Bob Engelhardt wrote:

John Doe wrote:

I hardly use the thing, unlikely it's from normal wear. It has gone through
three or four blades, about one per session of light use.

I usually cut small pieces of 1/8-1/4 inch thick aluminum (6061).

That is extremely unusual. My 1st guess would be cheap blades. You
don't need bi-metal for aluminum, but don't cheap out either.

2nd guess is operator error. Most likely is twisting the blade in the
cut. Around either axis - I hope you get what I mean 'cause it's hard
to explain. Thinking about it- this is more likely the problem than
blade quality.

I try to cut a straight line by rotating the piece left and right to keep it
on track. Being a 1/2" wide blade, that causes the blade to twist. Seems
strange it is so sensitive, but that twisting theory is easy enough to prove.
Will also use a guide when possible. The blades are all good.