Susan Kingsley
kingsley@redshift.com

I have made a startling discovery that I think people should know about. One-inch acrylic spacers can, over time and use, compress, causing the top and bottom surfaces to no longer be parallel. I am not talking about the small dents, dimples and creases in the surface, which can also cause problems, but compression over the whole block that causes one corner or one side to be measurably "thinner" than the other. For most applications, this is not a big deal. But the amount of deformation, as much as 2 mm, which may be doubled when you are using two spacers, is enough to cause blanking dies to fail.

I discovered this after teaching a workshop. I couldn't figure out why the student's correctly made dies weren't cutting. After determining that the press platens were parallel, I could see that when raising the platen with two spacers in place, there was a noticible "gap" on one side. When I checked my press at home, I found the same problem —which is when I measured the spacers. All of my well-used, at-least-ten-year-old spacers and those at the school were "off" in significant amounts. Then, over the last week a friend was having a serious crisis over having both (professionally made) old dies and then new replacement dies that wouldn't cut. Her 1.5-inch spacer was off by 3mm!

However, don't throw away your old spacers. If when using them with matrix dies or embossing dies your pressing is deeper or more pronounced on one side, press a second time with everything rotated 180 degrees.  But for blanking dies, and the precision needed for bending straight even folds (ie. boxes), you need to use "good" spacers. I am going to keep a separate set for this. Since very little pressure is used for either of these applications, and it is concentrated (rather than overt the whole 6 x 6 surface) they will probably not develop this problem. You should use a clean flat surface for blanking dies anyway because dented or damaged spacers can damage your die.

Anyway,
As Gilda Radner used to say, "It's always something!"