REVIEW: Carbatec cryogenic scrapers and hollowing turning tools

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Words and photos: Terry Martin

4-piece tungsten carbide stainless steel scraper set

The four-piece ‘medium/large’ scraper set has replaceable tungsten carbide cutters: one 12mm round cutter, one 11 x 28mm round-point diamond detail cutter, one 11mm radius edge square TCT cutter and one 11mm flat edge square cutter. The shafts are all solid stainless steel. They are very impressive in appearance and the finish on the handles and tools is excellent. In fact I think the shafts on these tools have the best finish I have seen on any tool. The handles are 30mm long, and the shafts are 160mm long.

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1. Undercutting a rim with the round scraper.

I chose tasks for each of these cutters to test their separate profiles. To test the round cutter I used a piece of very dry mango wood, which is very hard and also very difficult to scape cleanly (photo 1). I cut what would have been the underside of a rolled-over rim, which presents a tricky combination of endgrain and side grain. It performed very well, firstly because it has such a sharp edge, and secondly because it is such a small radius and so very little of the edge was in contact at any time. The finish was as good or better than I can get with any other tool.

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2. Cutting a recess with the square scraper.

The test the fully square cutter I mounted a piece of deep yellow wood and cut what would be a recess for expansion chucking. I eased the corner into the wood and the two edges gave me a perfect 90° recess with no pick-out at all (photo 2). I then used the slightly rounded square scraper to cut a dish shape and it performed just as well.

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3. A series of decorative grooves cut with the diamond cutter.

The final tool was the ‘round point diamond detail cutter’. I took this to mean that it was intended to cut tiny decorative coves in the wood, so I turned a series of grooves inside the dish shape and, again, this cutter performed very well. It also occurred to me that this cutter might perform well as a shear-scraper on the outside of a bowl (photo 3).

My conclusion is that these tools do an excellent job. Their size will partly limit them to smaller work, such as pens and trinkets, but some medium size work should also be possible.

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 3-piece deep swan neck hollowing chisel set

These tungsten carbide hollowing tools are also scrapers, albeit with smaller cutters, 9mm in diameter. The shafts are 175–210mm in length, and the handles are 390mm in length.

Two of the tools have curved necks for going ‘around the corner’ when you start to open the interior. The cutter tip is in line with the shaft, so the curve doesn’t cause any extra torque to be applied to the tool – as long as the entire curved portion hangs over the tool rest. The flat shaft means it is easy to keep the cutter at 90° to the wood.

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4. The hollowing tools have small cutters and take very fine cuts.

I had an 180mm tall hollow vessel that I had roughed out of wet banksia, so finishing the dried interior was an ideal way to test these tools. I used the tool with the largest curve to ease around the corner and take fine cuts. Because the cutter is so small, it took very fine cuts with no chatter (photo 4). Further in, I switched to the tool with the more open curve to finish the sides, and then the straight tool for inside the base.

The performance of these tools was excellent and if you don’t mind buying replacement cutters, they will do a fine job. However, the claim they are ‘heavy’ with ‘oversized shanks’, and ‘designed for deep hollowing work’ concerns me. After you subtract the space needed for the tool rest, the maximum overhang you can get with the longest shaft is around 170mm, not what I would call ‘deep’. Also, the long shaft, which will be used with the most overhang, is only 10mm square at the base and tapers to 6mm at the tip. It will probably be fine for most jobs of this size, but it is nowhere near ‘oversized’.

Opinions on scrapers range from them being able to do almost anything, to the claim that ‘real’ turners never use them. The truth is somewhere in between. A major selling point is that they are easier to use than other tools and that you can do everything with them. Used properly, scrapers can give you a better finish for some cuts than other tools, but they have their limits. It isn’t true that you can do anything with them, but if you work within their limits, these two scraper sets will perform very well.

Review tools supplied by Carbatec, www.carbatec.com.au

Pricing and information for the 4-piece large turning set is here

Pricing and information for the hollowing chisels is here

Terry Martin is a Qld wood artist. See www.terrymartinwoodartist.com.au

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