Changing bevel angle, preferred method?

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Vips
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Changing bevel angle, preferred method?

Tue Apr 19, 2016 4:42 am

Now that I have a few Kanna, I wanted to explore the idea of changing the bevel angle to suit the work I intend to do with them. They're all currently honed to 25 degrees, with all the Kanna having around 38 degree bedding.

I'm considering changing the roughing.intermediate planes to around 27-29 degrees to better cope with medium hardwoods whilst retaining one acute for softwood smoothing and another around 27-29 for hardwood smoothing. I may attempt to make different bedding angle dai at another stage.

What's perhaps the usual way to change the bevel angle of a kanna and even nomi? In the past I've resorted to a grinder, which I don't particularly like, given the high chance of overheating the blade. As for stones, the thread below mentions grits around 120, but are these usually used with a jig to change bevel angles such as the Grintec K2? I'm assuming if I choose this route of stones, then I would require something along the lines of the Grintec for kanna blades, and a Veritas jig for Nomi? I've also noticed that perhaps a Tormek whetstone grinder may be an option. Anyone use one of these?

Thanks,

Vips
Last edited by Vips on Mon May 09, 2016 5:05 am, edited 1 time in total.
toscano
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Re: Changing bevel angle, preferred method?

Tue Apr 19, 2016 6:22 am

Hi Vips,

if I understand your question correctly, increasing the bevel angle is easy to do with whetstones and hand sharpening: just don't establish a full new bevel with the first sharpening, but just a few mm. As you continue sharpening at this new angle, the bevel size will continue increasing till it becomes fully established.

I do wonder though: won't the bevel interfere if its angle is higher than the bedding angle?

cheers,
_t
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Brian
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Re: Changing bevel angle, preferred method?

Tue Apr 19, 2016 7:27 am

The grindtec is a great jig.

I would assume the bedding angle of your kanna is actually about 38 degrees. The major thing to keep in mind is clearance angle, Ive found anything under 10 degrees of clearance to make for many trips to the sharpening stones because the clearance runs out quickly.

I dont grind at all, let alone anything that creates much heat my logic behind that is that the temperature used to temper plane blades is often very low (as low as 100c).
Vips
Sweeper of Floors, Maker of Tea
Posts: 63
Joined: Tue Mar 31, 2015 3:48 am

Re: Changing bevel angle, preferred method?

Tue Apr 19, 2016 8:52 am

That's interesting Toscano. I had thought about that technique but figured it would be difficult to maintain. I will try this out if I notice any poor edge retention, thanks. Do you use a guide block initially, and what sort of grit do you start with?

So it does look like I only have a few degrees to play with if I am to change the bevel angle and keep the clearance angle suitable. So far, I'm quite happy with the edges, they've held up well, much better than the PMV11 irons.

I'll have to look into the Grindtec if I cannot do as Toscano mentioned, else it can be yet another reason I'm justifying a Tormek :)

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