Turning Speed and direction

[Ray Bell]

Iwas reading the thread on the Laguna lathe,and these thoughts always pop up. Is it advantageous to turn at a slower speed for sanding? I can understand why you may want to slow it down for applying finishes, but does it make a difference while sanding? Also I have seen mention of reversing the direction when sanding. Does this help?

Thanks, Ray

[Al Wasser]

Sanding at high speed can increase heat buildup which can cause cracking in many woods so slower is recommended -- just how slow is your call. to me it depends on the diameter I am turning. With a small diameter I go a little higher speed. Yes, reversing does help. I also like to wet the wood with a damp paper towel. This raises the grain and then final sand.

[Bernie Weishapl]

Al hit the nail on the head. On most woods that I have turned and some are worse than others if you sand at high speeds a large amount of heat builds and can crack a nice piece sometimes pretty bad. I also sand in reverse and it can make a big difference in the looks and feel. On some woods I will dampen and finish sanding with 320 grit. I rarely sand over 400. I generally never sand above 500 rpm and most times it is between 300 to 500 rpm sanding with a light touch.

[Jim Silva]

I agree with Bernie and Al also. I don't sand above 500rpm normally unless it's a finial or something spindle oriented and quite small.
This is primarily for heat and paper clogging purposes.

On larger pieces, particularly ones turned from green or wet wood in one sitting, as the piece acclimates on the lathe it warps causing dips and bumps. Sanding at a higher speed will also cause you to just hit the "high" spots while doing very little with the "low".
Slower speeds allow following closer to the contour of the piece.

I LOVE the ability to reverse sand. I'll typically reverse for the most coarse grit after I've sanded it in the normal direction. Then I'll generally only reverse for alternate grits as I work my way up.

Raising the grain with a mist of water or quick wipe with mineral spirits is very helpful. I tend to go with MS just because it evaporates a little quicker but I'm not a fanatic about it. Just make sure if you are reversing that you have a set screw on the chuck to keep it from backing off the spindle. (Don't ask how I know this)

J.

[Richard Madison]

Depends. Power sanding at 100 to 200 rpm lathe speed, and sometimes 0 rpm for bad spots, max. of half the drill speed or less, sometimes checking the disc temp. Hand sanding at 700-800 with only moderate pressure and keeping the paper moving, sometimes sanding with the grain at 0 rpm before moving to the next grit. Good advice above.

[Ray Bell]

Thanks all, good sensible advise. I have noticed small cracks developing, but always thought they were defects in the wood. I know it gets really hot on my fingers.

[Dick Sowa]

Don't forget that as sandpaper wears, the grit fractures and provides newly sharpened pieces of grit. But eventually, the grit is worn down, and becomes ineffective. At high speed, that can happen pretty quickly. Heat can also affect the glue holding the grit in place, and it can disappear even faster.

I find that if the paper gets hot, then I am putting too much pressure on it, or are sanding too fast. I also prefer to sand at a pretty slow speed and replenish my sandpaper frequently.

[Richard Madison]

Happiness is a fresh piece of sandpaper.

[Frank Drew]

Sanding is a principle reason to get a lathe that reverses direction; outboard turning is another.