Prop Shafts Difficult to Rotate

Discussion in 'Propulsion' started by GeekSpeed, Oct 11, 2015.

  1. GeekSpeed

    GeekSpeed Active Member

    Joined:
    Dec 9, 2010
    Posts:
    245
    Location:
    SoCal
    Hey everyone.

    I am working on installing stuffing tubes, prop shafts, and props. I made the tubes using brass tubing and some oilite bushings from McMaster Carr. I am using 1/8" steel rod for the shafts. The problem is that the shafts seem awfully hard to turn. Should I polish the shafts somehow or drill out the bushings a little bit? What would you guys suggest? Thanks.
     
  2. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

    Joined:
    Dec 6, 2006
    Posts:
    2,512
    Depending on shaft, bushings, and installation method, the end result can easily be shaft bigger than bushings or sufficiently misaligned to cause binding. Generally I will try to figure out which it is. if it is misalignment I usually scrap the tube and start over. if it is aligned but overly tight I will sometimes roughen a sacrificial shaft and use it to slowly and carefully remove just enough material for them to freely rotate.
     
  3. NickMyers

    NickMyers Admin RCWC Staff

    Joined:
    Nov 15, 2007
    Posts:
    4,404
    Location:
    Federal Way, WA
    I've used a needle file chucked up in a drill to carefully open up the bushing. You don't need to remove much material. If you end up removing too much, well, it just becomes sloppy like a lot of stuffing tubes made of telescoping k&s brass and you just need some thick grease to plug it up.
     
  4. SteveT44

    SteveT44 Well-Known Member

    Joined:
    Nov 1, 2009
    Posts:
    1,855
    Location:
    MD
    Do the bushings individually spin easy on a shaft? If not, the bushing are tight and need to be opened up a bit. If so, it's an alignment problem. Installed in the stuffing tube, Is the shaft equally stiff 360 degrees around or just at one point? If at one point, the shaft could be slightly bent.
     
  5. GeekSpeed

    GeekSpeed Active Member

    Joined:
    Dec 9, 2010
    Posts:
    245
    Location:
    SoCal
    Errr..... they don't rotate at all. I kind of epoxied them into the shafts.

    I'll try opening them up a little bit like Nick suggested. Hopefully I don't have to completely cut these out (again) and rebuild them.
     
  6. GregMcFadden

    GregMcFadden Facilitator RCWC Staff

    Joined:
    Dec 6, 2006
    Posts:
    2,512
    wait a minute, did you epoxy them into the stuffing tubes or onto the shaft?
     
  7. GeekSpeed

    GeekSpeed Active Member

    Joined:
    Dec 9, 2010
    Posts:
    245
    Location:
    SoCal
    Epoxied into the tube.
     
  8. NickMyers

    NickMyers Admin RCWC Staff

    Joined:
    Nov 15, 2007
    Posts:
    4,404
    Location:
    Federal Way, WA
    You can pull your shafts through so that you can try spinning them in each bushing independent of the others if you wanted to test in the manner Steve suggests.

    My guess though is that you've primarily got a tight fit as every 1/8" bore oilite bushing i've had has been a tight fit for every supposedly 1/8" shaft I've used in them. Either open them up with something (needle file, tears of Seahawks fans, etc) or try to break them in by running the shafts for a lengthy duration. I could also suggest trying to take some diameter off the shaft, but you're using steel shafts so its easier to work the bushing.
     
  9. GeekSpeed

    GeekSpeed Active Member

    Joined:
    Dec 9, 2010
    Posts:
    245
    Location:
    SoCal
    Ok, thanks. I think I will try to bore out the bushings. Thanks for the help, guys.
     
  10. SteveT44

    SteveT44 Well-Known Member

    Joined:
    Nov 1, 2009
    Posts:
    1,855
    Location:
    MD
    Do what Greg mentions above. Take some spare shafting and roughen it up lengthwise with course sandpaper or a file. Insert into your stuffing tube and rotate with a drill to hone out the bushings.
     
  11. NickMyers

    NickMyers Admin RCWC Staff

    Joined:
    Nov 15, 2007
    Posts:
    4,404
    Location:
    Federal Way, WA
    After chatting with @Tugboat, while the needle file has worked well for me, i really like the suggestion of @GregMcFadden and @SteveT44 - harder to completely destroy the bushing's utility their way. If you have a spare shaft, do it their way.
     
  12. GeekSpeed

    GeekSpeed Active Member

    Joined:
    Dec 9, 2010
    Posts:
    245
    Location:
    SoCal
    Update:

    The needle file ended up working. I am good to go now. Thanks!
     
    NickMyers, Tugboat and Beaver like this.