[toddwinnburns]

GEOF: Thanks alot for your help. The only constant is the pulley on the mill. It is 12. In your answer you put it at 9". How would this effect the calculation?

[Geof]

Okay, I had 3" driving 9" for the final stage but you have a 12" pulley so the second shaft will have a 4" pulley driving the 12" for the necessary 3 : 1 reduction.

[toddwinnburns]

Geof:
I have been trying to get an answer to this question for two weeks. I own a draft beer equipment company and I often answer technical questions for customers that are not able to calculate formulas. I was completely thrown for a loop on this calculation. It is different being on the other end and being the one completely in the dark. I really appreciate your help!
Todd

[Al_The_Man]

If you want a high reduction without the need for precision gear box, I would also look at a worm gear, if this is a one-off then ebay have some good deals on 60:1 reducers, there is a NOS baldor that cost $1265.00 for $50.00.
Also this one item #380260131705, if you run a 1760rpm 4 pole motor you get around 30rpm or a 3480rpm 2 pole motor for ~ 60rpm.
Al.

[amberajax]

I have the exact same situation. I have the same grain mill and the same motor, but I don't have any pulley yet. It sounds like you would need very large pulleys to accomplish turning the grain mill pulley. Someone mentioned a gear box and it was also suggested that you could use more Pulleys? If anyone has and suggestions concerning the best setup to use I would LOVE to have a workable solution. I have a 12" pulley on the grain mill and I have a 1725 RPM motor with no pulley yet installed (it has a 1/2" shank) I have to get the RPM on the mill to between 55 and 60 RPM. Thanks in advance for any help you can give me. I have been working on this project for some time and I would love to find a workable solution.
Todd

Forgive me, as this quote is almost two years old, but only tonight did I find this forum, then this thread, with my pulley question.

I, too, have a grain mill, Monster mfg. I suspect I need to get the same 55-60 rpm at the mill. My motor is also 1725 rpm & 1/2 in. shank.

Largest pulley I can find to buy is 12 inches. Smallest is 1.5 in.

Therefore, my question is How do you compute the ratio going from the 1.5 to the 12 inch? Will that get me to 55-60 rpm. Or, do we need to find a larger dia. pulley.

I will keep reading this thread as I may find my answer. Looks like a wonderful forum.
gary

[amberajax]

Below is the link to Stock Drive Products that Al has shared in this thread. I only found it, and not yet used it to reduce my 1725 rpm motor to run the grain mill at 55 - 60 rpm. However, from reading Al's comments, I think we need a gearbox. If anyone has taken that route, please let me know.

I am brand new to this forum and trust my ability to share this link will work.

gary


SDP/SI

[Edward76]

I have been trying to get an answer to this question for two weeks. I own a draft beer equipment company and I often answer technical questions for customers that are not able to calculate formulas. I was completely thrown for a loop on this calculation. It is different being on the other end and being the one completely in the dark. I really appreciate your help!

[KOC62]

Coming from an electronic technological background, I'd be inclined to drive the mill with a stepper motor and manual speed control. No, I haven't worked out the details.

I didn't get the motor HP rating used, just 1750RPM, but assumed it to be a 1/4 HP and thus thought "stepper", rather than pulleys to get a final 60RPM.

[KOC62]

This gearbox has a 1/2" output shaft and a 5/16" input shaft.
Right Angle Speed Reducers, Right Angle Speed Reducer and Gear Reducers, Made in USA

Using a 10:1 reducer, e.g. item #70122, and a 4" pulley for the 1/2" output shaft, you should get around 57.5 RPM.

If your motor is a 1/2" shaft, you need a coupler, e.g. McMaster Carr #6208K571, where one side is for 5/16" shaft and the other side is for a 1/2" shaft. This has to be specified when ordering.

I did not hunt for cheaper prices, just a possible solution.

[cowboy66]

Cardamom

OK - I'm wondering if y'all can help me with this! I'm still trying to do the calculations... I have a grain mill attached to a 1725 rpm motor with v-belt pulleys gearing it down. There is a 2" diameter pulley on the 5/8" motor shaft driving a 2.5" pulley on an intermediate 3/4" shaft. Also on the intermediate shaft is a 6" pulley driving the 12" flywheel of the mill.

Can someone walk me through the calculations to get to the speed of my mill? I did it once and came out with 119.79 rpm. Another time, came out with 95.83. Still another time, and came out with 690! I think I'm mixing up formulas... I'm so confused.

I want the mill to run between 50 and 60 rpm, so I'm trying to come up with what pulley sizes I would need.

Thanks for any help!

toddwinnburns

I have the exact same situation. I have the same grain mill and the same motor, but I don't have any pulley yet. It sounds like you would need very large pulleys to accomplish turning the grain mill pulley. Someone mentioned a gear box and it was also suggested that you could use more Pulleys? If anyone has and suggestions concerning the best setup to use I would LOVE to have a workable solution. I have a 12" pulley on the grain mill and I have a 1725 RPM motor with no pulley yet installed (it has a 1/2" shank) I have to get the RPM on the mill to between 55 and 60 RPM. Thanks in advance for any help you can give me. I have been working on this project for some time and I would love to find a workable solution.
Todd

ok, all this tech stuff aside I use this setup:
1725 RPM 1 HP motor with a 1.5 inch pulley on it.

then use 2ea. 5/8" bearing blocks with a 6 inch and a 1.75 inch pulley side by side on a 5/8" keyed shaft between the bearing blocks.

run belt from motor to the 6 inch pulley and a belt from the 1.75 inch pulley to the 12 inch grain mill pulley and you have 62.89 RPM on that grain mill and it works beautifully.
you can grind 7 cups of wheat in 15 minutes or less
go to this link and scroll down to the HORIZONTAL INSTALLATION picture for setting up the bearing blocks and stuff.
To Motorize

that's it
enjoy