String trimmer hack: Installing a 12-inch miter saw blade. What could possibly go wrong?

Hack a Kobalt 40V String trimmer KST-2540-06 into a multi-purpose saw. Please do not try anything you see in this video.

[crispysocksss]

If it breaks off, it's going to be a bey blade 😂

[bobp]

Famous last words
"Don't worry it's perfectly safe" 😂

[aultraman]

Put some sort of plexiglass shield to keep flying debris from hitting you.

[keepingup]

It's called "The Executioner".

[Menstral]

They make weed eaters that accept this kind of tool. I used to use them on Creek Banks where the angle was too aggressive to mow

[fun_ghoul]

Yeah...no. There are a few safety issues here.
1. The bolt is not meant to put up with the stresses of the saw blade. If it breaks, someone's going to the hospital.
2. Similarly, the gearbox isn't built for the rigours of turning that bad boy. Think of the blade vs. the original trimmer assembly in ebike wheel/motor terms, namely the centrifugal forces of a 12" steel blade vs. the original string assembly, which is perhaps 4" and made of plastic. A failed gearbox might not send you to the hospital...but it might. Again, if you insist, perhaps contemplate a smaller diameter blade.
3. As with 2x4s and hedges, that blade will go through the plastic grass guard -- and whatever else it hits before stopping -- "like butter". If you insist, then you might weld up a guard from 1/4" plate steel...which will make the unit too heavy to be practical.

As "Menstral" says elsewhere in these comments, there are products manufactured to use such a blade. I used one as a teen golf course worker, on thick weeds. It was a Shindaiwa (the golf course's "normal" string trimmers were Stihl and Echo), and the blade was 9" diameter. I have no idea if the gearbox is uprated vs. the "normal" model, and also, no idea about the ratio.

If you do none of the above, please at least consider limiting the RPM electrically. The actual trimmer RPM is the same as a circ saw (roughly 5500-6000 RPM), but the circ saw has a big fat bolt and a steel guard. Again, contemplate in ebike terms: Half the speed = 1/4 the forces. Stay safe, Vu...don't lose your head! ✊

[Sylvan_dB]

I'm thinking this is just like the commercial "Weed Eater" brush cutter I used as a kid and would be perfect to solve a little problem I have...

I have a patch of black locust that has sprouted up from a neighbor. Probably 2-3 dozen trees with trunks up to 3in diameter (but most only 1-2in) and 20 feet tall. That would not be too bad, except for the 1-2in long thorns that cover these trees!

[tims]

I had to quit watching after about halfway. You're gonna hurt yourself. Those weed wackers spin at tens of thousands of RPMs. Circular saw blades are made for only a few thousands. Stop it man. I don't want you to get hurt.