The Harbor Freight mini shear appears to be the same as the one
offered by Micro-Mark at
http://www.ares-server.com/Ares/Ares.asp?MerchantID=RET01229&Action=Catalog&Type=Product&ID=82820
I bought the Micro-Mark shear/brake (on sale) a month or so ago and
have used it a few times to shear 0.031 and 0.062 FR4. I have
difficulty keeping the PCB in place while shearing. The shear tends
to push it out as the cut is being made. Some sort of clamp would be
handy. On the other hand, it does make a fine little brake. Made a
couple of nice metal boxes using it.
This shear is not a precision tool. The first one I received had to
be returned because of a poorly made gear. The shear is nice and
rugged but not well made.
If I want a clean right-angle cut, I use my radial arm saw with a
plywood blade. Have to watch those finger tho!