Free 173 Best Homemade Tools eBook:  
Become a founding member: 500+ tool plans, full site access, and more.

User Tag List

Results 1 to 9 of 9

Thread: Polygon turning - GIFs

  1. #1
    Content Editor
    Supporting Member
    Altair's Avatar
    Join Date
    Aug 2013
    Posts
    3,576
    Thanks
    824
    Thanked 8,798 Times in 2,577 Posts

    Polygon turning - GIFs

    Polygon turning.










    Previously:

    Machining a multi-start thread - video
    Crankshaft machining - GIF
    Machining a giant ball valve - GIF
    Machining a guilloche pattern on watch face - GIF
    Hobbing and gashing machine - video

    173 Best Homemade Tools eBook

  2. The Following 6 Users Say Thank You to Altair For This Useful Post:

    johncg (Feb 27, 2021), mwmkravchenko (Feb 26, 2021), NortonDommi (Feb 26, 2021), Ralphxyz (Feb 26, 2021), steamingbill (Feb 27, 2021), thehomeengineer (Mar 3, 2021)

  3. #2
    Supporting Member NortonDommi's Avatar
    Join Date
    Jul 2014
    Location
    North Island, New Zealand.
    Posts
    438
    Thanks
    1,013
    Thanked 217 Times in 142 Posts

    NortonDommi's Tools
    Does that lathe attachment work on the same principle as a gear hobber? Looks to be very handy. Where can I get one?

  4. #3
    Supporting Member mwmkravchenko's Avatar
    Join Date
    Nov 2017
    Location
    Perth Ontario Canada
    Posts
    283
    Thanks
    1,565
    Thanked 114 Times in 70 Posts
    Looks like a combination of number of cutters and synchronised rotation. Pretty ingenious.

  5. #4
    Supporting Member Skun Knuckles's Avatar
    Join Date
    Dec 2017
    Location
    Gippsland Victoria Australia
    Posts
    23
    Thanks
    18
    Thanked 15 Times in 9 Posts

    Skun Knuckles's Tools
    I used to think rotary broaching was a form of trickery, then I saw this!

  6. #5

    Join Date
    Dec 2017
    Posts
    74
    Thanks
    28
    Thanked 18 Times in 14 Posts
    How?
    I would like to see it in slow motion, I can't quite visualize the way that works.

  7. #6
    Supporting Member mwmkravchenko's Avatar
    Join Date
    Nov 2017
    Location
    Perth Ontario Canada
    Posts
    283
    Thanks
    1,565
    Thanked 114 Times in 70 Posts
    This is only guessing. But follow me.

    You have lathe spindle rotational speed.

    You have these variables on the spinning cutter head.

    Rotational speed
    Number of cutters
    Diameter of cutter tip

    So if the two are the same speed the cutter will not cut all if the diameter of the cutter tip and the rotational speed of the part in the lathe are equal.
    As in if both have the same distance covered in feet per minute or meters per second.

    If you change the surface speed of the cutting head to 1/2 that of the lathe you will cut on two places. ( I think ) if it is a quarter then 4 places. I think this applies to a single rotating cutter. If you have two rotating cutters then you are again making two cuts for each rotation of the cutter head.

    Looking carefully you will see one of the cut parts is done with one cutter and another of the cut parts is done with 2 cutters.
    And if I am correct again, there is room for 4 cutters on the rotating cutter block. So there is a synchronised setup that can be accomplished to cut facets in the round stock.

    I may be wrong on the indexing of cuts versus speed fractions. As in 1/2 speed may cut on two sizes of the lathes rotation.

  8. #7
    Supporting Member NortonDommi's Avatar
    Join Date
    Jul 2014
    Location
    North Island, New Zealand.
    Posts
    438
    Thanks
    1,013
    Thanked 217 Times in 142 Posts

    NortonDommi's Tools
    Nice explanation mwmkravchenko, works just like a gear hob where there relationship between work and cutter rotation determine number of teeth cut. I had never thought about that phenomenon being used to cut polygons. The surfaces will not be truly flat but that is of no consequence for a bolt head and may actually be advantages for spanner or socket purchase especially when using a flank drive.
    I have seen a great design for a lathe hobbing attachment that was driven off the tailstock end of the leadscrew which enabled the gearbox and a couple of gears to set the work/cutter relationship.
    One day .........

  9. #8
    Supporting Member mwmkravchenko's Avatar
    Join Date
    Nov 2017
    Location
    Perth Ontario Canada
    Posts
    283
    Thanks
    1,565
    Thanked 114 Times in 70 Posts
    Quote Originally Posted by NortonDommi View Post
    Nice explanation mwmkravchenko, works just like a gear hob where there relationship between work and cutter rotation determine number of teeth cut. I had never thought about that phenomenon being used to cut polygons. The surfaces will not be truly flat but that is of no consequence for a bolt head and may actually be advantages for spanner or socket purchase especially when using a flank drive.
    I have seen a great design for a lathe hobbing attachment that was driven off the tailstock end of the leadscrew which enabled the gearbox and a couple of gears to set the work/cutter relationship.
    One day .........
    Probably the larger the cutting radius the flatter the flats will be.

    And it was mostly a guess. But derived from what I knew about. Nothing ventured, nothing gained!

  10. #9

    Join Date
    Jan 2013
    Location
    Essex, UK
    Posts
    2
    Thanks
    0
    Thanked 1 Time in 1 Post

    Spark plug hexagons

    I once worked at an aerospace company that supplied a specialised spark plug manufacturer - they supported all sorts of classic/ancient plug types - the various sizes of hexagons needed for these old plugs were generated the same way. The machines in use were six-spindle autos.
    Fascinating to watch.



    173 Best Homemade Tools eBook

  11. The Following User Says Thank You to bill_gj For This Useful Post:

    mwmkravchenko (Mar 4, 2021)

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

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
  •