Not a lot going on this week. I spent a lot of time in the shop, either doing work work or doing office work.
An update on the Duwamish
The Duwamish’s air compressor is in pieces in my shop:
I’ve been cleaning and honing the cylinders, but I still do not know the make or model. I’ve found a few numbers stamped into it, but that’s all.
Clamor about the John Cobb
Everyone is talking about the NOAA ship John Cobb – there’s a lot of interest in what will happen to the boat now that its engine is damaged (details last week). I won’t repeat all the rumors I hear here, but I don’t think that NOAA will just walk away from the boat even with a broken crankshaft.
It’s still slated for decommissioning this fall, and I’ve heard lots of speculation on what’s next for the boat. I hope that whatever happens, the engine will be repaired or replaced with a heavy-duty from the same era – maybe a direct-reversing Enterprise diesel.
Old Tacoma Marine Inc on eBay
In our latest effort to take over the internet one site at a time, OTM Inc is now open for business on eBay. We hope to sell some miscellany related to heavy-duty diesels and other old-time engines, starting with some neat things we’ve had around the shop forever but will never use in any of our projects.
First up: a vintage brass grease cup for engine bearings. We’ve got more information and pictures on the listing, so check it out – or buy it.
We hope to sell a new item each week, so keep checking in.
Slope of Grain versus Runout
While acting as a consultant to Northwest Seaport regarding the lumber purchase for the Lightship #83, we’ve been learning about the language used by shipwrights to define wood grades. Two terms we’ve encountered are “slope of grain” and “runout.” We’ve found that these are often mis-used even by the experts, so it’s been difficult defining them. While researching, we found that there are plenty of sources out there that tell you what causes slope of grain and runout, and how to cut boards to achieve a good slope of grain and runout, but not many firm definition of what they are in the first place. Different people and books also define the terms differently.
Despite all that, we’re now pretty sure that runout is the grain running off the top side of a board and slope of grain is the grain running off the sides. These definitions don’t leave us feeling very much more enlightened, though. If we’ve gotten them confused, or if you have a better definition, please leave a comment on this post – we want to get it right.
I think that maybe the reason it’s so confusing is that the only people who really care are the folks at the mill, who are known as “sawyers.” The slope of grain and runout have a lot to do with the strength retained in the board, so a sawyer will try to produce the best quality (strongest) wood by getting a good slope of grain and runout they can anyway. It’s rare that a wood buyer needs to include those figures in an order.
We did need to include them in the Lightship bid request, though. Our client is required to accept the lowest cost bid, so it had to specify exactly what quality wood they need for the job.