MightyMig 100 Erratic Feed Cured

  1. catceefer Member

    Messages:
    72
    Location:
    Aylesbury, England
    Quite some time ago I was given an old MightyMig 100. The feed was very erratic: the wire would not feed smoothly or it would simply stop, even though the motor was running smoothly. Constant adjustment, new liners, clean rollers, new tips and fresh wire made no difference.

    I then looked closely at the roller assembly and realised that the plastic from which the outer support for the feed roller was made was slowly crumbling like Edinburgh rock. The more that I adjusted the tension, the worse it crumbled, stopping the roller from exerting any pressure on the wire.

    I fabricated an alluminium replacement part and the machine now welds faultlessly.

    If anyone else has similar, elusive problems, it might be worth inspecting this part carefully.

    James.
     
    a111r, slim_boy_fat and RonA like this.
  2. RonA

    RonA specialist in repairing sealed for life equipment

    Messages:
    1,654
    Location:
    Stockton on Tees, UK
    I had similar drive problems on my Cebora till I realised the pressure exerted on the drive roller by the ball bearing roller was being dissipated by the plastic pivot bending. Made a small bracket to prevent the pivot bending & never looked back. The drive mechanism is definitely the “achilles heel” of budget welders.
    RonA
     
    gordon stephenson likes this.
  3. a111r Member

    Messages:
    888
    Location:
    London
    I've got a spare tensioner arm from an early MightyMig, if anyone needs that part.
     
    slim_boy_fat likes this.
  4. catceefer Member

    Messages:
    72
    Location:
    Aylesbury, England
    That is useful to know. I shall bear it in mind as the rest of the assembly is not in the first flush of youth. The outlet where the wire runs is showing signs of cracking as well.

    James.
     
  5. a111r Member

    Messages:
    888
    Location:
    London
    I'll also be getting the a whole MM wire feed mech. and torch in next week, if you need a replacement.
    I've found the weakest link with these is the plastic gear train losing teeth.
    Also, the 'hold down' piece for the torch lead tends to break (which is why it is missing from the photo below)
     
    Last edited: Mar 7, 2020
  6. a111r Member

    Messages:
    888
    Location:
    London
    Actually, it seems I have nearly the whole plastic assembly already, including the motor (not shown).

    DSCN3420.JPG
     
    Last edited: Mar 7, 2020
  7. frank horton

    frank horton V twins are great but 4"s rule.........

    Messages:
    2,227
    Location:
    Soon 2 B Crete
    ud think by now there would be an adaptable alloy unit avaiable to cobble up......
    my mig also suffers but have an extra long lead..... and can only use 0.8 wire now....
     
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