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  1. #1
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    Default How to turn rounded ends accurately?

    I'm turning up a great many spindles as very long mushrooms, think Shitake style. They are long, such as 200mm

    The heads are obviously round. Im getting very favourable accuracy with the measurements and thicknesses. Once I part off both ends, how to I finish the top so it's spherical/rounded and smooth?

    I've been doing it by hand on my big lathe disk sander, but there must be an easier way! I was thinking of a 125mm disk sander with an ultra-soft underpad. I just stuff the end in the middle and the conforming pad rounds it up...but this seems too technical.

    Any idea friends?

    (many thanks to for his past insistence on beads and coves, beads and coves, grasshopper!)

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  3. #2
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    May 2007
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    Default

    I'll wait for 's words of wisdom
    regards
    Nick
    veni, vidi,
    tornavi
    Without wood it's just ...

  4. #3
    Join Date
    Jul 2001
    Location
    South Australia
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    650

    Default

    How about driving the blank with in a chuck, backing off the tailstock, reducing the speed, and supporting the work with your left hand and part off leaving a small nib (3 to 4 mm) that could be hand sanded.

    I find it much easier to get a good shape off the lathe, rather than try to blend it in on a disc sander.

    This method requires a slightly longer blank to allow for the waste in the chuck.

    I am assuming that your very long spindles are 200mm and not a misprint. (2000mm?).

    Hope this helps

    Cheers

    Tim
    Some days I turns thisaway, somedays I turns thataway and other days I don't give a stuff so I don't turn at all.

  5. #4
    Join Date
    Jun 2004
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    Mareeba Far Nth Qld
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    Default

    Quote Originally Posted by Tim the Timber Turner View Post
    How about driving the blank with in a chuck, backing off the tailstock, reducing the speed, and supporting the work with your left hand and part off leaving a small nib (3 to 4 mm) that could be hand sanded.

    I find it much easier to get a good shape off the lathe, rather than try to blend it in on a disc sander.

    This method requires a slightly longer blank to allow for the waste in the chuck.

    I am assuming that your very long spindles are 200mm and not a misprint. (2000mm?).

    Hope this helps

    Cheers

    Tim
    Assuming that 200mm is correct, I can agree with Tim, except that I would cut off completely with the long point of the skew. But then if the mushrooms are to stand on that end, shouldn't the end be square or even slightly under cut?
    Jim
    Sometimes in the daily challenges that life gives us, we miss what is really important...

  6. #5
    Join Date
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    BELL POST HILL, 3215
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    Default The Rounded End.

    Hi Evanism,
    I've watched Guilio Marcolongo turn Balls with a reasonably big Roughing Gouge, & I now do the same, & it works perfectly.
    So you do the rounded end 1st. up, sand & finish. This is of course with no Tailstock.
    I use 35 or 45mm. Spigot Jaws, that will hold at least 25mm. & not like the Bowl jaws that only hold approx.13mm.

    I don't even own any 50mm. jaws now. Chucked 'em.

    8 in. sticking out of my jaws are no problem at all. I wood turn them on close to 3000 RPM.
    As for parting off, I use a 12 x 3mm. P&N Skew, with a pretty long Curved Bevel, & use the long point, so that you can get into small areas.

    My Blade overall wood only be 4in. - 100mm. long.
    Regards,
    issatree.
    Have Lathe, Wood Travel.

  7. #6
    Join Date
    May 1999
    Location
    Grovedale, Victoria Australia
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    3,894

    Default

    As Lewis indicated either the Nova spigot jaws or the Vicmarc shark jaws are the way to hold the peice in the lathe for turning.

    You just have to work the same as you would doing a goblet.

    Turn the top end first and finish of then turn the thinner part next then the base.

    Part of and sand the base.
    Jim Carroll
    One Good Turn Deserves Another. CWS, Vicmarc, Robert Sorby, Woodcut, Tormek, Woodfast
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  8. #7
    Join Date
    May 1999
    Location
    Tooradin,Victoria,Australia
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    Default

    What the rest said.

  9. #8
    Join Date
    Jul 2001
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    South Australia
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    Default

    Quote Originally Posted by Jim Carroll View Post
    As Lewis indicated either the Nova spigot jaws or the Vicmarc shark jaws are the way to hold the peice in the lathe for turning.
    I'm going to disagree somewhat with Jim on this one.

    I'm not going to say Shark or Spigot jaws are no good but using them instead of dovetail jaws puts the work further out (up to 40mm) from the bearings of the lathe and will increase vibrations.

    This is a bigger problem when hollowing on a light duty lathe.

    I have both types of jaws and seldom use the longer type.

    In my experience a properly sized and shaped dovetail has as plenty of holding capacity.

    For maximum holding power with dovetail jaws the dovetail needs to be just short of the jaw depth and with a shoulder on the work to make contact with the face of the jaws.

    The chuck jaws should have a gap of 2 or 3mm when tightened onto the dovetail.

    So I think you get a trade off, increased distance from the bearings using spigot jaws against less wood to metal contact using dovetail jaws.

    That's been my experience.

    Your mileage may vary.

    Cheers

    Tim
    Some days I turns thisaway, somedays I turns thataway and other days I don't give a stuff so I don't turn at all.

  10. #9
    Join Date
    May 1999
    Location
    Grovedale, Victoria Australia
    Age
    66
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    Default

    Tim I agree to disagree

    Properly shaped tenons are a must even with the shark jaws, and you still sit the peice flush on the face of the jaws.

    I think for what Evan is doing there is no extra strain on the bearings as you ar only adding 15mm to the lengh of the peice.

    Prefer the longer tenon just in case there is a catch and less chance of the tenon snapping of.
    Jim Carroll
    One Good Turn Deserves Another. CWS, Vicmarc, Robert Sorby, Woodcut, Tormek, Woodfast
    Are you a registered member? Why not? click here to register. It's free and only takes 37 seconds!

  11. #10
    Join Date
    Aug 2008
    Location
    Normanhurst NSW 2076
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    484

    Default saning mushrooms - shitake wood type.

    Agree with Jim, whole heartedly. Drillit.



    Quote Originally Posted by Evanism View Post
    I'm turning up a great many spindles as very long mushrooms, think Shitake style. They are long, such as 200mm

    The heads are obviously round. Im getting very favourable accuracy with the measurements and thicknesses. Once I part off both ends, how to I finish the top so it's spherical/rounded and smooth?

    I've been doing it by hand on my big lathe disk sander, but there must be an easier way! I was thinking of a 125mm disk sander with an ultra-soft underpad. I just stuff the end in the middle and the conforming pad rounds it up...but this seems too technical.

    Any idea friends?

    (many thanks to for his past insistence on beads and coves, beads and coves, grasshopper!)

  12. #11
    Join Date
    Nov 2010
    Location
    Gippsland Victoria
    Posts
    706

    Default This tool works for me

    This one works for me.

    Produces very nice spherical bobbles on the end of things ie chess pawns.

    They would all be identical sizes with minimal effort.

    I think it has potential to assist with shitake mushrooms.

    https://www.woodworkforums.com/attach...6&d=1390132328

    Bill

  13. #12
    Join Date
    May 2008
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    BELL POST HILL, 3215
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    Default Rounded End Again.

    Hi Tim,
    8 in. hanging out of 50mm. Jaws, wood certainly not be for me.
    You wood be looking at Death in front of you.
    There is no Vibration with Speed & a good P&N 25mm. Roughing Gouge.
    Do you think I wood be silly enough, if it was going to come out, & to Print it so others could read it.
    I really don't like putting my life on the line by using a set of 50mm. jaws doing that kind of work.
    I Print, with 33yrs of Turning behind me, & Demoing in front of Turners better than me.
    Regards,
    issatree.
    Have Lathe, Wood Travel.

  14. #13
    Join Date
    Jun 2006
    Location
    East Warburton, Vic
    Age
    54
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    14,138

    Default

    Before we all go off tangent here and I must admit I'm leaning towards Tim's answer here.

    Evan can you confirm that you're turning mushrooms end grain to end grain which is the grain running parallel to the bed of the lathe and between the headstock and tailstock?
    Cheers

    DJ


    ADMIN

  15. #14
    Join Date
    May 2012
    Location
    Canberra
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    Default

    I'll try to get to all the questions....

    They are 200mm long, the heads are 36mm and the stalks taper from 16mm to 12mm.

    I was thinking about how things like chisel handles, cudgels, chess pieces or rolling pins are turned.

    The wood is regular 90x45 pine from my most hated hardware retailer (cut to 45x45 in ~250 lengths) Knot free pieces are chosen with straight grain. They hate me there pulling apart 400 bits from the pile so I can find one that isn't Failure Grade.

    I've turned them beautifully and now have the absolute hang of it. My template lets me get every curve to within a mm.

    I need more sandpaper. Should have taken up that overstock I saw at one of the advertisers here.

    No need for agro guys, I have most of the gear here except deep jaws. Ive been turning between a crowned steb and a good volcano-style live centre. (reminds me, I need a better steb). There is a nova chuck here with a few jaws, but all of them are for bowls....I think there might be some pin jaws, I'll take a dig tomorrow morning. Might need to order one Jim

    Many thanks for all the ideas!
    Last edited by Evanism; 2nd April 2014 at 12:34 AM. Reason: Details

  16. #15
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    May 2012
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    Canberra
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    Default

    Quote Originally Posted by steamingbill View Post
    This one works for me.

    Produces very nice spherical bobbles on the end of things ie chess pawns.

    They would all be identical sizes with minimal effort.

    I think it has potential to assist with shitake mushrooms.

    https://www.woodworkforums.com/attach...6&d=1390132328

    Bill
    I LOVE IT!!!!

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