Sanding Curves

Sanding something that is flat has been well worked out over the years.

Shop-based sanders came out in the early 1800s, but it wasn’t until 1927 that Porter Cable released a portable belt sander, called the Take About Sander.

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Dremel was next to come up with something new, and released an oscillating sander in 1948, called the Moto-sander

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Next was Festo (now Festool), releasing an orbital sander in 1951, the Festo RTK


Then in 1976, Festo came up with the concept of a random orbital sander.  These were aimed at the automotive finishing industry, but were very suitable for woodworkers as well.

There is one common concept with all these sanders however.  They are all about sanding a surface flat, or at most on a convex curve.  I know that is a bit simplistic, but you get the point.

What happens if you want to sand inside a concave region?

If you are using a lathe, then you can use a rotary sander that is spun by contact with the workpiece, such as this rotary sander from U Beaut


But if your object is not mounted on a lathe, what other options are there?

I’ve got a couple (and I know there are others).  One is the Festool Interface pad, as I have previously mentioned back in 2012


It is a foam disk that attaches by hook&loop (which we commonly call Velcro!) to the sander, and then attaches the sanding paper to the other side.  It provides a cushioned surface that can get into concave curves (and is good for convex ones as well).  The one I was using finally gave up the ghost (it is a consumable after all), so I picked up a replacement.

The other solution that I got from Carbatec, is a product from Arbortech called the Contour Random Sander


It fits to your angle grinder, and I am particularly interested in trying this out.  It can get into deeper areas and tighter curves, yet still has a random orbital effect, as the sanding disk is free spinning and (just) offcentre.

After all, not all woodworking is about items that are flat!

ROS, TWC: TLA Heaven

To translate: you can now fit a number of Random Orbital Sanders to the Torque Workcentre!

What I have here is a prototype, but actual versions should not be too far off. Fits Bosch, Triton, DeWalt, Milwaukee and I’m sure there are plenty of others with a similar body.

ROS Attachment for TWC

Where a random orbital sander is used as a finishing device with a fine-grit sandpaper, it is not a stock removal tool, and it removes enough material to end up with a smooth surface, but not necessarily flat (and that is fine when at the final finishing stages).

On the other hand, if you want to use one for flattening a surface it is just not possible….until now.

Load the ROS with 80, 60 or even 40 grit, and with the tool mounted in the TWC, it will be kept at the same level across the entire surface, allowing the ROS to flatten out the peaks, lower and repeat until the surface is flat.

It could also help dust clearance, preventing clogging as the grit in the paper is touching and cutting, not the entire paper resting on the surface.  It can also decrease the amount of heat generated for the same reason.  And one other benefit, if you are often too heavy-handed with the ROS, you can prevent it achieving a fully random sanding effect – having your focus changed to moving the ROS across the surface rather than pushing it down into the surface will produce a better result.

I’d still use the ROS handheld for fine finishing – this is more a bulk material removal and flattening technique with the ROS mounted to the TWC.

Just another attachment that improves the already impressive functionality of the Torque Workcentre.

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