Spine Thickness Does Matter

[jmforge]

Marko, don't you have a TW 90? If so, have you bought the surface grinding fixture? I would think that might be handy for experimenting with things like this.

[Marko Tsourkan]

$1000 surface grinding option is a bit too much for me, to be honest. I would rather save the money for another TW90 or a real surface grinder. I don't find it difficult to grind a distal taper by hand (I would be looking in other options, if I did).

Mario, just that we are on the same page, by midsection I mean half-way between spine and edge, and middle of the blade is halfway between handle and tip (approximately).

M

[jmforge]

True. The easy to use sine block feature of the TW90 gadget seems kind of attractive though.

$1000 surface grinding option is a bit too much for me, to be honest. I would rather save the money for another TW90 or a real surface grinder. I don't find it difficult to grind a distal taper by hand (I would be looking in other options, if I did).

Mario, just that we are on the same page, by midsection I mean half-way between spine and edge, and middle of the blade is halfway between handle and tip (approximately).

M

[Marko Tsourkan]

Sine block feature would allow you to set an angle, as on a sine magnetic chuck. I don't think you can do that on TW-90 attachment, at least I don't see it in a video.

To grind a distal taper on TW-90 surface grinding attachment, you would have to shim the blade, but I don't think the magnets on the chuck are strong enough to hold the blade with shims. Plus, you would need to buy a demagnetizer. I can think of better ways to spend 1K on tools.

M

[jmforge]

You would have to shim the blade if you wanted to grind in the taper after your ground the bevels. Otherwise, I would think that it would be just like tapering a tang. It may be different with these thin kitchen knives, but I forge the taper into my blades before I forge out the bevels and the guys who I have seen making Japanese swords do the same thing. Of course, even if you ground your bevels halfway up, I think you might be able to do whatever taper you needed and then go back and finish beveling and blending. The only shimming you might have to do would be perhaps at the heel and maybe the tip to keep the flat of the blade stuck to the magnet and not the bevel.
Why would you need to buy a demagnetizer?

Sine block feature would allow you to set an angle, as on a sine magnetic chuck. I don't think you can do that on TW-90 attachment, at least I don't see it in a video.

To grind a distal taper on TW-90 surface grinding attachment, you would have to shim the blade, but I don't think the magnets on the chuck are strong enough to hold the blade with shims. Plus, you would need to buy a demagnetizer. I can think of better ways to spend 1K on tools.

M

[jmforge]

I'm not trying to argue with you, Marko, just axing. There will come a time in the near future where I have to decide on whether to get another KMG chassis and motor and buy and modify a used surface grinder to run with 72" belts or just buy a full boat TW90 with the surface grinding attachment. Can't do both in the foreseeable future.

[Marko Tsourkan]

I didn't interpreted as as an argument. You mentioned a sine block feature, so I clarified that TW-90 didn't have one.

A piece will be magnetized on the chuck and stay magnetized, so you need to demagnetize it. Same with all magnetic chucks. Less powerful ones, like on TW90, the level of magnetization will be smaller.

M

[stevenStefano]

I think I generally like knives that are a little thicker than most people, but one thing I find problematic with knives that have a thick spine and thin behind the edge is that they are sometimes difficult to "aim." Might seem like an incredibly dumb/obvious thing to say but with some thick knives it is hard to know where the edge is if there is a big difference between the edge thickness and spine thickness

[jmforge]

Maybe I am misusing the term, but I thought that the TW 90 had sine block ypte adjustment for tapering lengthwise.

I didn't interpreted as as an argument. You mentioned a sine block feature, so I clarified that TW-90 didn't have one.

A piece will be magnetized on the chuck and stay magnetized, so you need to demagnetize it. Same with all magnetic chucks. Less powerful ones, like on TW90, the level of magnetization will be smaller.

M

[Marko Tsourkan]

Maybe it does, but I watched a video and Travis doesn't mention it, but is possible that it includes that feature.

M