Friday, August 07, 2009

Why We Needed a Scarf in August

scarf 2 (skärf)
n. pl. scarfs (skärfs)
1. A joint made by cutting or notching the ends of two pieces correspondingly and strapping or bolting them together. Also called scarf joint.
2. Either of the correspondingly cut or notched ends that fit together to form such a joint.
tr.v. scarfed, scarf·ing, scarfs
1. To join by means of a scarf.
2. To cut a scarf in.
[Middle English skarf, as in scarfnail, probably from Old Norse skarfr, end piece of a board cut off on the bias.]

--Free Online Dictionary

So one of the great joys of working with salvaged materials is making them fit. All our floor joists were roughly 142 inches long, which was what we used on the east-west pieces of the pergola cross bars. That gave us just short of a two foot overhang. To get boards with a corresponding overhang on the north-south pieces we needed to scarf pieces together.

To start we clamped the boards side by side to each other, without overlapping, for the scarf joint distance. Then cut a series of 1" deep passes over both the boards with the circle saw. Since the boards are 2" thick taking out half of each board will give us the correct depth for the scarf joint.

Then we took a hammer and knocked out what was left between the grooves.

Our next step was to then take a wood chisel and get rid of any obviously high parts. After that we hit them with the plane

We then put the boards together in a dry fit to see if we liked it. Here we did

To keep the joint together we used Gorilla Glue. You don't want to get that on your fingers or anything else you value. We used a little chunk of wood to spread it on the end of each joint.

Then we put glue on the scarf area of both boards

We put the two sides together and clamped them. Then we sent five stainless steel screws into the first side.

Then we flipped it over and did the same on the other side.

After letting it dry we put it up on the pergola and clamped it into place so we could drill it for the carriage bolts that hold it in place.

Of the four north-south boards three have a single scarf joint and one has two scarf joints. My guess is that in a few years with enough vegetation growing on top of it, none of them will be noticeable!


Jenni said...

That is going to be a great space.

Mike said...

Thanks Jenni, we already are spending lots of time out there.