This final blog post is a little overdue. I finished the Chevalet build a little over a week ago, but I ran into some issues getting it to cut properly. Yesterday I found the root of my problem and today I finished up the final tuning.
When I was first starting to tune the Chevalet, I was having have an issue with it cutting straight. I thought maybe the blade clamps might be twisted a bit, so I thought I would give them a little twist to straighten them up. Well I was a little too firm in my twisting and cracked one of the mounts.
Luckily I was able to fix the crack with some Epoxy. It seems to be holding well. You might notice the repaired crack in some of the other pictures.
As I started to cut some keyhole tests and I quickly maxed out the Vertical Adjustment, before achieving a satisfactory cut. I racked my brain trying to find the problem. I decided to post my issue over on Patrick's Forum. I got a lot good information on what to look for. Patrick was right on, when he talked about how the saw frame needed to be square and horizontal. No matter how I checked for this, I seemed to be coming up “square”. Then it hit me, I wasn’t checking for “square” in relationship to the a “packet” being held in the jaws.
So, I clamped a square in the jaws, and eureka problem found! This is picture is with my Vertical Adjustment maxed out. I would need more adjustment room to get where I needed.
The root of the problem I think are a couple things. The plans for the Chevalet have the jaws tapered in thickness. This causes the “fixed” jaw face not to be parallel to the Main Post it’s attached to.
When I start to tune up the jaws, I really only focused on the “movable” jaw. This meant a packet being held in the jaws would reference off the “fixed” jaw, which wasn’t parallel to the Main Post. If in my initial tuning, I made the jaws parallel to the Main Post, I might have avoided this issue.
So to test my theory, I made a quick replacement jaw for the fixed jaw. It’s just a piece of plywood, but the clamping face is now parallel to the Main Post.
After this quick fix, it only took a few test cuts and adjustments to get a perfect cut!
Here’s another shot, that shows you can check for “squareness” to the face too.
After solving this problem, I made a new “nicer” fixed jaw. I started out with a “square” piece of wood. I left the top portion flat and square, then tapered the lower portion.
Now that I knew the fixed jaw was square and parallel to the Main Post, I could easily tune up the movable jaw in relation to it. I started by marking the face of the jaw, so I could see which area was being worked.
Then I attached some sandpaper to board and used that to work on the movable jaw. I lightly clamped the board in the jaws and moved it side to side and up & down. This actually worked really well.
I did one last test cut and adjustment. I have to say I cut a lot keyholes trying to solve my problem and went through a few pieces of wood. I started to grab some 1/2” plywood for my tests, and it turned out to have and added benefit.
After I thought I was where I needed to be. I took the test cut and split off the back layer. I then laid if over the front and checked how close I was. I was dead on, I couldn’t even feel a difference between the the two pieces.
Now it’s time to cut something for real! In preparation for this, I made up a couple trays to hold the pieces as I cut them. I think I might a few other supplies before I really get going, so I better get on that too!