T-shank
Common on modern tool-free jigsaws, with a tang profile that locks into the clamp.
U-shank
Found on some older or screw-clamp models and not interchangeable with every T-shank system.
Roller and guide setup
Correct seating, guide alignment, and low blade play reduce wandering and bevel.
Method for this decision
- Read the tool manual or clamp marking and identify the accepted shank profile.
- Seat the blade fully, confirm the teeth face the intended direction, and check the roller or guide contact.
- Run a short supported test cut at a controlled feed before starting the finished part.
Worked example
Example: a T-shank blade can lock into many tool-free modern jigsaws, while an older screw-clamp tool may require a U-shank. “Universal” packaging cannot override the machine’s actual clamp.
Limits and stop conditions
A seated shank does not prove the blade is long, thick, or rated for the material. Disconnect power before reseating and replace a bent shank or blade with damaged teeth.