MichaelMouse said:
Only one zone can be optimum, no? The rest can only be a second-rate cut at best?
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Tool usage does more for the surface than speed. The suggestion that there is an optimum speed seems quite valid. That speed would vary from foot to rim on the outside and from rim to bottom on the inside.
My goal on a bowl is to get a 220 surface off the tool,then sand with 180,220,320.., I change speeds as I go.
My roughing cut brings the bowl to shape quickly. I cut leading a bit with the tip and lower wing slightly off the bevel. With a 5/8 dia bar ellsworth gind gouge I take 3/4" wide shaving and leave considerable tearout. I then switch to a bevel riding push cut amazing 1/4, 1/8, 1/16 shavings as I shape the foot, rim,and refine the outside curve. I sharpen my tool for the finish cut and take tiny shavings and examine the back side of the endgrain where there is always some tiny tearout because some of the cut is tangential to the bowl and there are no fibers supporting the cut in the tangential direction on the back side of the endgrain. On most woods I can shear scrape and sand.
If I can see the tearout i try a flute up shear cut.
If i still see tear out i switch to a handle down pull cut with wing slicing just below the nose at high angle.
If there is still some visible tearout I spritz with water and try the shear cut again,
If there is still tearout, I try a 1/4 bowl gouge This takes 95 percent of the bowls to a tool finish I can shearcrape and sand.
If i have sometimg really bad i try a spindle gouge then a square scraper in a shear scraping position.
I haven't found any good quality wood where these techniques fail to produce a quality tool finish
On the inside it use the bevel riding pushcut taking smaller cuts as I approach finish thickness. I then use my 1/4 bowl gouge for a finish cut as far as it will go usually 2 inches, then use a flut up sheare cut to finish the rest of the inside. If I'm getting too much bevel drag I'll grind the heel off the bevel to shorten the bevel. On most bowls I can sand the inside with 180,220,320 May need 120 in few spots.
If I'm having a bad day and don't nail the bottom, I'll use a round nose scraper to refine the bottom.
This is all can seem daunting to a beginner. In a beginning bowl class when the students master the bevel riding push cut they are going to get good tool finishes.
Mastering that one cut leads to success.
Have fun,
Al