Woodworker's Journal 1994-18-6, страница 21

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to V" in diameter. Bird carvers prefer the slim, pencil-style No. 8 handpiece for fine detail work. It features a retractable chuck guard which slides down close to the bit for greater control, and accepts Vu." to '/»" collets plus a 3mm collet.

Foredom has put together a Ilex-shaft can ing kit (no. 5240) that includes a hang-up model SR (reversible) motor, a no. 44 handpiece, a foot-operated speed-control switch, and 10 popular carving bits. I tried this kit in my review: at about $260, it's an excellent choice for beginners. Add the no, 8 handpiece and a good selection of bits, and you've got a highly versatile carving system.

I also tried four other flex-shaft units: the Dremel model 332 Moto-Flex tool, the Dremel model 7360 heavy-duty flex-shaft kit, the AMT model 5111, and the Woodtek model 876-768. The Dremel Moto-Flex features a slightly larger version of the Moto-Tool connected to a pencil-style handpiece via a flexible shaft. The ball-bearing, variable-speed motor operates at 7,500 to 25,000 rpm and can be mounted on a swivel base or a wall hanger, both of which are included. A three-position switch enables you to operate the toot at full speed or in variable-speed mode by means of a dial on the back end of the

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Photo 4: Dremel model 232 Moto-Flex tool comes with swivel base and hanger I single-speed version shown here, about $90): the author tested the variable-speed model 332 (about SUM)). Photo courtesy Dremel Co.

Photo 3: Foredom offers 22 different handpieces for their flev-shaft tools. Shown here are the most popular for carving: the no. 30 (tup), the no. 44 (renter): and the no. X (bottom). Photo courtesy Foredom Electric Co.

tool. With its 0.95-amp motor, it wasn't as gutsy as the other flex-shaft tools I tried (1.7 to 2 amps) but had plenty of power for small caning projects and detail work. In my tests, the Moto-Flex (about S90) had a bit more torque than the Moto-Tools and was more comfortable to use, thanks to its thinner handpiece and lower vibration level. You can also buy a single-speed version (model 232. photo 4).

The Dremel heavy-duty flex-shaft tool (model 7360) sports a !4-hp. 2-amp motor and comes with a heavy-duty, collet-type handpiece that includes % and V" collets. The kit form (about S200) includes a variable-speed fool control, a bench-mounted hanger, extra cable and brushes, and a 27-piece, general-purpose accessory set.

The AMT and Woodtek machines feature nearly identical 54-hp, 2-anip motors, each offering a 1 5.000-rpm maximum speed. I suspect that both motors come from the same Taiwanese manufacturer. The AMT. however. features a hanging motor with a rev ersible

switch, while the Woodtek comes in a bench-mount style with forward speed only. The flexible shafts and variable-speed foot sw itches also appear to be identical. AMT provides a collet-style handpiece with three collets ('/», Yn, and 'A"), whereas the Woodtek handpiece has a Jacobs-style chuck that accepts shafts up to Vv.". While the Jacobs-style chuck makes bit-changing much easier and accepts an infinite range of shank diameters, it doesn't offer as much support for the bit. This causes more vibration than collet systems produce. In addition, Jacobs chucks tend to loosen when the motor runs in reverse.

If you have read many tool articles, you've probably heard the old truisms about horse-power ratings versus amperage versus actual power. In the case of these tools, the AMT and Woodtek machines list the maximum dev eloped horse-power of the motor at %-hp (no-load speed), while Foredom assigns a more conservative %-hp rating, taken under an arbitrary load condition. In my "bog-dow n" motor tests, the /s-hp. 2-amp Dremel heavy-duty flex-shaft tool provided a bit less torque than the /»-hp. 1.7-amp Foredom, although the Dremel operated at 22,000 rpm, as opposed to 18.000 rpm for the Foredom. Typically, as speed increases, torque decreases, given the same amperage draw. The Dremel theoretically has a more powerful motor than the Foredom. but the Dremel sacrifices torque in favor of a higher no-load speed. For the carver, this means that the Dremel performs better for light stock removal (the higher the speed, the cleaner the cut) while the Foredom will be less likely to bog down when making deep, heavy cuts with larger bits. At 16.000 rpm. the AMT and Woodtek 'A-hp motors seemed to have only slightly more torque than the Foredom. despite their lower speeds and higher horsepower ratings.

While the AMT and Woodtek motors were a bit quieter than the Foredom and Dremel. I noticed more handpiece vibration on both of these two Taiwanese imports. Also, their foot

Woodworker s Journal

Novembcr/December 1994 1<1