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Thread: Sanding turnings to "exact" size.

  1. #16
    Join Date
    Nov 2009
    Location
    Peoria, IL
    Posts
    2,566
    Quote Originally Posted by Gordon Stump View Post
    Thanks to all the great responses and ideas from the turners. I took as much as I could from each post. I was in the middle of a run of Oboe pegs when I said screw this and stopped. The detail cutter on the duplicator is getting dull leaving flaky cutter marks. The coarse sandpaper I was using cut like butter on the walnut and left scratch marks to be sanded off with more sandpaper. Bad circular logic!

    Based on what I learned here I set the template oversize and then moved around to the front of the lathe (my duplicator is on the back) and used a skew with a planer cut to bring down to .5 mm over and remove the cutter marks. I then started with 150G and up to 320 to bring the pegs down to size.

    I am a little afraid of the skew so I ordered a carbide skew which is more like a scraper and has a 30 degree shaft. I am hoping to sand starting with higher grits. This is still a work in progress but no more melting down pegs in a cloud of dust!

    My father-on-law always said: "Green you're growing, ripe you're rotten.

    Thanks,

    Gordon
    If you have the diamond shaped carbide cutter on your duplicator, turn the rpm on the lathe way up. It works best at 2,500 rpm or more. Carbide skew? Sounds like snake oil tool to me. You can't sharpen carbide to shaving sharp unless it's a super nano carbide and even then I'd be very surprised that it meets the same quality shearing edge you get with a honed HSS skew.

  2. #17
    Join Date
    Oct 2018
    Location
    New Boston, Michigan
    Posts
    163
    Quote Originally Posted by Richard Coers View Post
    If you have the diamond shaped carbide cutter on your duplicator, turn the rpm on the lathe way up. It works best at 2,500 rpm or more. Carbide skew? Sounds like snake oil tool to me. You can't sharpen carbide to shaving sharp unless it's a super nano carbide and even then I'd be very surprised that it meets the same quality shearing edge you get with a honed HSS skew.
    Thanks Richard I do run the lathe fast. I ordered a new diamond cutter. I also prefer hss over carbide. And I have kept away from the carbide turning tools. I had moment of weakness!! I designed some measuring little sticks with the bottom and top measurement of the contoured pegs. A cnc router makes this easy. calipers.jpg
    Ask a woodworker to "make your bed" and he/she makes a bed.

  3. #18
    Join Date
    Nov 2006
    Location
    TX, NM or on the road
    Posts
    844
    If you search Google "Eugen Schlaak miniature tart press video", you will find that he used a "semaphore jig", It is basically a set of arms that drop down as a certain size is reached. There is also a book that has a good description of semaphore jig for lathe, but the name escapes me. I have one that I used to make tenons on game calls, easy to adjust the size because the falling arm has to adjustments. To get to the size before sanding is strictly a guestimate, or a SWAG. It will take a while to get it set up the first few times, but after awhile you will find a method to make another jig so that it only takes a minute or 2.

  4. #19
    Join Date
    Oct 2018
    Location
    New Boston, Michigan
    Posts
    163
    Quote Originally Posted by Marvin Hasenak View Post
    If you search Google "Eugen Schlaak miniature tart press video", you will find that he used a "semaphore jig", It is basically a set of arms that drop down as a certain size is reached. There is also a book that has a good description of semaphore jig for lathe, but the name escapes me. I have one that I used to make tenons on game calls, easy to adjust the size because the falling arm has to adjustments. To get to the size before sanding is strictly a guestimate, or a SWAG. It will take a while to get it set up the first few times, but after awhile you will find a method to make another jig so that it only takes a minute or 2.
    Thanks. There is so much to learn from those who came before.
    Ask a woodworker to "make your bed" and he/she makes a bed.

  5. #20
    Join Date
    Sep 2015
    Location
    San Diego, Ca
    Posts
    1,538
    I think that most lower cost duplicators use a scraping action to remove wood. It is accepted by most that scraping leaves a rougher finish (e.g. tear-out) than, say, using a skew. A sharp skew used in the slicing mode can leave a great finish - - say starting sanding at 220 grit or better. It takes a little practice but isn't all that hard if you practice.

    There is a production turner in the UK that is a master on the skew. On Facebook his id is The Woodturners. On Youtube, either google Steve Jones or Woodturner21. There are also a lot of other good videos on using a skew. And some bad ones.

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