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  1. #1
    Join Date
    Dec 2007
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    Adelaide
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    574

    Default Belt sander issue

    A while back I picked up one of these belt/disk sanders (Gumtree) to replace the old hand held belt sander that I used to turn upside down and sit it on the bench, I ordered a selection pak of belts from Ebay with various grits, and set it up with the belt in the vertical position and up until now I have only used it for wood, plastic and fibreglass sheet with no issues. I had need to shape some brass and have noticed that there is marked thump as the join on the belt passes the brass being shaped, I have never noticed this from the old hand held belt sander - is this normal or have I just got a cheap set of belts with poor lumpy joins ?
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  2. #2
    Join Date
    Sep 2012
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    York, North Yorkshire UK
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    Hi Familyguy,

    I've got one of those. Mine thumps as well even putting the belt on facing the right way makes no difference. DAMHIKT. I find that it stalls very easily. I replaced the capacitor thinking that it was bad, but it made no difference. Just not enough motor power from 250 Watts for anything but wood. Biggest improvement was a new smaller section belt. I've been meaning to put a treadmill motor on mine for ages, but not got round to doing it !
    Best Regards:
    Baron J.

  3. #3
    BobL is offline Member: Blue and white apron brigade
    Join Date
    Feb 2006
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    Perth
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    7,182

    Default

    Quote Originally Posted by familyguy View Post
    A while back I picked up one of these belt/disk sanders (Gumtree) to replace the old hand held belt sander that I used to turn upside down and sit it on the bench, I ordered a selection pak of belts from Ebay with various grits, and set it up with the belt in the vertical position and up until now I have only used it for wood, plastic and fibreglass sheet with no issues. I had need to shape some brass and have noticed that there is marked thump as the join on the belt passes the brass being shaped, I have never noticed this from the old hand held belt sander - is this normal or have I just got a cheap set of belts with poor lumpy joins ?
    Cheap belts or belt not tensioned tight enough perhaps?

  4. #4
    Join Date
    Dec 2013
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    56
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    1,416

    Default

    I had 2 of them, as said not enough power and mine always thumped like yours.
    Ended up selling both years ago and bought the biggest 240v model from H&F.
    Using Tapatalk

  5. #5
    Join Date
    Nov 2004
    Location
    Bungama SA
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    52
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    960

    Default

    They all thump, I've messed around with mine trying to get rid of it. It does improve with higher quality belts but never disappears completely.
    I found by adding a stick on slip pad thingo helped a lot(cant remember what its called... its pretty slick stuff graphite impregnated I think)under the belt on the plattern/work area, I got it from Timbecon years ago but they dont seem to list it anymore?
    ....................................................................

  6. #6
    Join Date
    Nov 2004
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    Bungama SA
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    52
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    960

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    Ah ha found some at Carbatec search for "GRAPHITE-150MM"
    ....................................................................

  7. #7
    Join Date
    Nov 2019
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    Brisbane
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    69
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    452

    Default Belt grinder

    Hello again.
    These cheap belt grinders are not good for metal removal. The small diameter drive wheel means the surface speed of the belt suits wood, but metal use leads to a poor finish and grain shedding. Still if you can't afford the right thing.
    Belts with tape joins will always thump as the thickness at the join increases. Well made lap joins with the abrasive skived off the top on one side and the backing ground to remove fillers and prepare the cloth or combination material should run well. Once again pay for good quality product.
    The graphite impregnated canvas used on the platten is called slip cloth and will help if it doesn't raise the plate above the belt tracking height.
    My small belt grinder has a Norton Blaze belt I received as a sample maybe 5 years ago. The top size coating is mostly gone but the grain keeps going. I keep well away from it when starting up in case the join fails.
    In my opinion the Multitool linisher attachment can't be beaten for value and working life for small industry.
    regards
    BC

  8. #8
    Join Date
    Dec 2005
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    South Australia
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    Default

    Are the belts overlapped or butt jointed.

  9. #9
    Join Date
    Dec 2007
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    Adelaide
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    Default

    The belts are overlapped, probably not the best idea to get the cheapest, more expensive brand name belts probably have better made joints.

    I haven't noticed any lack of power with the stuff I've been sanding so far, some the comments made in this thread mention that these things are under powered so I tried to grind a radius on a mild steel bar around 30mm wide 8mm thick - pressing as hard as I dare due to the thump/knock from the join in the belt and it did not appear slow it down, radius was ground with no issues, it's hard to read but it looks as if the motor is labeled 0.18Kw or 180 watts and 2.5 amps - doesn't say much for the efficiency of the motor, I always thought small induction motors were around 55% - 60% efficient, with Chinese motors who knows, they seem to have their own standards.
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  10. #10
    Join Date
    Sep 2012
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    York, North Yorkshire UK
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    Hi Familyguy, Guys,

    Mine definitely says 250W, but it couldn't pull the skin off a rice pudding !

    I've actually got a spare motor for this machine that originally came off the original one that I had. That one had a seized up roller. I managed to break the plastic trying to get it apart.

    Both my machines came from the scrapyard as rescued ones.
    Best Regards:
    Baron J.

  11. #11
    Join Date
    Dec 2005
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    South Australia
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    Many people replace the motors on these with more powerful units, plus using butt jointed belts will all but eliminate the bump

  12. #12
    Join Date
    Jul 2006
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    Athelstone, SA 5076
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    4,255

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    I am at a loss to comprehend how a under powered belt grinder can be the cause of the thump i experience with a 3 mm radius on 4mm flat bar with a 2 x 72inch belt grinder driven by 3hp motor.

  13. #13
    Join Date
    Aug 2008
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    I don't know if they still do, but the large Norton Metallite belts we used on the linisher at my old work had a squiggly butt join with tape on the back for strength; very smooth running.

  14. #14
    Join Date
    Dec 2005
    Location
    South Australia
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    Default

    The bump is caused by the cheap over lapped joints on the belt

  15. #15
    Join Date
    May 2011
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    Murray Bridge S Aust.
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    It's not only cheap belt that have the overlaps. Good quality belts have tape over the butt angled joint, they are harder to find.
    Kryn
    To grow old is mandatory, growing up is optional.

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