Predominately most of my printing is for flat cards cut from parent sheets. Not until I’ve been doing a few business cards (with type close to the edge) and folded cards, I’ve notice my Triumph 4810 cutter is not cutting straight. If you were to take 10 inch paper from the cutter, the right edge is about 1-2mm shorter than the left edge from the top. Not noticeable for an A7 card, but won’t be flush when folded.
I tried tightening the bolts to the blade, but nothing seems loose. Maybe I should remove and try to remount? Maybe it’s just the limitations of my cutter.
As I was debating this, I was wondering if my parent sheets were even straight. What tools and process do you guys use to properly square a sheet? How do you establish a base to cut from? Maybe I’m over thinking this.
My process is to make my initial cuts on the parent sheet with a Kutrimmer, and then cut my stacks on the Triumph.
Thanks for the help.
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One could very carefully measure top to bottom on both sides of the parent sheet to see if they are equal. Then do the same across the sides at top and bottom. This is a test of trueness of measure. It does not guarantee squareness as the sheet might be a slight parralelogram that is not a rectangle.
With the cutter, the back gauge must be parallel to the blade. There is usually a small bit of adjustment that can be made to the back gauge. Adjusting and shimming the blade is difficult.
Jog up a couple of scrap or inexpensive sheets of paper about 10” long. Jog them well against the back gauge and cut. Mark the sheet L and R. Fold and see if both sides are the same length. The L and R are to remind you which side was which. If there is adjustment for the back gauge, do so.
I adjusted my back gauge as far as I could and still needed just a bit more. I shim the back of one side of my stack of paper two thicknesses of #67 Bristol stock. Now true.
Keep in mind that all but a very sharp blade will mess up the trueness and measure of any stack of stock.
Wow! Thanks for the help Inky. I didn’t know there was a back gauge for my cutter. Once i’m back at the shop, I’ll have to investigate.
You didn’t mention what kind of paper you’re cutting. Soft paper or textured paper can not be clamped tight enough, without marring it, to prevent the blade pulling it a little during the cut if the blade is not newly sharpened. So you could be getting just a slight amount of pulling of the lift during the cut. Measure your cut sheets at the top and bottom of the stack after a cut — if they are exactly the same pulling is probably not the problem.
To determine if the cut is square, i.e., 90 degrees at each corner, measure from left top corner to right bottom corner and then measure from top right corner to lower left corner. If the measurements are not exactly the same, it not “square” on all 4 corners. (this is an old woodworking test!)
Measuring corner to corner is the only way to check something is square if you cant use a square or dont hve one its a typical test in most construction !
The side cheeks on a guillotine should be set at 90 deg to the knife ,the back fence may rock a little but the cheeks wont , so try to get the hang of this , knock up the pile and place to the left cheek , take a cut , turn clockways 90deg place again to the left cheek cut again , repeat again and all will be square , . really the right cheek should be square too and ,if it is, then you can observe proper guillotine practice . In proper guillotine practice the back fence is for measuring the sheet / positioning it a given length from the knife , because they rock a bit even on 115 cm polars etc you can only be certain the cheeks are square constantly so you keep the job tight to the cheek and push the sheet to the back fence only to get a reference point ,this way your sheets will be square.
To yamski, inky, ADLibPress, LetterpressDad, Peter Luckhurst et al:
After asking a friend, the following is suggested:
Put one sheet of paper flat on a clean surface, then another on top; the guillotine table can be used, so that putting the sheets against a side cheek of the guillotine will line-up one side of the sheets; look carefully to see if the other sides coincide; then turn over only the top sheet and after putting it on top of the first sheet, repeat the checking to see if the sides of the 2 sheets of paper again line up. There are other ways, just using one sheet of paper, but this is simple and does not destroy a sheet. One other method I knew of is less accurate, one sheet is folded so that it is only half as long as the forementioned method.
A light table can be useful occasionally to check work, but in my experience (if not used frequently) can become encumbered with stacks of paper put aside for later attention.
P.S.: I am not experienced on guillotines. — A.
If you want to see if paper is square, take two sheets and flip one over so they are face to face. Put them on a level surface or grip the corners tightly. If they are square they will line up well. If they are a paralleagram it will be very evident. As stated above a soft sheet and a dull knife are two things that will promote out of square cutting. However if you want to true up the fence with the knife bring down the knife and put a rectangle block that you know to be square behind the knife and bring the back fence up and adjust the back fence to be flush with the block.
When ever you cut paper, mark the side lightly with a pencil and make sure you feed a common side into the cutter and importantly into you press.
If you rotate your lifts, or flip lifts over front to back between your cutter and your press you are less likely to get consistent registration. Also try to feed a consistent side as it came from the cutter.