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Adjust Morso cut to be square with the table?

more_so

SGF, Supreme Grumble Framer
Trying to fix a Morso chopper that does not seem to cut the notch exactly square with the table guides.

When I cut a mitre with the wings in the normal position, the length of the diagonal cut on a piece of 3” moulding under my right hand is about 1/32 longer than the piece under my left hand.

Also, to get a perfect 90 degree corner I have to swing the left wing about ½ degree towards me. The angle of the joined cuts is correct but the moulding pieces don't match up visually.

Also, as I make a cut I can feel the piece under my left hand moving slightly away from the blade, even with newly sharpened blades. The motion is less than 1/100 inch, but enough to feel.

I checked the vertical accuracy of the blade motion with a machinist's tool and it's perfect.

The table guides seem to be correct and true with the factor registration pins. If I run an accurate straight edge across the wings and along the guides, everything lines up. If I grab the chopper head itself I can't feel any play. Everything is correctly lubed. I get the same problem with both old and new blade sets.

So one or more things are out of alignment. If I could rotate the table and guides about ½ degree relative to the blades, I think the problem might be fixed. Is there a procedure to do this? But I suspect there's some more basic problem.

The table guides seem to be correct and true with the factory registration pins. If I run an accurate straight edge across the wings and along the guides, everything seems to lines up. If I grab the chopper head itself I can't feel any play. Everything is correctly lubed.

Does this sound familiar to anyone? It's kinda baffling. Would appreciate your input, thanks. :nuts:
 
888

prospero

SPFG, Supreme Picture Framing God
Without trying the machine it is very hard to make a diagnosis, but it sounds very much like incorrectly ground blades to me. A more likely explanation than the cutter head being twisted out of alignment with the bed.
It is usual practice to tweak the left fence in the manner you describe, especially as the blades start to lose their edge. You seem to behaving to do the same thing to extreme lengths, to the point where the difference in the diagonal length starts to be noticeable. The blades may be sharp, but if they are not ground to the correct angle then they won't produce accurate mitres.
 

artfolio

SGF, Supreme Grumble Framer
I am with Prospero.

A guillotine is a pretty simple machine and there just isn't much that can go wrong with it. My money would be on the blades being incorrectly ground..
 

Paul Cascio

SGF, Supreme Grumble Framer
First, I think this requires you to change your screen name. :)

If I understand the problem correctly, all you need is a long straight edge - I've used a length on Neilson 75 moulding to do this, but a steel bar is better.

Loosen both wings. Then, lay the straight edge along the fence and move the wings so they are touching the straight edge and lock them into place. Your chopper is now aligned.
 

Jeff Rodier

SPFG, Supreme Picture Framing God
I think I heard the problem in your explanation. You said the leg in your left hand has moved as you cut through. The cut starts through the lip and the moulding slides as you get to the final cuts. This can cause the lip edge of the moulding to be shorter than the other length even though you slide it through to the stop. The outer edge will measure the same.

Get a piece of very thin emery cloth and adhere it to the top of the chopper table where you lay the moulding down and apply pressure. Cut another 2 legs and they should now be the same inside and outer edges. The bottom side of some wide mouldings will cause them to slide. If the moulding is plastic it is more common than wood mouldings.
 

David N Waldmann

SGF, Supreme Grumble Framer
Loosen both wings. Then, lay the straight edge along the fence and move the wings so they are touching the straight edge and lock them into place. Your chopper is now aligned.
Sorry, Paul, but I have never found this to work.

Morsos are good machines, but they were not made to extremely high tolerances in the alignment category. The only way I have been able to make perfect 45°s on both sides is to individually adjust each fence to achieve a perfect 45° on that side*, and then align the extension fence to the right main fence as best you can. Understand that if you have the "modern" direct read measuring system that it may no longer be accurate.

*that is a whole procedure I have written on before.
 

Bill Henry-

SPFG, Supreme Picture Framing God
Like Paul, I use a full 10’ length of Nielsen moulding to align the right and left fences.

The Morsø knife block is factory set at a perfect 90°. But even if the block and the fences are not at exactly at a 45° angle to each other, the cut moulding should still join at 90°. For example, if the fences and blades are 1° off such that the right is, say, 44°, the left has to be 46°, so the join will still be 90°.

I would suggest removing both blades and examine the knife block for grit or debris that might keep one of the blades from sitting flat against the block. I generally clean the goop with lighter fluid then lightly polish the block with a fine mesh steel wool to make sure that the block is perfectly smooth.

Especially if both blades are behaving the same way, to me it seems unlikely that they would both have been honed incorrectly.
 

Jeff Rodier

SPFG, Supreme Picture Framing God
Especially if both blades are behaving the same way, to me it seems unlikely that they would both have been honed incorrectly.
Sharpening can not change the angle of the cut unless it has been done so poorly that it leaves a gap against the table top edge. My bet is the moulding is simply sliding during the cuts and only the left side is able to slide since the stop prevents the right length from sliding.
 

more_so

SGF, Supreme Grumble Framer
Thanks for the tips!

I broke out a brand new pair of virginal 2009, factory fresh hollow ground blades, and I still get the problem.

Most of my blades are flat ground. OK Baer, what is the correct angle for flat ground blades? I think I've been getting 30 degrees.

Don't have the problem on the other shop Morso with the exact same blades.

Will knock my head against this over the weekend (which will include my 65th birthday). Will try Jeff's sandpaper schtick in particular. If I can't solve it I will either kill myself or buy a new machine, depending on which is cheaper.

Trivia Question for the experts...why are my newer blades marked "2Morso" and older ones just "Morso"? Was there a change in the blade design?

Yes Paul is right, I need to turn in my screen name! Maybe the Beast within my chopper is taking revenge. :eek:
 

Jay H

PFG, Picture Framing God
To square up your miters, you do use a straight edge for the right fence (as you face the machine). You can go ahead and also square the left one but it will need to be adjusted in the next step.

Now cut a wide (2-3 inches) flatish profile into four equal legs and join them. Now look at the gap in the frame. Is it on the back edge or the front by the rabbit? If it's on the front then move the left fence back a hair. If it's on the back move the left fence toward the blades a bit.

Now repeat.
 

more_so

SGF, Supreme Grumble Framer
Thought I would follow up on this in case anybody else finds his or her self in this pickle.

Turns out the chopper was mechanically distorted. As the cutting head moved in and out, the path of the bottom blades was not a perfectly straight line, but a curved path! The height of the lower blades was about 1/32 lower than the infeed and outfeed tables in the middle part of the motion, compared to the start or end. So this meant the moulding got warped somewhere around the middle of the cut by being shoved down towards the too-low bottom blades. Which also gave a slightly cupped joint surface on the moulding.

The chopper came from a (non-framing oriented) surplus dealer, and I suspect something very, very heavy had been stacked on top of the cutting head. So the chopper cost me $50, but I wasted about a week scratching my head. Is there a moral there somewhere? At least the blades seem OK.

What made me look for the problem is I glued some of the thinnest sandpaper I could find to the input & outside table surfaces. Which immediately made the problem much worse since the moulding was now floating even further above the lower blades, and therefore subject to more flexing during the cut. So I think the sandpaper thing is more appropriate for saws than choppers, unless you feel like gluing sandpaper on top of the both the feed tables AND the surface of the lower blades, which is not possible with the moving rebate supports on this particular chopper.
 

neilframer

PFG, Picture Framing God
Another thing to look for that I have seen on many Morso choppers is the handle that moves the blades in and out. A lot of chopper users don't push down on this handle as they move the blades to take bites out of the moulding.
They drag it back and forth over the notches of the semi circle and this eventually grinds the hook off of the handle. The handle will no longer lock in to the notches of the semi circle and the blades will move slightly when you make your final cut.
I have replaced the handle on two of the choppers that I have used recently and the blades are now locked solid when they cut.
 

more_so

SGF, Supreme Grumble Framer
Another thing to look for that I have seen on many Morso choppers is the handle that moves the blades in and out. A lot of chopper users don't push down on this handle as they move the blades to take bites out of the moulding.
They drag it back and forth over the notches of the semi circle and this eventually grinds the hook off of the handle. The handle will no longer lock in to the notches of the semi circle and the blades will move slightly when you make your final cut.
I have replaced the handle on two of the choppers that I have used recently and the blades are now locked solid when they cut.
Have also seen that one. If it hasn't been done already a few times, you can insert a flat tip screwdriver under the little notch below the tooth on the handle and bend it up so it makes contact again. It may be easier to get access to the notch if you loosen the two nuts & bolts that secure the silver crescent thing, but you don't have to take the crescent all the way off.

I usually don't even let the tooth engage the notches until the last 2 or 3 cuts, which also let's me adjust the bite increments to best suit the moulding depending on how thick it is for any given cut.
 

Jeremiah.U

Grumbler in Training
To square up your miters, you do use a straight edge for the right fence (as you face the machine). You can go ahead and also square the left one but it will need to be adjusted in the next step.

Now cut a wide (2-3 inches) flatish profile into four equal legs and join them. Now look at the gap in the frame. Is it on the back edge or the front by the rabbit? If it's on the front then move the left fence back a hair. If it's on the back move the left fence toward the blades a bit.

Now repeat.
So I know this is an old thread..but your advice helped me completely 100%...but..I dont know how.
Here was my dilema. I bought an old morso...had to clean this thing up..had blades sharpened. I tried the whole run a straight edge across and it was off.

So I moved each fence minutely so that when I took my digital reader I would get perfect 45 degrees on my moulding...doing this on both fences. But when I put the frame together..it was off horribly! How can this be????
So I found this thread...and saw your comment..and did what you said. But what doesnt register in my brain is the fact that when it finally worked perfectly...the angle on the left measures out to be 44.8 degrees. How is this so? If this sounds confusing Im sorry..but I just dont get how off angles work rather than perfectly measured 45s
 

prospero

SPFG, Supreme Picture Framing God
First of all, it is no use altering the right fence as it needs to remain aligned with the measuring guide.

You have to remember that wood is an organic material and can behave strangely when cut. The left
fence tweak is really to compensate for this inconsistency. Using highly accurate measuring guages to
calibrate the blades is largely futile as just because they are set to a dead 45º angle doesn't mean they
will cut one. Sounds mad but they can cut 'off track' depending on the wood and grain direction, particularly
if the blades haven't been ground to the exact specs.
 

Jeremiah.U

Grumbler in Training
First of all, it is no use altering the right fence as it needs to remain aligned with the measuring guide.

You have to remember that wood is an organic material and can behave strangely when cut. The left
fence tweak is really to compensate for this inconsistency. Using highly accurate measuring guages to
calibrate the blades is largely futile as just because they are set to a dead 45º angle doesn't mean they
will cut one. Sounds mad but they can cut 'off track' depending on the wood and grain direction, particularly
if the blades haven't been ground to the exact specs.
I guess so huh. Just blows my mind that even the two fences are not even completely straight with eachother. But some how..the mitres are coming out perfect now.
 

prospero

SPFG, Supreme Picture Framing God
I guess so huh. Just blows my mind that even the two fences are not even completely straight with eachother. But some how..the mitres are coming out perfect now.
That's one of the anomalies of frame cutting. Sometimes things are counter-intuitive. 😳
 
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