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Reversing Direction of Power Tool Answered

It would be nice to be able to reverse direction of angle grinder, mototool, and similar tools. Sparks may be flying toward ones face in certain positions. The tool also may also tend to kick due to wheel direction.

These tools arent made to reverse. How can one change this?  How can one keep the wheel from unscrewing and flying loose once the motor is reversed? 


You really don't want to change this!
Take your angle grinder:
In the normal direction the thing spins so the nut holding the disc will secure itself.
If you reverse the direction this nut can and will come loose - the result is the disk shattering, slipping or even flying around.
In any case severy bodily harm can be the result.
This goes for every tool that has attachment secured with a nut.
A drill with a proper chuck is no problem though....

thats exactly the problem i address in the question at the end of my post. You have made it more graphic, however, and perhaps spelled out the problem better to others than I had.

Im seeking a solution to that problem. One could, theoretically replace the right hand nut and spindle with left hand ones. But thats a major undertaking.

Is there another way to keep the grinding wheel secure even in the wrong spin direction?

The only way I have seen was on a professional tool.
And there they used spindle mounts that were not round but octagonal to prevent slipping.
The disc itself was held in place by "simple" clamp mechanism screw.
Basically you had a flip handle on the screw and once thightend two pins on the handle would lock into the bottom parts to prevent it from becoming loose.
There are ways to incorporate this to a normal angle grinder or so but it woud require some good engeneering and the option to hraden steel parts.

For example on the standard spindle as we all know it:
Cut a slot into the top and design a nut with a flip over bar that fits into the slot of the spindle.
Only big problem is to design it in a way that it is still nicely balanced.
And of course hardening the entire thing for long life would be good.
If you want something more fancy it would require a new custom spindle and I doubt a normal haooby workshop is capable of making one as the gear is not straight (at least not on any of my angle grinders).

Perhaps shopping for the right tool is a better option. Found this vid, but havent found the tool in "shopping" search.

So they are already out there...
Only question is where to find them if you llok for these tools.
Maybe a dedicated trademan tool shop?

yeah. Maybe tool king.

Or getting back to modifications... weld the nut onto the shaft. Or a locking nut, if theres enough thread on the shaft.

Hmmm, how about dirt cheap and simple?
I guess adding a switch to allow the motor to run in reverse is not the biggest problem.
While at it maybe even a speed control?
For the locking nut:
How about using these nuts like you have on your car? (on the wheel hub)
By drilling (or better using EDM [Electrical Discharge Machining]) the 3 holes you can use a simple locking pin for the nut.
And I doubt it will affect the balance too much.
There are even these keyrings with pin for this job if you want a "quick release system".

But don't ask me what they are called ;)

Im not sure i follow your ideas, xactly. How are u at sketching? :)

f=(m v^2)/r centripetal force

I might crunch numbers later. Gut feeling is that cotter pin is ok as long as you dont hit the workpiece with it. Good idea.

I think theres also a locking washer of sorts. One bends the washer up against one face of the hex nut.

Ive switched the brushes. Since this motor has field aaaaand rotor coils, this should reverse motor. Two concerns at this point. Brushes may bind in reverse, they are secured with 1 screw each. 90 degree gear may not work right in reverse. Iirc, these gears have angled teath (slightly slanted like a screw) So, it may put forces on bearings opposite to that which theyre meant for. We will see what happens when turned on.