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.

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

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!

Tokunaga Furniture and The Art of Wood Working Without Sandpaper | Spoon & Tamago

Tokunaga Furniture and The Art of Wood Working Without Sandpaper

An interesting article, particularly the difference in microscopic view of a piece of timber that is planed vs one that is sanded.

One surface to protect them all

One surface to resist glue, One surface to deny it
One surface to protect the rest and save your machines besides
In the Land of the Shed, where the glue resides

The Wood River Silicone Bench Mat from Professional Woodworkers Supplies is the solution to a problem you forgot you had.  I know – seems strange, why solve a problem you didn’t remember?

The fact is, there are a number of activities in the shed that would cause problems if not dealt with, and we normally resort to a variety of make-shift solutions, that this simple 18″x24″ silicone bench mat solves.

First one – glue-ups.  You have a workbench that is used for a myriad of activities, including glueups, but the one thing you don’t want to do is drip glue all over it.  And more importantly, you don’t want to inadvertently glue your project to it!

In steps the silicone bench mat.  Problem solved.

 

Glue will not stick to the surface.  Any glue that dries on the surface peels straight off.  Cleanup is simple, and the project will not become a permanent fixture either.  You can still use your good workbench (or your tablesaw!) for glueups, without risking the glue wrecking things, or sticking objects to one another that were not meant to be joined.

The silicone mat is also good as a non-slip surface, waterproof and oilproof, and with a couple of mm thickness, makes it a good surface to sand or plane on, or sharpen on as a couple of examples.

If you want to protect a larger area, a couple of overlapping mats works well, as the overlapping area doesn’t slip (easily).

Back to gluing for a second (and it doesn’t just have to be gluing).  Do you use a machine for some operations where glue, or a finish is easily dripped or flung off?  For example, using CA glue on the lathe (such as when pen turning), or applying oil to a moving surface.  The silicone mat can be used to protect the surface of the machine (or floor).

Here the mat is protecting the bed of the lathe, as a CA glueup is completed.  It is also very useful when doing the polishing step, as the micro mesh acrylic sanders drip a lot of water onto the cast iron lathe bed – not a good idea.

I think Wood River could take the whole concept further, developing a small range of products from the material, including a shop apron particularly suited to very messy operations.

It is not only messy operations where the mat excels. As a soft, forgiving surface it is ideal for machine maintenance, such as changing blades.  Items put on the mat tend not to roll around or slip off, and the amount of give in the surface protects tools dropped on it.  Here, a blade change is operation is enhanced – the table top is protected from scratches, while the tungsten carbide teeth are protected from being chipped and damaged on the hard CI surface.

I’m seriously starting to think that just one of these mats is not enough.  2, even 3 would not go astray in a workshop for all the different roles they can perform.

I don’t think the mats are listed on PWS’ website yet – contact Grahame for their availability – sure it won’t take long, especially if there is a bit of interest shown!

Revelations

Now I know this will be a bit of a shock to the system, especially coming from me – the “Electron Murdering Woodworker”, but, not every job in the workshop is best done with power tools.

I know, I know – breathe – here is a paper bag each, we can hypoventilate until the panic subsides.

I’m not referring to pneumatic tools either.  I’m talking about handtools, and elbow grease.

When sanding components, there are times when a power tool just is not the right tool – whether it is unnecessary overkill, or it cannot get into the area of concern, or it would turn a 2 second job into a 2 minute one.  When that happens, out comes some sandpaper, and it is wrapped around a sanding block to tackle the task.

Now there are some problems that can occur with this (at least by my experience)

1. The paper grips on the workpiece too well, and the block rotates rather than slides, and you give your knuckles a good rap.  Done it before, don’t know how – must be a handtool thing 😉

2. The paper slips off the block a bit, and you sand with an edge of the paper, rather than the middle (which then folds and scratches)

3. You catch the paper on a sharp corner, and it catches and tears

4. You regularly need to reposition the sandpaper on the block to expose a fresh portion

5. Some sanding blocks need the paper correctly sized, causing wastage

 

All these things to dissuade me from hand sanding in preference to a power sander.

 

But there is another solution.  How about using a belt of sandpaper, rather than a sheet?  It is cloth-backed, and much more tear resistant.  Being a belt, finding a fresh portion (without using a portion with a previously-created fold) is easy, and the entire belt can be used for sanding, rather than some of the sheet of sandpaper never being accessed, as it was just being used to secure the sheet to the block.

How about a block that carries the sandpaper firmly, yet with a quick-release allows the paper to be rotated to a fresh portion?

And one that isn’t just a lump of timber or cork (technically, a piece of cork is a lump of timber……), but the working surface can be larger as it will not waste sandpaper unnecessarily.

I refer to the Sand Devil, from Professional Woodworkers Supplies

It takes a standard belt of sandpaper, and has a quick-release lever to remove tension, allowing the belt to be quickly repositioned to expose a fresh cutting surface, or offset the paper on the block to get right into tight corners.

As you can see, there are a few different profiles on the Devil – a square corner, a larger radius corner, a smaller radius point, and the tapered section to help get into tighter places.  The rear shoe is moved by the quick release lever to apply or release tension.

You can check out more details at PWS (including some videos Sand Devil have made)

Sanding at 13000 RPM – the Rotabrade

We’ve all done it- using sandpaper as a stock removal tool, as a shaping tool. And an effective tool it is too! Woodturners joke about having used the 80 grit chisel to finish off a profile.

Three Sixty Innovative have taken that concept to new heights with the introduction for the Rotabrade.

I first saw the product on the New Inventors and as I am always particularly inspired by new products that are made, or at least developed down under, decided to take a closer peek. At $20, it is a very cheap investment.

It fits onto your angle grinder using a captive nut to secure it, and a guard made especially for the job. The guard as seen here, and on the New Inventors is still in prototype and not yet available.

The guard serves two purposes. First, it keeps your fingers away from the sandpaper. At these speeds, at the rate it can abrade wood, it would have no problem at all in causing a real injury. In saying that however, if used in a normal manner there is no real likelihood that you should be at risk. It isn’t like a tablesaw where you can find yourself in very close proximity to the blade if not being careful and vigilant.

Secondly, the guard acts as a fence, maintaining the tool perpendicular to the edge you are shaping. I did find that this wasn’t critical for the operation, so will be interested to see what the guard design ends up like when out of prototype.

So onto the tool function- this thing can really generate some sawdust! And in doing so, you have the ability to really do some serious shaping. For example, if you have just used a jigsaw to cut out a shape (such as a circle), the the Rotabrade will very quickly run around the inside of the circle (or the outside, depending on which part is important!) and remove all the jigsaw cut marks. It can also be used to shape the work, as the rate it can sand is significant indeed.

I can well imagine using it to form some complex shape which will then be a template for a copying bit on the router table.

It is not unlike a spindle sander, although operating at a much higher speed and stock removal rate, and you bring the spindle to the workpiece, and not the other way around (and it’s a LOT cheaper!)

You do need some serious dust collection on hand – this can create a mushroom cloud of dust in no time flat. There is no provision for on-tool dust collection – it would get in the way, but it might be worth considering as part of an optional additional guard, perhaps sucking through a perforated guard with a hose connected to the back of the angle grinder head? (Design suggestion for the manufacturer). For the operator, bring your 4″ hose in close, and wear breathing (and eye, and hearing) protection. Those new dust masks from YHS would be perfect 😉

It is a fun tool to use, that raw destructive power (insert a Tim the Toolman grunt), the ability to be as subtle or as aggressive as you want/as the job warrants.

Attaching the guard was very simple on the Dewalt – it used exactly the same holes and screws as the angle grinder’s own guard. I did try attaching it to the Triton angle grinder (yes, there was once such an animal), but unsurprising, the Triton angle grinder (probably a rebadged GMC) didn’t use the standard guard fitting arragement, or at least not the same as the Dewalt. I don’t have any other brands to compare it to, but I can well imagine the inventor of the Rotabrade has considered that for maximum compatiblity.

I haven’t tried changing sandpaper yet- it comes with 3 sleeves, and it uses a standard size, so available from any decent consumable supplier. From what I gather (didn’t find any instructions), the tool that comes with the Rotabrade loosens the core of the Rotabrade, allowing the sandpaper to slip off. Should prove to be an easy operation.

So that is the Rotabrade in a nutshell. Cheap, Australian, effective, destructive (he he he), and did I mention cheap?

Available from the inventor’s website Three Sixty Innovative

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.

Rockler Bench Cookies

Out of the mists at the recent AFWS show in Las Vegas they appeared – futuristic looking like they had been sent back in time to the woodworkers of today as a gift from the future.

Looking not unlike blue hockey pucks, the word was out – the Rockler Bench Cookies had arrived.  No more would woodworkers have to use antislip mats under their work when freehand routing, or sanding operations (and then having to try to get that little polka-dot pattern left by oil residues in the mat off their work).  The Bench Cookies are designed to lift, grip and protect both your workpiece, as well as the bench underneath.

With a surface on their top and bottom with a little give, and a lot of grip, one placed in each corner (of a smaller piece, or a couple more in the middle of larger ones), they allow the full edge of the workpiece to be exposed, so when running your router around the edge with a fence, or a bearing bit, it can protrude below the base, and still there is plenty of grip of the workpiece so you can safely route without needing to clamp the piece down.

When sanding, the piece is held firmly as you’d expect, and then finishing – the edge is fully exposed so you can get your finish right to the bottom of the edge, and not find a bead of it pooling in the lower corner. They work whether clean or dusty, as the YouTube video below will demonstrate.

Rockler Bench Cookie

What’s more, they are cheap – a set of 4 costing under $US12 (get the actual pricing from the Rockler Store) Check with them what shipping costs though if you are purchasing outside the States- I haven’t found that out as yet.

This YouTube video was produced by http://www.consultingwoodworker.com.  A quick tap and sweep with your fingers is what is recommended to clean it, but that is not even done here. I’ll make my own version of a video when I have a chance.