Help with Single Flute Straight Bit and Plywood

Hello, read somewhere out there that the Single Flute Straight is best for working on plywood,
but in our experience in the country at the end of the Earth (Hello from Chile) we are really not getting the expected results:

We have the 1000x1000 X Carve Dewalt 611, using a 3/16 inch Single Flute Straight bit.
So we tried different feed/rates with different RPM rates (1-6 Dewalt)

So, yes, it does look like the machine is getting early age Parkinsons. What I find “alarming” is that we test for example 2500mm/min with a 1.5 in the Dewalt 611, the first time it was perfect (top right) and the last test (bottom left) is a lobotomy of a job.

Are we doing something wrong, is the machine supposed to cut with single flute straight thru plywood or am I just wasting my time and get a 2 flute straigth for this job?

Thank you community!

Thank you Phil!

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single flute is good for acrylic and other materials where heating will be an issue. It also will pull up bigger chips easier whereas a 2 flute will clog up in some situations such as acrylic. More or the less, you are “slowing down” the spindle.

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Down spiral bit is going to make a clean cut on the top of your material bit side. Upcut spiral is going to make a clean cut on the bottom. A combination or compression bit is supposed to make a clean cut on both sides. I just ordered one to try it out to see if it works well.

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let us know how it turns out… I have been thinking about trying one, However, if your taking small passes I think it’s going to still have the same results as an upcut since the bottom of the bit is upcut and the top is down usually.

That’s what I have been figuring… however, that bit he posted, the first 1/4" is upcut… so maybe the first pass going deeper like .3?

I’ve had the best luck with a down-spiral bit and using a sacrificial piece of “hardboard” to cut well past the bottom of the board.

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Phil, to a good/reasonable (1/8") down spiral? I would. Thanks