My Favorites are Wilcox .
I have what was a 22" Wilcox from Kellyco.

from Sharpening over the Years it is now a 20" Wilcox
one of the first things I found Necessary Was the Padding on the Handle to Stop Getting a Sore Hand pushing it into the Ground.
The other, is Hammer the digger end into a scoop .
If you dig like I do & use it to Pry Rocks & Roots
it will bend here if you don't
With the Adjustment it becomes indestructible.
as you can see I still bend the tip occasionally and need to hammer it back in place
But These days I Mainly use it as a Cane, To help Steady myself as I Stand up after Digging,
& occasionally as a Pry Bar or very deep targets .
my other indispensable tool is a 13" Wilcox Weeder .

The Narrow Tip
Makes it Great for Clay & Hard Dry Ground. and is virtually indestructible.
and that's saying allot. I destroy almost all diggers other then Wilcox,
usually on the first day out.
The Exception is some Heavy Stainless Scoops Made by a former Member of TreasureNet.
And Yes I Did Bend the 13" one on the First day Out
The Small one has Started to Curve Back.
So I went Back to the Wilcox's.
I've also Snapped all the Blade type Diggers I've Owned,
shortly after using them
