Odd issue I thought I’d put here. I made a DIY cicle jig for my old jigsaw - a Black and decker from probably 1980something. I recently bought a Bosch 470EB barrel grip jig saw. SO I modded my jig - and had high hopes.
Which failed tragically. Well not tragically just 3 broken blades a chipped up jig, and circles cut out of 1/4 birch ply and luan. (yes 2 different sheets) and the 1/4 ply ones all have a bevel to them. Smaller circles were worse than the larger (5 inch radius vs 12 inch radius)
I don’t understand why it works so poorly. The old one with a quality scroll U -shank blade cut a good circle. The Bosch with either scroll blades or the precision wood blades cut with lots of deflection and would break a blade. I even used the base plate and zero clearance insert with my modded jig thinking that would help - no dice and it ate up the insert.
Usually the blade would flex and jump off the guide rollers. I turned the speed down to 2 or so (out of 6) and I kept the orbital set to 0 so straight plunge. Any help would be appreciated.