A reader wrote in with a very interesting question about adjustable vs. variable speed terminology as it pertains to power tools.
Just to warn you, this is going to be somewhat of a philosophical discussion on tool semantics. Please feel free to join the discussion and share your take in the comments section!
Mike wrote:
Milwaukee is advertising this grinder (model 2888-20) as “5-speed” AND “variable speed”. Any insight?
I looked into it, and there’s a speed control dial located at the end of the handle that sets the maximum speed.
The paddle switch and slide switch grinders are both described as variable speed tools.
Mike responded with:
I guess it’s a matter of semantics. I would call it “adjustable speed”. To me, “variable speed” is when I can vary the speed according to how far I pull the trigger.
Here’s where things get complicated.
A cordless drill with variable speed trigger allows for instantaneous speed adjustments depending on finger pressure. When you talk about a cordless drill with variable speed trigger switch, there’s a common understanding about how it works.
When you have a set-and-forget speed control dial that’s completely separate from an on/off switch, is that a variable speed dial, or adjustable speed?
When talking about drill presses, variable speed is used when speed settings can be changed electronically via dial or buttons, as opposed to having to change belts and pulleys or other such adjustable mechanisms.
Variable speed is never used when belt changes or similar are needed.
So, you can have two drill presses, one with variable speed, and the other with adjustable speed, with the difference being electronic vs. mechanical settings.
Dremel rotary tools are advertised as having variable speed, and this usually involves a rotating dial that’s separate from on/off controls.
Barrel grip jig saws are often described as having variable speed motors, similar to D-handle jig saws. D-handle jig saws often have variable speed trigger switches as well, while barrel grip jig saws have speed settings and a separate on/off switch.
Most cordless drills – except for the cheapest entry-level models – have 2 or more gears and speed ranges, with a sliding switch toggling between them. That’s not usually referred to as either a variable speed or adjustable speed feature.
Here’s a good example, at least in my opinion. On the left is a Foredom foot pedal variable speed controller, and on the right is a Foredom tabletop variable speed controller.
The foot pedal works in a similar way as a cordless drill’s trigger switch, while the tabletop controller works similar to a speed control dial on an angle grinder, rotary tool, barrel grip jig saw, or other such tools.
Wouldn’t both tools be described as variable speed controllers? One adjusts the speed based on real-time user foot pressure, while the other is more of a set-and-forget dial.
My opinion is that either can be added to a Foredom flex shaft tool to provide variable speed features.
I would generalize things, to say that if you can adjust the speed or speed range via electromechanical switch, that’s variable speed. If speed changes can only be accomplished via mechanical changes, such as by moving a drill press’s belt to a different pair of drive pulleys, that’s adjustable speed.
The reader made an excellent point, but I believe it is generally understood that variable speed need not be instantaneous by means of a pressure-sensitive switch or similar.
Can the speed or speed range settings be adjusted via electromechanical switch? Variable speed. Can the speed or speed range settings be changed via mechanical adjustments? Adjustable speed.
That’s my take on this. There’s the potential for exceptions, but I haven’t come up with any yet.
Do you agree? Disagree?
And if if you’re wondering “why is any of this important?!”, it’s not, but I found the question and topic to be interesting, and thought some of you would too.
