Trouble motorizing a grain mill

[bjvanst]

I'm in the process of trying to motorize my dual roller grain mill, have run in to a dilemma, and I'm looking for suggestions.

My mill is a Cereal Killer which is advertised as having a 3/8" crank shaft. So, I went out and got myself a used 1725RPM motor, 11.75" sheave, a 2" sheave, a belt, and a 3/8" bore split tapered bushing.

Turns out, the mill's crank shaft is closer to 25/64 inches in most spots instead of 3/8 and the split taper bushing doesn't fit. I could try a 10mm bushing but I don't know if the .1mm will cause issues.

Anyone with a little more mechanical experience have any suggestions?

 

[greybush]

I ran into the same issue. I rigged up the shaft of my cereal killer to a heavy duty rubber band and a cordless drill to make a makeshift lathe. I used a coarse file to take down the thickness of the shaft just enough to fit the 2" sheave on the shaft.

It was still a little tight so I used a bar clamp to press it on by pressing on the opposite end of the shaft. It turns out that pressing the sheave onto the shaft was a mistake because I bent the shaft and introduced a wobble that took quite a bit of tinkering to get rid of.

 

[acidrain]

Is this the one you have? http://www.homebrewing.org/Cereal-Killer-Grain-Mill_p_2310.html
It says 10mm, not 3/8".
Does yours have the upgrades ball bearing rollers? If so, probably no problem going with an offset motor/pulley system, but there are some serious side-loads to consider when building an offset system... that's why they recommend using a drill motor instead.
It may be as simple as getting a 10 mm ID pulley.

 

[bjvanst]

Is this the one you have? http://www.homebrewing.org/Cereal-Killer-Grain-Mill_p_2310.html
It says 10mm, not 3/8".
Does yours have the upgrades ball bearing rollers? If so, probably no problem going with an offset motor/pulley system, but there are some serious side-loads to consider when building an offset system... that's why they recommend using a drill motor instead.
It may be as simple as getting a 10 mm ID pulley.

I got mine from here. They advertise 3/8". I measured 9.9mm but it's possible that my calipers are wrong.

You bring up a good point about the side loads. I had not considered that.

edit: fwiw, I went with the sheave I did based on price. The Canadian sites I visited had new sheaves listed for $100+. This one was $40 + the $7 split taper bushing.

 

[acidrain]

When you say sheave, are you meaning an adjustable pulley? Why not just go with a fixed pulley? They are much cheaper.

 

[bjvanst]

When you say sheave, are you meaning an adjustable pulley? Why not just go with a fixed pulley? They are much cheaper.

This is what I purchased:
http://www.princessauto.com/en/detail/11-75-in-spoked-cast-iron-sheave/A-p8046179e

It seemed to be the most cost effective option available to me.

 

[acidrain]

Ah, slightly different meaning here I think.
A sheave (at least here in the US) is usually a pulley inside of a frame, and usually used for rope, so the groove is rounded.
Or it's an adjustable pulley that when tightened or loosed makes the diameter bigger or smaller.
Here is the Wiki: https://en.wikipedia.org/wiki/Sheave
Is there a chance you can get somebody to make you an insert to make the diameter the right size?
I could do it, but shipping is sometimes problematic into Canada. I used to build and anodize paintball gun parts, and sometimes parts were held up for weeks at customs.

 

[John53189]

Here's my cereal killer, in case your interested

 

[govner1]

I avoided a sheave setup, i.e., two wheels w/ a belt drive to reduce the RPM's to the mill for safety reasons.
I'm essentially one armed & the bad arm lacks feeling. Hence, a potentially dangerous situation.
I went w/ a direct drive, gear reduction motor w/ a 180 RPM output.
View attachment ImageUploadedByHome Brew1448591392.272316.jpg

 

[Drumminguy81]

I also opted away from belt and pulley. I figured I would end up getting caught up in it at some point. I went with a 1725 rpm motor and a 10:1 gear reducer. It was a little pricier than belts and pulleys but works great. Best of luck with your setup! Its nice being able to flip a switch and just dump grain.

View attachment 1448636868665.jpg

 

[bjvanst]

Thanks for sharing your builds.

Mine is still a work in progress. Thanks to acidrain, I ended up ordering a 10mm split-taper bushing. It seems to fit the bill. Once the sheave is fit and secured with the bolts, it'll be a solid connection. As is, I've tested by press fitting it by hand and the unloaded rollers spin just fine. Just need to get some sort of sheet good to build the cabinet I had in mind for it.

The goal is to cover the majority of the belt, motor, and sheave so I'm not too worried about the safety aspect.

 

[augiedoggy]

I motorized my CK mill with pulleys a while back.... put around 6 or 7 sacks of grain through since with no issues or noticable wear from the sideload yet...

I used an old 110v DC gear reduction motor and used a wall light dimmer with a $3 rectifier to convert the ac wall power to a dc wavelength...works well and I can use the dimmer to adjust the speed of the motor. I cut up and recycled an old particle board entertainment center to make the stand.

as far as the shaft I got lucky and found an old washing machine motor that had a pulley that fit well with a bushing adapter from tractor supply if I remember correctly.

PS my brewing area is a disaster because im doing some rearranging so please disregard the disgusting looking floor...