Morso chopper question

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WBZ

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I have had my chopper for about 3 months and having good luck with it. The first problem has just occured. I am working with a 3 inch moulding from decor, item 9311. Up til now about 2.5 inches is the widest moulding I have used, I had to raise the drawbar to get this moulding to cut. I am using several chops and everthing goes fine until The last cut. I am having trouble on the final trim cuts, the rabbet is splintering.
It looks to me like the problem starts when I get to the point that the flat end of the blade comes into play. It seems to be causing to much downward pressure. i talked to a guy at techmark where I bought the chopper and he said he has heard of this with certain imported woods. He didn't think the problem is with the blade. I have found it seems to help If I go very slow on the trim cut.
Am I missing something????
 
How many cuts do you make? And is the final cut a small sliver....the last two notches on the arm setting?

John
 
John Ranes II said:
How many cuts do you make? And is the final cut a small sliver....the last two notches on the arm setting?

John
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About 6 cuts or more, and the final trim cut is the last notch which as I understand is half of the other notches. I wonder if I would be better off to make the final cut bigger so the blade isn't as close to the edge since that seem to be where I am getting in trouble??
 
It is possible to take an extra slice with the knob somewhere between the last two notches, which may help with some mouldings. OTOH, sometimes you can avoid chipping by taking a rather aggressive final cut, maybe even skipping the second to last indent.

Are you rebates adjusted correctly? Check in particular if they are too high. Slide the moulding left and right over the rebates, the rebates should be at a height just barely below where they would wiggle a little. Also try withdrawing the rebates out about 1/8" horizontally, but still under the rabbet. Sometimes rabbet depth varies slightly between various sticks of the same moulding.

More than likely, your blades are dull. Dull blades need more downward pressure to do the job, and they crush more. Got to keep 'em very sharp indeed, especially for veneers, glossy surfaces, etc. And sometimes you just have to accept that you can't get perfect cuts on every type of moulding.
 
I have only made about 100 frames so far and most of them have been smaller mouldings. How many frames on average should I get from a sharp set of blades? I think the idea of making a more agressive final cut might work in this case. Thanks for your thoughts
 
I usually start to think about sharpening after about 20 to 30 all-wood frames with about 3" moulding. With poly or compo, as few as 12. It kinda comes down to how much work it is to re-sharpen, versus how much work it is to get funky corners to join acceptably. But 100 frames out of anything except maybe Balsa wood is taking it too far.

Have been honing my own blades lately, it only takes about 15 minutes total to remove, sharpen, and re-install. So I sharpen a lot more often than when I had to either ship them or drive them across town. Has got me really spoiled, I do like those lovely craftsmanlike corners and so do a few of my collectors. But you would have to flat-grind your blades first, stock blades come hollow ground.
 
How exactly is it splintering? A few whiskers on the underside is normal. If the whole rabbet is cracking off it could be just the design of the moulding. Some are very prone to this. Depends on how much wood there is left in that area after milling. Careful adjustment of the supports is needed.
Sometimes moulding gets spiral-wrapped too tightly at the factory and this can weaken the rabbet.
 
My first thought is "how snug under the lip, are the supports?"

They should be snug enough that when you slide them under, you can feel it... but still get under. If they can flick in and out..... you have a gap between the support and lip.... that lip is coming right off.

Either way, it's always a dance.
 
Baer Charlton said:
My first thought is "how snug under the lip, are the supports?"

They should be snug enough that when you slide them under, you can feel it... but still get under. If they can flick in and out..... you have a gap between the support and lip.... that lip is coming right off.

Either way, it's always a dance.
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The supports may also be slightly high - they will still slide in but will raise the moulding. When you cut the knives will cut the rebate nicely until it hits the main moulding body and then the pressure will force the rebates up and the moulding body down causing them to crack the rebates.

The rebate support adjustment is very important. Like Baer said "They should be snug enough that when you slide them under, you can feel it... but still get under". If the support adjustment is to low or too high the knives will damage the rebate, make sure they are adjusted to the same height and slides under the rebate without leaving a gap or lifting the moulding.
 
But the bottom line is, no amount of adjusting or fiddling around with rebate supports and such will help you 1/10 as much as having nice sharp blades at the git-go. If your blades are razor sharp, rebate support is almost optional for a lot of mouldings.

Almost all chopper woes come from dull blades.
 
more_so said:
But the bottom line is, no amount of adjusting or fiddling around with rebate supports and such will help you 1/10 as much as having nice sharp blades at the git-go. If your blades are razor sharp, rebate support is almost optional for a lot of mouldings.

Almost all chopper woes come from dull blades.
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Yup - totally agree but I do recommend that you always use the rebate supports.

There are some mouldings that you will not be able to use a chopper on. After a little time you will learn which profiles are not chopable and I'm sure will not sell them or you will order them pre cut.
 
UPDATE!!!!!!

I think I may have solved this mystery. After several of you mentioned blades I decided to have a look at the extra set that came with my chopper. What I found was that they look different, they are longer and don't have the flat end. After calling tech-mark again it sounds like the set that came on the machine are reversible blades which are only good up to about 2.5 inches and I am trying to cut a 3 inch moulding:cry:
I just installed the other set and am getting much better results. Thanks to everyone and to tech-mark. I should have figured this out myself. Also the set I just installed seem to be not as tall. I wonder if this means they are older and have been sharpened more times? Is there a way to tell by measuring?
 
If you leave too little material for the last cut, the stick is only held together by a thread. The slightest movement of a molding can break it. Try leaving a little extra for the last cut.
 
When you said you are getting to the "flat end of the blade" at the end of the cut I immediately thought of the end that is NOT blade, which would most certainly be the case on reversible knives; in other words the moulding is wider than the cutting edge of the blade and you are crushing that last 1/4" or so. The original type of knives are longer and will handle wider mouldings better. I know I have seen the rabbet edge crushed on a wide moulding when the cutting edge of the blade ends inside the lip of the moulding. 3" is about the maximum my older Morso can handle with the traditional style knives installed.

But other than that, agree that sharp knives and good adjustment of the rebate support are important to a quality cut.
 
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where the flat part of the blade come into play
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Are you using the reversable blades? They are shorter than regular blades. You may need to get a pair of regular blades. Whoever you use to sharpen the blades should be able to sell you a set for ~ $150-200.
 
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