Large bronze bearing clearance - Page 2
Close
Login to Your Account
Page 2 of 2 FirstFirst 12
Results 21 to 34 of 34
  1. #21
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Colorado
    Posts
    2,848
    Post Thanks / Like
    Likes (Given)
    3366
    Likes (Received)
    784

    Default

    Quote Originally Posted by DIVEBUZZARDS View Post
    Erik

    Thanks for the feedback. This is a vintage 1930's forming roll for steel. The original bearing was wiped out so no numbers can be ascertained from the original parts. Rpm for this application is in the range of 1 to 2 RPM's. and this is for short cycles.

    Thanks
    Gary
    Gary ,

    Thanks man, that's a great help...

    Will attempt to get my razor out find the simplest useful path.

    At least some sort of base line can be established and how "reality" may deviate from that.

    I am always very suspicious of any engineered systems that assumes linear scaling, as that rarely works out well, from optics/ photonics to rocketry … these things don't scale so well by orders of magnitude.

    Ta.

  2. #22
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Colorado
    Posts
    2,848
    Post Thanks / Like
    Likes (Given)
    3366
    Likes (Received)
    784

    Default

    Quote Originally Posted by Limy Sami View Post
    That's an interesting discussion very similar problems and practical issues to Gary's quandary here (Nice One) some potentially good refs in there.

    Kinda funny how (as cited in your linked thread) the specialists that do this for a "Day job" and even suppliers keep their cards close to their chest on simple clearances etc.

    A few weeks in a decent engineering library you could kind of "Bust" 85% what these specialists do but still no engineering library is gonna close in on a top drawer company that's been doing this kind of specialized work for decades, but a plain journal bearing (bronze) and grease packed should not be beyond the "Wit of man" YKWIM ? lol.

  3. Likes DIVEBUZZARDS liked this post
  4. #23
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,522
    Post Thanks / Like
    Likes (Given)
    1772
    Likes (Received)
    5236

    Default

    Shouldn't there be a similar (identical) bearing on the other side? If the roll is out measurements of shaft and bore can be taken, along with pictures of the bushing bore to show any lube feed grooves, etc.

    And now that we know the application and speed, we can say comfortably that there's not going to be significant thermal input from speed (1-2RPM), but if this is actually used for compressive forming of metals you may have to watch growth from adiabatic heating or (if a hot billet) conduction. But as a demonstration mill I don't think these will be significant either given the mass of the roll.

    Where in MA is this device? I'd be interested in seeing it.

  5. Likes cameraman, DIVEBUZZARDS liked this post
  6. #24
    Join Date
    Nov 2014
    Country
    UNITED STATES
    State/Province
    Colorado
    Posts
    2,848
    Post Thanks / Like
    Likes (Given)
    3366
    Likes (Received)
    784

    Default

    Quote Originally Posted by Milland View Post
    Shouldn't there be an similar (identical) bearing on the other side? If the roll is out measurements of shaft and bore can be taken, along with pictures of the bushing bore to show any lube feed grooves, etc.

    And now that we know the application and speed, we can say comfortably that there's not going to be significant thermal input from speed (1-2RPM), but if this is actually used for compressive forming of metals you may have to watch growth from adiabatic heating or (if a hot billet) conduction. But as a demonstration mill I don't think these will be significant either given the mass of the roll.

    Where in MA is this device? I'd be interested in seeing it.
    I was wondering that too... What's on the other side of the shaft , it's not floating in space all on it's own. Curious as to how it failed and how long it was in service.

    Also kinda interested to dig through older references like machinery's handbook "Machinery's Handbook Collector's Edition: 1914 First Edition Replica" to see if there are more detailed descriptions on large grease lubricated bronze bearings. Given that is not such a "contemporary" application / method.

    Some of the newer fangled research is based on deviations from the "old formulae" but on the other hand there probably isn't a lot of modern research being carried out on a 90 year old + bearing designs.

    Good to know at least it's not a bearing for a 'Sketchy" carnival ride where people might get killed from an incorrect clearance spec like some 1970's disaster movie.

  7. Likes DIVEBUZZARDS liked this post
  8. #25
    Join Date
    Dec 2019
    Country
    UNITED STATES
    State/Province
    Massachusetts
    Posts
    6
    Post Thanks / Like
    Likes (Given)
    14
    Likes (Received)
    1

    Default

    Thank you very much. Looking forward to reading this one.

  9. #26
    Join Date
    May 2005
    Location
    Republic of Arizonia
    Posts
    1,586
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    466

    Default

    1942 Marks engineers handbook ......less then 600 FPM .001 per inch plus .001 for clearance.

    I've worked on 150 ton ball mills Bronze bearings 40" journals 19 RPM flood lube.... original clearance spec .015 plus scraped for contact.

    That being said the mill hands are (fill in the blank) .......so the bearings are bastardized currently running .065 to .080 .....currently have a good track record the burned bearing count is way down this year.

    .....Figure a heavy tacky grease. if it is a total loss system grease while running. The point of contact somewhere around 30 to 40 degrees off the bottom of journal that will also be the start of the load zone. Machine reverses so it'll mirror on the opposite side of the bearing.

    Where does the grease get introduced into the bearing? top, side, etc?

  10. Likes DIVEBUZZARDS liked this post
  11. #27
    Join Date
    Aug 2005
    Location
    Tucson AZ
    Posts
    6,329
    Post Thanks / Like
    Likes (Given)
    9463
    Likes (Received)
    2972

    Default

    I don't have a first edition but my 5th edition from 1919 says:

    "The allowance made for the running fit of the box and shaft is about 0.0005(D+1), In which D is the nominal diameter of the shaft in inches. Some manufacturers of fast running machinery make the diameter of the box exceed that of the shaft by nearly twice this amount. The oil should be introduced at the point where the forces acting tend to separate the shaft and the box. At this point oil grooves must be cut in the surface of the box so as to distribute the lubricant evenly over the entire length of the journal. Additional oil grooves should not be used, as these merely tend to rupture the oil film."

    It also recommends "a cylinder oil of good body". JR would have gotten a kick out of that.

    Worth noting that the formula predates the convention of performing operations in parentheses first I believe so it is really 0.0005X D +.001= clearance.

  12. Likes DIVEBUZZARDS liked this post
  13. #28
    Join Date
    Jul 2006
    Location
    Hillsboro, New Hampshire
    Posts
    7,522
    Post Thanks / Like
    Likes (Given)
    1772
    Likes (Received)
    5236

    Default

    Quote Originally Posted by tdmidget View Post
    Worth noting that the formula predates the convention of performing operations in parentheses first I believe so it is really 0.0005X D +.001= clearance.
    For oil-fed bearings. For grease (thick, intermittent lube) I think you'd want greater clearances.

  14. Likes eKretz, DIVEBUZZARDS liked this post
  15. #29
    Join Date
    Aug 2005
    Location
    Tucson AZ
    Posts
    6,329
    Post Thanks / Like
    Likes (Given)
    9463
    Likes (Received)
    2972

    Default

    Quote Originally Posted by Milland View Post
    For oil-fed bearings. For grease (thick, intermittent lube) I think you'd want greater clearances.

    I agree but that is all it said about bearings that was remotely applicable. The "cylinder oil of good body" would be about like STP or such so sort of close.
    Last edited by tdmidget; 12-05-2019 at 03:10 PM.

  16. Likes DIVEBUZZARDS liked this post
  17. #30
    Join Date
    Aug 2012
    Location
    California, Central Coast
    Posts
    3,558
    Post Thanks / Like
    Likes (Given)
    2187
    Likes (Received)
    1385

    Default

    Quote Originally Posted by tdmidget View Post
    It also recommends "a cylinder oil of good body". JR would have gotten a kick out of that.
    The german oil co. liqui moly has a lock on that in their calendar
    This NSFW Motor Oil Calendar from Germany Will Get Your Engine Running - Maxim

  18. #31
    Join Date
    Jan 2007
    Location
    Norfolk, UK
    Posts
    18,809
    Post Thanks / Like
    Likes (Given)
    14320
    Likes (Received)
    14365

    Default

    Quote Originally Posted by Rob F. View Post
    The german oil co. liqui moly has a lock on that in their calendar
    This NSFW Motor Oil Calendar from Germany Will Get Your Engine Running - Maxim
    Too much silicone, I much prefer non synthetic.

  19. #32
    Join Date
    May 2005
    Location
    Republic of Arizonia
    Posts
    1,586
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    466

    Default

    Guessing that, Syncon R & O 480 or 560 oil would work instead of grease. Just noticed they don't offer 560 anymore so 680..

    It sticks to everything and when used as a way oil. As an example: I can move the G&L HBM table with very little effort.

    Applications

    • Plain and rolling-element bearings operating at very high or very low
    temperatures, and sealed-for-life bearings
    • Lightly to moderately loaded enclosed industrial gear drives that do not
    require a compounded or extreme-pressure (EP) gear lubricant
    • Circulating systems of paper machine dryer sections and calender stacks

    • Industrial blowers
    • Industrial worm gear drives with bronze-on-steel gears
    • Reciprocating air compressors where the manufacturer specifies a PAO -
    based lubricant (ISO VG 100 or 150, typically)
    • Lubrication of the upper cylinders of gas compressors handling natural
    gas or process gas (ISO VG 150 or 220, typically)
    • Industrial equipment operating over a wide temperature range where uninhibited
    mineral oil is recommended

  20. #33
    Join Date
    Apr 2004
    Location
    Modesto, CA USA
    Posts
    6,885
    Post Thanks / Like
    Likes (Given)
    0
    Likes (Received)
    1150

    Default

    I would suggest looking into a plastic bearing material. A new piece of bronze that size will cost a good bit. plastics have come a long way in only ninety years.
    Or some sort of spray metal coating onto the old bearing. Do they make spray babbit? I saw a spray lead gun for car body work. It sprayed molten lead onto a car body to fill in dents. I think it needed a welder and a air hose.
    Bil lD

  21. #34
    Join Date
    Sep 2002
    Location
    People's Republic
    Posts
    3,152
    Post Thanks / Like
    Likes (Given)
    234
    Likes (Received)
    2109

    Default

    Quote Originally Posted by Rob F. View Post
    Why would the shaft increase in size with heat and not the housing? They should both grow together to some degree.
    I think it would depend on a lot of factors including how the heat can escape

    One would think designing something that would bind under foreseeable circumstances would be silly

    Interesting that the antique source seems to agree in that the clearance amounts to a largish amount


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
  •