Mini Mite clone - slow build thread

Discussion in 'Sand Mullers' started by Guster, Jul 26, 2019.

  1. Guster

    Guster Silver

    Had about an hour or two before the storm arrived on Saturday. Just enough time to take the muller tub outside to remove all the loose rust with a knotted wire cup wheel on my angle grinder. While the steel was clean I put on some rustconverter till I decide to paint it.
    [​IMG]
     
    Tobho Mott and joe yard like this.
  2. Guster

    Guster Silver

    Found some inspiration in food processing machine and decided to put a 10deg taper on the larger of the rollers for the muller. As well as a very subtle crown to help it track easier. This makes the axle attachment a bit harder but now provides some much needed clearance. Especially for the fore and aft outboard wheel edges and the drum. Making it easier to add rise and fall as well as trail. Just happened to have this piece of 30mm roundbar to use as a drive shaft. Also cut the leaf spring down and drilled a second hole next to the existing one to mount it as a wiper.
    [​IMG]

    While I was making a mess of my workshop and my nostrils machining this malleable cast iron I thought I'd add the bearing pockets too. First by boring one side on the mill, concentric to the OD. Then doing the other side concentric to it on the lathe, using the other bearing pocket to mount it. Machine to my favourite fit, just slightly tighter than a slip fit but not quite a press fit.
    [​IMG]

    Currently doing a mockup in CAD for the axle mount options etc.
     
  3. Guster

    Guster Silver

    With other projects on hold and needing the space on my work bench it is time to see this done. I was hoping to sort out the motor and gearbox mount first but that may involve some casting. We've had a fire-ban all summer and had outdoor fire restrictions during our cv-19 lockdown period. Also don't have all the material on hand to build it the way I designed it. Since getting material is out of the question I will just need to make do with scraps on hand. That means rather than machining whole parts I have to patch them together from available scraps. First the main shaft for the wiper and roller assembly. Shaft already has the keyslot milled to match the reduction gearbox.
    [​IMG]

    Then the lid for the muller to hold the self aligning bearing. Still have to fabricate the gearbox/motor mount and an inlet scoop for the sand. The lid will also get some key lugs to stop it spinning on the drum.
    [​IMG]

    While at it I decided it was time for a pattern making table. Since I use plastic barrels to store my sand I decided to use an old laundry sink for the spillover and deflasking. The sink is mounted at the height of the barrel and the 20mm wood top is actually sitting on top of a bunch of 2x4s and 2x8s so it is pretty solid for tamping flasks on. It still needs a good sanding and paint or varnish... to be decided. Thinking of adding a way to mount the muller over the sink as well. Else have it running to the side and over a plastic barrel. Would be nice to keep the table mobile as it will live under the house when not in use.
    [​IMG]

    Will make a bit more progress on the lid and the motor mount to the gearbox I have. Thank goodness I titled a slow build process... ;)
     
    Tobho Mott likes this.
  4. DavidF

    DavidF Administrator Staff Member Banner Member

    Slow and steady wins the race... you'll enjoy it when it's up and running...
     
  5. Petee716

    Petee716 Gold Banner Member

    Good progress Guster
     
  6. Guster

    Guster Silver

    Cheer David. Definitely not in any race here :oops:

    As you say it will be very nice to have the muller ready when I'm let out to play again.


    Thanks Petee
     
  7. Guster

    Guster Silver

    Little more on the muller this weekend. Finished the fabrication on the lid and gave it a coat of hammer finish green.
    [​IMG]

    Can start assembly and figure out how I want to mount the motor to the gearbox.
     
  8. DavidF

    DavidF Administrator Staff Member Banner Member

    That looks down right spiffy.
    I'd buy one :D
     
  9. Guster

    Guster Silver

    Thanks David. The over engineered cake mixer is quite the heavy beastie now. Hoping to get it assembled to decide how I will mount/support it. As it is I'm already making old man sounds when I have to pick it up or move it. Don't think I'll want to have to man handle it too often.

    Best of all... I can see part of my workbench again!
     
  10. Tobho Mott

    Tobho Mott Gold Banner Member

    Just think about all the old man sounds you would be making trying to hand mull all your sand... It's gonna be so worth it!

    Jeff
     
  11. Petee716

    Petee716 Gold Banner Member

    LOL. I've got some bad news for you young man. Once you start making those sounds you've reached a milestone, and there ain't no goin back! Lol.
     
  12. Guster

    Guster Silver

    The grumbling ones or the groaning ones? :D Could do with some core exercises though. :oops:

    It will be nice to have the sand reprocessed after casting so it is ready to use straight away, next time without wasting time waiting to have it ready. Even freshly mulled sand seems better after it has sat for a week.

    Shush now... enjoy the country side and forget about the milestones. ;)

    The graying fox looking back at me in the rear view mirror knows the road ahead is getting shorter and no hurry to get there. :)
     
  13. Petee716

    Petee716 Gold Banner Member

    Nice.
     
  14. Guster

    Guster Silver

    Assembled the muller lid by bolting the self aligning bearing on. Fit it over the spindle I had put in the bowl and bolted on the gearbox losely. Purposely left the key out so I could turn the spindle and align it a bit before bolting the gearbox in place. Then inserted the key, made a little endcap and bolted it the the threaded end of the spindle. Ready to receive a motor. The shaft for the motor I had intended to use is 16mm diameter and the gearbox is 18mm. Rather than stuff around I found another motor that laready has a threaded face and should be easier to attach to the gearbox. Yup, it's heavy!!! :eek:
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    Little internal shot of the action end.
    [​IMG]

    Found some white wood primer after lunch and gave the pattern making table a coat. White can be a bit glarey in the sun. Might put some machinery grey enamel over the lot and call it done. Just waiting for the motor now.
     
  15. Petee716

    Petee716 Gold Banner Member

    Looking good! It's hard to tell from the pics but it looks like the plow/wiper assembly are attached to the shaft by cap screws instead of welded? Probably a good thing so that if you decide to change the way sand flows in the muller you can (more) easily change your configuration. Plus it's never a bad idea to build a weak point into the mechanism in case there's a jamup. The wiper would be most likely spot. I built a Von Torne style muller years ago and the second time I used it I got a piece of tramp metal jammed between the scraper and bottom-about the size of a pea- and the frame of the machine folded right in half. On the rebuild I incorporated a shear pin and run the belt between the motor and gearbox loose to allow for slip. I try to be more careful about what goes into the muller as well, but there's only so much you can do. I know yours is a different mechanism than what I'm talking about but the same considerations apply.

    Pete
     
    Chazza likes this.
  16. Al2O3

    Al2O3 Administrator Staff Member Banner Member

    Coming along nicely Guster. How are you planning to mount the muller? Are there legs that attach or a stand of some sort?

    Best,
    Kelly
     
  17. Looking really good mate.

    I want to see it run in sand!
     
  18. Guster

    Guster Silver

    Yes, the wiper is a section of trailer leaf spring bolted on with two M8 capscrews. I was originally thinking of adding a shear pin to the shaft. Still not hard to do but hard to work on if not done right. Belt drive would be nice but there is so little real estate on this thing already. Alternative is to use aluminium key stock for the shaft key though that is even harder to replace, having to remove the gearbox off the shaft to replace it. For now I'll just run it attended and turn it off when it stalls.
    [​IMG]

    Good question Kelly. Originally the MiniMite sits on a a little tub which is OK for the small amounts but tedious in general.
    http://forums.thehomefoundry.org/index.php?threads/new-to-me-mini-mite-muller.513/

    Oldironfarmer modified his to sit on a swingarm mounted to the wall.
    http://forums.thehomefoundry.org/index.php?threads/mini-mite-muller-mount.608/

    First wanting to see how heavy mine is over all and then how it balances. Worst case I lose some patternmaking bench real estate by having it on legs or cantilevered over the table. Else I was intending Mount it similar to OIF so it can swing a little out of the way when not needed. Just have to be cautious of the weight and how much it swings. Either way I may have to do a little more welding and (re)painting.

    Thanks OIF! Really keen to see it run myself. Motor should arrive next weekend and should not take long to mount once I've machined the shaft down a bit. Our pandemic management restrictions have been lifted a bit so a little casting might be on the cards sometime soon. Not this weekend perhaps as there is much needed rain on the way as well.
     
  19. My muller has the fill opening and the discharge gate about 60 degrees apart. I needed to be able to swing it to get each over the heap. I see yours are aligned. If mine had been aligned I might have put it on skids and slid it back and forth on the adjacent table.

    Looks like you used Mini-Mite green!:cool:
     
  20. Guster

    Guster Silver

    Might just make a little pedestal stand for it in the mean time and see where it takes me. Aligning the openings also made sense in case this plonker forgets to close the gate as it is easy to see.

    Mini mite green and Hammerite green must be similar. :cool: Left over paint from the bandsaw rebuild and only paint other than machinery grey and black enamel I had on hand. 3 weeks ago it was still war time rations and not knowing when next well be allowed to buy paint again. o_O
     

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