Tool Post choices

  1. steviec_lj

    steviec_lj Rust Welding Professional

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    2,483
    Location:
    Barnetby, N.Lincs
    It’s only taken me two years so far, but I’m finally getting around to “refurbishing” the lathes I picked up.

    A Colchester Student Mk2 Round Head and a Kerry Mk3 Model C.

    Thoughts have currently moved toward tool post choices, and of course tooling. But the choice is quite overwhelming and to be honest a little confusing.

    Both lathes are 6” swing, so I assume the tool posts can be identical, allowing tooling to be moved between them should the need arise.

    But what size tooling and holders should I be looking at? I’m assuming the larger the tooling the stronger it is too?

    All information and guidance is greatly appreciated.
     
  2. R-D-R Forum Supporter

    Messages:
    1,017
    Location:
    Derbyshire - England
    I went with a generic quick change tool post that takes size 250-202 holders. So far proven perfect for my Harrison m250. The holders are cheap and available from many sources. Often there are offers where you can pick them up for £15. And at that price you dont mind modifying them to take dials etc.
     
    Hopefuldave likes this.
  3. Brad93

    Brad93 M J B Engineering

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    6,622
    Location:
    Essex
    You need to match tool holder and tool size to the lathe
     
  4. Dr.Al

    Dr.Al Forum Supporter

    Messages:
    314
    Location:
    Gloucestershire, UK
    Larger tools mean less flexibility when they're stuck out a long way from the tool holder. You can still use small tools if you want with some simple adaptors (like these that I made): the small tools are a lot quicker to grind and the HSS bits are cheaper, but the adaptor means they can stick a long way out without the tool post hitting the tailstock.

    Having identical tool posts will definitely be an advantage as you can never have too many tool holders (I mostly made my own and have 34 of them at the moment). They probably won't be that easy to swap directly as I'd guess the centre-to-top-slide height will be different on the two lathes, so the tool height adjustment will have to be different. I guess if the two are relatively close in centre-to-top-slide height, you could mount one of the tool posts on a carefully sized spacer (or machine a bit off the bottom of one if it isn't hardened) so that the adjustment surface is at the same height relative to centre on both lathes - that would save a lot of time in the long run.

    They're are lots of types of tool posts. Obviously there's the various types of non-quick-change post (e.g. four way) in which you use shims to get to the right height (I used to keep the shims with the tools, so it didn't take that long). A quick-change tool post (QCTP) will save a lot of time and they're frankly brilliant.

    My M250 came with a Dickson tool post, but I didn't get on with it really. The Dickson tool post has very little height adjustment, so if you want to fit (e.g.) a 12 mm tool in a tool post designed for 16 mm tools, you need a shim to raise the tool up by 4 mm. If you want to mount a tool upside down (which I do very often for threading, machining brass etc), you're out of luck.

    I bought a wedge-type Aloris copy and it's fantastic - loads of adjustment height depending on the tool you're fitting (enough that you can mount tools upside down if you want to). The wedge-type (as opposed to piston type) posts pull the tool holder into the tool post and that gives a very consistent and robust hold on the tool holder (it arguably also reduces the tolerance requirements if you make your own holders). The Aloris type holders in general have a big tommy bar on the top, so you don't have to reach for the special Dickson spanner to change tools.

    I'm sure there are lots of other designs as well as the Aloris and Dickson ones, but they're the only ones I've tried (apart from a two different home-made ones for my mini-lathe), so I can't comment on alternatives.

    If you go with the Aloris type, you probably want a BXA size one (also known as 200 series for the copies I think).
     
    Kram likes this.
  5. Seadog

    Seadog Forum Supporter

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    Location:
    NE London - UK
    +1 for the wedge style. They're more expensive but far, far superior to the piston version in terms of rigidity. I think the 200 series is correct. I use the 100 series on my Boxford.
     
  6. MetalMonkey Member

    Messages:
    123
    Location:
    UK
    I've heard good things about the multifix style ones, but never used one - no idea how good the copies are, the orginals are silly money.
     
  7. Hopefuldave Intergalactic pot-mender

    Messages:
    1,151
    Location:
    The Shed of Danger, surrey, England
    I've the choice of a Dickson T2 (too few holders to be that useful) or a Chinesium Cheapy 200/BX size (baker's dozen of holders - not enough!), the cheapy takes 5/8 tools max and JUST goes low enough to get the top of a 5/8 tool on centre height (the Holbrook C13 has quite a tall topslide) - I can measure top of slide to top of tool slot tomorrow if you need?

    Dave H. (the other one)
     
  8. Wedg1e

    Wedg1e They call me Mr. Bodge-angles

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    6,194
    Location:
    Teesside, England
    A Student Mk 2 'round head'...? The two are contradictory. The Mk2 had the squared-off head and tailstock, ribbed on top for extra pleasure :D
     
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