Easy way to cut 32”x40” mat board in half (cleanly + safely)?

[Heroique]

Maybe this framing problem has a simple solution:

I have a lot of 32”x40” (4-ply) mat board, but my mat cutter accepts sides no wider than 28.5.”

This means I have to rely on something else for my first (down-sizing) cut. Problem is, I often need this initial cut to be clean & perfectly straight. To get the job done, I’ve been relying on a metal yardstick & box-cutter (w/ a sharp blade), but even when I’m super-careful, sometimes this arrangement just, well, “doesn’t cut it.” It’s not the blade that fails so much; it’s the occasional instability of the yardstick.

I’m considering a better straightedge, and I found one possible solution (below). It’s heavy and stable, it has a rubber base, and I like that safety handle. Looks great! But for such a very simple job, it does seem quite expensive. And since I’m not a professional framer, my cuts are occasional at most. But I do like my cuts to be faultless.

Makes me curious if there’s a less-expensive option (or technique) that’s as effective.

How would you do it?

[h2oman]

I'm not sure I fully understand your setup or the problem, but in the past I've clamped everything to a table with C-clamps. Also, something that is very straight and more solid than a yardstick is a level.

[Vick Vickery]

Place your mat on a 1/2"+ piece of flat plywood just a little larger than the mat; measure and mark the two sides of the mat where you want the cut to be; place metal yard stick on mat and C-clamp each end; cut with knife held vertically and a hand steading the center of the metal straight-edge. Cut in several passes if necessary. Good luck!

[anchored]

Should be easy enough to measure and cutting with a razor knife, but would also suggest to check matboards for true squareness and dimension before cutting. I've noted 32"x40" matboards are not always perfectly dimensioned... have had more than one board slightly out of square (and that's using archival Bainebridge or Crescent boards... not "no-named poster boards."

[BetterSense]

Maybe you should try using the straightedge (clamped sounds like a good idea) but doing the cutting with one of those hand-cutters. It might be a lot easier to slide along the straightedge than a knife blade.

[Ivan J. Eberle]

A box cutter and a straight-edge works well enough if you can keep it from moving around and keep your hands and fingers out of the way; that T-shaped one looks about perfect.
The cut goes smoother and will have a cleaner edge if the utility knife also is cutting a sacrificial layer that's underneath the mat. Corrugated cardboard is what I've always used.

[Maris Rusis]

I do this cut with a steel straight edge and an ordinary snap-blade knife. The key for me is to go slowly, hold the straight edge down near where the knife is, and get a perfectly straight shallow first cut.

The perfect shallow first cut will guide the knife reliably for the multiple passes needed to get through all four plies. About five passes does it for me.

[Chuck Pere]

Maybe you can find a Dexter mat cutter. They must have sold a lot of them so they should be cheap used. Check Ebay.

[erie patsellis]

if you live near a hobby lobby, sign up for their email newsletter, every few weeks they have a coupon for 50% off any one item. Logan makes a pull type cutter for around $35 or so that is guided when using their straightedge/ruler, or better yet, a 750 with a cutter and mat cutter (the 750 will handle a 40" board) can be had for ~$120 or so with the coupon.

[jeroldharter]

I would get something like the Logan 750. Mat board costs have gone through the roof. You will save money in the long run by having a proper mat cutter. I use the Logan 650 and it works pretty well.