Seiun Saku are the standard ryoba for carpentry and joinery work, the angle between the centreline and the toothline is carefully calculated to give a rapid yet smooth cut and the heat treatment is optimised for springiness, i.e. the degree to which the blade can be distorted and still return to its original shape.
Blade Length
210mm
240mm
240mmfine tooth
270mm
300mm
Model No.
660
661
662
663
664
Blade Depth
70 - 87mm
77 - 97mm
77 - 97mm
90 - 115mm
95 - 120mm
Overall Length
530mm
560mm
560mm
645mm
680mm
Blade Thickness
0.45mm
0.5mm
0.45mm
0.6mm
0.7mm
Pitch XC
1.5mm16.9tpi
1.7mm 14.9tpi
1.3mm 19.5tpi
2.5mm 10.2tpi
3mm 8.7tpi
Pitch Rip
3.7-2.5mm6.9-10.2tpi
3.8-2.4mm6.7-10.6tpi
3.8-2.4mm6.7-10.6tpi
5.6-3.8mm4.5-6.7tpi
5.6-3.5mm4.5-7.3tpi
Set per Side
0.125mmm
0.125mm
0.125mm
0.125mm
0.125mm
Max Depth
∞
∞
∞
∞
∞
Replacement Blade
S605
S610
S611
S615
S616
Accepts Blades
S610S611S649S650S651
S605S611S649S650S651
S605S610S649S650S651
S616S655
S615S655
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.
