Depth of cut question

[deepsplinter]

I like to take it easy on my tools and tooling, but sometimes I think I overdo it. Yesterday, I made a bunch of crown molding, and ran it through taking 1/16" off per pass. I wasn't concerned about my molder/planer, but I wanted to take it easy on my (HHS) molder knives.

Is it any easier on tooling to make four 1/16" passes rather than two 1/8" passes?

[sawduster]

On the one hand, making two shallow cuts rather than one deeper one puts the cutters crashing into the wood twice as many times. But on the other hand, the deeper cut may add stresses to other things like belts and motors. Guess I really don't have a clue which is best. I do know that I take very shallow cuts on my planer.

[Beamer]

I believe it's better to take lighter passes for lots of reasons. Tearout being one of the biggest reasons I take ligth passes. Precision - it's much easier to sneak up on a dimension than it is to try and nail it the first time, especially if you nail right past it. Wear and tear on the machines.

I think you DO sacrifice some of your cutter sharpness by doing so many passes - but I think it's worth it. It might actually be easier on the edge in some cases since it isn't burying itself so deep in a cut - that has to add some stress to the edge, but I couldn't begin to figure how much or if it's more than multiple light passes. I go with the above reasons instead, and worry less about dulling things too fast.

[fredbelknap]

I also think that a shallow cut helps if you have a snipe problem. at least it isn't as deep. On my planer I get some snipe on the infeed side on wider boards, don't get any on narrow boards. It may be gunk on the rollers.

[TDHofstetter]

Neither is "better" if all you're doing is removing wood. Each approach has its peculiar benefits & drawbacks - like most things in life, it's all about tradeoffs.

Few large passes saves time & electricity & edge sharpness, but at the cost of heavier work on the whole mechanism and grade of finish. A large pass can sometimes tear out deeper than can be cleaned up by a shallow finishing followup pass, but I ordinarily like to work the machine harder for most of the job by taking fairly deep passes until I get close to where I'm going. The last pass or two are - in my shop - done shallow just for the sake of the finish.

[art3427]

When it comes to the life of a cutting edge, a shallow cut can be more harmful than a heavier one. This is true for either HHS or TC. The shaving is what carries away heat from the cutting edge. This heat is the result of cutting friction. Your shavings should be warm to the touch when they come out off the knife. To little a shaving cannot carry enough heat and over a long run the cutter edge will overheat.

Cutting depth is relative to feed speed. The shallower the cut, the faster the feed should be. When I set up to run molding I want shavings that look like snowflakes. Once you start spitting out chunks your just overloading the cutter and degrading the material.

art