Page 1 of 2 12 LastLast
Results 1 to 10 of 13

Thread: Stone setting burs won't cut!

  1. #1
    Join Date
    Aug 2021
    Location
    Hampshire
    Posts
    9

    Default Stone setting burs won't cut!

    I am just getting started with stone setting, and have a question about the use of stone setting burrs.
    I have a selection of Busch burrs.

    I'm starting with a drill, then removing the bulk of material with a ball burr, and then attempting to cut the finished seat with either a stone setting burr or a hart burr.

    The problem I have, is that the stone setting and hart burrs don't seem to cut! It almost feels like they are permanently clogged up, and all they seem to do is polish the metal and get very hot.

    I am using "cut lube" on all burrs, as recommended by Cookson, and have also tried beeswax. My material is sterling silver.

    What am I doing wrong?

  2. #2
    Join Date
    Dec 2009
    Location
    Central London
    Posts
    8,406

    Default

    There can only be one obvious reason: your machine is in reverse. Dennis.

  3. #3
    Join Date
    Jul 2009
    Location
    Romsey
    Posts
    5,077

    Default

    What speed are you running at, and was there any chatter when using the ball burr?
    TBH, I don't think you'll find many setters using setting burrs as standard - the hart burrs are useful for undercutting bearings sometimes, but it's the ball burrs do the heavy lifting.

  4. #4
    Join Date
    Aug 2021
    Location
    Hampshire
    Posts
    9

    Default

    Quote Originally Posted by Dennis View Post
    There can only be one obvious reason: your machine is in reverse. Dennis.
    Definitely not in reverse! Drills and ball burrs cut just fine.

  5. #5
    Join Date
    Aug 2021
    Location
    Hampshire
    Posts
    9

    Default

    Quote Originally Posted by ps_bond View Post
    What speed are you running at, and was there any chatter when using the ball burr?
    TBH, I don't think you'll find many setters using setting burrs as standard - the hart burrs are useful for undercutting bearings sometimes, but it's the ball burrs do the heavy lifting.
    I run the ball burrs slowly, and they seem to grind away metal efficiently. No chatter. I started the setting burr at about 5,000 rpm (2mm diameter burr), and gradually increased all the way to 20,000 rpm when it didn't seem to be doing anything.

  6. #6
    Join Date
    Mar 2011
    Location
    Manchester UK
    Posts
    807

    Default

    you need to run the burs as slow as you can, the slower the better 100 rpm slow .If they are getting hot they will be dead.

  7. #7
    Join Date
    Feb 2016
    Location
    East Anglian
    Posts
    395

    Default

    Yes. I have a 5mm setting burr that I over revved by mistake. Not only did it heat up the silver very fast and “burnt” my fingers, it also went blue! No use at all now!


    Sent from my iPad using Tapatalk

  8. #8
    Join Date
    Dec 2009
    Location
    Central London
    Posts
    8,406

    Default

    If that is the case, and your machine cannot be run slowly enough, when you buy new setting burrs, also get a universal handle, https://www.cooksongold.com/Jeweller...prcode-999-AZM
    Tightened in one of those, you can easily refine the seats by hand and preserve your burrs for longer.

    The preferred lubricant at hand speed, is a tiny drop of oil. Dennis.
    Last edited by Dennis; 09-08-2021 at 09:06 PM.

  9. #9
    Join Date
    Aug 2021
    Location
    Hampshire
    Posts
    9

    Default

    Thank you all for the tips and suggestions!

  10. #10
    Join Date
    Jul 2009
    Location
    Romsey
    Posts
    5,077

    Default

    Just to put some numbers on it - when running a burr up to 1.5ish mm I usually run it at 3krpm. A larger burr, with it's greater diameter (and therefore circumference) needs to go even slower rotationally to get the same linear speed.

Tags for this Thread

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
  •