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  1. #1
    BobL is offline Member: Blue and white apron brigade
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    Default Another design question

    I have an old muffle furnace I'm attempting to resurrect.
    I scored this thing 8 years ago and have had have had no room to fit it into my shed.
    Attempts to convince SWMBO to let me install it on the back veranda came quickly to a stalemate - the main thing being the cost of installing a 20A circuit t power this thingy. I can do what I like in the shed but SWMBO wants me to use a sparky for electrics in the house.
    So it has sat on the back veranda for 8 years but recently I sold my gas powered forge so there is finally room for it in my shed.

    IMG_3760.jpg

    The furnace has a base of about 500 mm square and is about 750 mm tall. I would like to mount it on a movable bench/trolley so I can tuck it out of the way when not in use. My guess is it weighs about 60kg? I'd like to have the base of the kiln about 900 mm above the floor so I don't have to bend over too far to see inside and so I can use an optical pyrometer to calibrate temperatures. (I also have a set of sturdy wheels from an old hospital gurney that I can use)

    To make the trolley, rather than buying more steel, I'm trying to use stuff from my stash and have several lengths of 30x30x5 mm and several more of 25x25x5 mm SS that could be used. The trolley would be about 900 mm high and 500 mm wide, by 650 mm deep to allow for some workspace in front of the front door.

    If I used some suitably placed braces do you think a frame made out of that size SS would be too light for this project?
    I realise using SS is bit of a waste but I can't think of anything else I will use it for, and at least I would not have to paint it.

    To power the furnace I have installed a 20A line/breaker/outlet in the shed. This required me to upgrade the shed breaker board which was full with 6 breakers and now has a 12 breaker box with 8 breakers.
    Last edited by BobL; 18th Jul 2021 at 08:23 PM.

  2. #2
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    Default

    60kg/4 corners = 15kg/corner, a bit of bracing and no probs bob, are you gunna cook apple pies...

  3. #3
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    25x25x5 would probably be fine if properly braced. I'd be more concerned about the size of the trolley and it being top heavy (and a bit tippy). I'd be making it as large as I could and have shelves down the bottom so that a bit of weight could be down there, just to pull the C of G down a bit.

    Michael

  4. #4
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by Michael G View Post
    25x25x5 would probably be fine if properly braced. I'd be more concerned about the size of the trolley and it being top heavy (and a bit tippy). I'd be making it as large as I could and have shelves down the bottom so that a bit of weight could be down there, just to pull the C of G down a bit.

    Michael
    Thanks, when I say move it around I don't mean wheeling it around the workshop, just pulling it a couple of 100 mm away from the shed wall and then back again but I take your point about it being top heavy. I am serious considering shelves/racks underneath to store offcuts. That would at also get some of them off the floor where they are ATM.

    The proposed wheels are large so will ride over small stuff on the floor better than smaller wheels.

    RE: are you gunna cook apple pies...
    It supposedly goes to1280ºç - could come out a bit crisp.

  5. #5
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    5mm to hold up 60kg...
    Two words.. Massive overkill

    But if you have it, and you don’t want to buy more, use it.

  6. #6
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by racingtadpole View Post
    5mm to hold up 60kg...
    Two words.. Massive overkill

    But if you have it, and you don’t want to buy more, use it.
    I agree but if I also use it to store some of my my offcuts stash that will easily add a couple of hundred kg to the weight so the 5mm will come in handy.

  7. #7
    BobL is offline Member: Blue and white apron brigade
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    Boiler maker BIL came over recently and gave me a refresher SS TIG tutorial.
    He also demoed a couple of welds on the 3 and 5mm SS angle I'm using to make the trolley for the furnace.
    He then watched me as I did a few welds and provided really useful feedback
    He is a really good teacher - If anyone around Perth needs a Welding teacher he said he is available for a small fee.

    Most of the welds are simple fusions with just a couple using 2.4mm filler rod.
    ITrolleyFrame.JPG
    BIL reckons it should be able to hold a couple of tons.

    The trolley is going to sit on 800 kg rated wheels and there will be 3 shelves made of chunky galv mesh on which I plan to store offcuts.

  8. #8
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    Looking good so far but I have a concern with the castors. I assume they will be attached to the members on the floor in the picture and the overhang is the front. If the cart is pulled towards you and the castors spin and align themselves with the wheel axles moving further back. The G of G moving back at the same time. Will it end up on your toes if one of the wheels stops on something? I would be tempted to have a bottom come forward like the top to lengthen the wheelbase.

    Pete

  9. #9
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    Maybe put fixed castors in the front and the revolvers on rear.
    Like a fork lift you then steer from rear and it won’t get the weight transfer problem.
    H.
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

  10. #10
    BobL is offline Member: Blue and white apron brigade
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    Quote Originally Posted by QC Inspector View Post
    Looking good so far but I have a concern with the castors. I assume they will be attached to the members on the floor in the picture and the overhang is the front. If the cart is pulled towards you and the castors spin and align themselves with the wheel axles moving further back. The G of G moving back at the same time. Will it end up on your toes if one of the wheels stops on something? I would be tempted to have a bottom come forward like the top to lengthen the wheelbase.

    Pete
    The overhang is space for a shelf in front of the furnace. The furnace will be positioned directly over the core of the frame.

    Good point and I have though about that - I'm thinking of using some 5mm thick flat bar extensions to position the castors about 50mm ahead of the front bottom or frame.

  11. #11
    BobL is offline Member: Blue and white apron brigade
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    Couple of my better fusion welds.

    IMG_5033p.JPG IMG_5034p.JPG

  12. #12
    BobL is offline Member: Blue and white apron brigade
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    Well, I managed to get a couple of hours away from the 3D printer this morning to finish the trolley.

    Here's the underside with the 5mm wheel support plates welded on.
    The plates are actually from pieces of 70 x 15 x 5 angle so there's no way they'll be flexing.
    Decided to stick with TIG fusion welding.
    BIL reckons trolley frame should hold a couple of tons
    Wheel mpount.JPG

    Here's teh underside with all 4 wheel plates are attached
    underside.JPG

    800kg wheels.
    Fully wheeled.JPG

    Ta da!
    Bottom two shelves will nominally hold stock/offcuts/etc.
    Top shelf is for furnace accessories eg gloves and tongs etc.
    FInished.JPG

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