What’s It #22 – commercial coffee grinder burrs

Grindmaster 875 - 5lb coffee grinder
Grindmaster 875 – 5lb coffee grinder

I've had a Grindmaster coffee grinder for a few years. Recently, while getting a tour of Eastern Shore Coastal Roasting Co., I spotted a similar (but much newer) Grindmaster. It turns out they had recently picked it up on the used market and it was in need of a good cleaning and tuneup.

I offered to take it home and go over it completely.

The machines are made to be easy to work on. I disassembled the outer housing and found lots of old coffee grounds inside. Add some humidity over a few years and there was caked on crud in random corners.

After getting it all clean on the outside, I removed the motor and disassembled the grinding unit. Once it was clean, I inspected the burrs.

One thing seemed odd. The burrs seemed to fit better than I had recalled from my own grinder. Curiosity got the better of me and I had to pull the burrs from my own unit and compare. Indeed they are different.

difference - ignore that the auger is attached to my burrs
difference – ignore that the auger is attached to my burrs

I finished the cleaning and reassembled the grinder (and put mine back together too). I polished the hardware and the grind setting knob for good measure. I then adjusted both grinders and ran a test grind at different settings to compare.

While the burrs of my unit are newer, the ESCR grinder actually runs easier. My grinder tends to want to clog at the finest setting.

grind test
grind test

Greasing hinges 16 feet in the air

Every year (or so) I need to grease the hinge pins which hold the 4000 lb door in place. It's not the most enjoyable task given my strong sense of self preservation and fear of heights.

Thankfully BARRETT helps out. You may recall BARRETT from July 2010 when I added “remote control“.


What’s It #22?

what is it?
what is it?

It’s been a while since a new visual quiz has appeared here. I’ve been working on a project for a friend and found this interesting. What is it?

VA to ME and back without refueling

950nm round trip
950nm round trip, 7 flight hous

I’m just back from this year’s Chicken-Palooza event in. Maine. I took lots of pictures and video and will put together a “documental” on the event over the next week.

In the mean time I thought someone might be interested in the performance of the auxiliary fuel tank in the RV-8. This trip was a perfect example of the type of trip it was designed for long trip with no fuel at the destination.

I won’t know my fuel totals until I fill up tomorrow but the AUX tank worked as advertised. I flew a total of 950nm with no useful tailwind (2-4kts head wind up and +/- 1kts tailwind home).I think I’ve got at least 10 gallons left but won’t know for sure until I go get more gas.

I made it from the Eastern Shore of VA past Concord, NH on the north bound leg before the AUX was dry. I used less than 5 gallons of fuel from the main tanks for the trip up. That left more than 35 gallons of fuel to get home. A typical one-way flight is 24-28 gallons.

The Devastator is a serious long range bomber now!

Another runway morning

RWY03 at 6AM
RWY03 at 6AM

Maintaining a grass runway is a lot of work but sometimes, just the ability to look at it, makes it all worth while.

Death of a starter solenoid

When the RV-8 started having sluggish starts over a year ago, I blamed the battery so I replaced the Odyssey 680 with a Shorai 18. The changed saved me 13lbs but did not improve the engine starts.

The problem was always worse first thing in the morning or after the plane sat for a while.

A thread on the VAF website talked about the starter solenoid. I considered the idea but my plane had less than 200 hours. Still, it would be cheap enough to find out. A new solenoid was less than $10. I ordered one and tossed it in the parts drawer.

Fast forward four months.

Today, while changing the oil, I pulled out the solenoid that had been in the drawer and went about swapping it for my old one.

They say, “R T F M”. Well the new solenoid had no instructions and looked much like the old one so I wired it up the same. But, when I turned the key there was silence. I looked and looked and then realized this solenoid was opposite of the old one. After swapping the wires I turned the key again. Silence.

OK, googled for instructions or a diagram or something. Bingo. The coil has no natural ground. Ground the coil. Turn the key. Propeller spins!

The engine starts like I vaguely recall from a couple years ago. Nice.

I took the old solenoid apart and it looks pitted on both the contacts and the pad. It looks just like all the other examples of bad solenoids.