7" angle grinder

[big bubba]

Horse power, if reported accurately would be a terrific figure of merit for rating/comparing grinders and such. Amps alone represents a questionable figure of merit as it does not take into consideration efficiency. A very inefficient tool might use lots of amps but much of the power consumed could be going to heat, not torque. You might have noticed really cheap poor tools often run hotter than high quality tools. That is more electrical energy going to heat than useful work as compared to the high quality tool.

there's so much more than raw power to a grinder. longevity weight safety features soft start ergonomics, etc.
as the years pass, i prefer a more refined tool w/additional qualities mentioned above as well as the sheer power that you mention. sometimes lighter weight alone is an added safety feature.

 

[DXN1EL]

Highly recommend Metabo W24-180.

 

[stuckmotor]

On one project, I had two or three of those low power 4 1/2 inch grinders going (probably not all Harbor Freight). One would cut until it got too hot then cool while another took it's place. If I remember right, I burned one of those little ones up before I realized I could buy cutting blades for the 9" grinder. The gyro effect of that 9" grinder used to tire me out pretty bad.

 

[California]

I bought the HF 9" angle grinder the year I had Inside Track special pricing and I just couldn't pass it up.

But I learned it's a tool for someone athletic. I used to work construction 40 years ago but now the thing is too much of a monster, I don't feel safe running it in awkward positions. I sold it.
Here's a post with photos where I hogged out cast iron to modify some wheel weights.

I bought HF's 7" angle grinder to replace the 9". Running a DeWalt disc, that meets my needs for a larger grinder.

But the HF 4.5" grinders with flap disc, grinding disc, wire brush are used more often. At 6 amps or less they aren't as powerful as a pro tool but I'm not in a hurry.

 

[Texasmark]

I still crack up when I read Hp ratings. The Bosch may be the cat's meow but they advertise 4hp. Huh??? I love Bosch but com'n man!

120v machine at 15amps is 1800watts. Equals 2.4hp. Please explain.

1974-8 | 7 In. 15 A High Performance Large Angle Grinder | Bosch Power Tools

The current craze of telling you that you are getting something when you aren't is to take the object and hook up oscilloscopes to the voltage and current. Get it in a clamp so that you can severely restrict the movement of the shaft. When the voltage starts falling and the current starts rising, the highest product observed during that exercise is the "rated" hp. Few do it but some folks also post the full load running amps which gives you the true picture of the items usefulness.

I have a 60 gallon air compressor with an advertised 6.5hp motor in big letters on the side of the tank. Reading the nameplate on the motor gives the real hp at less than 2.

The biggest farce is home vacuum cleaners. Check out the power cord AWG and figuring 400 circular mils per amp as a safe load, no way will that power cord sustain the advertised HP on anything but a quick burst.

 

[Texasmark]

My 9" actually scares me somewhat. When that thing gets would up, it's like a gyroscope, it has it's own state of equilibrium and if that thing were to get away from me and come after me, it could do some serious damage.....to my body parts! I have to fight it to get it to move in the direction I want. As I said, it's a beast, but it's a HF elcheapo and has never let me down.

 

[California]

Years ago Sears lost a case re unobtainable horsepower ratings. i thought it was compressors but it could have been vacuums.

HF has reduced their compressor ratings. The one I bought that they rated (90 psi), something like '5.8 cfm' is now rated more like '4.8 SCFM'. Same hardware. Still claimed 2.5 hp at 13 amps or less, that's impossible.

 

[California]

My 9" actually scares me somewhat. When that thing gets would up, it's like a gyroscope, it has it's own state of equilibrium and if that thing were to get away from me and come after me, it could do some serious damage.....to my body parts! I have to fight it to get it to move in the direction I want.

As I related above I had a similar experience with the HF 'dremel'. I bought cheap brass wire brush tools for it off Ebay, and bent one. With that tiny tool badly off balance the dremel was near impossible to hold on to and I was afraid to simply throw it. The vibration felt the same as electric shock. After too much thinking about it I got my other hand on the off switch.

I hate to think what vibration half a 9" grinding disc could cause - aside from the surprise shrapnel problem.

 

[dragoneggs]

I really like my Makita 7 inch. Very smooth.

Which one do you have? I see two on Amazon, both 15amp but one is 6600rpm and the other 8500rpm and a bit bigger. Recommendations?

 

[Big Barn]

Which one do you have? I see two on Amazon, both 15amp but one is 6600rpm and the other 8500rpm and a bit bigger. Recommendations?

Hi Mark. Don’t know about Dave’s but mine is 8500 RPM.