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  1. #1
    Join Date
    Jul 2019
    Location
    Texas
    Posts
    15

    Default Casting a new part for an old motor

    I was replacing bearings on the motor for a bandsaw restoration project. The bandsaw is a 1957 delta wood and metal.cutting model. It has a 6 pole ac motor that runs around 1200rpm. It also has a centrifugal switch to disconnect the starter winding when it gets up to speed. I clumsily broke a little plastic part of the switch while replacing the bearings in the motor.

    Went to the motor shop, the replacement part was almost $100usd. Apparently 1200 rpm isn't all that common. I decided to make my own aluminum replacement part out of melted down beer cans. Recycling and all. I have attached a few pictures and a link to a short video of the process.

    https://youtu.be/--HhSJGqmww

    Sent from my SM-G950U using Tapatalk

  2. #2
    Join Date
    Sep 2012
    Location
    North Yorkshire UK
    Posts
    3,119

    Default

    Hi Weekend.Warrior,

    Whilst I admire your skill in making a casting for the part for your motor, I would be very concerned about its suitability for that particular replacement part.

    The original part is made from an electrically insulating material for a very good reason.

    If I were making a replacement part, I would have used some fibreglass or paxolin sheet, the stuff that PCB's are made from would be ideal. You would of course have to etch the copper off first !
    Best Regards:
    Baron J.

  3. #3
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    63
    Posts
    202

    Default

    Good that you were able to make the part.

    Don`t know how much casting you have done but there are better ways to make the mould. Can explain if you want.

    The main point is NEVER cast with your face or body parts directly over the mould no matter what protection you are wearing. Weld a handle on you ladle or put it in a cradle so you can poor while standing off to the side. I have been around enough exploding moulds to understand the damage that can be done.

    Tony

  4. #4
    Join Date
    Jul 2019
    Location
    Texas
    Posts
    15

    Default

    Quote Originally Posted by bts View Post
    Good that you were able to make the part.

    Don`t know how much casting you have done but there are better ways to make the mould. Can explain if you want.

    The main point is NEVER cast with your face or body parts directly over the mould no matter what protection you are wearing. Weld a handle on you ladle or put it in a cradle so you can poor while standing off to the side. I have been around enough exploding moulds to understand the damage that can be done.

    Tony
    It was my second time. Definitely investing in tongs and a face shield after some things I saw on youtube. Also something more substantial than a steel bucket.

    Sent from my SM-G950U using Tapatalk

  5. #5
    Join Date
    Aug 2011
    Location
    Perth, Western Australia
    Age
    63
    Posts
    202

    Default

    Good effort for early days.

    A round steel container with a bit of a pouring lip would be fine.
    Use a some tongs to remove that from the furnace and place it in a cradle with a handle coming off to the side. This will give better control over the pouring.

    Tony

  6. #6
    Join Date
    Jul 2019
    Location
    Texas
    Posts
    15

    Default

    Quote Originally Posted by BaronJ View Post
    Hi Weekend.Warrior,

    Whilst I admire your skill in making a casting for the part for your motor, I would be very concerned about its suitability for that particular replacement part.

    The original part is made from an electrically insulating material for a very good reason.

    If I were making a replacement part, I would have used some fibreglass or paxolin sheet, the stuff that PCB's are made from would be ideal. You would of course have to etch the copper off first !
    You make a good point about electrical conductivity. I went back and forth for a few days with my father, who is an engineer.

    Ultimately, we agreed that in this case, aluminum would be ok. It is not readily apparent from the pictures, but this piece was originally made from plastic, we believe, for cost purposes, not for electrical properties. It is like a rotating piece that pushes on the switch to engage the contacts. It is not in contact while the motor is spinning at full speed.

    All of that, and also considering that I may use the saw itself only an hour or two per month, and we decided that aluminum was suitable.

    Sent from my SM-G950U using Tapatalk

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