Sharpening & convexing a FBM LE

B

bm11

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Nov 28, 2011
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Just picked up a FBM LE, used but in nice shape. The edge is sharp, but not quite as polished and "air bleeding" sharp as I like. I tried to get it into my Wicked Edge, but the .320" flat grind blade was just too thick for it.

So next idea is to convex it. Do I need to buy a 1x42 belt sander, or can a 10" blade be convexed on a mousepad?

How do you sharpen your really big blades?

Thanks,

-Bob
 
I would get a belt sander or some other powered sharpening system. I think you'll be happier with the investment in the long run. Just my 2 cents.
 
i sharpen all my large blades by hand. Its a little more difficult but not too bad. I just did my NMFBM and it did just fine. I use a piece of balsa wood and I adhere a piece of linoleum to it with glue. (found at art stores and used for carving out the negative part of a stamp) The linoleum has enough give for a good convex edge but is not near as soft as a mousepad. I find it to work much better. I use sandpapers in grits 320 to 400 - 600 - 800 - 1000 - 1500 - 2000. I then use I then use honing pastes that are 6 microns in size then one thats 3 microns in size. After those I use diamond sprays in 1 micron, .5 micron, and .25 micron sizes. For the pastes and diamond sprays I have cowhide glued to a piece of balsa on one side and on the other side I have craft foam for a really soft "mousepad" feel. You can easily stop at 1 micron diamond for a mirror edge, but I'm a little anal about sharpening. Also, and easier solution is after the sandpapers you can just strop on a belt loaded with a hone spray/paste of your liking. Goodwill has real leather belts for cheap. Hope that helps!

(linoleum, foam, balsa)
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(linoleum, leather, foam)
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I have perfect results with the Work Sharp and Harbor Freight 1x30. The Work sharp is nice to set the angle and easier to master,you just need to be careful not to round the tips. The 1x30 is great,once you get the hang of it, it will produce professional results. Either way, every knife you own will be popping hair.

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I would have to agree with the belt sander as well, they're really not NEARLY as terrifying or dangerous to your blades as they're made out to be, so long as you're careful. Heat has never been an issue for me, in fact most of my mistakes came at first from being much too worried about building up heat. Doing the tips is the trickiest part, you have to make sure the edge never goes beyond half of the belt, or the belt will flex over the tip and destroy it. Otherwise, belt sanders really are one of the quickest ways to get polished convex edges.
 
Thanks guys, maybe I'll make the investment. If I got the belt setup, I could get some leather stropping belts too and really speed up the polishing process.
 
I might need to invest in one of those belt sanders. What do they run? How about the belts? aaand what grit belts can you buy?
 
I think I got that 1x30 on sale for under $40 bucks, it is an entry level cheepo but works great. There are many places on line to buy the belts. I have 80 through 1200grit and every thing in between. Also a 3000 and leather strop. I am not crazy about the leather I have better results by hand, though many will swear by them. Do a search on this forum as there is a lot of in depth information on belts and technique.
 
Christo, those Harbor Freight 1x30 belt sanders can be found south of the $40 mark as noted by FTR-14c, if you watch for their sales and discount coupons. HF stocks various grit belts for them, as do the following three vendors, among others.
Klingspor:
http://www.woodworkingshop.com/search.aspx?q=1x30+belt
Grainger:
http://www.grainger.com/Grainger/wwg/start.shtml (I find their site Search function sux, YMMV)
IA:
http://www.industrialabrasives.com

As a follow-up to polish edges, I use a Harbor Freight el-cheapo buffer with a hard-sewn muslin wheel charged with white rouge.
Buffer: http://www.harborfreight.com/6-inch-buffer-94393.html
(comes with 2 muslin wheels -- 1 hard sewn, 1 soft unsewn)

White rouge can be found all over like at hardware stores, Grainger, metalworking suppliers, etc.
 
I bought a kalamazoo. It was expensive but works great, and is easy to use (after a few hours of practice on cheap knives). And you can buy the belts from Lee Valley. I just put a mirrored-convex on my rodent rucki, taking it from 40-2000, and then some leather :)
 
I did an FBMLE by hand once. Took me a long time. The results were worth it.

I have a 1x30 belt sander that I have used with good results also.

If you can buy the nicer calamazoo or other sander it will be worth it, but I've been using the 1x30 for about 4 or so years.

Get the disk combo, and you have a handy little tool.
 
I use a Kalamazoo, after using the Harbor freight one for a couple of years.
WARNING: sharp learning curve ahead! Practice on cheap knives first! There is nothing wrong with using the manual method first, and the belt sander later.
 
Thanks for the advice guys. Tom- did you convex the HHFSH I bought from you on your belt sander?
 
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