So far we have looked at how to prepare our wood, choose a blade, cast on and off a piece and cut outside curves and corners. Now it is time we do some inside cutting.
Most people associate scroll sawing with cutting fretwork. At first many people don’t understand that in order to cut fretwork pieces, you need to drill entry holes in the ‘waste area’ (or the part of the pattern that drops away when you finish your cut) and thread the blade through that drilled hole to cut out the inside piece. This is why it is so important to many scroll sawyers to have a scroll saw that uses pinless blades, or blades that have flat ends and attach to the scroll saw by a chuck or a screw squeezing the blade tight to hold it in place while you are cutting.
Many older and industrial saws used pin ended blades. . These are blades have a small pin going through the end of them and look kind of like a ‘t’.
The end of the blade rests in some sort of channel on the end of the arm of the scroll saw and the tension is then tightened to hold the blade in place. While this is an effective way to hold the blade in the saw, it is not always the most practical when doing decorative and delicate scroll saw work.
The pins at the end of the blades mean that in order to thread the blade through the wood, you would need a much wider entry hole in order to do so. This may be acceptable if you are doing larger pieces, such as fretwork brackets for shelves and trim work, but if you are doing smaller items such as ornaments and other delicate work, you will find that having to use pin ended blades will severely limit the scope of the work you can do. It is for that reason that I highly recommend using a saw that uses pinless blades. Most of the newer saws on the market today fall into this category.
I often am asked questions as to where to drill the entry holes in a project. While you can certainly drill them anywhere convenient in the waste area, there are usually some better choices that will minimize the time and effort in making a piece.
When I have a piece with lots of sharp corners, I like to start cutting fairly close a corner. For the same reasons that we started in a corner when doing an outside cut, I feel that it is also best to do so when making an inside cut. The place where we enter and exit our cuts sometimes makes a small bump, and I feel that by starting in an inconspicuous area near a corner, even if there is a small ridge where we enter and exit, it will be very difficult if not impossible to see.
For this lesson, I have prepared a practice pattern that has lots of sharp inside cuts. You can download the pattern at my Google Documents file here:
This is part of a pattern for a self-framing plaque that I designed. It is a pattern that I sell on my site, but I enlarged it a bit so that it would be a little easier for you to practice on. For this lesson, we are only going to work on the frame of the project so I only included that part on the pattern. Next time we will be working on the inside cuts and I will have that part of the pattern for you to download. (You will need to come back for that!)
Begin by preparing the piece as I showed you in previous lessons, with blue painter’s tape and then applying the pattern. (Or use your own favorite method) Cut around the perimeter of the piece so that it is a comfortable size to work with. Place a small drill bit in your drill press and drill out the holes in the waste are of the design. From the picture below you can see that I marked some suggested starting places you can drill.
Of course they don’t have to be exactly where I indicated – any thing close will do.
Drill using the smallest bit that will fit your blade through it comfortably. By ‘comfortably’ I mean that you shouldn’t have to struggle to push your blade through the hole, as this could result in bending the blade – especially if you are using a small blade. But you want to keep the entry hole as small as you can. When you are finished drilling the holes, be sure to sand the back of the plaque with some sand paper. Otherwise the bumps from the back of the drill holes will interfere with allowing your piece to sit flat on the scroll saw table.
After drilling and sanding, we are now ready to cut.
For my own piece here, I am using 1/2” (Maple) and a size 2-reverse tooth scroll saw blade. You can use anything similar and get the same results.
Begin by cutting toward the nearest sharp corner. Aim for the pointiest part of the corner. Remember to let up the pressure as you approach it so you don’t overshoot the cut. This is a common mistake that beginners make. (you can go back and review lesson #4 HERE if you want to refresh yourself about not putting too much pressure on the blade and getting not over cutting.) When you reach the end of the point – STOP:
Back up the saw blade slightly (perhaps a quarter of an inch or so) WITHOUT TURNING IT – simply pull the piece slightly back through the saw:
Now cut forward again toward the line, only this time go slightly to the LEFT of the line your just cut. Again you are going to stop as you get to your line:
When you are at the line, you should pivot your piece so that you can cut back to meet the tip of the point.
At this point, the little triangular piece should fall out (as indicated by the grey area in the illustration):
You are then going to turn your piece so that you will be cutting in a clockwise direction and following the line to the next corner. When you get to the next corner, stop again:
You will then back your blade up just as you did before (approximately 1/4 of an inch or so) without turning the piece or the blade:
Now just as we did on the first corner, we are going to cut to the left of the corner and stop at the line:
And after the small triangle falls out, turn your piece so you can continue in a clockwise direction and continue on to the next corner:
Continue in this manner until you come around to where you started. Be sure to back off the pressure you are pushing on your saw when you are approaching the end. If you push too hard, you will have a tendency to over cut into the piece past your starting point.
For very sharp angles, there is sometimes an easier way to turn the corners – especially when you are using a very small blade. In the second set of pictures, I have a shape with a very acute angle and an obtuse angle (over 90 degrees) to each side of it. In this case, I drilled my entry hole near the obtuse angle, and began cutting from the hole to the corner of it.
When I reached the line, instead of backing up the blade and cutting a small triangle out like I did in the last example, I simply turned the piece and began following the line in a clockwise direction and continued cutting:
I am able to do this because of the large angle. Depending on which size blade you are using, you should be able to turn most obtuse angles in this manner and still have a nice sharp corner. Remember when you are turning to pivot on the corner and slightly lean your piece to the back of the blade to insure that there is no forward moving while you pivot. Continue along the line until you reach the point of the acute angle.
When you reach that point, you will once again back up your piece about 1/4” and then pivot your piece (toward the waste area)
Now you will back all the way into the corner:
And from that point you will continue cutting in a clockwise direction:
I hope this gives you a clear idea of how to cut corners. Of course, if you are cutting in a counter-clockwise direction, you will just cut the little triangle out from the opposite side and continue accordingly. Once you get the hang of the process, it will be fairly easy and come second nature to you.
You will find that as most of the time with scroll sawing, the process is a matter of judgement calls. You will learn by practicing which way of turning is best for the particular area you are at. The thing we are aiming for is to have nice, sharp defined corners without ‘spin holes’ which are rounded areas made from turning the blade. Crisp and clean angles will make your piece look professional and nice.
Your homework for this week is to finish cutting all the inside cuts of the frame piece provided. This will be really
good practice for you and by the time you are finished, you should be feeling a bit more comfortable in doing the process. Next lesson we will learn how to do other types of inside cuts and later on we will learn to bevel cut the piece to make a self-framing plaque.
Below is the video that will demonstrate these three types of turns that I just explained. I think it will help clarify the steps that I showed you in the drawings above.
Of course, there are other ways that you can turn too. I am sure that others will have some good input as to other methods that work well for them too. As with most of scroll sawing, there are several correct ways to do things.
I would suggest you use a board approximately 1/2” thick and a #2 reverse tooth scroll saw blade. If you have something else available, I am sure that will work fine too. Try to use the smallest blade you can and still have control and not have to work too hard moving your piece through the saw. If you have to push hard, or if your blade is wandering too much, try going up a size. You will soon get a feel for what is right for the type of wood you have.
Feel free to ask questions if there is anything that I missed here. I will be finishing up editing the video and getting it posted here as soon as it is done, so be sure to check back later. But for now, this will get you started.
Thank you again for participating in the class. I hope you are all having fun!
-- Contributing Editor, Creative Woodworks and Crafts, Sheila Landry Designs http://www.sheilalandrydesigns.com "Knowledge is Power"