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Probat L12 Coffee Roaster Restoration Project | Part 3

Posted on July 8, 2013 by Venia Coffee Roasters | Keith There have been 0 comments

OK, We have been busy, busy, busy around here and I haven't gotten around to an update on the our Probat L12 Coffee Roaster restoration project. Thanks for all the interest in the project, we are sorry to keep you waiting!

Tear-down has been a bit slower than I had hoped, but the need to document the process so re-assembly will happen smoothly is important. I really don't want to finish putting the roaster back together only to have that proverbial extra mystery part in hand leaving scratching our heads...more to come on that.

Drum removal had me a bit nervous as I didn't really know exactly how heavy it was going to be. The good folks a Probat Burns said it was s 2-3 person job. Turns out it was a bit easier than anticipated. Whew!


Drum Removed


Up to now, we have run into 5 bolts and screws that would not break loose easily. One has required a tap and die set to remove, others broke loose with plenty of PB Blaster and patience, while two snapped off entirely.

One of the broken bolts was one of the tie-rods that hold the front and rear plates of the roaster together. After nearly 30 minutes of trying to coax the nut loose with everything at my disposal, I busted out the air-ratchet. Within 5 seconds the end of the tie-rod snapped off. Doh! Not sure if these are replaceable but something I think we can easily fabricate on the lathe using some rod stock.


Tie Rod holding drum together.  Tie Rod holding drum together.

Broken Tie Rod Broken Tie Rod


The other breakage occurred from the threaded rod that holds the heat shield in place that protects the drum from direct flame contact from the burners. Three of the four came right off, but the fourth wouldn't budge. Knowing this was an easy rod to replace I intentionally gave the socket wrench a full 1 1/2 turns before the snapped in half.


Heat shield. Heat shield.

L12 Disassembly_20130706_0410 Hole where the burner assembly resides.

Doh! Doh!


Turns out the rear bearing on the drum is the same used on KTM 450 4-stroke motorcycles...who knew?


L12 Disassembly_20130706_0400

Rear drum bearing & assembly.  Rear drum bearing & assembly.  It looks like at some point the roaster was operated without the bearing in place as there is a significant amount of wear where there should be no contact with the drum shaft.  Perplexing.


My day ended a bit short when I realized that a special tool would be required to disassemble the rear cooling tray agitator bearing.


Cooling try agitator rear bearing. Cooling try agitator rear bearing.

Thinking a special tool that we don't have is needed to remove... Thinking a special tool that we don't have is needed to remove...


Once the rest of the roaster is stripped down we will start the sand blasting process in preparation of powder-coating.


Calling it a day. Calling it a day.


On clean-up, I discovered this little piece.  I currently have no clue where it came from.  could it be the proverbial extra part?

The proverbial extra part. The proverbial extra part.



This post was posted in News and was tagged with Coffee Roasting, Coffee Roaster, Probat, Probat L12 Rebuild


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