Bosch professional jigsaw blades for scaffolding boards

[baldkev]

Yesterday i was on daddy daycare duty, so i couldnt look at my jigsaw. Today im back on site. @Doug71 Is correct, the blade actually moves backwards when swing is engaged, not forwards as i said..... with zero swing the blade is at 90 to the base. My makita moves backwards about 5mm on full swing from the very top of the blade to the bottom.
The swing must be on a cam or something with the blade holder as it swings back furthest at full plunge depth, then as the blade goes up, it swings forward...... however, it does not get to 90°, it has about 3mm of travel so with full swing the bottom of the blade is out of square by 2mm ish.

I have always thought it was the opposite, so how does a down cutting blade jump about and get caught up with the swing on? It engages the top surface of the material first but i would have thought the waste would clear as it cut because the bottom section isnt engaging at that point?
I guess that as the blade comes back up and is swinging forward, it is riding on the uncut area and as the teeth come back down and get purchase, it tries to lift the saw. Even on speed 1, the blade was moving quick enough that it does about 3 plunges a second, so at speed 6......

 

[baldkev]

I just ran it along the edge of a piece of mdf abd in fact, it does end up square on full swing at its top position the blade is back to being square

 

[baldkev]

The pendulum action should be OFF when cutting curves. Blades, and blade holders, will break easily.

Ive been doing it with pendulum on for about 26 years and have never broken a holder. Ive had a couple of blades snap but that has mostly happened on straight cuts doing laminate when that was an in thing..... and the pendulum definitely speeds up curves, it'd be interesting to do a few tests in 2" softwood to see if it affects blade wander positively or negatively ( but i cant be bothered )