I am about to place an order for more chisels with Stuart. I intend to make quite a few cabinets in the near future and have lots of drawers and door frames to look forward to. I see large numbers of door frames and drawer dovetails in my future. I have been following many threads on SMC and watching videos on tools and methods for this work, Kingshott (Mortise & Tenons, Dovetails), Charlesworth (Technigues for Precision Joinery), Glen Huey (Cheating at Hand-cut Dovetails, which did not turn out to be about what I thought it was). I have also followed the exploits and posts of our own Derek Cohen. I have decided to invest in a couple specialized Japanese mortise chisels and a couple Parring Chisels as well. I have been studying the Tools From Japan products in these areas and would like a little help figuring a few differences in the makers and types of tools available for this work.
Why Japanese Chisels
I was watching Jim Kingshott's video on mortising and was surprise that he used Japanese chisels for the work instead of the more traditional "pig stickers". As I understood his reasoning, he felt it was easier to make an entire mortise with these chisels due to the design of the sides of the chisel blades. The sides of the chisels Jim used were actually hollow ground with rather sharp edges on both sides. I do not know that the hollow ground sides is a big issue and I am sure there are arguments for many different designs. I have read Derek's description of the accurate work he has accomplished with Japanese chisels and a gennou. I have also seen the beautiful work Derek has done using these tools, and his fret saw. I have witnessed the very accurate work Charlesworth does with similar techniques. I also see some possible advantages in the greater variety of sizes Japanese chisels typically are offered in. Certainly there are some advantages to the Japanese steels. I am interested in selecting from the two different mortise chisel types Stu offers on his pages unless there is another alternative I should consider.
Mortise Chisel Manufacturers
The two makers I see that offer mortise chisels are Fujikawa and Koyamaichi. I am speculating that both of these makers turn out quality chisels. I believe Fujikawa built their reputation on mortise chisels and I have read at least one post by a fellow Creeker who likes these chisels. Koyamaichi is a favorite maker of chisels on these pages in regard to their Oire-Nomi, "Dovetail" and I think Parring chisels. I don't think I have found any information regarding their mortise chisels here though. Although the Fujikawa chisels are a little less expensive the difference is not enough to steer me in either direction.
The whole sizing thing
I am struggling to wrap my head around choosing metric size chisels in my imperial world. I have come to understand that particularly in regard to mortises where I will be setting a double gauge by a chisel size, it is ratios not specific sizes that counts. I am also fully aware that chisels for various reasons may not always be expected to be exact sizes. Still I have to buy "specific" sizes. I am a little frustrated when people post that they use imperial chisel sizes that I don't think are manufactured in those sizes (3/16 and 5/16" for instance). I suspect that posters are referring to metric size tools that they are rounding up or down to imperial sizes? If I leap further into the Japanese chisels I have to find some way to reconcile metric and imperial sizing? Unless Stu or someone is having Japanese makers make chisels in off imperial sizes? Even if Stu can have chisels like this made I do not really see a need for them with all the metric sizes available.
In a post on these pages Derek mentions his "favorite" mortise chisel sizes- 1/4, also 1/8 and 5/16. I am betting at least some of Dereks chisels are metric. I am not quite as ambitious as Derek so I plan to skip the 1/8. The issue is the Japanese chisels I am looking at are metric. Kingshott discusses the principal of mortises being 1/3 the size of the piece of wood. Kingshott mentions, in regard to the 1/3 rule, the principal of choosing the slightly larger rather than slightly smaller chisel. Considering that typical door frames are 3/4" and the Japanese mortise chisels come in 6mm (.23622047") and 7.5mm (.29527559") I am trying to figure out which size is better for mortises in typical 3/4" wood? Most US companies list 6mm as 1/4 when it is actually less than 1/4, less than 1/3 of 3/4". For some reason the Japanese chisels seem to skip 7mm and go to 7.5. I am wondering if a 7.5mm falls within Kingshott's realm of a little larger than 1/4", making it a better choice for mortises in 3/4" wood? Might Derek use his 5/16 (.3125") chisel for mortises in 3/4" wood? Maybe Derek's 5/16" (.3125") is actually a 7.5mm (29527559") or just a little more than 1/3 of 7/8"(.29166667")? Since I buy wood finished on both sides and one edge, usually 4/4 or 8/4 I may end up with 7/8" finished boards frequently.
Parring & other Chisels
I want a couple of the classic Japanese push or paring chisels. Stu offers Koyamaichi Usu-nomi chisels. Is there anything else I should look at? Derek mentions a Japanese chisel in his chisel steel test, used to clean up the work from the other chisels, "I used a Funmatsu-Nezumi-Haisu (from Tools from Japan). This is a PM-HSS chisel. A right royal pain in the bottom to sharpen, but it holds an edge like nothing else ..." I don't see this exact chisel on Stu's pages but I do find 'Funmatsu-Nezumi' oire-nomi, made with Hitachi PM-HSS. Are these similar chisels?