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huge Re-saws and rip and bandsaw maintenance

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  • huge Re-saws and rip and bandsaw maintenance

    I have a friend who owns a saw mill

    he has a couple of huge saws..........tables or trolleys on rails sort of things .. 50- 60 feet long powered by big gardener diesel engines


    makes are robinson..and the other dankart or something or other..probably over well 60 years old

    all the time he is experiencing trouble with bearings bushings etc .

    he uses a grease gun regularly on them ...i have suggested that maybe the saws require oil from an oil gun...like the metalworking machines do

    on the instructions on the side of them one of them says grease such and such every so often ..on the same plate is information on the other bearings ...and the words are "charge once daily" ...does charge mean oil ???

    my friend looked at me like i was from another world when i mentioned oil ..

    i told him that his grease nipples could very well be oil nipples

    anyone here know .?

    ive also posted this in the OWWM forum

    all the best.markj
    Last edited by aboard_epsilon; 05-12-2010, 01:32 PM.

  • #2
    What kind of bearings? Is it possible he's putting in too much grease?

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    • #3
      not sure ....

      the spindle bearings are open roller bearings, he just had two new ones ...hundreds of £££.. the spindles, they are about about 6 inches in diameter.

      the reversing trolley section has brass bushes or something ..its like a belt driven gearbox under the rails

      on the reversing trolley arrangement he has heaps of free-play in the shafts ..1/4 inch in the bearings "wear".....belts are now coming off.

      all I'm suggesting is maybe his grease is is not supposed to be grease ..and that oil could prolong the life of the things

      all the best.markj

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      • #4
        he just had two new ones ...hundreds of £££..
        Where did he get them? Can he ask them for the proper lubrication specs?

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        • #5
          Mark , Surely when he gets new bearings they will have instructions with them as to whether they are oil or grease type bearings .It seems as if he's in business he should know that already ,or maybe he did have grease bearings which were swopped for oil a while ago and he wasn't told about the change.Alistair
          Please excuse my typing as I have a form of parkinsons disease

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          • #6
            bearings came from ...not the proper source, company who made the saw no longer exist ..he just got the codes off them ..and replaced them with the same .

            so no information weather on this saw they run on grease or oil .

            bearings don't come with instructions .

            all the best.markj

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            • #7
              when i was in school i worked at a timberyard in neath [south wales] called robinson david, there was a great rack saw of the description you gave, it was greased twice daily with,.. lithium grease not yellow grease, it was black.it may be the grease was the wrong grease? EP greases have been around a while, i dont ever remember a bearing change, as the manager of a local quarry i know used to say, "you cant beat grease boy"
              mark

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              • #8
                I used to service a McDonough resaw,older unit had copper tubing running up to all the bearings from a central distribution block. One pump per zerk per 8hr shift was all it took.

                The other even more important question is what is the preload supposed to be?Roller bearings imply either tapered cone or barrel roller type.Tapered will have a preload spec and barrel will have a internal clearance spec.If either one of those isn't right no amount of grease or oil will work.
                I just need one more tool,just one!

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                • #9
                  The new bearings might not come with instructions but at £100s a time, surely its worth a phone call to the bearing manufacturer to ask them what they recommend? There is often lengthy discussion on this site regarding the correct grade of oil for a particular machine. Its the same with grease, different grades, different properties. I bet its cold up where the OP lives? When i got my current lathe, some **** had packed the taper roller bearings with nasty sticky grease, when they were meant to be oiled. Before I got round to dismantling everything and cleaning it out, I went in the workshop on a cold day, and couldn't move the spindle at all. Turns out to have been the grease, gone so stiff with cold, it was solid. Those big saw bearings are normally pretty free running. If the bearing manufacturer can't help, try thinner grease, then oil.

                  Richard

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                  • #10
                    You've got to find out why the bearings are failing before you spend any more time getting your shirt spattered with oil and grease.

                    This link appeared on a post a few days ago IIRC, and I thought it was the bees knees.

                    http://www.bardenbearings.com/scan%2...20Brochure.pdf

                    I guess Timken and others might have similar literature.
                    Richard - SW London, UK, EU.

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                    • #11
                      I suspect the bearing failure is due more to contamination than incorrect lubricant. Building shields over the bearings may be useful.

                      Incidently, in really hight contamination applicaitons such as disc harrows they used to use wooden bearings, but that was very low RPM.

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                      • #12
                        I read it and reread it and I THINK you are talking about circular saws. If they are indeed 60 years old, goodness knows what bearings are original. In any case, this is a saw mill and the secondary product is SAWDUST. Mix well with lubricant, (your choice,) and you have frequent bearing failure, UNLESS you have a) sealed bearings or b) flow-through lubrication to wash out the gunge. Bearing maintenance in a production sawmill is HELL! I would think that with open roller bearings, you might as well tack the boxes they came in over the ends for a few minutes more life. I would also expect that the bushings on the carriage return, log turner, and anything else that moves, will be worn to a "toss fit," and that is why the belts wont keep tension. If the mill is producing tapered boards, then it is almost time for a rebuild/replacement. Duffy
                        Duffy, Gatineau, Quebec

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                        • #13
                          What kind of SFM do those units run?

                          Does he keep his blades sharp? I mean as in teeth replaced, blade professionally set, and SHARP? A dull blade increases the load on everything, A LOT.

                          You should reset a blade every two or three times you sharpen. And you should sharpen every two to four hours cutting! That means you might need to reset and sharpen the blade EVERY DAY. If you are cutting heavy plan on blade swaps frequently. You know your set is off when you get wavy boards or boards that are heavily scored. A blade that has lost its set will dive or climb heavily, killing bearings in no time.
                          James Kilroy

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                          • #14
                            The brass (or more likely bronze) bushings require oil, not grease. Plane bearings are hydrodynamic bearings. They ride on a film of oil. Grease won't flow well enough to fill the large area of a plane bearing.
                            Free software for calculating bolt circles and similar: Click Here

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                            • #15
                              I just remembered something,from having built and ran several smaller bandsaw mills the blade tension can also be the culprit.Especially if the tension adjustment is ridgid(not spring or hydraulic dampened)

                              As the mill is started up and the blade heats up it expands and grows in length.If tension is added once the blade has expanded once the saw is shutdown if the tension isn't released the blade will shrink back to it's normal nominal length once cool and apply tremendous force to the bearings and shafts.Upon startup the bearings and shafts run at much higher loads until the blade expands again.

                              I had one mill where this force was so great it actually fatigued the shaft at a shoulder and the blade wheel dropped off.That was the first mill I had and it wound up being modified to reply on a spring for constant tension,a definate improvement that solved a lot of problems.
                              I just need one more tool,just one!

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