I've been working on converting a 500Kg pneumatic press to use it for injection molding.

In order to do that though I'd like to raise the cylinder up maybe 12". So I fabricated 4 5/8 CR rods and drilled/tapped m10 1.5 holes in the ends. (Same as the tie rods on the cylinder, that bolt into the top casting of that cylinder.)

So my current thinking is tie rod screws into top of standoff rod, bottom of rod has 10m 1.5 stud that screws into top casting of the press. Because this thing will be under cyclic load I figure it should be preloaded. The original tie rods just screwed into the casting. There's not enough clearance inside the casting to use full on bolts coming up from the bottom.

Can I just torque the whole stack at once and forget about it, or does introducing these additional elements complicate things? The face of the cylinder is no longer against the top face of the casting. Not sure how much that affects things. I don't expect a lot of side loads. Here's a rough cad image of what I'm considering. Sorry the tie rod ends don't like up with the extension rods in that picture. blush

Does this seem reasonable? Should I try some other locking strategy? Is this crazy?

enter image description here

  • $\begingroup$ if you can get everything centered and coaxial, sure. stand far away and wear safety goggles. if it the yellow cylinder wedges into the pink one, something might snap. $\endgroup$
    – Pete W
    Commented Dec 7, 2021 at 3:37
  • 1
    $\begingroup$ I would just make the rear cylindrical support longer and I assume it has some clamping mechanism already. Then fewer adapter bits are needed making it safer. $\endgroup$
    – Solar Mike
    Commented Dec 7, 2021 at 6:19
  • $\begingroup$ Originally I had thought about extending the main column as you suggest, but that complicates the mounting of the heating chamber (pink cylinder) It also positions the pink cylinder in a bad location to load plastic into it. So I eventually punted on that. $\endgroup$ Commented Dec 7, 2021 at 17:31


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