I grew PA Dutch Lancaster Co .. (Pa Swiss/German) , a bastardized dialect from the Palatine or or perhaps a Swiss twist ..
After 300 years of mixing in English and their own words ... now we a chopped soup of words that only the locals will make sense of .. (maybe) !!!
Schnibble is normally used a for a small piece of something .. apple piece , broken piece of cake .. etc etc .. You get my drift ..
I my case here , a small itsy piece of steel to keep the patchbox lid from falling off the gun !!
Sorry for the confusion ... well not really !!
Al