I am making a knife sheath which requires triple layers (knife sheath folded over plus a welt to protect the stitching from the blade edge). I was using the titanium awl (which I love by the way) in the traditional manner: pricking iron to mark the stitches then pushing through with the awl. I was trying to get through about 9.2 mm of leather glued together. The needles didn’t want to go through easily and required use of parallel pliers which slowed me down a lot. Needles were harness needles size “0” which measures at 1.05mm.
I wouldn’t have thought it should be that difficult. Maybe I need thinner needles or a larger size blade in the awl? I want to master the traditional stitching technique rather than use "diamond" pricking irons that punch right through the leather leaving larger needle holes (as is commonly used by knife makers). Any suggestions?
I would use John James 004 needles which is a measured 0.8mm for me. That little bit makes quite a difference.
You may also need a slightly larger awl blade. The titanium awl really isn't singing it's best song through almost a CM of hide, I would look for a blade 2.5-3mm wide with straight sides rather than tapered so that the hole is consistent making stitching easier.
get a Cobra class 4 Machine it sews up to 7/8" leather like butter