Curved blade grinding help please.

[izafireman]

I made these two knives recently and as you can see the curved blade has a 'Scandi' grind for deer gralloching ie stomach removal in the field.
The curved blade was a challenge as I had the blade in a jig and had to move it along the belt in a sweeping/ curving motion in order to grind it as impossible of course to grind it like a straight bladed Scandi. This led to an issue where I was going off the back of the table as the blade moved around the belt to the tip when grounding....hope I am explaining this so you can follow?

Now I want to find a faster / easier process to do this curved grind. My thought are to make a table that extends a few inches behind the platen so I wont go off the back or I was thinking, though this mean a lot more work maybe a platen with a curved face that the belt would follow.....but would the belt track OK for the plunge lines?

So they are my ideas, might be dumb, I don't know but if anyone can help me or point my to videos that might explain this better it would be much appreciated.

Thanks in advance

Pete

 

[Rick Otts]

Try a bubble jig it is as close to free hand as it gets and you will learn freehand faster.

 

[izafireman]

Try a bubble jig it is as close to free hand as it gets and you will learn freehand faster.

I have done free hand on hollow grinds but I think I would find it difficult to be precise on Scandi grinds..

Though I have thought of getting a bubble jig before.

Cheers

 

[flatblackcapo]

I made these two knives recently and as you can see the curved blade has a 'Scandi' grind for deer gralloching ie stomach removal in the field.
The curved blade was a challenge as I had the blade in a jig and had to move it along the belt in a sweeping/ curving motion in order to grind it as impossible of course to grind it like a straight bladed Scandi. This led to an issue where I was going off the back of the table as the blade moved around the belt to the tip when grounding....hope I am explaining this so you can follow?

Now I want to find a faster / easier process to do this curved grind. My thought are to make a table that extends a few inches behind the platen so I wont go off the back or I was thinking, though this mean a lot more work maybe a platen with a curved face that the belt would follow.....but would the belt track OK for the plunge lines?

So they are my ideas, might be dumb, I don't know but if anyone can help me or point my to videos that might explain this better it would be much appreciated.

Thanks in advance

Pete

I have been thinking about making a work rest extender plate using a piece of steel and magnets. Same construction idea as the Wuertz Doubler Plate.
That way I can just stick it to my existing work rest when I need the extra length and pop it off when I am done. Neodymium / Rare Earth magnets are pretty inexpensive and I was going to try using JB Weld to stick them to the steel plate.
Maybe that could work for you.

 

[izafireman]

I have been thinking about making a work rest extender plate using a piece of steel and magnets. Same construction idea as the Wuertz Doubler Plate.
That way I can just stick it to my existing work rest when I need the extra length and pop it off when I am done. Neodymium / Rare Earth magnets are pretty inexpensive and I was going to try using JB Weld to stick them to the steel plate.
Maybe that could work for you.

Now this is the part where I punch myself!...….Glad you posted this as I was going to make a double for my other grinder, never thought of one for my smaller grinder I do Scandis on, reckon we might have it sorted as I have the magnets

Here's another tips using micarta, pity I have glass platens as I would have made an aluminium version that I could bot on.......Wonder if a steel platen could be used with magnetic mounted platens? You could have the normal face, a glass platen with magnets on the rear and a metal one with magnets on the back with radius conrers... instant platen changes.

 

[springer82]

If I was going to grind a "curved" blade. Curved more then a normal blade I would find a way to tip my Bader3 90°. A vertical grinder would help. Good luck.

 

[izafireman]

If I was going to grind a "curved" blade. Curved more then a normal blade I would find a way to tip my Bader3 90°. A vertical grinder would help. Good luck.

Thanks, I will crack it as thee one in the image was my first ever attempt and thinking about it I jigged it first and thought it ok but if wasn't sharp enough. I then did it every so carefully free hand....I forgot that bit.

 

[springer82]

One of these days I'm going to make a karambit or a kris blade. I'll make a mounting plate with a way large hinge. Sometimes 0,,, sometimes -90°. It's all good. Best of luck to you.

 

[izafireman]

One of these days I'm going to make a karambit or a kris blade. I'll make a mounting plate with a way large hinge. Sometimes 0,,, sometimes -90°. It's all good. Best of luck to you.

Well in the end I opted to make a new table for my grinder. A long table in order if I want to make a kitchen knife and use a jig I can and I also put a deep slot in the table with a 'V' shape (v formed by either side of the slot edges) so the grit can escape when grinding. I can now sweep the blade around the sides of the belt without running out of table support. I spoke to my mate about this who does curved blades the same way and it was a case of why re-invent the wheel?

I am though going to learn to free hand, I know I will be able to do it but it is just a mental block , like writers block I suppose. I can do a hollow freehand so why not a flat ....grrrrr . I think I will buy a bubble jig and give it a whirl also.
Now get on and get those two blades ground out

 

[flatblackcapo]

Now this is the part where I punch myself!...….Glad you posted this as I was going to make a double for my other grinder, never thought of one for my smaller grinder I do Scandis on, reckon we might have it sorted as I have the magnets

Here's another tips using micarta, pity I have glass platens as I would have made an aluminium version that I could bot on.......Wonder if a steel platen could be used with magnetic mounted platens? You could have the normal face, a glass platen with magnets on the rear and a metal one with magnets on the back with radius conrers... instant platen changes.

I certainly like the idea of quick change platens but I am having a hard time trusting having only a magnetic attachment on a platen. If you end up giving it a go, let me know how it works.
To be clear, I am not saying it won't work, I am just saying I am having a hard time trusting it.

 

[izafireman]

I certainly like the idea of quick change platens but I am having a hard time trusting having only a magnetic attachment on a platen. If you end up giving it a go, let me know how it works.
To be clear, I am not saying it won't work, I am just saying I am having a hard time trusting it.

I think the magnetic platens will work but I decided to take mine right back to scratch and straight away I found errors that had been there all the time such as a few parts slightly out of square etc. I think by the time the will be finished there will he a huge improvements.

Edit...… Well I just decided to try a few rare earth magnets I have before I drilled the tables....I have a feeling I wont be drilling the tables to hold them in position as the magnets are so good. Not only that I think I will be able to use the same table on both of my machines. The same table if I get my head around it should possibly be able to be used as a doubler plate for hollow grinding as a few small tables that came with the machine originally which I can utilise.