Free 186 More Best Homemade Tools eBook:  
Get 2,000+ tool plans, full site access, and more.

User Tag List

Page 2 of 2 FirstFirst 1 2
Results 11 to 18 of 18

Thread: Centering aid for polygonal stock

  1. #11
    Supporting Member Ralphxyz's Avatar
    Join Date
    Dec 2016
    Posts
    1,564
    Thanks
    2,378
    Thanked 279 Times in 228 Posts

    Ralphxyz's Tools
    3 Jaw in 4 Jaw now that is interesting, thank you!

    Ralph

    186 More Best Homemade Tools eBook

  2. #12
    Supporting Member thehomeengineer's Avatar
    Join Date
    Nov 2017
    Location
    Berkshire UK
    Posts
    705
    Thanks
    720
    Thanked 2,062 Times in 406 Posts

    thehomeengineer's Tools
    This method is great if your 3-Jaw chuck jaws are worn as you can true it up in the 4-Jaw so it again runs concentric once again.
    But, I like this method for eccentric turning. When you have, several components all needing the same offset this can be achieved by adjusting the 4-Jaw to get the 3-Jaw to run out by the required throw/displacement and then each component can be put into the 3-jaw one after another knowing it has to be the same as the previous machined offset.
    One note: when using a 4-Jaw you may need to slow the spindle RPM right down due to the eccentricity of the work. Larger chucks can have weights added as counter balances to overcome this issue.
    The Home Engineer

    2000 Tool Plans

  3. #13
    Supporting Member mklotz's Avatar
    Join Date
    Aug 2015
    Location
    LA, CA, USA
    Posts
    3,434
    Thanks
    357
    Thanked 6,380 Times in 2,117 Posts

    mklotz's Tools
    Mounting a square collet block in the 4jaw or a hexagonal collet block in the 3jaw allows you to use collets without removing whatever chuck is mounted on the lathe.

    This can be particularly handy when the work sequence demands going back and forth between the mill and the lathe.
    ---
    Regards, Marv

    Home Shop Freeware
    https://www.myvirtualnetwork.com/mklotz

  4. The Following User Says Thank You to mklotz For This Useful Post:

    Paul Jones (Feb 7, 2018)

  5. #14
    Supporting Member Ralphxyz's Avatar
    Join Date
    Dec 2016
    Posts
    1,564
    Thanks
    2,378
    Thanked 279 Times in 228 Posts

    Ralphxyz's Tools
    Quote Originally Posted by mklotz View Post
    Mounting a square collet block in the 4jaw or a hexagonal collet block in the 3jaw allows you to use collets without removing whatever chuck is mounted on the lathe.

    This can be particularly handy when the work sequence demands going back and forth between the mill and the lathe.
    Marv, in order to remove/change the stock when using collet blocks you have to remove the collet block at least on the 5C collet block I just received. Mounting the 3 jaw chuck in the 4 jaw avoids this problem.

    Possible you know of some other collet blocks?

    Ralph

  6. #15
    Supporting Member Paul Jones's Avatar
    Join Date
    May 2014
    Location
    Del Mar, California
    Posts
    1,231
    Thanks
    5,810
    Thanked 1,440 Times in 655 Posts

    Paul Jones's Tools
    Marv, The Home Engineer and Ralph,

    I added mandrel mountings to the back of a couple of my smaller 3-Jaw and 4-Jaw chucks for mounting into my larger 6-Jaw Adjust True chuck. I use the smaller chucks for holding diameters too small for the larger chucks (see http://www.homemadetools.net/forum/c...4848#post80696 and http://www.homemadetools.net/forum/c...0262#post72147 ). Another great technique is using a high precision ER32 collet chuck mounted in the 6-Jaw chuck for very precise 2nd operation work (see http://www.homemadetools.net/forum/e...aw-chuck-65548 ). The error in the chuck and collect chuck tend to cancel each other out within typically around 0.0002" to 0.0003" TIR depending on how much time you spend initially making the Adjust Tru adjustments to the 6-jaw chuck.

    Regards,

    Paul

  7. The Following User Says Thank You to Paul Jones For This Useful Post:

    thehomeengineer (Feb 7, 2018)

  8. #16
    Supporting Member mklotz's Avatar
    Join Date
    Aug 2015
    Location
    LA, CA, USA
    Posts
    3,434
    Thanks
    357
    Thanked 6,380 Times in 2,117 Posts

    mklotz's Tools
    Quote Originally Posted by Ralphxyz View Post
    Marv, in order to remove/change the stock when using collet blocks you have to remove the collet block at least on the 5C collet block I just received. Mounting the 3 jaw chuck in the 4 jaw avoids this problem.

    Possible you know of some other collet blocks?

    Ralph
    Collets can handle diameters far smaller than any lathe chuck can close to. If you're going to be doing a lot of collet swapping you really need to build a proper collet chuck for your lathe. That's what I did so the collet-block-in-chuck thing is only used very occasionally.
    ---
    Regards, Marv

    Home Shop Freeware
    https://www.myvirtualnetwork.com/mklotz

  9. #17
    Supporting Member Ralphxyz's Avatar
    Join Date
    Dec 2016
    Posts
    1,564
    Thanks
    2,378
    Thanked 279 Times in 228 Posts

    Ralphxyz's Tools
    I have 5C collets and collet blocks but the block has to be removed from the chuck to change the workpiece.

    I have ER25 collets that use a screw compression nut so these could be mounted in a 3 jaw chuck mounted in a 4 jaw chuck and multiple pieces could be turned
    with the exact same placement easily, of course I do not have any ER25 collet blocks.

    I guess once I learn how to cut threads and turn tapers I will have to make up collet blocks and nuts.

    They are on ebay but kinda expensive for me.

    Ralph

  10. #18
    Supporting Member Toolmaker51's Avatar
    Join Date
    Feb 2016
    Location
    Midwest USA
    Posts
    5,330
    Thanks
    7,041
    Thanked 2,977 Times in 1,892 Posts

    Toolmaker51's Tools
    Quote Originally Posted by thehomeengineer View Post
    Hi mklotz
    Thank you for the explanation all makes sense now.
    I often put a 3-Jaw chuck into the massive 4-Jaw. As I cannot be bothered to get the crane to change the chuck. This is a common practice in the UK. This is also why the chuck keys are normally square on a 3-jaw and hexagon on a 4-jaw. Just put the hex one out of reach (in a cupboard) and then you can’t operate the wrong chuck and have the 3 jaw, job, etc. all crashing out of the 4-j. It is amazing how often you naturally go to the chuck that is, attached to the nose of the lathe spindle and not the one being held.
    Thank you again
    The Home Engineer
    .
    At one employer, our 2 different 16" Clausings often held smaller 3 or 4 jaw chucks for precise reason Marv, thehomeengineer, and RalphXYZ observe. They had no 5C closers. Larger chuck capacity, means proportional increase in minimum size too...Even a passable 3 jaw can be clocked for better concentricity in a 4 jaw - provided the same key socket is used, consistent part size, and jaws are tightened in a uniform manner.
    We made .250 and .400 ⌀ offset 'cams' periodically, combining a 3 and 4 jaw made it quick work.



    186 More Best Homemade Tools eBook
    Sincerely,
    Toolmaker51
    ...we'll learn more by wandering than searching...

  11. The Following User Says Thank You to Toolmaker51 For This Useful Post:

    thehomeengineer (Feb 11, 2018)

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •