Curved plunge

which grinding method ?? full flat would be easiest.. grind everything then add the swoop maybe using a carbide file guide.
after the main grind is done hang the belt over the edge round the corner a bit then hang more belt off the edge.
again use a file guide to prevent going too far.. remember you are going to only use the very edge of the belt to get the swoop
so be very careful there... as you break the corner and move more belt onto the corner you only need to be careful in how high it climb sup the blade..
 
I did these with an angle grinder

uc

uc

uc
 
Last edited:
Richard338 said:
I think you could better understand the geometry if you had an example on hand and could lay a ruler on the bevel etc.
The shape you want is generally achieved with a flat platen. I think seeing the projection of the plunge you want as curved and thinking about a disc is wrong. You don't want a curved plunge with straight walls.
The curve arises from how quickly the top of the plunge approaches the spine. If it is abrupt, then you get a square plunge. More slowly creates the curve.
Click to expand...
Richard , I think that I understand geometry .What you describe would happen only if I keep blade steady on disk while I grind that part. I will move blade across disk as I grind on flat platen while I work on that part to get that nice small curve .......
I don't know, I am more and more convinced that this is the only way for me to do it right . Only problem I see is that motors I have do not have reverse ...........I will need to flip motor up side down and put work rest again from that side 🤣
 
Natlek said:
Richard , I think that I understand geometry .What you describe would happen only if I keep blade steady on disk while I grind that part. I will move blade across disk as I grind on flat platen while I work on that part to get that nice small curve .......
I don't know, I am more and more convinced that this is the only way for me to do it right . Only problem I see is that motors I have do not have reverse ...........I will need to flip motor up side down and put work rest again from that side 🤣
Click to expand...
Ha, see now even with the disc you need to finesse it a little. We're going to drag you kicking and screaming into freehand grinding! I want you to suffer the same stress and mistakes that I do.
 
Richard338 said:
Ha, see now even with the disc you need to finesse it a little. We're going to drag you kicking and screaming into freehand grinding! I want you to suffer the same stress and mistakes that I do.
Click to expand...
🤣
I was there , don t worry ......... :) prefect grind on left side and then disaster on right side, again and again .... I give up long time ago , I can t do that .I will make if I need ten jig and seven work rest for one curved plunge .At least I enjoy while I make tools 🤣
 
I am already half away with disk 🤣
XR5l8pZ.jpg

1nZaP10.jpg

And I forget that already I have motor prefect for this task .......I use it to sharpen tungsten carbide drills and that diamond disk is removable :)

8zUcRaN.jpg
 
When I hear the words "jig" and see specific wheel measurements being translated to blade geometries, I get the intention that you are looking for a setup that minimizes human error (i.e. need for skill). I get that. Unfortunately, that thought + inexpensive doesn't usually go together well. Many of us rely on trial & error combined with upping our craftsmanship (hopefully!) in time to get these complex geometries that look great. Your targeted grind is accomplished in many ways...need to find the one that matches up with your skills, and budget.

By the way, know why you want this cool look? Because it's hard to do by hand! :cool:
 
Natlek ok im going to "Share" a great "Secret" with you .. Clamp the blade to a table/workbench and use a "Right Angle" ?welders grinder to grind the blade..
after using the coarse disc to remove most of what you want gone.. change to a "Flap Disc" to clean it all up and blend in your radius cuts..
from there you can use metal "Scotch Brite" type of discs to make it perty.. i can grind any size with one of these... they have 3/4 1/2 inch wheels as well as a7 or 9 inch disc..
just watch out so you don't take a finger off or something.. this can get Dangerous real fast !! i know you are in Maldova so the US Safety standards do not apply ..
Please be care full...
 
Madness , if someone had told me last year that I would do this . . . . . 🤣

oCLSiF9.jpg

UbM58KH.jpg

qJXVDS2.jpg

pW7ovJe.jpg

3KuaFxl.jpg

GqpyiMN.jpg

I chose a 6500 RPM motor with 9mm shaft
NsRV4Eb.jpg

kjuKIRs.jpg


Now I need to make * clever work rest * 🤣 It depends on work rest whether I will do this properly or no :)
 
Backyard said:
I built something very much like this. Based on the file guide but made to hold angle grinder. Positioned at the right length and for the sweep of the blade it makes those plunge lines that you want

IMG_0670.jpg
Click to expand...
Little more user friendly .................

x5w3HHK.jpg
 
Thesian said:
When I hear the words "jig" and see specific wheel measurements being translated to blade geometries, I get the intention that you are looking for a setup that minimizes human error (i.e. need for skill). I get that. Unfortunately, that thought + inexpensive doesn't usually go together well. Many of us rely on trial & error combined with upping our craftsmanship (hopefully!) in time to get these complex geometries that look great. Your targeted grind is accomplished in many ways...need to find the one that matches up with your skills, and budget.

By the way, know why you want this cool look? Because it's hard to do by hand! :cool:
Click to expand...
Why you need to make knives for living ? All you need is to RUN faster then Usain Bolt . It is simple skill to develop , you just need to move your legs faster then Bolt :) I tried it , but no matter how hard I tried, I didn't get anywhere near his time, so I give up and learn to fix cars and fast bikes , easy skill to learn for me 🤣
The fact that I theoretically know what I need to do with hands to get that curve does not mean that I can implement it in practice.
Of course, I'm looking for a way to minimize human error . I am human not CNC and human make mistakes .I can drill straight hole with hand held drill BUT I use drill press ;)
BTW , this summer I intend to make contact wheel for grinding perfect convex bevels :)
Speaking of skills ......I can repeat this grinds with jig hundreds time without error. Finish is from 40 grit ceramic belt .I have belts only in 40 grit ceramic so I developed some skills to get better finish from them :cool: can anyone do this free hand ?

4LyvhgU.jpg
 
Last edited:
Natlek said:
Why you need to make knives for living ? All you need is to RUN faster then Usain Bolt . It is simple skill to develop , you just need to move your legs faster then Bolt :) I tried it , but no matter how hard I tried, I didn't get anywhere near his time, so I give up and learn to fix cars and fast bikes , easy skill to learn for me 🤣
The fact that I theoretically know what I need to do with hands to get that curve does not mean that I can implement it in practice.
Of course, I'm looking for a way to minimize human error . I am human not CNC and human make mistakes .I can drill straight hole with hand held drill BUT I use drill press ;)
BTW , this summer I intend to make contact wheel for grinding perfect convex bevels :)
Speaking of skills ......I can repeat this grinds with jig hundreds time without error. Finish is from 40 grit ceramic belt .I have belts only in 40 grit ceramic so I developed some skills to get better finish from them :cool: can anyone do this free hand ?

4LyvhgU.jpg
Click to expand...
Nice looking grinds. Perhaps my point was not clear. I simply meant that the reason this is appealing is due to the difficulty in producing it. Of course any jig or machine reduces some human error.

By the way, if I made knives for a living, I would be very hungry and cold. 😊

Good luck in your trials! You are obviously creative and determined. That is a great combo.
 
Thesian said:
Nice looking grinds. Perhaps my point was not clear. I simply meant that the reason this is appealing is due to the difficulty in producing it. Of course any jig or machine reduces some human error.

By the way, if I made knives for a living, I would be very hungry and cold. 😊

Good luck in your trials! You are obviously creative and determined. That is a great combo.
Click to expand...
It s OK my friend ,I get your point in previous post :thumbsup: Since we all cannot be Usain Bolt ....... we invented bikes and small disc grinders of course 🤣
Broken blank on pictures is mild steel , I shape it and grind hollow bevels for practice before I make two knives in real steel .I cut it to see bevels shape ......
Now ..........................lets fun begin :cool:


finishing disk

ugWfU88.jpg

qwKRhkf.jpg

cmPd7ow.jpg


for real steel I will use 40 grit zirconia
AcT5zWY.jpg

uqNq6WP.jpg

2nmr8LB.jpg

RFPPktF.jpg

I will make real machine with more disks in different Dia. ! I will use this jukebox just for that one knife
Now all I need to worry is to make plunges symmetrical 😍

n2NCayA.jpg


BTW one is 20 years older, guess which one :rolleyes:
 
Last edited:
You must log in or register to reply here.
Back
Top