Concave or spherical cutter?

[Paulkellum]

I was going buy a Masakuni Concave Branch Cutter but then started seeing more about the spherical version. Anyone got anything good or bad to say. I love my other masakuni tools and have small concave cutter but need a larger one. Smaller one was kinda a waste but live and learn. Thanks for your help

 

[Poink88]

Spherical will be a bit more difficult to maintain/sharpen.

 

[Paulkellum]

With that is the cut that great that makes up for it hard to sharpen.

 

[Poink88]

I assume you at least used both a regular concave cutter and a knob cutter. The spherical concave cutter is like a hybrid of the two. It is up to you (personal preference) if you like that or not.

The advantage of the spherical (because of the rounded nature) is that it is in effect stronger than the regular "straight" concave cutter and less prone to breakage (for same force or abuse applied).

 

[Paulkellum]

I assume you at least used both a regular concave cutter and a knob cutter. The spherical concave cutter is like a hybrid of the two. It is up to you (personal preference) if you like that or not.

The advantage of the spherical (because of the rounded nature) is that it is in effect stronger than the regular "straight" concave cutter and less prone to breakage (for same force or abuse applied).

Thanks for that how do you sharpen a sphere

 

[Poink88]

Thanks for that how do you sharpen a sphere

The outside curve is easy, you can use what ever you have just multiple pass along the edge unlike once on a straight edge. For the inside, I use a round diamond file. Some wood carving supply stores also sell curved stone for such purpose (for gouge sharpening). You can also use a fine sandpaper wrapped on a wooden dowel in a pinch.

Note that the 2 cutting edges do not meet. When I sharpen (not re-profiling the edges because of a break or chip)...I sharpen the outside part of the outer cutting edge only and the inside part only of the inner cutter. This help maintain the proper clearance between the two. There may be a time later when you need to adjust both though.

Good luck with your choice!

 

[nathanbs]

Once i've used a spherical concave i've never gone back to regular concave cutters. I bought myself a good pair of masakunis and haven't had to sharpen them yet. 2 years and lots and lots of cuts so far

 

[Poink88]

Once i've used a spherical concave i've never gone back to regular concave cutters. I bought myself a good pair of masakuni ones and haven't had to sharpen them yet. 2 years and lots and lots of cuts so far

Two years is a long time (if used frequently) even for a great tool.

One thing I've learned, we all have different definition of "sharp". Some want scary sharp, some settle with sharp enough, some settle with as long as it still cuts.

For my bonsai tools, I test them with my finger nails. If they dig in and not slide then they are still sharp enough. If I can see a light reflection at the cutting edge then it is time for a touch up. I do not bring them to shaving sharp just because I do not think it is worth it but also do not let them get dull.

Until I attended a bonsai convention, I didn't know the problem is more of the norm rather than exception. Seen countless people using super dull tools during the classes...it was pitiful.

 

[nathanbs]

Two years is a long time (if used frequently) even for a great tool.

One thing I've learned, we all have different definition of "sharp". Some want scary sharp, some settle with sharp enough, some settle with as long as it still cuts.

For my bonsai tools, I test them with my finger nails. If they dig in and not slide then they are still sharp enough. If I can see a light reflection at the cutting edge then it is time for a touch up. I do not bring them to shaving sharp just because I do not think it is worth it but also do not let them get dull.

Until I attended a bonsai convention, I didn't know the problem is more of the norm rather than exception. Seen countless people using super dull tools during the classes...it was pitiful.

So are you saying they were pitifully dull because they were visibly crushing tissue or because you borrowed them and couldn't properly cut your nails?

 

[Poink88]

So are you saying they were pitifully dull because they were visibly crushing tissue or because you borrowed them and couldn't properly cut your nails?

LOL the first plus they strain when cutting (when they shouldn't be) and you hear this unmistakable sound of snap after each cut.