Problem With Bevel Steapening In Middle of Long Cut Logan 650

[Drewsky]

When I cut a bevel over 20 inches long I find that sometimes the bevel steapens and approaches a verticle towards the half way mark of the cut.  This more verticle cut persists for 6 to 12 inches and then slants properly to finish the cut as the selected bevel.  I am using 4 ply mat board of good quality.  I am using a new blade for each mat.  I am using a Logan 650 Framers Edge and Logan blades.  I am using a scratch board and the blade is adjusted to cut 1/3rd way through the scratch board.  This doesn't always happen.  The problem is intermittent.  I have no idea what is causing this steapening of the blade in the middle of the cut.  Does anyone know what may be causing this problem?

[raydee]

Perhaps you are moving the cutter to fast in the middle, which might result in too much drag and thus flex of the blade? If you start slowly on the start mark and slow down as you approach the end (stop?) the blade might cope with the drag as intended...

[JeanMichel]

Hi,
You blade is set much too deep, it only need to scratch the backing board.
Jean-Michel

[DeanChriss]

I'm using a different mat cutter so I don't know what adjustments you have available but...

As Jean-Michel said, you may be cutting too deep into the slip sheet (scratch board). If on subsequent cuts the blade intersects cuts on the slip sheet that aren't aligned with the cut you're making, the previously cut channels can pull the blade tip in one direction or another.

There may be play or slop in the bearings the cutter rides on. With some cutters this is adjustable.

When making the cut, you may be inadvertently putting pressure on the cutting head that's perpendicular to the cut direction. That would exacerbate any slop in the bearings and if it's enough pressure it can temporarily deform the bar that guides the cutter. If the cutter is pushed inward (toward the mat window opening) while cutting the cut would get more vertical. Try standing at the end of the cutter and pull the blade directly toward you.

Some blade holders have a set screw that can be adjusted to put pressure on the blade tip. The adjustment is usually used to correct for hooked corners. I don't think that's what you're describing, but it's worth mentioning.

Beyond that, I'm out of ideas.

[AFairley]

Sorry, I can't help.  I routinely make 22" cuts on 4-ply with the 650 and have never seen what you describe....

[Drewsky]

Thank you.  I shall try these suggestions.

[framah]

First, you actually ARE setting the blade to the correct depth.. 1/3rd of the way into the slip sheet. That's how it is taught  and it is how it should be.
"Barely scratching" is NOT the proper setting, period.

So, now that we have debunked THAT little tidbit, I do agree that you need to look at the  bearings being a bit sloppy and you also might look at what you have  the cutter sitting on. If it isn't solid enough along the full length of the cutter, you might be getting some flexing of the machine as  you press down while you are cutting. Which brings me to another possibility... pressing down while cutting.

You notice that it doesn't happen at the beginning or the end... because you aren't bearing down on the cutter head at those points as much as you are  concentrating on starting and stopping the cut. During the run of the cut you might be pushing too hard which would cause it to flex and possibly change the angle of the blade. That combined with the worn bearings just might cause your problem.

Also...be conscious of how you are holding the cutter head as you run the cut. If you move  your position relative to the cutter head as you make the cut AND the bearings are worn, then you could be slightly rotating the head.
(As I go back and read what I typed, I think this might be the main problem.)


When I first set up me 60" Fletcher cutter, I had to add a 3" wide length of channel iron to the underside of the table to stiffen it up so it wouldn't flex.

Try looking at these and experiment to see if anything is causing the problem.

anyhoo.. good luck.

[Drewsky]

Thanks,  I will try cutting some scrap mats and try to figure this out.

[Drewsky]

After cutting several dozen more mats I have come to the conclusion that it was most probably due to riding into preexisting cuts in the scratch sheet.  I have changed the scratch sheets to purposely avoid this problem, and the problem has not reappeared.   Thank you so much for your help.