Crankandstein 328D jam

[epateddy]

Hey all.

Went big on my mill and got the 328D. Picked up a 1 HP 1725 rpm motor off of ebay, and 1.5" and 10" sheaves to turn a v-belt. Planned on dropping 25 lbs of grain at a time into the hopper, but my test with ONE pound of grain was a disaster. The rollers jammed up almost instantly. The motor kept turing the 1.5" sheave but not the belt, and nothing was grinding. Motor seems more than powerful enough (because it keeps turning). Any suggestions on how to make sure the belt stays engaged on the motor end?

 

[watermelon83]

How tight is the belt? Take a ruler and set it on the table top. Mark the ruler where the belt crosses it. Push down as hard as you can (without serious pain) and mark where the belt crosses the ruler now. What's the difference? I can't judge the distance between the pulley's to tell you what that distance should be, but there are plenty of online resources for recommended belt tensions.

Looking at the picture it looks like you have it tight enough to fully seat the belts. Past that point, you'll probably want to engineer a way to apply force while keeping the motor and rollers parallel. Like a sliding base with a bolt adjuster.

 

[DRog00]

A local homebrew shop bought one and I fitted it to a stand. It would work perfectly for a few runs, then jam. It was embarrassing.

Things to check:
Your end plates are mounted square with each other.
The gap between the roller and the end is minimal (tenths of an inch).
Your 3rd roller is set at the same setting on both cams. If you get it sitting at an angle, that is trouble.

The shop ended up ordering a new drive roller, and we fitted a gear drive to the top two rollers. They still had jams, but not as often. They fixed the jams by removing the adjustment and just installing ball bearings on the bottom roller. I *think* it works everytime now, but I haven't talked to them for some time.

 

[bja]

Either the belt is too loose or the 1-1/2" sheave is too small, or both.

Try tightening the belt more but don't make it overly tight. You'll run the risk of prematurely wearing out the bushings in the mill.

If it still slips after tightening the belt, you'll need a bigger sheave to provide more contact area between it and the belt.

 

[RiverCityBrewer]

I had similar issues with an 1 1/2" sheave and a 3L belt... under load the 1 1/2" would just spin without turning the belt. Moved to a 2" sheave and the extra friction made all the difference. It puts a few extra RPMs on the mill, but I have no issues with slippage now.

 

[KartRacer54]

The 1 1/2" sheet euro is the problem. If you need to use the small she eve get a v belt that has the teeth type underside. It allows the belt to form around the small sleeve.

 

[camiller]

The 1 1/2" sheet euro is the problem. If you need to use the small she eve get a v belt that has the teeth type underside. It allows the belt to form around the small sleeve.

Even that doesn't work particularly well especially as the belt get a little worn. We use the same mill with a "link belt" in our shop (I work there part time on saturdays) and it seems to be a matter of how fast you are feeding the grain. When I built the hopper I put in a sort of sliding gate in case a rock (it happens some times) was in the grain and jammed things up. If I have the 1" opening fully open it bogs down and stops even if the mill was already running. If I only open the gate 3/8" or so it will purr along just fine.

So my suggestion is throttle the feed rate a bit.

 

[epateddy]

Thanks for all the responses and ideas.

I tried mounting the motor on a separate board on hinges, so gravity would pull the mill towards the table and tighten the belt via the weight of the motor. But the mill still jammed.

DRog00 - I'm feeling kinda stupid because I didn't know there was a cam on BOTH sides of the mill. Wow. I'll check that to make sure the setting is the same. Really hope that does the trick. This mill is a beast and I can't believe that it's choking on such a small amount of grain.

If that doesn't work I'll up the motor sheave.

If that doesn't work I may also reduce the opening in the hopper to slow the flow of grain into the mill.

if that doesn't work.......I don't know what else to try.

Here are a couple of vids of the problem...

[ame="https://vimeo.com/126566203"]Grain Mill Jam 1[/ame]

[ame="https://vimeo.com/126566202"]Grain Mill Jam 2[/ame]

 

[bja]

I tried mounting the motor on a separate board on hinges, so gravity would pull the mill towards the table and tighten the belt via the weight of the motor. But the mill still jammed.

That is not going to be tight enough. The friction is actually pulling the motor towards the mill and loosening the belt.

 

[govner1]

Thanks for all the responses and ideas.

I tried mounting the motor on a separate board on hinges, so gravity would pull the mill towards the table and tighten the belt via the weight of the motor. But the mill still jammed.

DRog00 - I'm feeling kinda stupid because I didn't know there was a cam on BOTH sides of the mill. Wow. I'll check that to make sure the setting is the same. Really hope that does the trick. This mill is a beast and I can't believe that it's choking on such a small amount of grain.

If that doesn't work I'll up the motor sheave.

If that doesn't work I may also reduce the opening in the hopper to slow the flow of grain into the mill.

if that doesn't work.......I don't know what else to try.

Here are a couple of vids of the problem...

Grain Mill Jam 1

Grain Mill Jam 2

You might want to investigate a gear reduction direct drive. That will eliminate the slippage and the inherent danger of dealing w/sheaves.

 

[helterscelter]

That is not going to be tight enough. The friction is actually pulling the motor towards the mill and loosening the belt.

If you put some down-force on the motor, thereby artificially tightening the belt while it's running/starting, does it still jam/slip? obviously you don't want to put too much side load on the mill bearings during normal operation, but as a troubleshooting/try-it it may give you more ideas about where to go next.

 

[DRog00]

When I say cam, make sure that your bottom roller is set to the same setting on both sides. I have a monster mill, so they don't have the detents like the CM does.

Make sure your end caps are square, and the end gap is minimal, tenths of an inch.

What is likely happening is your 3rd roller is getting jammed up, which stops any of the grain from passing through. Again, make sure the gap of the 3rd roller is the same across the entire gap. If it is off, it can cause this kind of jam.

 

[jdlawlis]

Hey all.

Went big on my mill and got the 328D. Picked up a 1 HP 1725 rpm motor off of ebay, and 1.5" and 10" sheaves to turn a v-belt. Planned on dropping 25 lbs of grain at a time into the hopper, but my test with ONE pound of grain was a disaster. The rollers jammed up almost instantly. The motor kept turing the 1.5" sheave but not the belt, and nothing was grinding. Motor seems more than powerful enough (because it keeps turning). Any suggestions on how to make sure the belt stays engaged on the motor end?

How did things end up? I had a similar problem with a 1.75" sheave and a 12" pulley, with the sheave spinning underneath a stationary 4L belt. After some reading, I realized that the most efficient power transfer for a belt pulley system is when the ratio of the diameter of the pulleys is 3:1 or less. I wish I had known this before I had designed my system! I am in the middle of rebuilding it with a two stage pulley system. If it works, I will post pictures and hopefully it will help the next person who comes along.