Wax piston sprue extruder?

Discussion in 'Lost wax casting' started by Zapins, May 21, 2018.

  1. Peedee

    Peedee Silver

    The thrust bearing plate on the augers I worked on were a square steel plate with a round collar welded on to receive the bearing. The auger tube had a matching square flange welded on and four bolt holes to secure. With clearance holes it was possible to line up the shaft and centre the bearing plate before mudering up retaining bolts. The only 'close machining' was the bore that took the bearing outer shell, the rest was alignment.

    Don't know that is much help with that end of things?
     
  2. Zapins

    Zapins Gold

    Found a local guy to machine the extrusion screw to dimensions, bore and key the shaft. More pics to follow.

    The outside of the screw is at dimension, next will be the shaft/key. Then I'll be able to set it up and start testing. Maybe in the next week or two it will be finished.

    I don't think it matters that the low lying areas are left rough, though maybe I'll give them a polish with a flap disc if I feel like the wax isn't extruding properly.
    5879308281(1).jpg
     
  3. Jason

    Jason Gold

    There ya go man! Onward and upward!
     
  4. Zapins

    Zapins Gold

    Yee-haww. I'll be happy to get this baby up and running. Couple hundred bucks invested in this thing so far for motors, gear boxes, pids, metal etc. I hope it works as well as I think it's going to lol...
     
  5. Jason

    Jason Gold

    I bet that was fun to center on that lathe. :eek: Look on the bright side, if this thing sucks, you can melt that thing down into a squid.:p
     
    Zapins likes this.
  6. Zapins

    Zapins Gold

    He machined this little defect out. Still waiting on the clean pic. He's going to cut the slot and key soon hopefully and update with pics. But here's a new pic for you all. I'm hoping I did a decent job welding the defects inside this little piece so when he keys it it's all solid.

    I've got to get a small 5x4x3/4" thick plate to him so he can machine a groove for the thrust bearing and I can weld in the plate at the base of the screw so the backward thrust of the screw is transferred to the bearing then to the plate to frame rather than directly to the drive shaft and motor.

    IMG_48481.jpg
     
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  7. Zapins

    Zapins Gold

    Machining done. The fit is good between the shaft and cylinder. Next step is I need to seat a thrust bearing into a thick steel plate so the screw can push back on it. Then I can weld up the frame.

    I wonder if wax will squirt out the back? If it does I can cut a slot for a rubber seal.

    20190829_173419.jpg 20190829_173137.jpg 5887940181.jpg 5887940851.jpg
     
    Mark's castings, Tobho Mott and Jason like this.
  8. Jason

    Jason Gold

    Your welding in the location of that key looks good zap. I bet that was easy as pie to broach. Besides being a little gummy, the stuff is nice to work with.
     
  9. Zapins

    Zapins Gold

    I bet. Glad its sorted. Just need to assemble it all and get that last part machined to accept the thrust bearing. How many thousandths undersized do I make the slot for the bearing?
     
  10. Jason

    Jason Gold

    That's a question for your machinest. Is he going to press it on?
     
  11. Zapins

    Zapins Gold

    I think I'll give it a shot on my lathe. He was saying its going to take about 2 hrs to bore through and make the slot on the lathe and was quoting about 75 bucks. I think I'll drill out the inside diameter with a hole saw then bring it up to final dimensions. Might be a good first project for me on the lathe. It's just a hole, hopefully it's not too difficult for a complete novice like me to do haha.
     
  12. If you are wanting a press fit about 1/2 a thousandth (0.0005"). If you want a slip fit, ten (0.010").
     
  13. Zapins

    Zapins Gold

    Maybe I should just have him make the slot for the bearing? Its 75 for 2 hrs work but that's about the same cost as me driving back to CT and paying tolls and gas. And doing it myself will delay the project many weeks if I can even set my lathe up to do it.
     
  14. Jason

    Jason Gold

    pay the man.
     
  15. crazybillybob

    crazybillybob Silver Banner Member

    what Jason said
     
  16. Zapins

    Zapins Gold

    The parts are made. Now I just need to build the frame.

    Thrust bearing plate is done. Nice work by the machinist if I do say so myself.
    20191102_023021.jpg 20191102_022758.jpg 20191102_022827.jpg
     
    joe yard and Mark's castings like this.
  17. Jason

    Jason Gold

    Good ol Timken. I just bought some aircraft spec timken bearings and got f'd $89bucks a piece. :eek:Same part at autozone is 11bucks.:rolleyes: And it didn't even come with races!
    Not changing them when ya replace a bearing is like taking a shower and putting on the same dirty drawers!:(

    Looks good zap. Is that a witness mark on the one side?:p
     
  18. Zapins

    Zapins Gold

    The mark is from the plasma cutter that cut this square out of a sheet of steel. I think it's the starting hole where it burns through. I bought the block as scrap for scrap prices. I'm thinking I mount it to a horizontal bar of steel with bolts, then mount that bar somehow into the frame of the extruder.

    I think these bearings cost about 13.50. They are new old stock and were sold cheaper than normal. I got 2 so I have a replacement in 40 years time when the bearing burns out and the company has gone out of business. Haha.
     
  19. Jason

    Jason Gold

    You'll never burn that bearing out. Bolting it together is a good idea.. But drilling a bunch of holes in thick stuff is gonna suck. Two words... DRILL DOCTOR! Dont buy the cheap ones, go straight to the top of the line. Dare ai say I actually like mine:oops:
     
  20. Peedee

    Peedee Silver

    I've never got on with those drill grinder units, that said I'm not that great free-hand either!! I guess there is good and bad and have cheaped out the the couple of units I had, they make great little grinders if you cut all the plastic s**t off.
     
    Jason likes this.

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