Tweaking the Feed Rollers on a Moulder

Woodworkers suggest reasons wood might get stuck going through the moulder, and suggest ways to fix the problem. December 6, 2006

Question
I have had my WH moulder for three or four months now, with good results on 3 1/2 crown. I just bought a small base cap profile (1 1/8 wide). I set it to take the full cut of 3/4. The problem is, sometimes the wood gets stuck - both rollers still turn, but I have to help it along. I experienced this some with the 3 1/2 crown, too. Another thing is with this base cap moulding, the highest point is only about 1/4 wide and it is chewing up the out feed roller in just that small place where the moulding rubs. I am thinking of trying to back off some and take it in two passes. The manual says not to do this, but I am confused why it would do this. The stock should not get stuck with such a small moulding. Any thoughts appreciated.

Forum Responses
(Cabinetmaking Forum)
From contributor A:
If this is straight trim and you are wearing your feed rollers, try using less pressure on your guides. A can of Bostich Top-cote will also help.

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From contributor F:
Aside from guides that pinch the molding blank too tightly, an unwaxed molder bed or worn feed rollers on a brand new machine, I can think of another possible cause.

I grind my own cutters by hand and I learned by accident that there is a relationship between the highest point on the molding in the feed position and the feed roller height. In other words, the deepest points on the molding knife need to be designed to be within a measurable tolerance with regard to their distance from the cutter head itself.

I accidentally made my first two knives correctly with regard to that, but on the third one, the deepest points on the knife cut the molding to an elevation that was below the effective pressure elevation of the feed rollers in the machine. I now have a target dimension with regard to the knives' deepest points as I design them, and everything feeds perfectly.

To see if this may be the problem, measure one of your profile knives that feeds molding correctly in your machine. Measure it from the deepest point on the profile knife to the opposite edge of the knife. Compare that measurement to the knife that does not feed properly. If the bad knife has a greater distance from its deepest point to the back of the knife, it may well be the problem.

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From contributor T:
Been using my W7H over 20 years, and one of the first things I did was modify the roller height. A rep from the company told me about it. What you do is this. Look at the place where the feed rollers stop. There's a pin which keeps the rollers from dropping further. Mark the feed roller brackets at that point, take them off and grind a slot about 1/4" long. Replace brackets. Now the feed rollers will engage without going full depth in one pass. I use a wood bed as well as wood guides. You'll be wise to waste out a section where the rollers are so you don't prematurely wear out rollers when they drop down after a moulding has passed. Beats the hell out of hogging waste by other methods.

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From contributor L:
Check to make sure the outfeed roller is significantly harder than the infeed roller. Mine is going on two years old, but I had the same problem after moderate use. Turns out my machine had two infeed rollers from the factory. They couldn't believe it, so I bought a hard outfeed roller and sent the chewed up roller back and they reimbursed me for all cost.