The following was an interesting exercise...and that's all it was--an exercise. "Quick and dirty." I am not claiming that this represents reality in the sense that the quality and moisture content of the leather and the usage of the tools is what they would be in context. However, the leather is similar to welting ...or at least the kind of leather that has traditionally been used for welting--such as insole shoulder; it has been moistened and allowed to dry back to just "tempered".
In the photos below, the pricking on the extreme right is my own "stitch prick."
To the left of that group is the manufactured prick.
And on the extreme left is the output of an unused
Barnsley fudge wheel set for 12spi.
The two example of stitch prick output were done with about the same pressure as I would apply to pricking up a welt.
I really had to lean on the fudge wheel to get as deep an impression as I did. I don't know if I could apply that much pressure in actual usage. It was more pressure certainly than was necessary for the stitch pricks. I think you'd have to go to a bench-top fudging machine to get comparable indentations. That said, I did not heat the fudge wheel so that's one strike against my technique with it...there may be others.
So...for what it's worth:
Edge on...notice how deep the indentations are:
--Edited by DWFII - 11/7/13 at 12:11pm