Everybody above is on the right track and has given you good advice. What isn't mentioned is that there is a distinct order of things to try. You want to try the least destructive solutions first. Your goal is to avoid damaging the threads in the Easy Wood Tools handle/shaft.
Here are things I might try in order, until one of them succeeds:
0. Make sure the screw is completely clean, so that the Allen wrench can seat itself as deep as possible.
1. Put the Allen wrench in the freezer. With a heat gun, heat the back side of the tool behind the screw - not excessively hot, okay? Take the Allen wrench from the freezer and try unscrewing the screw. If it isn't working, try the "wiggle" trick (back and forth) that
@Lee58 suggested. With the outer threads hot (expansion) and the screw cold (contraction) it may be enough to break the bond.
2. Penetrating lubes and oils. Apply your favorite PB Blaster, Liquid Wrench, etc. Let it soak for a few hours or overnight. Try unscrewing the screw.
3. After applying the penetrating lubes, try the heat gun trick (step 1) again.
4. Search the internet to see images of "screw extractor". This is similar to the "left twist drill" suggested by
@Displaced Canadian. Screw extractors come in many different types. You want the kind with a left spiral. Some have have the spiral at the tip only, while others have the spiral running up the shaft. I have both types. Sometimes one works better than the other. Use the largest size that will grab tightly in the screw. Sometimes a gentle tap with a hammer can get it to seat tightly. Use a wrench on the screw extractor to unscrew the screw.
5. At this point, you are now looking at more dangerous solutions.
-> Have you thought of contacting Easy Wood Tools for help? For the cost of shipping, they may be willing to fix your issue.
6. With your fingers, try a very very small drill in the hole. See if the drill centers itself well. If so, drill a small, straight, centered hole in the middle of the screw. The hole should about 3/4 of the screw length in depth. Make the hole as straight as possible, but such holes are rarely perfect. They usually angle slightly, and you don't want to damage the threads, which is why you don't want to go too deep. Try a screw extractor using the small hole.
7. If step #6 doesn't work, use the next largest drill bit to enlarge the hole. It should be barely larger than the previous drill and it should enlarge the hole very slightly, very easy. Repeat the screw extractor attempt. If that fails, repeat this step carefully until it works. Eventually there will not be as much of the screw left, and it should come out. Please Please Please be careful not to damage the threads in your handle.
I hope this helps.
