Ron Peterson

In my last post, I milled some logs in the field into large slabs. I typically mill these slabs into smaller boards before I stack the wood to dry. I built a sled to hold odd-shaped lengths of wood straight and steady as I run them through my band saw.

The sled is constructed from 3/4" plywood. Sliding stops on either end hold the log in place while I slide it through the saw.

The end stops slide in T tracks. Toggle clamps hold the end stops in place.

I put friction tape on the bottom of the end stops to keep them from sliding. The clamps alone are not sufficient.

I mounted nailing plates upside down on the inside faces of my end stops to hold the log. Once the log is in position, I use a heavy rubber mallet to tap the stops into the end grain before clamping them down.

A 3/4" x 3/8" polycarbonate extrusion which fits the band saw's track is mounted on the bottom to guide the sled in a straight line. I used my router table to mitre a very shallow 3/4" groove on the bottom to hold the extrusion perfectly straight before I mounted it with wood screws. I hold the sled up on either side of the saw with roller stands. A 3/8" thick strip of plywood on the side provides a level base for the sled to roll on. The bottom is also waxed so that it slides easily when heavily loaded.

Here's what the log looks like after a first pass through the saw. At this point, I could stop using the sled, and continue ripping dimensioned boards by running the straight edge I just made against a fence. I find that the sled does a better job of holding things straight, though. It's a little more work to use the sled, because I have to mark and carefully position each end of the log for every pass, but the results are better.

I use a 3/4" wood slicer resaw blade. It alternates between 3 and 4 TPI (teeth per inch) along the blade. This alternating pattern reduces vibration. Resaw blades are wide to provide stability. They also have deep gullets between the teeth so that they can remove all of the material from the cut. Shallow teeth would quickly gum up and fail to cut well. It's important to have a sharp blade in the saw. You can tell when the blade is getting dull because it will cut a wavy line.

I ripped this piece of log into approx. 2" wide planks. I chose the direction of the cut so that the ring pattern is roughly perpendicular to my cut - i.e. these boards are quarter sawn. Quarter sawn boards cannot be as wide as a plain sawn board, but they are more dimensionally stable.

Now I just need to find a place to store all this stuff...

...and that's OK.

LITS's very own Beth Johnson lost a very beautiful cherry tree to the crazy storm we had just before Halloween. She didn't want to see such nice wood go to waste so, knowing I had a milling attachment for my giant chainsaw (who doesn't), she graciously invited me over to help mill it up. I took a few pictures, because I have a hard time explaining to people exactly what I'm talking about when I tell them about my little hobby.

The first cut with the chainsaw mill is performed by running it over two parallel tracks fastened to the log. The bar of the chainsaw is fastened to the milling attachment on either end, as you can see in the picture below.

The mill runs over the plane made by the first cut for subsequent cuts. There are wedges driven into the cut behind the saw to keep the saw from binding. The slab in this picture is about 5 1/2 inches thick.

I'll mill the rest on a big band saw. The kerf of the bandsaw blade is much thinner than a chainsaw, so less wood is wasted. I won't cut these down too much more though until I know what I want to use them for. I can always cut it later, but I can't uncut it. In the meantime, I'll paint the ends with polyurethane. Wood contracts as it cures. If the end grain is left unprotected, it will dry faster than the interior wood, and the differential contraction will cause the wood to check.

If you're like my wife, you are perhaps wondering what I plan to do with all the wood I'm collecting this way. That's a good question; maybe I'll post an answer here some day. The thickest pieces here will take a couple of years to dry properly, so I have some time to think about it.

The MHC community rowing program took off in earnest this summer with the dedication and opening of the new MHC boathouse. Several dozen people have taken introductory rowing classes and we've been having a great time. We're usually out on the river around six AM or so. The quiet, the early morning fog, the various moods of the river can seem magical. I took a few pictures the other morning that I thought I'd share. It was a particularly foggy morning, so we attached lights to the bow to improve our visibility. Once we got up river a thousand yards or so, the fog lifted, and it was a quite beautiful morning.

Setting up an eight

Chris and his Alden Star

Getting ready to launch


Sweep rowing

Good morning dad

Bringing the eight up the ramp

Adaline checking out Dad's oar

Boathouse interior

Boathouse deck, looking towards the dock

From time to time, I do some work that requires I write some documentation. This is for my own benefit as well as my colleagues, because odds are, given a bit of time, I myself won't recall exactly what I did. Sometimes the work I do may have utility outside of MHC, in which case I've taken a shine to publishing my documentation in Linux Gazette. It's work I have to do anyway, and by doing so, someone else might benefit from the work I did. It's been a while since I did this, but I just published an article on using RSyslog to log to PostgreSQL. If nothing else, this will make it easier for me to find my own documentation when I need it.

The MHC student basketball team sent the faculty/staff team limping home to defeat in a really exciting game last night. The students took an early and commanding lead, but the F/S team rallied back and the game remained tied up for most of the next two quarters. But the final quarter was a rout, the F/S fell behind by nine, and stayed there. Final score: 61-55.

Everyone had a great time, but most importantly, we raised a significant sum to assist w/ Haiti relief efforts. Thanks to everyone who helped organize this event, thanks for coming to watch, thanks to the players, and thank god for ibuprofen and Bengay.

The Diversions and the M&C's also came to sing the Star Spangled Banner and to perform at halftime. They were terrific!

Coach Ken Tucker

Team Photo

Hi-Res version of team photo

Crowd starting to arrive

Hi-Res version of crowd photo

Come to Kendall at 7:30 on Tuesday night, March 2nd, to watch the MHC basketball team square off against the MHC staff and faculty! It's the best and worst of basketball, all rolled into one. We try to organize a game every year to benefit a charitable organization. This year, Cause will be collecting voluntary contributions at the door (suggested donation: $2, additional generosity much appreciated) to benefit Haiti. Hope you can make it.

Youth challenges the master on the mountain. Via my friend Ben Okopnik.

I caught wind of this TED talk from CNN. It's nice to see women's issues getting such attention. Eve Ensler is probably best known for the play "The Vagina Monologues". I was particularly struck by this CNN byline:

...and launched safe houses in the Congo, Haiti, Kenya, South Dakota, Egypt and Iraq.

I grew up in SD, and to see my state in this list is rather appalling. But appropriate, given my home state's stance on the abortion issue. Not every South Dakotan leans so far right, and so I thought I'd share this.

A few snapshots from the recent LITS Open House.

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Why wasn't chorus this cool when I was a kid?

Of all the best-of and worst-of end-of-year retrospectives, my macabre favorite is always the Darwin Awards. The (official?) logo reminds me of a favorite expression of mine: "Extrapolation is when, upon reaching the edge of a cliff, you keep walking, because the ground has been flat so far."

This year doesn't seem to quite match up to earlier years. One entry in particular - "Tennessee Pee" - has me confused. I mean, who wouldn't climb a clearly marked barbed wire fence to climb on top of a high power transformer to pee on a wasp nest that obviously shouldn't be there?

I'd been working on a bow saw, but got stuck figuring out how to attach the saw blade to the frame. I sat on it for a while, and then finally came up with this solution. I sawed the threads off of a couple of 5/8" carriage bolts. Then I cut slots in the ends of the bolts, and drilled a small hole in each for a small machine screw to hold the blade in place. A nice feature is that I can turn the bolts 90 degrees, so that I can use the saw to rip through a long board if I want to.

Many of you may know Ron Zissell from his work tending the telescopes at the Williston Observatory. Or perhaps you've seen him in full Scottish regalia playing the bagpipes on special occasions. In addition to these things, Ron has also been keeping the Mount Holyoke campus on time since July 1st, 1976, when he was given the keys to the Mary Lyon clock tower by the previous caretaker, Charlie Lang Lyon.

I spent some time this afternoon helping Ron with one of the observatory computers. After we were done, Ron brought me with him while he ascended the tower to perform some routine maintenance. The staircase into the tower happens to be in Elizabeth Braun's office. Tanya Williams' office is right around the corner. Her office mates had made the trip before, but she had not, so she also came along.

It's not a trip most people get to make, so I thought I'd share some pictures.

The large bell used to be rung by a rope around the large pulley, but everything is now driven by the clock mechanism. The rods going through the ceiling are attached to the striking mechanism, which is driven by the clock mechanism.

Tanya signing her name to the guest register, which dates back to 1975. Ron knows almost everyone on the list, of course, and has lots of great stories to tell. One of the guests was an alum who made the trip up and down the rickety ladders in a white dress while attending her 50th reunion.

This is the main clock mechanism. The tower shifts very slightly with the seasons, so Ron carefully balances the pendulum to keep proper time.

This is part of the bell striking mechanism. You can see a couple of the rods extending down through the floor to the bell room.

When oil came from whales, clock makers used the finest grade, extracted by tapping the blubber at extremely cold temperatures. There's just a little left in this bottle from long ago. It smells really terrible.

I've been whiling away the evening hours writing a set of cryptography functions for PostgreSQL. First in importance, but the last thing I wrote, is a cryptographically strong pseudorandom number generator. I chose to implement the Blum Blum Shub algorithm. My attraction to this algorithm lies in the fact that it is supported by a security proof very similar to that behind the RSA PKCS #1 v2.1 standard, which relates to the difficulty of factoring large integers. This algorithm has been subjected to lengthy and intense scrutiny, and has withstood the test of time. This code is available to use under the terms of the GNU Affero GPL v3.0.

I've wrestled with kpartx before. This time I thought I might lose what hair I have left. This post is a little wonkish, but as before, I hope posting about my experience will help some other sap someday.

For the uninitiated, kpartx is the linux utility called by udev to assign device names to disk partitions when using multipath. Kpartx has a -p option which is used to assign the string you'd like to use as the partition delimiter in these device names. So say you have a disk called 'foo', with three partitions, and you give kpartx the string 'bar' as the argument to -p. Then you should end up with device names under /dev/mapper that look like foobar1, foobar2, foobar3. Fair enough.

In the process of setting up a new server, we elected to ensure we knew how to configure this by setting the delimiter to 'quack'. It worked fine. Of course 'quack' is not what we really wanted in production, so a few weeks later we set this back to plain old 'p'. After a reboot, however, the device names came up 'quack' again. (!) (@$%#$%). If we cleared the device names (multipath -F) and recreated them (multipath -v2) they came back the way we expected. We searched high and low for where 'quack' could be hiding, but couldn't find it.

Finally, I sent a query to the dm-devel list. These are the linux programmer gurus who write the device mapper utilities. Mike Anderson from IBM sent this helpful reply: "It sounds like there is a copy of the old rules in your initrd." Bingo! Between our original test and when we tried to revert, I had compiled a later version of the kernel for this server, which of course updated my initrd. Another compile with kpartx configured correctly, and the machine now boots with the correct names.