Lower Auger Bearing

Lower Auger Bearing

Postby mhauer on Sun Jan 11, 2009 8:24 pm

I have found that when you change out an auger or lower bearing, you will drop "cement juice" on the first few jobs that you do. This usually goes into the bearing as well and makes a mess and reduces the life of the bearing. To fix this, all you need to do is put a seal on the shaft of the auger. I make my own out of 1/2" thick sheet rubber. You can use old auger boot rubber, conveyor belting, two layers of mudflap, a tire sidewall or whatever --don't be afraid to get creative!
To make a seal, take the piece of rubber and cut it into a 4" square and then cut a hole in the center of it with a hole saw that is the diameter of the auger shaft that fits into the bearing, mine is 2" dia. In order to hold the rubber so it can be cut with the hole saw, sandwich it between two pieces of plywood, or screw the four corners to a board. When cutting rubber with a 2" hole saw, it will stretch a little and the hole will be a little smaller than 2". This is okay, you want a tight fit.
To install, lube the seal and force it onto the auger shaft , (after the auger is installed in the cage--the seal goes directly under the bearing, not on the "concrete side")and then put the bearing on. The corners of the seal will fit in between the bolt holes on the bearing and keep the seal from turning with the auger.
I have found that the bearings last for about 3 augers now instead of just one. The seals last also such that when I change augers now, all I do is loosen the auger and use a gear puller to push the auger out of the old bearing and seal then just push the new auger back through the old seal and bearing and life is good!
Also, if you do need a new bearing you can always get one from Elkin or locally, but I have found that the lower bearing is just a standard, plain old Dodge 2"flange bearing that has one bolt hole cut off with a hacksaw. Look on ebay and you will almost always find several for sale for around $30 to $40 each brand new. Not bad considering they usually go for about $140 -$175 off the shelf.
I hope this helps , if you have any questions, just ask me.
Mike Hauer
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Re: Lower Auger Bearing

Postby smnstn on Sat Jan 17, 2009 6:12 pm

Mike -- Simon Stanfield here. Some mixer manufacturers of stationary batchers as well as mobile augers are integrating a "CAT" seal onto the shaft in front of the bearing. It's called that because it is similar to the engineering used on top-driven Caterpillar Tractors. This can be two steel disks, plates or composite materials such as hard wearing rubber. Clamped into place with retaining rings or framework, they are then filled with grease under pressure. This eliminates leakage onto the bearing, if it's kept filled with grease. Grease can be pumped in by hand whenever cleaning up the mix auger, or an automatic grease system can be added to do this without having to think about it beyond keeping the reservoir filled. In this configuration, you would purge the grease seal with new grease when cleaning up manually, but would only give a couple of squirts to the bearing itself, if any at all is recommended. Ironically, as you probably know, the biggest enemy to bearings is grease. Too much grease blows the seal out of the bearing race, and causes it to leak and rotate off-center.

Anyway, it looks like you are on the right track. Keep us all posted.

S.
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Re: Lower Auger Bearing

Postby mhauer on Sun Jan 18, 2009 6:42 pm

Simon-
Thanks for the good input. I have seen the CAT style seals and I know that some mixers are already using them. I must remind you , and everyone else reading this, that the seal that I made needs no daily maintenance. This also translates into being "fool-proof" as one can't overgrease it.
One thing that hangs in the back of my mind is the question of where does this grease eventually go if an operator is periodically adding grease to those CAT style seals? It either goes into the auger cage to be mixed into the concrete, or it goes onto the ground. Putting grease into concrete is really bad. Putting grease on the ground is just plain wrong if not illegal. Most of my work is performed at landscaped or finished jobsites. I cannot put oil or grease on floors or driveways it just isn't tolerated with all of this friggin' "green" thinking going on. Yes, it's true...even Prius owners buy concrete from time to time.
Mike Hauer
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Re: Lower Auger Bearing

Postby smnstn on Sat Mar 21, 2009 1:27 pm

Sorry about how long it is taking me to figure out how to use this forum. The following observation may be of interest.

Of course, you're right, Mike. Where does the grease that's used up go? Nobody in the industry that recommends this type of Cat seal has given me a satisfactory answer. The machines having this type of seal do not seem to leak onto the ground. They also, don't use very much grease. My instinct tells me that the grease leeches very slowly into the concrete itself where it's "encapsulated". Unless there are balls of hardened grease, it's compatible with the cement paste and the tiny amounts per cubic foot or yard actually become blended right into the paste. Let's not forget that you're mixing with a very large kitchen blender. The stuff becomes homogenized and stable. In a concentrated form, it's a bond breaker, but tiny amounts, fractions of ounces, dispersed in thousands of pounds of sand, stone and cement are negligible. My guess is they wouldn't even turn up in petrographic analysis. We could go on to talk about the chemistry -- petroleum compounds are hydrocarbons. Cement is hydraulic. Cement can, I suppose, in its process of hydration, bond to the water molecules in oil or grease. If we were really concerned about this as a society, we should be really nervous about asphalt paving.

In Japan, France and a couple of other countries, petro-sludges are actually mixed into paving concrete on purpose to get rid of them. The waste products become encapsulated (completely surrounded by paste) and remain stable as part of the infrastructure. All conceivable testing performed on these pavements has not resulted in releasing the noxious substances back into the environment. When failures occur, the concrete itself remains stable, even though it has become fragmented. I helped design and sell stabilization equipment to the hazardous sludge division of a large oil conglomerate. It was put into operation to mix cementitious materials with toxic petro-sludges for stabilization and "storage", not actual usage. The results were good, and the machine remains in operation today, stabilizing many nasty greasy substances.

I have nothing "concrete" to offer beyond this anecdotal evidence. Please don't view my comments as criticism. I had originally intended them to be supportive -- simply a variation on a proven technology -- and your good refinement for this application.

S.
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