Results 1 to 8 of 8

Thread: Parting off

  1. #1
    Should Get Out More icarus1859's Avatar
    Join Date
    Dec 2007
    Location
    Not at home
    Posts
    31,994
    Like
    2,282
    Liked 5,295 in 2,738 posts

    Default Parting off

    Copied from my other post...

    Parting off usually involves blunting my parting off tool at least twice, snagging it and blowing a fuse in the lathe, then saying bollocks to it and getting the hacksaw out.
    The parting off tool either sits there doing nothing, or I apply more speed and pressure and it melts the end off!!
    I hate parting off with a passion on this mini lathe - which is strange, because when I used to use the big Harrison lathe at work I don't ever remember having an issue parting off, it just did it no problem and I'm using the same type of HSS bits as I did then.

    I've read about the right speeds to part off at, I've read which material to use lube and which not to, I've made sure my HSS tool is sharp, etc.
    But it's still the same.

  2. #2
    Should Get Out More Horse's Avatar
    Join Date
    Dec 2007
    Location
    Always Sunny Central Southern England
    Posts
    18,623
    Like
    1,819
    Liked 2,438 in 1,603 posts

    Default Re: Parting off

    I thought this was a flounce thread

  3. The following 3 users liked this useful post by Horse:


  4. #3
    Really Bored
    Join Date
    Jan 2008
    Location
    In the comfy chair
    Posts
    2,485
    Like
    454
    Liked 479 in 240 posts

    Default Re: Parting off

    The guy that taught me lathe work said to make an initial cut then another one slightly to the side, then go back to the original cut and so on. He also added small cup to the end of the tool so it looked a bit like a scoop.

    The main issue I have with my mini lathe is play in the cross-slide allowing the tool to dig in

    Its still a bit hit and miss so I'm interested in what the experts have to say.

  5. #4
    At Work
    Join Date
    Dec 2007
    Location
    Stockport
    Posts
    1,394
    Like
    349
    Liked 768 in 265 posts

    Default Re: Parting off

    I often struggle on my Myford , If I am parting Alloy it cuts great until about 5mm in then I get alloy sticking
    on the cutting edge stopping the cut. Lube helps but I usually do as Crust says and cut another slot to widen
    the cut.
    Brass is ok but steel often jams so I use a hack saw.
    Have tried loads of blades and also have a rear mount parting tool.

  6. #5
    Should Get Out More Big Pete's Avatar
    Join Date
    May 2008
    Location
    Ilkeston
    Posts
    7,937
    Like
    1,637
    Liked 1,116 in 660 posts

    Default Re: Parting off

    It's a royal PITA on small lathes because they don't have the stiffness needed for parting. When I moved up to my Colchester, parting became a whole lot easier. I go as slow as possible, like 25-30 rpm and very gentle on the feed. It's important the tool is at right angles to the work as well. For your lathe I would trim it with the hacksaw and then face off as required, at least for steel.

    That said, if you really want to do it there are a couple of things you can do, one is build a dedicated parting holder from a steel block that bolts to the cross slide, which gets rid of a lot of the stiffness losing interfaces which are present with a normal toolholder setup, the other is to flip the tool upside down and part from the back of the lathe, which loads the sliding parts in a better manner. You can also do both of the above combined together.

  7. #6
    Should Get Out More Ant's Avatar
    Join Date
    Oct 2009
    Location
    Sausagechester
    Posts
    16,635
    Like
    152
    Liked 1,126 in 793 posts

    Default Re: Parting off

    I use carbide tipped tools, but on a regular size lathe. So not sure if that'd improve things for you over HSS, but carbide is my choice over HSS.

  8. #7
    Should Get Out More Big Pete's Avatar
    Join Date
    May 2008
    Location
    Ilkeston
    Posts
    7,937
    Like
    1,637
    Liked 1,116 in 660 posts

    Default Re: Parting off

    carbide is great if the setup is stiff enough, most small lathes aren't, I could never get decent results with carbide on my small lathe, HSS worked fine tho.

  9. #8
    Should Get Out More Pirahna's Avatar
    Join Date
    Jan 2008
    Posts
    5,986
    Like
    777
    Liked 1,240 in 647 posts

    Default Re: Parting off

    I don't remember having any issues but then I'm a time server toolmaker wiv flashy indenture papers and everyfink.

    The last time I used a lathe was 1990.

    If the parting tool is ground correctly you shouldn't have any problems, I trained before carbide tools were widely available. From a dim memory it's easier if you set the tool slightly lower than centre, we're talking microns, and stick a file over the end to remove the nipple. If the tool is a smidge too high it never worked than well.

Go Back to Forum My Forum