Drill RPM

[najel]

So I recently ordered a grain mill and I am thinking that I will probably use it with a drill rather than the handle. Now the mill, as most of them do, states that it should be run at 300 RPM when using a motor. My question is if you use a variable speed electric drill (I will be using a cordless Dewalt, pretty sure it has plenty of power for this), how would you go about estimating the RPM it runs at? Or asked differently, how do you figure out where about 300 rpm is?
I assume it does not have to be spot on, but too fast would put excessive wear on the mill and lead to a poor grind, too slow would probably be bad, too.

 

[Bensiff]

No, it doesn't have to be spot on...300RPM is the top end of the recommended range. Generally go as slow as you can go without stalling. I can't tell you how to estimate 300 rpm, maybe see what the manufacturer says is its top RPM and go from there. You might want to consider picking up a 1/3-1/2 hp motor on ebay which once setup takes all the variable out of it and you won't have to worry about burning up a drill motor.

 

[MachineShopBrewing]

I have the MM-3 mill and I use a 12v Dewalt in low gear to mill my grain. I did buy a cheap corded one to use for this at first, but the power band would not allow me to run it at a low enough speed. You need a fair bit of torque at low rpm, which the Dewalt does great. Full trigger in low speed is pretty much the perfect speed for my drill and mill combination.

Bensiff, you must be a machinist? Only a machinist would call it a drill motor and not just a drill.

 

[najel]

Thanks for your advice guys!
Makes more sense now. I think I will try it with the Dewalt first and see how it fairs. I am quite confident since I know those things are pretty powerful. Having the knowledge that the given RPM should be considered the high end will help me a lot. I also saw that Dewalt post the RPM range of their tools in the different speed settings on the website, so with that I should be able to get a good idea of what speed I want to be at.

 

[Bensiff]

Bensiff, you must be a machinist? Only a machinist would call it a drill motor and not just a drill.

Not by trade, I'm endlessly fascinated with attempting to understand how things work and figure I might as well build something on my own to figure it out and in the research I pick up the proper lingo. Now my dad, he is an aerospace machinist, but he just calls it a drill .

 

[MachineShopBrewing]

Not by trade, I'm endlessly fascinated with attempting to understand how things work and figure I might as well build something on my own to figure it out and in the research I pick up the proper lingo. Now my dad, he is an aerospace machinist, but he just calls it a drill .

Haha. I never heard drill motor before I went to trade school. I have been a machinist for about six years and only the old timers call it a drill motor.