Circular Saw Emergency Stop Embiggener

The NVR "stop" button on my Ryobi circular saw left a lot to be desired. It's 300mm below the table, set back quite a way, and has a surface area of about 15 X 10 mm (ish).

Turning it off in normal usage was quite a fumble. It often needed two or three goes to actually hit and depress the button successfully, and then was only really possible by using an extended finger. I dread to think how difficult it would be to operate in an emergency, especially if there's fingers flying around like an explosion in a hot dog factory.

It's always been at the back of my mind to come up with a more effective switch. At one time I bought a larger aftermarket switch to fit. But the replacement didn't have the connections for the blade braking required in the UK market (it works by shorting the motor when the switch releases, and quickly stops the blade from spinning after the power is removed).

I could have simply done away with the extra wires for this, but I quite like the rapid stopping it provides and, in any case, it would have needed me to hack larger holes in the saw's body - something I didn't really want to do.

So the new switch ended up on my router table, and I simply carried on with the Ryobi's frustrating switch assembly, cursing every time I used it.

Today was the day when I set about changing that situation. My design constraints were that I shouldn't need to irreversibly alter anything on the saw, and that it had to be tough enough to hit with anything from the flat of a hand, to a bit of two by four.

Here's the result. The start button can be easily accessed via the hole on the front, or by lifting the "STOP" flap. But the rest of the time the flap is the only thing you can hit without having to think about it.

It attaches using the switch's original upper mounting hole (albeit with a longer bolt), and is big and chunky enough to take the abuse, and (hopefully) won't break if it is ever called on in an emergency situation.

In order to fit the two parts together, I put both pieces in hot water. This makes them flexible enough that the pins on the "STOP" flap can be gently forced (oxymoron, right there!) over the hinge component where they clip into place in their respective holes. The rounded edges on the hinge legs are a great help with this step.

One minor niggle: On my saw, the last few millimetres of the flap's travel are obstructed slightly by the shape of the Ryobi's body moulding. Fortunately, the switch itself has already acted well before that point is reached, so it's not really an issue. However, if I ever remake the flap for any reason, I'll simply add a 5 degree taper on the underside of the flap to clear the body.

Other than that, it's a perfectly cromulent job.

Happy printing!

Print Settings

Printer Brand:

Creality

Printer:

Rafts:

No

Supports:

Resolution:

0.2 for the flap, 0.15 for the hinge

Infill:

Filament: E-DA PLA Red/Black

Notes:

Category: DIY