Milling 95A polyurethane
Close
Login to Your Account
Results 1 to 5 of 5
  1. #1
    Join Date
    Aug 2006
    Location
    greensboro,northcarolina
    Posts
    2,387
    Post Thanks / Like
    Likes (Given)
    150
    Likes (Received)
    585

    Default Milling 95A polyurethane

    Is this hard enough to mill without too many problems? I have milled plenty of Delrin, nylon, UHMW, but never had too much luck with polyurethane. But I don't recall what durometer I have tried in the past.

  2. #2
    Join Date
    May 2017
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    314
    Post Thanks / Like
    Likes (Given)
    323
    Likes (Received)
    159

    Default

    RJT-

    I've recently used 95A to fabricate some vibration-isolating (and break-away) motorcycle crash bar mounting studs for a BMW K-75. Was excellent to work with (meaning easy to mix, pour and form) but I was not principally looking to shape it. That said, I crashed my bike a few weeks ago and damaged the mounting studs. The 95A performed well. It held sufficiently to allow the crash bars to absorb the impact but gave sufficiently that the engine mounting holes were undamaged by the crash.

    So...I recently had occasion to have to machine the 95A. I bored it out of the isolation mount on the lathe in order to repour the studs. As you would expect it didn't machine great. It was gummy and soft (more like nylon than Delrin). I was simply boring it completely out of a cup, so holding tolerance wasn't the goal. Based on how it felt to machine, I think you'd experience similar results to nylon. Super sharp tools with high positive rake and small depth of cut would probably be best IMHO. It's going to want to push out of the way instead of break a clean chip. Again, less like Delrin, more like nylon would be my best description.

    Caveat (I'm not a professional machinist so YMMV)

    -DD

  3. #3
    Join Date
    Feb 2007
    Location
    St. George, Utah
    Posts
    905
    Post Thanks / Like
    Likes (Given)
    454
    Likes (Received)
    598

    Default

    I do, from time to time, turn 8" dia X 4" wide polyurethane wheels of that hardness and even softer. I start with sharp HSS tooling and finish with a medium rasp or emery cloth at moderate speed (sometimes an angle grinder with flap wheel). Both roughing and finishing are messy. The turning leaves long, stretchy and extremely annoying swarf and the the finishing leaves a heavy layer of dust on everything. After finishing I don't have a shiny 'cast' finish, but it is to the proper contour and becomes smooth with use.

  4. #4
    Join Date
    Oct 2010
    Location
    Dewees Texas
    Posts
    2,395
    Post Thanks / Like
    Likes (Given)
    27
    Likes (Received)
    654

    Default

    I have tried to turn 95A with the same set up that worked with Teflon (very sharp, high positive rake tools) and the material just moved away from the cutters. I thought machining freshly chewed chewing gum would be easier.

    I tried freezing it in alcohol and dry ice but could not machine it quick enough before it warmed up. Final solution for me was a Vortex cold air gun. Wait till it is iced up before cutting and pause between passes so the surface can ice up again.

  5. Likes Gordon Heaton liked this post
  6. #5
    Join Date
    Mar 2006
    Location
    jacksonville,fl.
    Posts
    1,128
    Post Thanks / Like
    Likes (Given)
    952
    Likes (Received)
    374

    Default

    I have roughed out polyurethane with a carbide tooth saw blade in a tp grinder then finished up by grinding with an induced porosity wheel 36gt.The finish is very smooth.

    Nylon cuts way better than polyurethane in my experience.I make a lot of all kinds of wheels out of polyurethane and grind the od's,mostly softer than 95a.I just buy tubing and bond it to aluminum hubs.I made a parting tool that uses a box cutter razor that works really well to cut off the tubing and also make thin washers when needed.

  7. Likes Dumpster_diving liked this post

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
  •