Convex Convert

R

RobertHankins

Joined
Jun 10, 2001
Messages
1,385
Rapidly becoming a Convex grind Convert...
Over the past 4 or 5 blades, I have been working on my Convex grind technique (Read that I screwed up three of them) and it's begining to grow on me.

Flat grinds are still my mainstay however I am finding the Convex to be a close second. Best thing when you mess up is that it becomes your next test blade. Convex grind is proving to be very strong and capable of taking a Razor sharp edge.

Well I guess I will be saving my pennies to get Rob Frink KMG1 with a Convex grinding attachment...
 
Robert, I have a Rob frink "Rotary Platen" for my Burr-King. I just got it the other day and have only played on it for a hour or so. I can see already that it is going to work really nice for a fine almost flat convex grind. There are two tensions which will give two different radious for big or small blades. It should work beutiful for finish work on blosters too. I like the way it puts a satin finish on without the bump bump on the steel platen too.
 
I've been doing the same thing Robert. I'm not quite sold yet on it being a close second but I admit it has it's place. I have two swords almost finished now, both with a convex blade. I like the look but still don't get the hair popping edge of a full flat grind. It does tend to hold an edge longer and produce a stronger edge.
 
peter you may not get the hair popping edge but you do get the dismembering and meat seperating edge that you can cut curcles with. i just got my rotary hardcore platen from rob and only had a hour or so to use it. but i can tell already that this will take my convex hunters and fighters to a new level.
 
I have found the convex grind to be the most exciting to work with. There are no limits, the more you learn about its potential, the more gates open for future excursions in to the science of cut. I am very pleased to see your comments.
 
Love convex for fighting class and full flat for most utility. Can make both pop hairs.
 
Hi,
You probably should consider hot melt gluing or center tap a few small screws into the bolts to hold a light guard plate to keep fingers out.
I used a license plate for mine. I doubt a finger will survive the trip through the pulley. Note I said pulley and not pullies because it won't be yours after the first one.
Other than that, I love it...Ken
 
Robert I'm glad to hear your experience. I've just ordered Rob's rotary platen for my BIII and expect to be trying convex grinding within the month. I'm going to be working on a Scagel-influenced knife next, which I think should be convex ground (anyone know for sure?). It'll be my first try. Thanks for all the info folks!

Dave
 
Every Scagel blade I have examined was convex grind. He did it the hard way, on round wheels that he made up the old way, glue and grit. When Bill Moran taught me the convex grind he ground on round wheels with the edge down. Belts now provide an easier way to complete the convex grind, when you look at the old convex blades, you have a new appreciation for the skill the past masters had developed.
 
WERE YOU SPRIT OF ADVENTURE? i already dod the once around the pulley on rob rotary. left a bunch of lines on my index finger and its a little stiff this morning. some times i press from the rear of the belt to get out a deep stratch. i my not do this in the future:eek:
 
All my knives are convex ground these days. I used to do hollow and flat, but convex gives me the performance I want.

I grind on a Pro Cut II grinder and most of my work is done in the slack area between the flat platen and the contact wheel. I have a hard oak board mounted on the platen with the bottom end rounded over. It creates extra tension on the belt at this point and I can adjust the geometry of my convex grinds right at this point.

I start with bevels forged in the blade and then clean up my flat areas and grind lengthwise and crosswise on the contact wheel to take alot of meat of the blade before I start the convex. Then I start the shoulders roughly on the face of the contact wheel, like I was hollow grinding upside down. Once I am satisfied with the amt. of material I have removed, I go to a 36 grit belt to start my convex, then to an 80, 220, and a 400 before HT....leaving it still a bit thick for the final water cooled, bare hand grind after HT.

I really like the Frink idea of the other roller, and I have been thinking about such an arrangement on my ProCut rather than the oak board.
 
You must log in or register to reply here.
Back
Top