I didn't want to throw away my shovel when the plastic handle broke so I whipped this up. The first PLA print I did broke after about 5 days of use trail building. I've since reprinted in ASA and it is holding up better. I opted for a wooden grip but the model has a modeled one, let me know if you try that.
The diameter of the shovel handle shaft is 1.25".
I would recommend printing in this orientation without any support:
I filled the top few inches of the fiberglass handle shaft tube with a piece of wood a cut roughly to fit and then used grabber screws to secure the handle arms and band to the shaft. I made my grip from wood and used lag bolts to attach. I used regular washers on the lag screws and fender washers on one of the pairs of grabber screws.
The shovel is usually/often only $10 at Harbor Freight: https://www.harborfreight.com/lawn-garden/gardening-garden-tools/shovels-spades-tampers/27-in-round-nose-mini-shovel-with-comfort-grip-handle-64922.html
The author marked this model as their own original creation.