| I was recently asked by one of my Internet Friend/Customer Anthony Perillo about the possibility of adding grab irons to my O scale Base Units – part of a Sanitary System Concrete part. The Base Units originally were printed on my FDM printer in PLA but that can be a bit “iffy” in printing smaller holes. I decided to print the Base Unit on my Resin Printer and it came out quite well. I wanted to use 22 AWG wire (sourced at my local Hobby Lobby in brass) for the grab irons as this is 0.025″/0.65mm .. ~ 1.2″ Full-Size. You can’t just make a hole in the CAD 0.65mm as there is shrinkage during curing of the print. That means I needed to use a larger hole in my CAD .. luckily I have done some tests and have come up with a chart to show what size CAD hole is needed. If you go to my 12-30 AWG Hole Test Print page you will find a chart at the bottom of the page which shows us that for a 22 AWG wire (nominally 0.025″/0.65mm) I need to create that hole in CAD .. 0.03″/0.84mm. |
 With that done I created a jig to bend the wire to fit the hole spacing (18″ Full-Size) of the holes printed in the base (and other units). To use the jig you cut off a length of 22 AWG wire, bend into a U-shape, insert the ends of the wire into the holes in the Jig then squeeze and press until the wire conforms to the shape. Remove the wire, cut off excess length and you are ready to install the Grab Irons. |
 To form the grab iron simply –
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