Grinding long blades?

[lazlo]

I'm starting to get comfortable grinding up to 10" blades with the standard elbows in, move your hips method of grinding.

But I've forged two wakizashis, and have been working on Nick's giant bowie forging, and I'm finding it's tough keeping the blade flat against the platen on longer blades.
I can't get much more than 10" of movements by sliding my body.

I took Howard Clark's katana class, and he does this beautiful swooping motion, but I have a feeling I'd have to ruin a hundred blades or so before I got the hang of that. Someone suggested that a 6x48 grinder would make long flats easier, but I'm really tight on space in my shop (i.e., my garage). But if it's that much easier, I'd certainly consider it...

So how do you guys grind long blades, like big bowies and swords?

 

[hodgescl]

i havnt made many knives, but most of them have been large and curvy (bowies). all of mine have a convex cross-section from my technique which is in response to the tools i have available. i have an old 4x36 grinder with one speed and angle and nowhere to attatch a jig.

i always keep the blade moving, and check often to make sure the grind is even. just remember that the middle of the blade will be in contact with the belt more than either end will (with a wide belt, the wider the belt the more extreme this is) , so be sure to check and see if you need to compensate and grind more at the ends. Before i go to a finer grit i always grind the blade lengthwise to make sure there are now humps or dips in the grind. if you do this they can easily be seen when there are gaps in the lengthwise grind marks.

it will take some time to figure it out how you can do what you need to do on your tools, but thats what trying new things is all about.

 

[Mike Davis]

If needed, work your blade in sections. when you get them all close to each other, about .015 before your finished thickness, start your full sweeps and blend them together.

 

[parbajtor]

I'm starting to get comfortable grinding up to 10" blades with the standard elbows in, move your hips method of grinding.

But I've forged two wakizashis, and have been working on Nick's giant bowie forging, and I'm finding it's tough keeping the blade flat against the platen on longer blades.
I can't get much more than 10" of movements by sliding my body.

I took Howard Clark's katana class, and he does this beautiful swooping motion, but I have a feeling I'd have to ruin a hundred blades or so before I got the hang of that. Someone suggested that a 6x48 grinder would make long flats easier, but I'm really tight on space in my shop (i.e., my garage). But if it's that much easier, I'd certainly consider it...

So how do you guys grind long blades, like big bowies and swords?

I spoke to Howard when he came over to blighty a couple of years back for Owen Bush's Hammer-in. He told me that he "borrowed" the technique from Tai-Chi. Perhaps a few Tai Chi classes would help?

PS. Fred Rowe's Bubble Jig is ideally suited for this kind of work.

 

[Fred.Rowe]

E-mail sent.

Fred

 

[Danbo]

If needed, work your blade in sections. when you get them all close to each other, about .015 before your finished thickness, start your full sweeps and blend them together.

This is exactly what Tim Hancock suggested to me, when I told him of my woes, when attempting a grind on a longer blade. He said do short sections and then "CAREFULLY" blend it all together.

 

[Josh Mason]

I understand that Tim uses a tool rest too? Maybe you can try that?

 

[lazlo]

I understand that Tim uses a tool rest too? Maybe you can try that?

That actually helped a lot -- J.R. Cook showed me how to use the tool rest with the push stick stationary, and pulling the blade through. That helps a *lot*, but you're still limited to ~ 10" or so (or maybe I just suck ), but it got 'r done on Nick's giant forging.

Tim Portier showed me a trick where you start at the plunge line, and then rotate the blade by ~ 60° while pulling it through (freehand, won't work with a rest), so you get the diagonal length of the flat platen. But I'm going to have to practice with some flat stock first.

It sounds like grinding long blades is just plain hard, and I just need a lot of grinder time on shorter blades first...