As my 1st major scroll saw project, I decided to build the Elegant Fretwork Clock from the book Wooden Clocks. Below is a picture of the finished clock from the book.
I decided to make the scroll saw piece of fretwork from a sheet of oak plywood. I cut out 2 blanks and stacked them together so I will cut out 2 clocks at once. I wrapped them in blue masking tape and used white Elmers glue to hold the paper pattern to the blanks.
I also made a zero clearance insert from cardboard and taped it to the scroll saw.
I decided to use No. 5 plain end skip tooth blades for the scroll saw. These small blades fit in only a 1/16" diameter hole..and this just fits in some of the small areas to be cut.
There are over 60 areas that must be drilled then scroll sawed. This means you must detach and re-attach the scroll saw blade over 60 times. At first I found it tough to know when the blade was tight enough. If you go too tight, the blade slips and will not tighten.
I found John Nelson's guideline of plucking the blade with your finger an excellent way to know if the blade is tight enough......of course with the saw not running.
Once I was done scroll sawing the inside cutouts, I went back to my 12" sears band saw to cut out the OD. The big band saw is much faster than the scroll saw. I band sawed just outside the OD of the clock faces, leaving stock to sand smooth on the drill press. As I band sawed each 1/4 of the OD, I added a piece of blue masking tape to keep the 2 blanks aligned. I also took the 2 blanks to the drill press and drum sanded to the exact line of the OD using a 2" diameter drum sander.
I then used a combination of 220 grit sandpaper and 2 small files to remove the burrs from the back side of each blank. I also carefully hand sanded the face with 220 grit. I cleaned all sanding dust by carefully rubbing the clock faces with a damp dish rag. The clock faces were then ready for their first coat of polyurethane.
I then glued up 2 pieces of maple to form each clock back face. To get the 9 inch rectangular blanks round, I had 2 choices. Choice #1 was to drill a small center pilot hole and use the router with a straight bit to round the OD. Choice #2 was to bandsaw to round and then drum sand on the drill press to exact OD.
On previous projects, I learned that you can make a very accurate OD using the bandsaw and drum sander method. Plus, it would take 3 depth settings on the router for 3/4" stock. I chose to use the band saw and drum sander method.
Cutting out the rectangle for the clock movement:
I then marked out a 2.25 inch square on the back of each maple piece to cut-out for the clock movement. Then I used a 2" dia Forstner bit and cut to within 1/8" of the face. Then I squared up the hole using a 1/4" straight router bit in the drill press using multiple depth passes. Sanding the maple pieces to 220 grit was the last step before polyurethane.
Then I did 2 rounds of 220 grit sanding and polyurethane.
I bought the movement and hands from Klock-it. It was their standard movement. It was #10052: Standard Push On Movement with Bushing (2) $5.98 and #66834: Push-On Hands: Black (2) $0.00
Glue and Finishing Process:
I finished the maple piece by using 2 rounds of 220 grit sanding and polyurethane. I finished the fret work by hand sanding carefully with 220 grit and then polyurethane.......for 2 rounds. I used a brush. I did not finish the back of the fret piece so the Titebond yellow glue would stick better. I was concerned about the glue sticking to the finished maple piece, but it worked ok. Next time, I should use some scrap pieces when I clamp the fret piece to the maple so the round clamp marks do not show up on the fret piece.
This is the first scroll saw project I ever did. I learned that for intricate work that has small areas to be cut out, you must use plain end versus pinned blades. An intricate project like this can be very time consuming. There was roughly 60 areas to saw out, so if you figure 5 minutes per area (you have to detach and reconnect blade for each hole).......this is 300 minutes or 5 hours of sawing time. The scroll saw blade teeth must also be pointed down.
To know if your blade is tight enough, it is helpful to pluck the blade with your finger and listen to the resultant tone. I had trouble with my scroll saw upper knob getting tight enough to hold the blade. I may have to redesign the upper knob assembly with a bigger knob so you can apply slightly more torque and squeeze force on the blade.
It would also save a lot of time if I had a Forstner bit large enough for the clock movement. My set only goes up to 2-1/8 and you need 2-1/4 or 2-1/2 inch diameter to fit in the movement.