I had some free time tonight, so I decided I would tackle another upgrade/modification on my La Pavoni. As some of you may recall, this machine was purchased off Craigslist and I have been modifying it here and there.
Some of the previous modifications include:
A home made DIY pressure regulator --> La Pavoni Mods - DIY adjustable pressure regulator
Cut-it-yourself DIY naked portafilter --> La Pavoni DIY Naked Portafilter
Group head O-ring repair --> La Pavoni O-ring gasket question - wrong size?
On my machine, since it's around 30 years old, the rear pivot hole in the lever had started to elongate. This resulted in some slop in the handle (during extractions). In order to halt this process and perhaps provide a little enhanced longevity, I decided that maybe I would drill the hole out and install some bronze bushings. If I'm not mistaken, someone else (Doug @ EO maybe?) did this same modification. I'm not sure where I ran across it - or who did it - but I remember thinking it was a good idea when I saw it.
Anyway, so after a little searching, I was able to find some bronze bushings (on Amazon of all places), made by a company called "Bunting Bearings". The size was perfect! 6.00 mm bore (which matches the cross pins that go through the lever on my machine) with a 9.00 mm OD and - perhaps best of all - 4.00 mm in length. The 4.00 mm length perfectly matched the width of the metal on the La Pavoni handle. As such, all I needed to do was drill out the hole to slightly under 9.00 mm, heat up the handle a bit, then chill the bearings and press everything together (this would provide a nice interference fit) - and, since the bearings were already the same length as the metal in the handle was wide, there would be little, if any, fine tuning required.
The bearings took almost a month to show up. I don't know if that's because they are made to order or what. In fact, they took so long to arrive, I actually tried to cancel the entire order (I had ordered several sizes originally). As luck would have it, four of the 9.00 mm OD bronze bushings shipped the day before I canceled the rest of the order. Once the bushings arrived at my door, I was on the hook to install them
As you can see from the photos below, the bushings turned out to be a perfect fit. I ended up drilling the handle out and then using a stack of nickels and quarters as a wedge. After checking everything with a digital caliper, I heated up the handle and pressed the bushing in using my old Wilton bench vise. It all worked like a charm. The only problem was that, because the bushings were in there so tight, it sort of squeezed them down a bit. This resulted in the 6.00 mm cross pins no longer fitting into the bushings. However, after a very slight amount of filing on the inside of the bushings, the pins slid right in again.
In the end, it turned out even better than I anticipated. For now, I have opted not to do the forward holes (the ones which hold the cross pin that goes into the group head piston rod), as these holes do not seem to take as much abuse and show little, if any, signs of elongation.
In any event, I thought members here might enjoy seeing the results. For anyone who wants to order the bushings, you should be able to search the part # AAM006009004 on Amazon.com. In fact, here's the link I used:http://www.amazon.com/Bunting-Bearings-...B0040GKB4A
Each bushing (at the time of this posting) cost $4.34 with free shipping.
P.S. - The final picture shows the replacement handle I bought (after the OEM one broke). I picked it up off mcmaster.com for about $9.50 - part # 3701T27
The lever, cross pins and bronze bushings prior to modification
Here is a close up
Here you can see how the rear hole was starting to turn into a slot
Close up shot of the bushings
After installation. I used some nickels and quarters to brace everything while pressing in the bushings
Close up shot
Another close up shot, showing the final results
Here is the handle, just before reinstalling it on the La Pavoni
Another shot of the finished lever
All done! This shows one of the 6.00 mm cross pins in place
Part # and bearing information
The replacement handle from McMaster - very heavy duty; great for extra leverage while pulling shots