Well, Stumpy Nubs seems to think no reason to run slower speeds, but https://www.sandpaper.com/articles/electric-sander-speeds-101/?utm_source=drip&utm_medium=email&utm_campaign=speeds-article

Ask any machinist.  Cut speed  means everything.  I think sandpaper deserves the same considerations.  The grit needs a chance to bite.  Too fast equals diminished bite.

We runs sanders full blast. No reason to sit and spin.

 

This kinda gets me.. Variable speed on things like belt sanders. I saw where woodworkers said you should run slower speeds on belt sanders on softwoods. Hum?? No...

I think a person who's running the machines has already tried different speeds if the machine is built that way and what ever turns him. Thats like telling your kids spinach tasted good for they already know thats is a lie. 

Hmmm. The only sander I have with variable speeds is the 6X48 Shopsmith belt sander. I just set that speed at the speed on the dial marked for it. None of my hand held belt sanders are VS. 

My attitude with sanding probably comes from history with shop bosses. When the man comes out and says

 

 

 

Completely makes sense to me! I like it. The thing is, unless we try it, we'll never know if it actually ups our game, or not? If you don't know what the "upped game" looks like, and don't try it, you'll always think you are at the top of your game.

Quote

Why sand at a slower speed?

While it may seem counterintuitive to sand at slower speeds, especially since most people want to get sanding done more quickly, it may be a wise choice to choose a lower RPM in certain circumstances.

For instance, using a lower speed could be helpful when doing projects that require a finer attention to detail, such as sanding thin materials like veneers, where over-sanding/sanding-through can quickly become a problem. Additionally, using the slower speeds could be helpful on finishing applications, such as sanding between coats of finish – particularly for stain/lacquer and sealer, where it’s important to not sand through the coating. Further, when sanding ornate edges, curves and profiles, a lower speed could be helpful to avoid flat-spotting or changing the shape of the piece.

In addition to these fine sanding applications, where it will be easier to control the sander at lower speeds, when sanding materials prone to melting, such as polyester, plastic or film, using a lower speed can be helpful to reduce heat, thereby preventing clogging.

The main disadvantage to slower sanding speeds is that it could take slightly longer to sand your piece. In addition, a caveat is that slowing an orbital sander down can contribute to the creation of sanding swirls, so it’s important to pay attention and use proper lighting to make sure your surface is smooth after sanding.

 

I enjoy doing it by hand,...whatever speed that is