Strip and Convex my FFBM

B

blue_drummer

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Apr 9, 2010
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I have an unused FFBM and want to know peoples opinions on Convexing a blade.

I am sure this has already been covered but I just want to make sure I am not going to regret a decision I have made.

Is Full Flat grind with a zero edge the same as a Convexed blade. If not what exactly is the difference? Which is better? Would either cause the FFBM to no longer be a heavyweight chopper?

Thank you for your opinions. Knowledge is power.

Andy
 
There is no right answer. The debate continues. Both sides have shaving sharp edges, and the FFBM will be a monster chopper with any good sharp edge.
 
Fully convexing a FFBM is difficult to do unless you have a grinder, I've done it by hand and managed to "half" convex it. There's a lot of INFI on a FFBM.
 
I thought all of the FBM's were convex or is it just the nuclear melt down? A convex is better because it puts more steel behind the edge of the blade which makes for a much better chopper. Also a good convex literally shoots out chunks of wood instead of biting in.
Here's a diagram that makes it very clear just why a convex(full or edge) is much tougher than any other grind. http://backyardbushman.com/?page_id=25
Best,
Gabriel.
 
blue_drummer said:
I have an unused FFBM and want to know peoples opinions on Convexing a blade.

I am sure this has already been covered but I just want to make sure I am not going to regret a decision I have made.

Is Full Flat grind with a zero edge the same as a Convexed blade. If not what exactly is the difference? Which is better? Would either cause the FFBM to no longer be a heavyweight chopper?

Thank you for your opinions. Knowledge is power.

Andy
Click to expand...

You won't do it by hand, just way too much steel in that sabre grind blade, you would need a belt grinder and a lot of belts and time.

You could do just the edge by hand, but it will take awhile.

Personally I like my FFBM just the way it is. :thumbup:
 
I would use it first.
once it gets to the point where it needs
an edge,then I would think about convexing it.
This way you will have something to compare the new edge to.
 
Convex has more edge behind the edge and will be more durable over time. Still, nothing wrong with the V edge as it will also hold a edge for a very long time (its INFI, afterall!). ;)

With the .30 or thicker FFBM, you might consider shipping it off to someone who specializes in such things and has the proper equipment. Otherwise, it will take a bit of time... and bear in mind that there is a bit of a learning curve to such things.

Either way... good luck! Post pics of the result... :)
 
You're not going to fully convex an FFBM without a belt grinder, taking down the saber grind to convex will take forever, I can't imagine the mental fortitude and patience it would take to sit there knocking down the grind on some paper.

To put things into perspective, it took me quite some time to grind a saber FFBM into a convex FFBM, and more than a couple 40 grit belts.

What I would do? Strip the coating, touch up the finish a little bit, leave the dimples and convex the edge and blend it a little bit.
 
I would advise convexing the edge first.

I convexed the edge on my FBMLE by hand. Took a while, and I had some sore shoulders after a while (you need to keep the weight light on the edge so you don't let the sand paper wrap the edge and actually dull it).

If you are going to do the process by hand, the best process is to take diamond stones (large ones preferably), and break the shoulder by hand. Extra course diamond stone, and remove a lot of the shoulder bevel by hand, then finish up with the sand paper.

I did not do this step, and my edge is nice and sharp, it took way longer than it would have with extra coarse stones though.

Blade forums has had some decent tutorials on doing this by hand.

Of course, if you have a belt sander it takes way less time to do with a slack belt, but you can screw up your knife lickity split with power tools, both removing too much metal, rounding the tip, and most importantly the heat treat if you get it too hot.

Read a lot, then try it out on some cheaper knives first. I convexed one folder before starting on my SS, then moving on to my Ash1 and finally my FBMLE. All done by hand. I had a belt sander with a slack belt, and had actually done it on several non infi knives, but chose to do a hand convexing to be careful, and not mess with the warranty.
 
Heres my FFBM stripped half satin and then the last 2 are pics of it fully convexed. It takes some patience and belt sander to make it convexed.

IMG_4326.jpg

IMG_4323.jpg

IMG_4309.jpg
 
Norcalblacktail, nice work :thumbup:
I want to use my FFBM a lot more before I strip it and do a lot of sanding, I hope it turns out half as nice as yours did. I'll be doing it b hand so it'll take some time, patience, and a lot of sand paper.
 
and the ankle bone connected
to the leg bone.
and the leg bone connected
to the knee bone,
:D
 
Unless you filed the edge flat the FFBM will always be a monster chopper. Even dull it would destroy all in its path.
 
Thank you for all the info.

Does anybody know if the warranty is still good if you strip and change the blade shape?
 
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