Help - Grinding a nail nick fly cutter

Cubane

Well-Known Member
Help - Grinding a nail nick fly cutter - Success!!

The next thing to do on my slip joints is to improve the nail nicks. I have been using a dremel cut off disk mounted in the milling machine so far but I would like to take the next step to improving my knives.

I have a fly cutter and a few bits of HSS but have no idea on how to grind the cutter tool. Can some one please step me through the process of grinding one?

Thanks in advance
Alistair
 
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Rusty McDonald

KNIFE MAKER
Grind a quarter round with the flat side up be sure to grind some off of the back side off so it won't hit on the way around
 

Bruce Bump

Forum Owner-Moderator
Hello Alistair,
I grind mine in after heat treatment with a 4" stone that has about a 45 degree bevel. I use the surface grinder and glue the blade down but you could clamp yours to a steel plate in your vice and adapt the stone to your milling machine.

The problem with a flycutter is you have to put the nail nick in before heat treatment and it may not be in the ideal place after the blade is finished. If you grind it in you can place it exactly where you want it.
 
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Cubane

Well-Known Member
Grind a quarter round with the flat side up be sure to grind some off of the back side off so it won't hit on the way around

Rusty, Not sure what you mean by the quarter round?

Bruce, I generally leave my liners oversize so I can adjust the amount the blade sticks out above after HT and I have it completely together for the first time. That said the pattern I have been using for my linerless ones is working really well and the nick has been in the same spot every time.

Alistair
 

Rusty McDonald

KNIFE MAKER
This is how I do it. I cut out my pattern, I set the spring and blade. then grind the side that the nick will be in to about 70% complete with out grinding the other side clamp it to a jig I have for making nail nicks. I cut my nicks in reverse on my mill but you can do it any direction you want just go slow and keep it clean.
 

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Cubane

Well-Known Member
They seems pretty clear.. just grind the curve and make sure it tapers up to the cutting face then grind a bevel on the top with the same kind of taper. I had better figure out which side to remove more from.. my mill isn't reversible.

What sort of finish do you take the ground of bits to? is there any other secondary bevel involved? or if I just grind those two corners it will all be good? Does the amount of taper matter?

Thanks,
Alistair
 

Rusty McDonald

KNIFE MAKER
I just grind it on a 220g belt on my KMG it's hardened steel so the finish is pretty clean, just dont get it too hot grind and cool it off. as for the angle/taper I just eye balled it. all depends on how big you want the cut to be. I have 2 one for big nicks one for smaller nicks
 

Nathan The Machinist

Well-Known Member
This is how I do it. I cut out my pattern, I set the spring and blade. then grind the side that the nick will be in to about 70% complete with out grinding the other side clamp it to a jig I have for making nail nicks. I cut my nicks in reverse on my mill but you can do it any direction you want just go slow and keep it clean.


You will get better results if you have less of the cutter protruding from the flycutter. Preferably no more than 1/2". That may mean needing a larger flycutter body. Also, use the largest lathe bit you can. Long and skinny = bad. Short and fat = good.
 

Cubane

Well-Known Member
I just grind it on a 220g belt on my KMG it's hardened steel so the finish is pretty clean, just dont get it too hot grind and cool it off. as for the angle/taper I just eye balled it. all depends on how big you want the cut to be. I have 2 one for big nicks one for smaller nicks

That's for that I will give it a go next time I get into the shed.

You will get better results if you have less of the cutter protruding from the flycutter. Preferably no more than 1/2". That may mean needing a larger flycutter body. Also, use the largest lathe bit you can. Long and skinny = bad. Short and fat = good.

That makes sense. The biggest flycutter body I have 1 1/2 inches so I will see how wide a nail nick that gives me. Otherwise it will be off to buy another one.

Alistair
 

Cubane

Well-Known Member
Well I had the chance to grind the fly cutter bit this morning and that was seriously so easy I don't know what I was so worried about. If anyone out there with a mini mill and is making slip joints still with nail nicks from a dremel then they are crazy.

I still need to do some more experimentation with the shape and width and depth but here is the first one I did on a scrap bit of steel

nailnick.jpg


Thanks everyone for your help.

Alistair
 

John T Wylie Jr.

Rockstar and ACE vBulletin troubleshooter
I still need to pick up a fly cutter for my mini mill , and the reason I got the mini mill is just for slip joints :)
 

Cubane

Well-Known Member
I still need to pick up a fly cutter for my mini mill , and the reason I got the mini mill is just for slip joints :)

That was the same with me. It has been so worth it in terms of taking my knives up to the next level. Now go get yourself a fly cutter. They are less then $50 here including the HSS cutter steel so I can't imagine how cheap you can get them in the US

Alistair
 
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