I trim mine before they are pressed open. Line the stitch line along the ruler at the size I want and use the right angle of the square ruler to trim one or two sides (usually only need one side trimmed unless I got a little careless w/ matching sizes of beginning squares)

I know you said you can only use any type of tape, but I have never heard of 'medical tape.'

Thanks for the tip and extra explanation, the second picture made more sense to me and seems like a great idea.

It's the kind of tape that holds gauze bandages on--a clear rubbery plastic--you can find it in any pharmacy. I usually use it for my rulers to keep them from slipping.

Wonderful tip, thanks!

I have a brand new June Taylor ruler like the one in the picture and a DGD who wants a quilt with half squares. Thanks for sharing your innovative technique. I'm in.

It's athletic tape. About an inch wide, and translucent. I love it because it doesn't let the ruler slip, but it's not so gritty that I can't slide the ruler to where I need it.

And just after I've spent all that money on Bloc-Loc...

Great idea. I usually use blue painters tape on top of the ruler. White tape under would make it easier to see.

The second picture helped me to understand what you are talking about. That is a great idea. Thanks

Thanks for the second pic, that's what I thought would be the process, but wanted to make sure. Thinking...that tape would work on any "square up" ruler...when you use it on the JT ruler, it better be for more than just a Few hst....and make sure you don't need to cut anything with the JT in the interim.....

I don't think it would matter much if the tape got sliced through while working on something else.