Garage door opener

[euge]

I have an old Craftsman garage door opener laying in my garage that needs to go. I'm wondering if the motor would be right for running my Barley Crusher.

It already has a sprocket and I might be able to use part of the chain if the links can come apart. All I'd need is another one for the mill.

Ideas? Suggestions?

[tschmidlin]

Hmmm . . . I've never looked inside one, but in my mind it would turn your mill really slowly.  What kind of RPMs do you get out of it?

[euge]

I don't know it came with the house. The sprocket diameter is pretty small on these things, but I'm looking for maybe 200 rpm at the mill.

[tschmidlin]

You'll need to put a much larger sprocket on the motor then, and move the small one to the mill.  I'd measure the RPM of the motor and then do some math to see if it even makes sense.

[weithman5]

i would play with it, bet it would work fine, with a little eugenuity.

[hopfenundmalz]

The only drawback is that a chain will not slip like a belt if a small rock gets into the rollers. I had one bag of British malt that had 4 small rocks in it.

[weithman5]

if you have to pull the sprocket off you could probably mount a pully to use a belt instead of a chain. in fact that would probably be easier than adjusting chain length anyway.

[euge]

I was thinking belt pulley too. Thinking back to analytical geometry... would a larger diameter pulley on the mill side make it work more efficiently?

[mtnrockhopper]

I was thinking belt pulley too. Thinking back to analytical geometry... would a larger diameter pulley on the mill side make it work more efficiently?

Define efficient. A larger wheel on the motor will increase rpm. A larger wheel on the mill end will decrease rpm.
 
Mill RPM = Motor RPM * (Motor Pulley Diameter / Mill Pulley Diameter)

[bluesman]

The ideal speed for a mill is 400rpm.  You would need to make a design change to allow for more rpm at the motor.  This would likely involve a larger drive pulley at the motor side. Again, you'll need to calculate the size pulley needed to drive the mill at approx. 400 rpm. 

[Thirsty_Monk]

The only drawback is that a chain will not slip like a belt if a small rock gets into the rollers. I had one bag of British malt that had 4 small rocks in it.

Those pesky Brits. The same happened to me with MO malt.

[hopfenundmalz]

The only drawback is that a chain will not slip like a belt if a small rock gets into the rollers. I had one bag of British malt that had 4 small rocks in it.

Those pesky Brits. The same happened to me with MO malt.

My conclusion was that the maltser needed to change some of the filter screens, must of had a hole in one.

[punatic]

The ideal speed for a mill is 400rpm.  You would need to make a design change to allow for more rpm at the motor.  This would likely involve a larger drive pulley at the motor side. Again, you'll need to calculate the size pulley needed to drive the mill at approx. 400 rpm.

Can you share where the 400 RPM number comes from?  6 and 2/3 revs per second seems a bit fast to me.

[weithman5]

i am more curious how speed affects the crush.  if 400rpm is ideal, there are a lot of hand millers suffering.

[jeffy]

I'm happy with my crush and I have the mill turning way slower than that.
I use a DC motor from a tread mill and chose a very large pulley for the grain mill to save the motor from too much stress.