L12: Finding my Bearings 


Getting started with a new (to me) roaster means I have to get down and dirty with it before I get too deep in production. It is a good idea that I get well acquainted with the rig as I ease into it. Even if you have had experience with a similar make and or model, there is bound to be at least some differences from roaster to roaster. I assume that somebody before me has done some modifications or “duct tape jobs” to keep the thing rollin’. I have had the opportunity to work on larger roasters (60 & 120 kilo), but this is my first time for me with taking apart a 12 kilo machine. Besides the obvious cleaning of resin, chaff and grease maintenance, I had to get inside this thing ASAP. I figure that it’s best for me to learn as much as I can about the roaster I’m on before I start making tweaks of my own to navigate the coffees outcome. I would like to share my findings with you along while documenting my work for any future roasters on this L12.

Recently when preforming the rear bearing maintenance, I found that the ball bearing cage was a bit tweaked. Now is the time to change it. There was nothing to indicate the need for replacement until I took it apart and saw the mangled piece. Most bearings for any machine are easy to obtain locally, but I ordered this one directly from Probat. It was around $20.00. I also had them send a new sight glass while I was at it. There was a few chips in the current one, and it never hurts to have an extra on hand!

I highly recommend having a fellow roaster’s contact info that has the same type of machine as you. Getting pointers from their experiences and issues with their machine could save you a lot of time and moooo-lahhh. So, I called an old friend of mine that has had A LOT of experience with many roaster makes and models to get a little advice about pulling this thing out. And with that advice I received, my confidence was elevated.

First the pulley and drive chain needs to come off. That’s easy if your screws and set bolt are in good shape… Ours were. Whew!

It took a little finessing to get the mount off the axle, but slow and steady gets this job done. I used the claw side of a hammer to pry while using another hammer to tap the housing with medium force. This helped loosen the grip between the inner race and the axle. I rotated the pry hammer around the housing to distribute the leverage tension. It took me about 15 – 20 minutes to get it off.

Getting the old bearing out was way easier than I thought it would be. I used a large socket and a hammer to get it out. This hammer was pretty heavy and was more weight than was needed. Gentle taps got it out with no problemo. If you don’t have a humungous socket to use, a piece of wood works just as good too. Actually anything that pushes out the bearing out evenly will work.

After cleaning out the grease with a rag, the new bearing slipped into the housing so easily, I had to laugh.

Putting the replaced bearing with housing back on was a bit more of a challenge. The bearing inner race and the drum axle is a very tight fit. I used a pipe that matched the size of the inner bearing race, a block of wood and a hammer to get it on. I repeatedly whacked at it pretty good until it was set in place. If all you have is a punch and a hammer, you would have to tap all the way around it and it would talk a lot longer.

Greased it up and put it all back together…

Plugged it in, flipped the power switch, and it was rollin’!. Half of the time spent doing this job was assessing the situation, looking for the tools and taking photos! I also want to give mad props out to Kyle, our warehouse manager, for his help. He has an extended background with car mechanics and is a skilled wrench with a beautiful smile!

-Danny Goot