Bluehard blades are designed for precise and careful work, they have a slightly shallower angle on the toothline making them less aggressive than a standard ryoba and the sawplate is heat treated to be a little stiffer.
| Blade Length | 210mm | 240mm | 240mm fine tooth |
270mm |
| Model No. | 665 | 666 | 667 | 668 |
| Blade Depth | 70 - 87mm | 65 - 83mm | 65 - 83mm | 79 - 96mm |
| Overall Length | 530mm | 560mm | 560mm | 645mm |
| Blade Thickness | 0.45mm | 0.5mm | 0.45mm | 0.6mm |
| Pitch XC | 1.5mm 16.9tpi |
1.7mm 14.9tpi |
1.3mm 19.5tpi |
2.5mm 10.2tpi |
| Pitch Rip | 3.7-2.5mm 6.9-10.2tpi |
3.8-2.4mm 6.7-10.6tpi |
3.8-2.4mm 6.7-10.6tpi |
5.6-3.8mm 4.5-6.7tpi |
| Set per Side | 0.125mmm | 0.125mm | 0.125mm | 0.125mm |
| Max Depth | ∞ | ∞ | ∞ | ∞ |
| Replacement Blade | S649 | S650 | S651 | S655 |
| Accepts Blades | S650 S651 S655 |
S649 S651 S655 |
S649 S650 S610 |
S649 S650 S651 |
Gyokucho razorsaws, the original replaceable blade Japanese saws, have long been renowned for their cutting efficiency and excellent durability. The latest generation of Gyokucho saws have blue handles made from TPE (thermoplastic elastomer) a remarkable material that is simultaneously hard and resilient yet feels velvety to the touch and affords a superb grip.
The blades of Gyokucho saws are treated using a process called electroless nickel plating, this has three functions. Firstly, it protects the blade against corrosion, secondly it provides a nice shiny mirror surface so you can gauge your cutting angles, and thirdly its low friction properties inhibit resins and sap from building up on the blade - anything that does manage to get stuck to them can easily be washed off with warm soapy water. The teeth are differentially impulse hardened, one by one, bringing the outer surfaces to RC68 or more whilst still leaving the 'root' of the tooth soft and therefore much less prone to fracture - not unlike tiny Japanese sword blades. They are equally happy working in softwoods or temperate hard woods and can, with care and a light touch, be used on exotic timbers too.
Ryoba are double edged saws (Ryo = Two, Ba = Edge). They have different tooth patterns on either side of the blade, usually one for ripping and the other for crosscutting.
Here's an interesting video by David Walton, YouTube's Unplugged Woodworker, on Ryoba Saw basics using a Gyokucho TPE saw.
