Yet Another Blade Sharpener Query

Discussion in 'Lawn Mowing' started by MOturkey, Jun 3, 2007.

  1. MOturkey

    MOturkey LawnSite Silver Member
    Posts: 2,761

    OK, so i've gotten a lot of good information from several of you on blade sharpening, and blade sharpeners. In the last thread on the subject, the advice seemed to lean toward "bigger is better" with regards to blade sharpeners, or more specifically, the size of the motor on the blade sharpener.

    As to brand, Magna-Matic seems to get the nod for a top-of-the-line unit.

    So, I check out the Magna-Matic website once again, and guess what? Their 8000 blade sharpener, which handles all standard blades (I never use mulching blades), is powered by a, you guessed it, 1/2 horsepower motor.

    So, why is it that the Magna-Matic with a 1/2 horse motor is top-of-the-line, while an Oregon or other brand in 1/2 horse is underpowered? I'm confused.:confused:
     
  2. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

  3. Eric D

    Eric D LawnSite Senior Member
    Posts: 295

    Good example of misleading consumer information. Instead of looking at the “HP” you would be better served looking at wattage. I’m sure you have seen the ads for vacuum cleaners that are rated at 5 to 6 hp, yet plug into a standard 110V wall outlet. It is about 755-watts for each hp. How could this be that a vacuum can produce 5 to 6 hp from a standard 1500-watt max wall outlet? Well, it seems that if you measure the power by quickly stopping a vacuum or other motors, there is a spike for a fraction of a second before it completely stops, that if you take this spike it could be as high as 5 to 6 hp. This is peak power, not continuous, as the advertisers would like us to believe.:nono: They play this same game for air compressors as well.:hammerhead:

    So, bottom line, don’t use the “HP” number to size it up, look at the wattage draw which will give you a better idea on how well it can maintain the power to do work. I say this with understanding there are other factors to take into account as well, but I won’t go into those.

    Let us know what you end up with and why.

    Eric D
     
  4. topsites

    topsites LawnSite Fanatic
    Posts: 21,653

    Ah no that's not a fair measure of HP, I thank you for pointing this out because any manufacturer using this method to measure the power of the motor is adding the centrifugal force of the various components in motion to the equation, and is thus being deceptive, or as you said, misleading.

    As a rule, I steer clear from folks using such deceptive methods.
    The only other thing I can say is try it out, that's always the ultimate test, if I can try it out before I buy it, or send it back if I don't like it, then I'm usually ok with whatever method they wish to use.

    But yeah, you're right, they do this crap all the time, blowers and mph / cfm too, funny guys.
     
  5. lawnmaniac883

    lawnmaniac883 LawnSite Silver Member
    Posts: 2,613

    I think he was looking at the mag 9000 specs
     
  6. Eric D

    Eric D LawnSite Senior Member
    Posts: 295

    Excellent point! Trying with the option to return is always best IMHO.:)
     
  7. MOturkey

    MOturkey LawnSite Silver Member
    Posts: 2,761

    My bad!!! You are right, I MEANT the 9000. The 8000, which is capable of doing mulching blades, is rated 1 hp, continous duty. The 9000 is 1/2.

    So, back to the original question. Does this mean the 9000 will be underpowerd? Thanks
     
  8. rodfather

    rodfather LawnSite Fanatic
    Posts: 9,501

    Somethng else to consider is the stone's rpm...I seem to recall it is 7800 on my 12", 1.5 hp Oregon.
     

Share This Page