Question about my trike

[model-a]

I have a old trike and the hub is striped out can I just make a straight axle and how would I go about this.

 

[RustySprockets]

Most trikes are only driven by one wheel--are you sure the "stripped out" one isn't the one that coasts? A straight axle will be problematic in tight turns. The outer wheel must turn faster than the inner one.