McNaughton Center saver knifes not symmetrical.

[Ted Judd]

I recently purchased the McNaughton Center saver from Lee Valley Tools.
I have noticed that the tips of both the straight and least curved knifes are not symmetrical.
It is not a problem, I am just wondering if this is by design or just lack of quality control.

 

[Richard Coers]

What do you mean by symmetrical? Not a constant radius?

 

[Ted Judd]

By symmetrical I am just referring to tip of the knife. l guess the picture did not upload.

 

[Dean Center]

The pointed tip was reportedly a response to a request from Mike Mahoney, who likes to drive the knife all the way to the bottom. Somebody may have come up with an 'improvement', to angle the point in the direction of the curve being cut. I'd suggest you ignore it.

Some of use have gone so far as to grind the point off, as the point, and it's great surface area, increases the amount of 'bevel' contact and therefore resistance in use. As with everything in woodturning, there is more than one way to do everything. If you want a symmetric point, carefully grind the tip.

 

[Ted Judd]

The pointed tip was reportedly a response to a request from Mike Mahoney, who likes to drive the knife all the way to the bottom. Somebody may have come up with an 'improvement', to angle the point in the direction of the curve being cut. I'd suggest you ignore it.

Some of use have gone so far as to grind the point off, as the point, and it's great surface area, increases the amount of 'bevel' contact and therefore resistance in use. As with everything in woodturning, there is more than one way to do everything. If you want a symmetric point, carefully grind the tip.

Thank you for the reply.
I would not say that I am concerned. It was just idle curiosity if the non-symmetrical nature of the two knifes was by design. There does not seem to be a manufactures' web page.
I did watch a Mike Mahoney video on the system. His gate was different that the one I have in that it has an extra bar in the rear of the gate to stop the knife from dropping down rather than remembering to hold the knife up.

I may try to grind one of my knifes flat. I did find that the knifes were grabby and tended to head up. I used spray bottle to cool the knife as the blank was green. I would not want to do that on a dry blank.
When you grind the tip off do you have a bevel back under the new flat face or is it square with the cutting tip?

 

[Neil S]

This what I did, as much to break up the shavings as anything. The leaving tip edge is on the circle radius. And, yes, I undercut the leading edge keeping in mind its not a bevel rubbing cut but a scraping cut...

 

[Dean Center]

Thank you for the reply.
I would not say that I am concerned. It was just idle curiosity if the non-symmetrical nature of the two knifes was by design. There does not seem to be a manufactures' web page.
I did watch a Mike Mahoney video on the system. His gate was different that the one I have in that it has an extra bar in the rear of the gate to stop the knife from dropping down rather than remembering to hold the knife up.

I may try to grind one of my knifes flat. I did find that the knifes were grabby and tended to head up. I used spray bottle to cool the knife as the blank was green. I would not want to do that on a dry blank.
When you grind the tip off do you have a bevel back under the new flat face or is it square with the cutting tip?

Yes, just like a regular scraper, you need some clearance under the edge, so grinding at something less than 90 degrees is needed. I believe 70 degrees is typical.

Just remember you NEVER grind the top, which is a piece of some magical extra hard material glued on. It's thin, like a layer of veneer, and can easily be ground off and then you're sunk.