When you complete the easy and inexpensive improvements discussed in this article you'll discover that the Porter Cable scroll saw is great for toy making and that it is a reliable and accurate saw especially considering the low cost of the saw and stand.
Above: MDF board screwed to the frame base of the Porter Cable saw controls saw vibration.
You can decrease the vibration of your Porter Cable scroll saw substantially by screwing 1/2" thick MDF (Medium Density Fiber Board) to the frame base as shown in the photo above. Lowes (in the USA) has 1/2" thick MDF in 2' x 4' sheets inexpensively. You can also buy it at Home Depot. It is good practice to cut all of the MDF panels to fit the saw frame and then drill the panels for the bolts. To mark the MDF for sawing take the saw off the frame and lay the frame down on the MDF to trace around the outside of the saw base frame with a pencil to make the sawing lines. It is a good idea to also mark for a toe-space out at the bottom of the three MDF sides that is about 4” high as shown in the photo. To maintain side stability allow enough MDF on each side of the toe-space opening to extend down to the rubber feet on the metal frame. The toe-space opening is for your toes when you want to get up close to the saw for detailed scrolling.
For fastening the panels to the frame use 1/4-20 thread x 1" long bolts with lock washers under each nut. You can use LockTite (a glue for locking nuts to bolts that comes in a tube at Lowes) on each bolt and nut to keep them from vibrating loose over time. If you can spend a little more you can buy lock-nuts and skip the lock washers and LockTite glue. You might have to ask a clerk to help you find the lock-nuts. They have a white plastic ring inside that creates pressure on the threads that prevent the nuts from vibrating loose.
When drilling the bolt holes through the MDF and the metal frame it helps to clamp the panels to the frame for drilling. That way you can use the holes that you drill in the panels as drilling guides as you drill through the metal frame. It speeds things up a bit to add a drop of motor oil or lubricating oil to the holes after the holes are drilled in the MDF to keep the drill bit cooler and to prevent dulling the bit when drilling through the metal sides. Cooking oil also works if nothing else is available. The holes that you drill for the bolts need to be close the diameter of the bolt for a tight fit and a 1/4" diameter bit for this purpose can be purchased at Lowes. A combo metal/wood drill bit is best. It is a good idea to buy a couple of drill bits if you buy cheap ones. They dull pretty quickly when drilling metal. The more expensive tungsten/carbide bits are harder and stay sharp a lot longer.
Once you have the frame strengthened with MDF and all of the bolts very tight you will see quite an increase in stability when sawing. If you want to decrease the vibration even more you can place concrete blocks, barbells or anything very heavy on the shelf below the saw to add weight to the base.
Another worthwhile improvement that you can make to the saw is to replace the plastic insert that fits around the blade. The plastic one that comes with the saw is not rigid enough for extremely detailed scrolling. I replaced my Porter Cable saw blade insert with one I made out of 1/8" masonite. I used the plastic one as a template for tracing the shape on the masonite then sawed it out on the scroll saw. I drilled a minimum size hole in my handmade masonite insert that was just big enough to clear the blade. I then sanded the edge of the insert until it fit perfectly in the opening in the table. Once that was done and with the insert in the table I used 80 grit sandpaper wrapped around a wood block to sand the new insert down to the exact level of the table. The new insert works perfectly and I can easily replace it any time as the hole for the saw blade gets too big with use. You can see the new MDF insert if you look closely in the photo.