Although I usually feel like a competent woodworker, any time I am faced with metal work I feel like I’ve gone back to kindergarten. This project has, however, forced me to get a little more comfortable with metal working.
But first, one important photo I forgot to share last time around:
Work holding isn’t always easy when working with an irregularly-shaped piece. That’s where a handscrew held upright in a bench vise gets really, really handy. I place a spacer block behind one of the jaws so that the bench vise clamps only one jaw, leaving the other free to move. That way, I can easily reposition the workpiece with a turn of the lower screw.
Once the saw handles were shaped and sanded, it was time for a little metal work. Both saw plates needed trimming to fit the handles. The panel saw also had at least two separate sets of handle holes drilled in it, so I opted to cut that whole section off the back, shortening the saw by maybe an inch and a half. I marked my lines with a black marker, taped the saw plate to a backer board, and cut it off with a hacksaw.
In retrospect, I should have just used the tape itself as the layout line, but oh well.
The dovetail saw plate also needed one corner clipped to fit into the handle slot. I filed both cuts smooth. Then I shaped the brass spine with a file and sandpaper. (Not wanting to get metal filings all over my camera, I opted not to take any pictures of that process.) The work went quickly, as brass is quite soft and easy to work. The drawback is that the brass is also easy to mar with an errant stroke of the file. After sanding the spine, I took it down to my buffing machine and put a nice shine on it. I went back and forth between the sandpaper and the buffer several times before I was satisfied with the surface finish on the spine.
The next challenge was drilling the holes for the bolts and nuts in the saw handles. This presents a challenge, as the holes must be lined up perfectly. It’s easy to drill a hole through one side and then counter-sink it for the head of the bolt. But how does one counter-sink the other side? Normally, one would do this with a special drill bit called a piloted countersink. But since I had only five holes (three of one size and two of another), I didn’t want to buy a special bit. There is a way to do this with regular drill bits, and while it’s time-consuming, it works just fine.
First, clamp down the workpiece on the drill press table and drill the narrow hole all the way through. Then, without moving the workpiece, counter-sink the bigger hole to the necessary depth. My drill press has a decent depth-stop, so getting a consistent depth was pretty easy. The smaller hole should be perfectly centered in the larger hole.
Now turn the workpiece over, put your smaller bit back into the chuck, and (without turning the drill press on), insert the drill bit into the original hole. Turn it backwards a few times to be sure the workpiece is in the right place. Clamp down the workpiece; it is now perfectly centered on that hole. Back out the small bit, put in the larger bit, and counter-bore it from this side.
It’s a lot of changing bits in and out, but the results are precise enough for my purposes here.
I then drilled holes in the saw plates for the bolts.
For the dovetail saw, I considered squeezing the slot in the spine so as to hold the saw plate by friction alone–which is the traditional way of constructing a backsaw. In my imagination, it seemed like the right thing to do. But when I started to try to close the slot, I found that the brass is pretty springy. The more I thought about it, the more I saw that the likelihood of my ever wanting to remove this saw plate from the spine is about nil. So, in a moment of weakness, I reached for the super glue. A dab in each end of the slot, and the saw plate was solidly seated in the spine. Sometimes chemistry wins out over mechanics.
So, at the end of the evening, I am almost finished. I will need to trim the screws to final length, apply a finish to the handles, and sharpen the saws.