Your Opinions re Variable Speed in a ROS

Re: Your Opinions re Variable Speed in a ROS

Larry Clinton At Frankfort, (Central) Indiana

I have 3 or 4 Bosch, a B&D, an air rotary sander. Some are variable speed, some not. Like you I can't remember when I have reduced the speed when using. I probably did when I first got the units to try them out, but soon settled on full speed. I may have reduced the speed when I "sanded" the plexiglass shield on my used Powermatic lathe using the sanding/polishing kit. It was a school lathe and had several years of paint specials, stain splatters and assorted other non transparent items. As I remember (I think) I may have reduced the speed then to prevent heating the plastic (kit did a great job).

Re: Variable Speed in a ROS

Mark Mandell - Gone Round In New Jersey

I use it all the time. Higher speed of course grit slower on the fines. My experience is that the finer grit paper seems to last longer at slower speed as there's less heat and less clogging of the paper.

YMMV

Re: Your Opinions re Variable Speed in a ROS

JL

I have had a number of ROS. I use the variable speed in a matter similar to Mark - higher speed for coarse and slower speed for fine.

I may go from 3 to 5 (on a 1-5 dial). I rarely use the slower two speeds.

Re: Your Opinions re Variable Speed in a ROS

Bill Tindall, E.Tn.

Air driven random orbital sanders are widely used in wood manufacturing. The main marketing claim for these sanders is how fast they spin, which would imply that faster is better both in terms of rate of material removal as well as quality of finish.

Useful, but not necessary...

John in NM

I've found some specific benefits to variable speed on one, but nothing I can't live without. Sanding narrow pieces of face frames, like less than 3" wide for example, seems a bit easier on a lower speed. I've never tried lower speed for fine grit like Mark mentions - going to have to give that a shot.

While You're At It

Mark Mandell - Gone Round In New Jersey

Try not pressing down on your sander; let the machine's weight and the paper do the work. You'll generate less heat on the surface which gets the lignin soft so it sticks to and clogs the abrasives. IIRC that was the point behind stearated papers.

If the job's not going fast enough, switch to a courser grit.

My main use for slower speed is,

Keith Newton

When I'm sanding something very delicate like rounding corners a tiny bit, or around carved stuff.

Unless you already have a bunch of 5" paper on hand, I would suggest that you move on up to 6". Adding that one more inch increases the area from 19.6 sq.in. to 28.27" sq. for an increase of 8.67", or a little less than a third more. It won't speed your sanding by 30%, but might by 20% or more. If you are a professional and figure how much you hourly rate, I think you'll find this pays the difference in cost pretty quickly.

Since all of my disk are worn more on the outside than in the middle, I think a pretty good argument could be made that this portion of the disk cuts faster than near the middle of the circle.

That is my 2¢

Re: Your Opinions re Variable Speed in a ROS

William Duffield

I definitely find the speed control on my Festool Rotex sanders useful. The additional aggressiveness of the Rotex mode can be difficult to control with certain grits at some speeds, and being able to fine tune the speed to dampen harmonic oscillations of the sander is essential, especially if you are heavy handed.

Re: Your Opinions re Variable Speed in a ROS

jesse cloud

I use a variety of sanders, ranging from aggressive to very smooth. 90 per cent of them are variable speed. I change the speed from highest on maybe 20 per cent of applications.

Vibration is not your friend. Besides making you annoyed and tired out, it slows down the process of getting a smooth flat, scratch-free surface. Whenever I encounter extra vibration, I experiment with the speed until I find the 'sweet spot'.

John nailed it, VS a good thing, but if need be I could work without it.

I strongly agree with the comments on the good sense of moving to 6 inch format, and letting the tool do the work without applying pressure.

I would not base a buying decision for my hobby shop on the practices of industrial shops or on marketing claims.

Re: Your Opinions re Variable Speed in a ROS

Jim Dillon

Howard, on balance I think variable speed worthwhile up to a point. My relatively new Bosch 5-inch and 6-inch ROS have 1-6 settings (6 being the fastest). I can't remember using the 1-4 settings, but the 5 and 6 provide a nice variation in speed. Maybe for materials other than wood, i.e. plastic, metal, synthetic countertops, polishing etc. the lower speeds might be useful but I have no experience in that area. Generally though, I set the sander to the fastest setting and pick the sandpaper grit appropriate to the task and let the weight of the sander do the work. As an aside, the 6-incher is a beast. I recently did newly installed hardwood floors (white oak) in a 16 x 12 foot room (yeah, I'm a masochist!) and it was up to the task - although my knees were not. Having said all this, I used my PC ROS (non-variable) for 20 years and it did just fine. Let your budget dictate your choice. My 2 cents. Jim

Yep, that one I do already...

John in NM

Let the sander do it all and your hand just moves the sander around. The other thing that helps both speed and paper life is having a vacuum hooked up. Probably the same reason as what you're talking about -- heat.

The other thing pushing hard does is to turn your RO sander into a regular orbital sander - little curly scratches instead of randomly oriented 1/3 circle scratches.

Had to explain that one over and over to the people in the sanding department when I worked in a furniture shop. Some of the really impatient ones even tipped the sander!

Re: Your Opinions re Variable Speed in a ROS

Todd Stock

Essential for dry sanding finishes like lacquer with Abranet disks, but not that useful otherwise.

Re: Your Opinions re Variable Speed in a ROS

Sgian Dubh

Typically I set a random orbital sander at a high speed for initial sanding using coarser papers on flat surfaces, e.g., 80, 100 or 120 grit. As I work down to the final grit of either 180 or 220 I reduce the speed by about a third. My theory here, unproven by anything scientifically tested on my part, is that the slower speed at these finer grit sizes result in less obvious swirl marks showing up through a finish, and even here I usually final prep with a bit of hand sanding working with the grain at the same grit size I used on the random orbital sander.

For narrow and/or many curved items that are quite delicate in form I frequently use a lower speed all through the sanding process from coarse to fine grit. By delicate or narrow, I mean sanding cabinet door frames for instance, or final sanding of something like a 16 - 30 mm+ radius ovolo moulding on the edge and end of a table top. The slower speed helps maintain control of the sanding process to help prevent destroying the profile, form, flatness, etc.

An interesting phenomenon I worked out many years ago follows much the same 'rule' I worked out about hand sanding, which is: every step up to the next finer grade only takes about half as long as the previous grade, e.g., 10 minutes required at 100 grit means about 5 - 6 minutes needed at 120 grit, about 3 minutes at 150 grit, and so on. Slainte.

Thank you for your replies and insight

Howard in Toronto

Makita VS it is! Picked it up yesterday.

Thank you for your replies and help.

Howard