I got myself a disposable dozuki from dictum to check the shape of the back and the teeth geometry. And more importantly, so my students don't break the teeth of my hand made saws.
The one I got is a 180mm. All the others I have (1 new, 2 buyee) are cross cut 240mm and they feel a bit large for most of the cross cut I make, to not mention for cutting dovetails in a normal 7/8'" piece.
Part of my diabolical plan with this dozuki is also to make replacement blades out of old ryobas I got. I'm thinking in particular in 2 thin ones that broke at the rip side.
Anyway, here it is. I keep on packing my stuff so no much workshop work or cutting pictures, I just let you know the geometry.
The teeth are cut like rip, ie 90 degrees to the plate with a third bevel that changes direction as the set does.
Fairly fat and slightly negative rake they should have no problem with hardwoods. As in tropical woods, not normal hard woods. Tried it in rosewood and cuts fine if a little rough on the cross cut. Didn't try dovetailing since had to make lunch.
And this is what I find most interesting:
A very fat and large top facet.
I didn't manage to catch on picture but there is a subtle blue at the very tip of the teeth on the sides. However the top facet doesn't seem to have it. My guess is that after a few months of use I will be able to sharpen with a normal file. That is, if I manage to find a one sided pack of files for then in Japan.
A few months ago I sent a mail to Gabe, Mark and Jason asking how we could turn a rip saw into a diagonal cutting one. Something like the madonoko but starting from a rip. Maybe this is the path albeit in the case of a rip saw the teeth increase in size along the length of the saw, and who knows how well this geometry works for larger pieces. What I want to say is that I haven't seen this in large saws, so there may be a reason for it.
Naja.
Me misses workshop and saw vice.
That geometry just so happens to be a nearly perfect match to what I've been putting on one of my "user" saws that I've been using on green wood. Kind of an out-in-jungle, guerilla ninja saw, haha, very stealth. A post happens to be in the works......not that I've got any particular insight, exactly.
ReplyDeleteAnother similarity in tooth shape would be to the ubiquitous kataba-kind of/pruning saw (I'm not clear on its real name). Mine have an almost rip tooth pattern, but with a vary small top facet.
My big question is.....Why don't all of these saws have some sort of "raker" tooth? I'm currently putting them on my saws at the same time as I deepen the gullets, when the teeth start looking short and chubby. When I remember, that is.
maybe money? Don's universal saw had one pattern on top of which it was two rip teeth every n cross. Like if the saw if first cut for one pattern and then for another in a different machine. Chumasaru's approach changes the spacing so if you would like to make that with a machine would need a dedicated one. So my guess is that's cheaper not to put the raker if you are doing it industrially.
DeleteOr maybe I didn't understand your question?
The only thing I know is that I really like the madonoko style for dozuki, it's a really fast way of turning a regular saw into an amazing tool.
Bring that post live, want to see more teeth.
Oopps, I think I missed that email?
ReplyDeleteBut what I do is create "rip" teeth in a cross-cut blade. It still functions like a cross-cut, but mitre cuts out to 50 degrees are improved. Then rip teeth (sharp!) do 40 to 0 degrees.
no, in fact you answered implying something like that, converting most of them to cross cut and leaving a few raker teeth. But I wanted something more like this, a rip that can be used for a bit of cross. A dovetail saw in fact. By the way, have you ever made the first few teeth of a rip saw cross cut? Like what some people do with a ryoba and start a rip wwith the cross side but then in just one side of the saw?
DeleteI love that idea!
Delete