Soil Block Press - Cylinder - PARAMETRIC REMIX

This is a lovely design which works really well with a wet mix of soil. There's a recipe if you google “bbc gardeners world soil blocks” and it should be the first result, but I can't include external links as I don't think they're allowed here. Use anything you like really as long as there's something to bind the soil if you're making freestanding soil blocks. The mix needs to be thorougly wet, shown in the video, you should get a bit of water coming out if you squeeze a handful. Press the Soil Block Press into the soil mix and the plunger will rise up, for long ones like this you need to press it into the mix 2-3 times to fully fill and compress the soil a bit, then it's ready to eject with one poke of the plunger. For making standalone soil blocks for seed planting, you'd need the extra dibbers by the original author - I don't have the pattern for that built into my design yet, but you could just cut the threads off a dibber and glue it to the bottom of the piston. If there's enough demand I could add the dibbers and an optional cutting body to create the holes for them. I haven't got around to making a parametric square/rectangular press yet as I didn't need one!

My specific requirement was for soil blocks which I could inject into the holes in the lawn made by a brilliant Weed Puller which is this one https://www.printables.com/model/461240-weed-puller-34-pvc although in my photo of it I'm showing my tweaked version as I only had a 22mm OD galvanised conduit available for the shaft which didn't match either of the designer's STLs. I also just cobbled a wooden handle for it instead of printing one, as I had suitable stock handy. With a short stem like I used, it even ought to be possible to print a stem instead of using stock pipe as not everyone will have that lying around.

After building the weed puller and testing it, and finding it fiddly to fill the little holes in the lawn with soil mix without making a right mess, I decided on making a Soil Block Press, and this design looked the most promising. The available sizes though weren't quite right for me, to match the holes made by the weed puller I needed a 25mm wide and 65mm long soil block, so I redesigned the original and made it parametric. In Fusion, go to Solid/Modify/fxChangeParameters and fiddle all you like :o)  I don't know what the limits are, but sensible sizes seem to redraw sensibly anyway, obviously if you want a large one then you'll need to bulk up the plunger stem and thicken up the plunger and possibly thicken the wall of the cylinder to keep the strength up. Works perfectly as it is with 25w by 65h, and I've included the STL for that in this remix as it matches the weed puller. Once you've changed the parameters, you need to make sure the whole component is selected (click on “Parametric:1” in the design tree and click in the radio button to its right if it's not got a dot in it) and then right-click on “Parametric:1” and choose “Save As Mesh” - in the new dialog choose Export to save the STL, or Print Utility to send it straight to your slicer.  

Thanks to the original author for this design idea! Our front lawn is crammed with dandelions and I'm completely fed up with trying to stop them reproducing even more, picking off the flowers every few days and inevitably forgetting and then they seed and… yeah, more bloomin' dandelions! Returfing isn't an option, sloping banks, awful soil, I just want to rip out the dandelions and repair the holes. Digging them out is backbreaking and makes a mess, even with the cut-a-triangle trick and putting the soil back, probably with a load of bits of root which will regrow, so the weed puller was salvation. Poke, twist, lift, weed gone, neat hole left to fill - well most of the time, but it's pretty good. 

After plugging the hole, I sprinkle a pinch of lawn seed, then a pinch of compost on top in the vain hope the wood pigeons won't spot the seed, and on to the next diabolical dandelion. If the hole isn't quite jammed full of soil, just load up a bit more and finish it off.

Hope this parametric version comes in handy for someone.

PRINT SETTINGS:

I used Elegoo PLA+ because that's all I have, it should work with anything but TPU. 

0.4mm nozzle, 0.2mm layers, but anything should do, with these settings I used 3 walls and 6 tops/bottoms.

Infill probably best to go for 30% lines or grid. The cylinder should be all walls, but the plunger and stem will have infill which could do with being a bit more than default density.

Adhesion - despite 25w and 65h being narrower and twice the height of the original, I had no adhesion issues but I do have a PEI bed. If your cylinder detaches then you could use an external-only brim, but a brim that ends up in the clearance space between cylinder and plunger would be difficult to trim off. Original designer supplied extra STLs with tags in the clearance gap which would have the same effect as in internal brim but be easier to trim off. You can add those tags yourself in Fusion by modifying the VentTemplate sketch to add blobs and then extrude them by the thickness of one print line, or I can include them if requested.

Supports not needed. Designed specifically to avoid the need for support.

Please Like this model if you find it useful.

If you REALLY like it, https://www.buymeacoffee.com/gigabeast :o)