I needed a spanner wrench to remove the blade base from my vitamix carafe. You could potentially use this technique for apllications that need a spanner wrench with holes instead of slots that doesnt have a shaft in the center that would block the allen keys.
Step 1: Choose Allen Keys That Fit Into the Holes
The size doent have to be perfect just close enough to work. Just be sure that the allen key is small enough to seat all the way down the hole.
Step 2: Grab Another Allen Key of Similar Size [or the Closest You Can Manage]
Here Im using one SAE and one Metric allen T-Handle I had close. Just be careful when applying pressure that the allen key ends arent damaging thie metal holes.
Step 3: Set One Allen in Length Ways and the Other One in on the Short Side and Carefully Turn
You could also use L shaped Allen keys for this technique.
Its best to use one hand to support the the allen key connection and one to twist [I couldn't take the picture with both hands]
I find its best to put a little tension so the allen keys find there binding position and then use little bursts of pressure to break the seal. Think of yourself as a very gentle air wrench or impact wrench. I find this helps keep from stripping screws and bolts and nuts as well. Just be patient and usually they will give up after a while. Do the same thing when tighening it back down just be sure not to over tighten as the burst of pressure will snug the nut down quite nicely.