Flat grinding on horiz contact wheel

W

Wapiti

Joined
Sep 25, 1999
Messages
500
Robert's recent posting of Mad Dog's shop tour reminded me of a question I had the first time I toured this site.
What do folks think of his way of grinding his bevels? Ever since I saw my first kinfe by Kevin, I liked the idea of a more gradual transition of the plunge and felt it would make a stronger knife (few chances of stress risers, etc.) and I just kind of like the look of the gradual plunge leading into the blade.
What do you think of this kind of plunge cut?
Has anyone else tried to grind a blade this way? I would think it would be very hard to grind on a horizontal contact wheel, but maybe not much harder than a hollow grind.
How would you get this kind of plunge when grinding on a regular platen, just go slow?
I know many people have personal opinions about Kevin, but maybe we can keep this discussion to technique and knives...maybe...
Thanks,
Brome
 
i grind some of my blades that way. it is a great way to get a distal taper on thick stock. and the way i grind kris or flame daggers.
 
99.9% of my flat and convex grinds are done on a
vertical contact wheel. Me and platens don't get along
very good and I find that this way works best in my
shop. Gib
 
same as working on the bottom of a vertical wheel. he just did this tour, its no more than say 20 threads down.
 
So how do you keep from getting dips in the blade as you grind it?
Do you just move the blade back and forth (if the contact wheel is horizontal), or in and out if the contact wheel is vertical, very quickly? I am really interested in trying this, but unsure about how to do it. I usually grind on the platen, but like the idea of a more gradual plunge.
Brome
 
I use a 10 inch diameter wheel on my Bader. The larger diameter helps keep the wheel from digging in as compaired to an 8 inch or 4 inch. Learned about this many years back at the ABS school.

Most of my grinding is done over flat platten. I took the original Bader platten (angle iron with one edge almost square and other edge very rounded)and welded up the two sides. One bead on the more square side and 3 or 4 beads on the rounded side. Then I used a friend's mill to cut my platten square and true while maintaing the 2.000 inch width. I am most happy with my platten.
 
keep the blade moving back and forth with a even pressure. start on some cheap steel to get a feel for it.
 
I am speculating, but if you're used to flat grinding on the platen, perhaps you should start the blade normally and finish by grinding along the wheel. Your initial plunge cuts shouldn't be hard to eliminate as long as you start them closer to the tip than normal.
 
I start with a FLAT forging, use a SHARP belt and even,
steady movement the full length of the blade using the
same pressure the whole way. Always have the blade
moving when it touches the wheel and you start to
remove metal. To put a taper on a blade start part way
down with light pressure then increase pressure as you
go. I don't know if this is clear but there is a lot
of feel in this method, practice, practice, practice.
I hope this helps. Gib
 
Thanks for the techniques.
Sound like any other grinding; practice, practice, practice.
Slow and steady...
Brett, prior to your post, I was actually thinking of trying to start with the wheel, just to get that gradual plunge, (maybe just doing the plunge on the wheel...) then going to the platen to smooth it up. Guess I will have to just give a try and see what works for me, or even if I like it at all.
Thanks,
Brome
 
I've had to repair a few plunge cuts. I used an idea from the Loveless book.

Take a round chainsaw sharpening file. Clamp to something, like a piece of angle iron and grind down a flat edge. Go about 1/3 of the way. The resulting cross-section looks like a letter D. Kinda.

Now place the flat part of the file on the bevel (perpendicular to the spine) and file a new plunge line. This creates a soft transition to the ricasso. Very easy to match sides.

For sanding it out I ran the belt over the edge of the platen and as I worked the belts on the bevel I let it float over the plunge cuts.

Just a thought.

Steve
 
I have had thoughts of this too, but only using the platen
like robs rotary platen, running it parallel to the surface.
like to say, if it's set up vertical grind vertical. who does it this way?:confused:
 
You must log in or register to reply here.
Back
Top