How many hours

Discussion in 'Lawn Mowing' started by siklid1066, Jan 4, 2008.

  1. siklid1066

    siklid1066 LawnSite Member
    Posts: 148

    How many hours can one get out of a blade clutch and starter?
     
  2. GravelyNut

    GravelyNut LawnSite Bronze Member
    Posts: 1,594

    Who's running it, on what type of equipment, and cutting what.
     
  3. siklid1066

    siklid1066 LawnSite Member
    Posts: 148

    Wright Stander mower,36,17hp.
     
  4. MOW ED

    MOW ED LawnSite Fanatic
    Posts: 5,028

    I have a Kohler 26EFI and its in a Walker. I have 1750 hours on it and just replaced the starter.
    That is the only starter I went thru.
    Clutches are a different story. I tried the famous double blade configuration on an electric clutch on a Toro WB. In fact I tried twice. I got about 80 to 100 hours per clutch, not my idea of production.
    Without the double blades it ran strong and I had over 600 hours on the final clutch.
     
  5. ed2hess

    ed2hess LawnSite Fanatic
    Posts: 13,328

    I got just a little over 600 hrs on the Kaw starter.....fortunately it fell just under warranty. In my opinion it is not as good a starter as the Kohler starters. The plunger stop broke apart.....probably a $1 part and it isn't replaceable.
     
  6. GravelyNut

    GravelyNut LawnSite Bronze Member
    Posts: 1,594

    Yeah, the old Onan and Kohlers could last for thousands of hours. Briggs and others, not so long. Depending on the use, 1000 hours on an electric clutch would be doing good. And that is from all makes. The most common things to fail on the modern mowers are:
    1. Spindles
    2. Belts
    3. Hydros
    4. Clutches
     
  7. marvinlee

    marvinlee LawnSite Member
    from Oregon
    Posts: 108

    Mowing deck spindles should easily last the life of the machine (1000-3000 hours) with proper design at the 90-95 percent confidence factor. What would be proper design? A labyrinth lower bearing seal on the bottom end, backed up with conventional seals just above, plus one at the top. Seals sound simple, but come in a wide variety of quality, materials and finishes. The best include those with highly temperature synthetic rubber, micro-grooved, and sometimes with additional coating to ****** wear. The seal rubbing surface is also critical. It should be hardened and have a low RMS (roughness) finish.

    Grease should be a low-oxidation type, which can be synthetic but also includes advanced oil-based greases. Some greases now have polyurea thickeners, which the Japanese seem to like, and which John Deere sells (among many other types). Since mower spindles often run in wet grass, spindle steel can usefully have sufficient chromium and other alloys to be rust resistant. Fully rust resistance alloys are not necessary since salt water immersion and constant water exposure is uncommon. Cleanliness is little discussed, but is important in steel making, grease, and spindle assembly. Unlike engine oil, the grease does not get cycled through a filter. It won't get cleaned in use, but sometimes small particles get crushed into harmlessness, depending on what the particles consist of.

    Filler materials to eliminate some dead space in the spindle will prevent much initial grease usage to fill up the cavity while not much affecting the lubrication quality. The grease saving is most true where the deck maker uses pre-greased bearings and leaves the cavity initially empty. Again, spindles are not like an engine where all the lubricant gets used. Grease often flows imperfectly and only a small amount enters the rolling arc of the bearings. Regreasing is problematic because of imperfect field conditions, variable amounts and qualities used, and lack of operator knowledge on how much grease is already in the spindle. For regreasable bearings, a small, spring-loaded valve can provide pressure relief. This is particularly valuable when power-driven, high speed, high volume, grease guns are used.

    Spindle costs rise with diameter, but a small increase of diameter, say from 1" to 1 1/8" offers a significant increase of rigidity greater than the percentage diameter difference. At least one maker now advertises 1 1/4" diameter spindles. Though not properly a spindle component, slip clutches can alleviate shock loading and possible spindle housing fracture. The spindle housing should not break, and additionally affects bearing life through its effect on cooling, which may explain why some commercial deck makers continue to use aluminum despite its lower strength.

    Dust cup effectiveness varies among mower deck makers. Some are too flimsy and bend in hard use, such as on my own ZTR. A good design will fit very closely to the spindle housing, offer a large cup for dust containment, and be sufficiently rigid to resist damage from rocks, stumps, lumps, and branches. I've never seen a dust cup with a rubber seal, but it is conceptually possible and can be an abradable contact seal that quickly wears to an optimal running clearance. A simple labyrinth dust cup fitment is also doable.

    A taller deck design can provide more space above the blade to contain space for debris to move about, rather than jamming between the blade and the deck.

    Bearings are a whole design issue, but either tapered roller or ball bearings are suitable. Tapered roller bearings can benefit from crowning of the rollers, which makes the bearings more tolerant of shaft deflections. Several major suppliers offer premium bearing lines which provide, for the same dimensions, harder, more dent-resistant steel and finer finish. One line now offers a design that permits more bearing balls to be used for a given shaft and OD size.

    A hidden factor is the amount of research and analysis the mower deck company has done on its spindles. No amount of pre-engineering can replace real-world information gathered by taking apart failed bearings to determine the possible causes. In-factory analysis can determine how often, if ever, regreasing is helpful, under what conditions, and which lubricants prove best. Belt tension, cooling conditions (open deck covers are better), RPM, and loads all affect spindle life.

    Last but not least, the owner's manual should specify if, and how, owner maintenance of the spindles should be conducted. There should be a schedule that responds to major usage variables. A spindle used in sandy conditions has different needs than one used where salt is present from ocean spray, as on some parts of the Oregon coast line. Constant mowing at max power and for long periods in hot weather puts different stress on spindles and lubricants than gentle mowing done only in clement conditions for short periods. Not all variables can be considered, but relying on only one maintenance schedule to fit all conditions is optimistic, to say the least.

    The driving factor is the concern of the manufacturer. Better decks cost a few dollars more and each maker must decide the importance attached to spindle life. Railroads, auto makers, commercial Class 8 trucks, commercial aircraft, and many industrial machinery suppliers expect very long spindle and wheel bearing life and so should commercial mower buyers.
     
  8. marvinlee

    marvinlee LawnSite Member
    from Oregon
    Posts: 108

    Mowing deck spindles, with proper design, should easily last the life of the machine (2500-3000 hours) at the 90-95 percent confidence factor. What would be proper design? A labyrinth lower bearing seal on the bottom end, backed up with conventional seals just above, plus one at the top is one possibility. Seals sound simple, but come in a wide variety of quality, materials and finishes. The best include those with highly temperature and wear resistant synthetic rubber, micro-grooved, and sometimes with additional coating to ****** wear. The seal rubbing surface is also critical. It should be hardened and have a low RMS (roughness) finish.

    Grease should be a low-oxidation type, which can be synthetic but also includes advanced oil-based greases. Some greases now have polyurea thickeners, which the Japanese seem to like, and which John Deere sells (among many other types). Since mower spindles often run in wet grass, spindle steel can usefully have sufficient chromium and other alloys to be rust resistant. Fully rust resistance alloys are not necessary since salt water immersion and constant water exposure is uncommon. Cleanliness is little discussed, but it is important in steel making, grease, and spindle assembly. Unlike engine oil, the grease does not get cycled through a filter. It won't get cleaned in use, but sometimes small particles get crushed into harmlessness, depending on what the particles consist of.

    Filler materials to eliminate some dead space in the spindle will prevent much initial grease usage to fill up the cavity while not much affecting the lubrication quality. The grease saving is most true where the deck maker uses pre-greased bearings and leaves the cavity initially empty. Again, spindles are not like an engine where all the lubricant gets used. Grease often flows imperfectly and only a small amount enters the rolling arc of the bearings. Regreasing is problematic because of imperfect field conditions, variable amounts and qualities used, and lack of operator knowledge on how much grease is already in the spindle. For regreasable bearings, a small, spring-loaded valve can provide pressure relief. This is particularly valuable when power-driven, high speed, high volume, grease guns are used.

    Spindle costs rise with diameter, but a small increase of diameter, say from 1" to 1 1/8" offers a significant increase of rigidity greater than the percentage diameter difference. At least one maker now advertises 1 1/4" diameter spindles. Though not properly a spindle component, slip clutches can alleviate shock loading and possible spindle housing fracture. The spindle housing should not break, and additionally affects bearing life through its effect on cooling, which may explain why some commercial deck makers continue to use aluminum despite its lower strength.

    Dust cup effectiveness varies among mower deck makers. Some are too flimsy and bend in hard use, such as on my own ZTR. A good design will fit very closely to the spindle housing, offer a large cup for dust containment, and be sufficiently rigid to resist damage from rocks, stumps, lumps, and branches. I've never seen a dust cup with a rubber seal, but it is conceptually possible and can be an abradable contact seal that quickly wears to an optimal running clearance. A simple labyrinth dust cup fitment is also doable.

    A taller deck design can provide more space above the blade to contain space for debris to move about, rather than jamming between the blade and the deck.

    Bearings are a whole design issue, but either tapered roller or ball bearings are suitable. Tapered roller bearings can benefit from crowning of the rollers, which makes the bearings more tolerant of shaft deflections. Several major suppliers offer premium bearing lines which provide, for the same dimensions, harder, more dent-resistant steel and finer finish. One line now offers a design that permits more bearing balls to be used for a given shaft and OD size.

    A hidden factor is the amount of research and analysis the mower deck company has done on its spindles. No amount of pre-engineering can replace real-world information gathered by taking apart failed bearings to determine the possible causes. In-factory analysis can determine how often, if ever, regreasing is helpful, under what conditions, and which lubricants prove best. Belt tension, cooling conditions (open deck covers are better), RPM, and loads all affect spindle life.

    Last but not least, the owner's manual should specify if, and how, owner maintenance of the spindles should be conducted. There should be a schedule that responds to major usage variables. A spindle used in sandy conditions has different needs than one used where salt is present from ocean spray, as on some parts of the Oregon coast line. Constant mowing at max power and for long periods in hot weather puts different stress on spindles and lubricants than gentle mowing done only in clement conditions for short periods. Not all variables can be considered, but relying on only one maintenance schedule to fit all conditions is optimistic, to say the least.

    The driving factor is the concern of the manufacturer. Better decks cost a few dollars more and each maker must decide the importance attached to spindle life. Railroads, auto makers, commercial Class 8 trucks, commercial aircraft, and many industrial machinery suppliers expect very long spindle and wheel bearing life and so should commercial mower buyers.
     
  9. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    Not to sound smart, but anywhere from 5 minutes to 8-10 years, all depends, who knows...
    Mostly a matter of getting that combination of parts that happens to last forever.
    Some do, some don't, such is life.
     

Share This Page