DK-8900 not cutting too well

shortrunpostersmatt

Grumbler in Training
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Nashville, TN
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Print shop cust/tec support/framing
We use a melamine coated MDF molding from Nickel molding and the morso dk-8900 (EH F.77323) makes jagged cuts or cuts at an angle leaving the bottom of the cut longer. The white melamine is worse. It's OK with a newly sharpened blade, but gets ugly the more cuts are on the blade. We don't sell a lot of frames, so we can't understand how it cuts like this when folks are cutting a lot more than us with no problems. The blades seem to need adjustment after a while because they creep out of position. We get 1-2 adjustments and then the bad cuts start. Any advice is appreciated. I didn't find any threads that matched. Thanks!
 
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For those of us that don't know what a dk-8900 is, it is a Morso Chopper. Maybe the rest of you know this but I had to Google it. Not sure how it is different from the Model F that most of us know.

 
What about how your blades are sharpened: the manufacturer is clear that they must be hollow ground, but many sharpening services ignore the recommendation. Perhaps try another sharpening service? Re the blades moving: I’ve never seen this.
 
TechMark in N. Little Rick specializes in sharpening this kind of blades, and does a fantastic job of it.
:cool: Rick
 
Re the blades moving: I’ve never seen this.
Although I have been Morso-free since 2008, I can't image the blades moving. They are held in place by large bolts and for the bolts to be loose enough for the blades to move, something is wrong.

There is no alternative to the blades being hollow ground. Hollow ground or nothing.
 
Although I have been Morso-free since 2008, I can't image the blades moving. They are held in place by large bolts and for the bolts to be loose enough for the blades to move, something is wrong.

There is no alternative to the blades being hollow ground. Hollow ground or nothing.
I'm not agree with this!
I made many different attempts - both with blades hollow ground at 29* degrees, and flat ground blaes at 28*.
With properly sharpened blades, and alligned perfectly to each other - I can absolutely, 100% claim that there is no differences in cutting performance of the Morso! I try polysterene moldings, wooden (hard and soft wood) moldings, also wooden strips from local carpainter. Pefect 90* degrees always, straight and finest cut.. Also discuss the difference in sharpening principal with manufacturer, and conclusion was - sharpen how it's suitable for you, there is NO wrong way!
It's all about geometry, using coolant on flat/hollow ground AND MOST IMPORTANT, spent a lot of time in manual honing freshly sharpened blade. I use oil stone NORTON 3000. Here is only difference, which you can see in both types of sharpening. When it's hollow ground, hand honing is much faster, then on falt ground. If you thing why, you will guess why?!

How about the problem of the MDF moldings - I don't think that moldings are the problem. It's impossible to relocate blades possitions while using the gilotine with your foot, if they are tightened enough!
First check if you are using genuine Morso blades.
Second - make sure that sharpening service is sharpening at 29/28 degrees (as we say above - depends on the used method), and using COOLANT, while sharpening. I hotly recommend hand honing by yourself.
Third - bite, step by step your molding, not at once!
Forth Check for excessive play at your guiding parallels of the machine.

Report if you have any success.
 
I finally figured out the “blades moving” thing: I think the OP means that the head moves back during the cut, leaving the bottom of the molding wider than the top. He’s using the EH model, so his problem must be with the clamps that hold the head tight during the downward cut. I don’t have this issue with the pneumatic model.
 
It looks to have been adjustment. It has never been adjusted so that the blade cuts out further as they got smaller from resharpening. We also got new blades and they're a bit bigger.
 
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