For a little background, I am a Master Fretsman and made a living for several years just doing scroll saw work. You can see some of my work at http://www.wiseacresart,com. A few years ago we started http://www.woodworkingparts.com to offer and help fellow woodworkers and crafters obtain quality and low cost supplies. I still do scroll saw work.

Now about the scroll saw blade.

The first thing to remember is that as the blade cuts it creates heat. This heat then burns the saw dust if it is not removed fast enough.
This creates the burned edge that so many have when cutting hardwood. The best saw blade I found to prevent this problem is a double tooth blade. It has 2 teeth and then a space and then 2 teeth all the way down the blade. This blade has the space that takes a lot of sawdust out in one stroke compared to a regular blade.

The reverse tooth blade is a poor choice. It has a few teeth on the bottom that is to make a cleaner cut on the bottom side. However these reverse teeth just pulls the sawdust back up into the cut creating more problems. I have never had a problem with the bottom side using a double tooth blade.

For size of blade you will hear all kinds of sizes. Usually people use SMALL blades like a #2. My advise (not suggestion) is a #9 double tooth saw blade. Yes I know you say no way, your nuts. You can not do small fine work with a big blade like that. Well your wrong. I use a #9 and nothing else. If I need to cut a hole smaller than 1/16 inch drill bit would make, I grind down the end of the blade so I can slide it into a tiny number drill hole. I will give advise on how to cut thick hardwood in one of my next postings that will help explain how to use just this #9 blade. I have made 5 stacked 1/4 inch thick oak trains which you may have seen that has over 300 holes so thickness is also a big item for the #9.

However, DO NOT go bigger than a #9. The bigger blades get thicker and all advantages go away with the double tooth. I have tried the large blade so this advise is tested.

What about Precision Ground blades? First off they have the reverse teeth which I already said do not use. Second they are expensive for a little extra sharpness. Third they break easy. So you should know now I do not advise the purchase of a precision ground blade. Instead you want to use an aggressive blade. The more aggressive, the faster cutting. We do not sell blades so I am not pushing any. My first choice (and only blade used) is the #9 Galaxy Double Tooth blade.

One last piece of advise on scroll saw blades is clean the ends before installing. The blades have a dry lubricant coating to help reduce heating and make them slip in the cut better. This lubricant will cause the to loosen and/or hard to keep in the blade end clamps.
To clean the ends, take a piece of sandpaper and fold it in half (just a small piece) and hold it between your fingers. Hold the blade in the other hand and slide it up and down between the folded sand paper. This removes the lubricant on just the ends and makes blade clamping much easier.