two "push" types. I'm now using a Dualco, which works better than the other two.I think they no longer tell you which grease to use in the instructions, only that they they sell a special grease for it. It's Monolec 4701. Let us know if you find a good way to grease it.


          Originally posted by 754 View Post
          Over greasing will likely make it run hotter. It should be greased from factory I would think..
          Daily greasing is recommended in the instructions. Excess oozes out as it expands, so I don't think you could overdo it.

          Comment


          • #6
            I wouldn't put a zerk in the rear of the center - on mine it gets a fair amount of pressure from the tailstock quill screw to pop it out of the taper. I keep a SHCS in it instead (this also makes it long enough that the screw can actually hit it...)

            Comment


            • #7
              Originally posted by pinstripe View Post
              Let us know if you find a good way to grease it.
              I looked at the posts over on PM, someone there typed in the mfg's instructions, which mention a Z-737 grease nozzle. if you google "alemite z737" you will see a picture of what that looks like. I turned up a copy from 1/2 inch round steel. the business end is about 0.16 inch to fit in the hole in the tailstock end of the live center. the other end of the nozzle is drilled Q and threaded 1/8 x 27 NPT to fit my little grip grease gun. the throughhole is 3/32. it worked fine, a few pumps had old grease oozing out around the center.

              Comment


              • #8
                What type of center is it? The low-profile spring-type needle bearing centers by Concentric use oil, not grease. Higher speed use requires lighter oils.

                Edit: This comment is incorrect. See post #15
                Last edited by chipmaker4130; 12-06-2019, 02:12 PM.

                Comment


                • #9
                  It's a revolving center..

                  Comment


                  • #10
                    Originally posted by dalee100 View Post
                    Hi,

                    I can't say about that specific brand, but yeah, the excess grease will push out from around point and seal. Just be careful and don't over grease the thing. They will over heat during use. And slow to medium speeds are recommended. No 3000+ rpms please.
                    If your pumping grease into a bearing and it's pushing out the other end then it's more than likely packed full. I don't know how you could do anything other than over grease it by doing that.
                    I made a thing to pump grease into shielded bearings, it works great. The excess grease will will just push out when the bearing is put to use.
                    If your worried about generating excess heat run it slow off and on and let the excess push out.

                    JL..........
                    Last edited by JoeLee; 12-06-2019, 12:33 AM.

                    Comment


                    • #11
                      Originally posted by gmax137 View Post
                      I looked at the posts over on PM, someone there typed in the mfg's instructions, which mention a Z-737 grease nozzle. if you google "alemite z737" you will see a picture of what that looks like. I turned up a copy from 1/2 inch round steel. the business end is about 0.16 inch to fit in the hole in the tailstock end of the live center. the other end of the nozzle is drilled Q and threaded 1/8 x 27 NPT to fit my little grip grease gun. the throughhole is 3/32. it worked fine, a few pumps had old grease oozing out around the center.
                      Excellent. I get a reasonable seal now, but I can't push grease all the way through. I suspect it will loosen up with a bit more use.


                      Originally posted by JoeLee View Post
                      If your worried about generating excess heat run it slow off and on and let the excess push out.
                      That's exactly what happens with this center. The grease oozes out the front as it warms up. It may be technically possible to over-grease it, but it won't stay in that state for long. The manufacturer says to grease it until it starts coming out the front. That will also help to flush out any coolant that may have found its way past the front seal.

                      Comment


                      • #12
                        When ever possible on a shielded bearing that I'm replacing or cleaning I always try to replace the metal shield with a rubber seal.
                        I have saved a lot of rubber seals from old bearings for this purpose if they are in good shape.

                        JL..............

                        Comment


                        • #13
                          These ones take grease. See https://www.concentrictool.com/live-...l-information/

                          Special lubricating grease required for Concentric centers:
                          14.5 oz. tube, part no. 17991
                          Heavy duty grease gun, part no. 17990
                          Low profile grease gun nozzle – # Z737, part no. 17993

                          The "special" grease is Monolec 4701. It's in the older instruction sheets.

                          Comment


                          • #14
                            These are the instructions that came with mine.


                            Click image for larger version

Name:	Front.jpg
Views:	50
Size:	46.0 KB
ID:	1841970

                            Click image for larger version

Name:	Back.jpg
Views:	50
Size:	60.5 KB
ID:	1841971

                            Comment


                            • #15
                              Originally posted by chipmaker4130

                              Thanks, but all live centers are revolving centers. The difference I was trying to point out is that while ball bearings are usually ok with grease, the needle bearing construction of the low-profile center made by Concentric requires oil. This is the one I was referring to: https://www.concentrictool.com/
                              Actually the way we were taught, a solid centre mounted in headstock, to drive work is a live centre. Same center mounted in tailstock is a dead center.
                              I didn't jump in and point it out at first, but some may not be aware of that.

                              Comment

                              Working...
                              X