How do I figure the RPM of this drill?

[Memorex88]

It's an old Black & Decker that I'd like to use for my grain mill. Problem is, the stickers are long gone and I wondered if there's a way to figure out the RPM?
It's only an on/off switch but it's got a trigger lock and plenty of torque.

I was hoping someone could recognize it and have a clue. I've tried it and it seems to do a fast job, but I'd like to stick to the 500 - 1000 RPM like they recommend.

 

[Joker]

You will need a revolution counter. Not sure it would be worth the price though.

Durant Lt Dty X Series Stroke Mechanical Counters: Compare Prices, View Price History and Read Reviews at NexTag

Perhaps with some more searching you could find one cheaper.

 

[david_42]

If it's a 1/4", most likely it runs 1200-1800 rpm. 3/8" 800-1200, 1/2" under 800.

 

[Memorex88]

You will need a revolution counter. Not sure it would be worth the price though.

Durant Lt Dty X Series Stroke Mechanical Counters: Compare Prices, View Price History and Read Reviews at NexTag

Perhaps with some more searching you could find one cheaper.

I won't spend any money on a counter. Thanks for the info thow.

If it's a 1/4", most likely it runs 1200-1800 rpm. 3/8" 800-1200, 1/2" under 800.

It's a 3/8", so if your sure of this, the lower end would be acceptable for the BC.

 

[uglygoat]

i've got one of similar vintage. it's an old machine shop drill i thinks...

have you tried it with just a little trigger? you should be able to get a feel for what it is as you give it a whirl or ten. see how it crushes some grain, or drives a screw.

edit: mine's a no 7000 115 volts ac 1/4" drill. 1/7hp, 2250 rpm. type a. i'll get a pic up for you asap.

 

[Memorex88]

have you tried it with just a little trigger? you should be able to get a feel for what it is as you give it a whirl or ten. see how it crushes some grain, or drives a screw.

Yes I have tried it. Seems a bit fast compared to the variable speed drill I used prior. This is the forth batch I made with it.
I tried it yesterday and I don't see an issue but I haven't brewed the grains I crushed yet. I think the grains are crushed well but the speed has me concerned.
Overheating the bushings maybe?
I just want to use my mill the way it's recommended. This way if something goes wrong I can say I followed the directions that came with it.

 

[EvilTOJ]

Bah you're overthinking it. I set my 3/8" drill to max speed and hit the button to keep it on, I've never had a problem with my barley crusher.