Doing most of the work with low grit belts?

Patrice Lemée

Patrice Lemée

Joined
Aug 13, 2002
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5,703
This week I had the hardest time working on the distal taper of a knife, doing it with a 220 belt, post HT. In chat, Mike Quesenberry said that he did most shaping with 60 grit belts. Can't remember the % sorry, but it was very high. I was scared to do too much with low grit belts but maybe this is a mistake. You've all seen Mike's knives, he doesn't make crowbars. To the contrary, he makes some of the finest and most elegant knives you will ever see. (Can you tell I am a big fan? ;))

So to help newbies or even more experienced newbies like me :o, let's hear what % of work you do with low grit belts.

Thanks

Pat
 
I do most of my work with 50 grit, I then go to 120, 220 and 320 just to take the heavy scratches out. I use to go higher but I don't like what the finer grits do to the blade because they have a light backing. I use this method also on blades that are ground post heat treat, I find the coarse grits don't heat up as fast as finer grits, so less likely to over heat a blade that has been heat treated.
 
I do most of the work with a 60 and use a 120 to clean up those scratches and a 220 to clean up the 120 scratches. I don't even try to match up the plunge lines until I get to the 220 belt. HT after that and clean up the HT scale with a 220 and then hand sand.
 
Thats a great question Pat !

It took a LONG time and lots of belts experimenting but I've finally settled in with a process that works for me. Still subject to change of course when Nick shows me the error of my ways :) :)

I'll grind roughly 75% pre HT.

I'll grind it right to where I want it with a used 50x blaze then refine the scratches at 80x then 220x. Then hand sand the entire perimeter of the blade at 220x so the scratches run in line with the spine and edge not across it.

Post HT.

I'll get back to completely clean steel with a used 50x Blaze and get to maybe 80% ground.

Depending on the shape of my 50x I'll either finish or get a new one and grind to roughly 95% BUT staying out of my plunge with the 50x just a little. I get my edge right to finished thickness with the 50x

After the 50x I go to a BRAND NEW 80x J-Flex. I'm hardly moving my grinds at all with the 80x. A little towards the spine and move the plunge back just a tiny bit to true it up. Sometimes, especially with larger blades, I find I need to grab another new 80x for the other side of the blade. I want a sharp 80x that CUTS and try my best to finish with a perfect pass from the plunge to the tip and flat from edge to spine.

I've found that for me the condition of my grinds at 80x determine the difficulty for finishing the blade the rest of the way. I won't move on until I'm golden at 80x.

I go from 80x right to a BRAND NEW 220x J-Flex- If I was truly good at 80x it only takes a couple passes on the 220 to refine the scratches.

-I never could find love for a 120x belt. I tried them a few times but just found them not necessary to go from 80x to 220x. I see so many others use the 120's I've been thinking about giving them another shot even though this method works pretty well for me.

After the 220x I'll throw a sheet of 320x on the disc grinder and make sure my flats are flat and save myself a little time hand sanding.

Start hand sanding at 320x and go from there to desired finish.

I didn't always do it this way. I used to do alot more grinding at 80x. As your grinding confidence and skill improve you can go further with a rougher belt. The fear of a late stage whoop-de-do with a rough belt has subsided these days so I go for it without worry at 50x.

Hope this helps Buddy !

Nick, Please don't pass on an oppertunity to show me the errors of my ways !!! I love advice and I'm willing to give anything a try.... at least once ;)

Have a great day fellas ! Josh
 
I do most of the work with a hammer, but any abrasive shaping is done with 60 or 80 grit then I use the finer belts to get to the bottom of the scratches left by the previous belt. After HT there isn't really shaping, just cleaning up scale and decarb

-Page
 
I do about 80% of my grind before HT with a 50 or 60 grit belt. Then I'll move to a 120 belt to get the deep scrathes out, and then 220. Depending on the blade, I'll then usually put a A65 gator belt on to get it really smooth, and then a 400 sheet on the disk to make sure everything is nice and flat. At this point I'm at about 99% of where I want to be. Blade is then off to HT. After HT, it's mainly scale removal and clean-up with a A65, then A45 then A30 gator belts. Then hand sanding from 400 to wherever I need it to be (1500 for satin, 2500 for polished finish before buffing).

I'm definitely still a newb, but this seems to work well for me. Like Josh, I'm always open to suggestions and trying things!
 
I'd say that my grinder is running 36-40-50 grit belts about 70-75% of the time. I probably go through more of these belts than other grits combined. All initial profiling, distal and tang tapering, and initial setting of bevels is done with these belts... followed by a quickt pre-HT clean-up to about 120-grit. Post HT I go back to SHARP 40-50 grit belts to take the bevels to where they need to be, then clean-up through the grits (80 ceramic {sometimes}, 120 gator {I don't use 120 ceramics anymore... they're just too bumpy at the splice}, and 220 gator. On hand sanded blades I may go as high as a 400 trizact on the machine, but usually will start hand sanding at 220. I'm kind of excited to get my new disc up and running... thinking about going from 220 belt to 220 disc before hand sanding.

Erin
 
I hog bevels with 36 or 60 depending how much metal I've got to remove, then clean up with a 100 or120 blaze.

I make less mistakes with a belt that is removing metal quickly. If I've got to make tons of passes with a finer belt eventually im going to make a bad one.

The next reason is economy. A 60 grit belt can probably remove 4 times as much metal as a 120 and costs nearly the same.
 
Patrice- Mike taught me everything he knows. Then I taught him everything I know. Then we had a 10 minute coffee break. 15 minutes after we started, we went back to work. ;) :D

Mike and I do a whole lot of things similarly because he and I are both always seeking the whole "super crisp and clean" thing, along with better profficiency. I used to buy a whole ton of belts, but Mike kept telling me how much work he was doing with his 9" disc. For years, I simply used my 9" disc for checking that my bevels were flat, in between belt grits, but not really for finishing blades.

I've always ground down pretty darn close to finish with a 50X belt, but I followed with 120, 220, 320, etc.

Anymore I grind even closer with the 50 or 60, hit the plunges with a 120X belt, and then go to the disc for taking all the scratches out from there.

I really have no idea what the % is ground with the coarse belt... so I'll just say, "a lot." :)
 
I rough out the profile and grind using the 60 grit, but also do some of the more detailed grinding on the 120 grit. At that point the knife is almost complete. Then I remove the deeper scratches and do some fine tuning using the 220 prior to HT. At this point the knife is done and goes for HT. If everthing turns out well from the HT its simply a matter of removing any scale and putting a finish on the blade prior to doing handles. Sometimes I get some warpage and then if I cannot fully straighten things out, then I have to grind and fine tune the blade further. That usually means going back to a fresh 120 and repeating the finer grits to remove any other flaws.
 
I switched to doing probably 75% of my bevel work with a 36 grit Blaze. I used to use a 60 grit for that, but decided I would try something a little faster, and low and behold, it worked like a charm. It won't get you a super true flat, but it will get the metal off in a hurry and allow you to step up to a 60 grit belt to even things out. I've been trying to use the disc more on the advice of Nick and a few others, but I need to get some better paper. The stuff I have just smears the steel after the initial cut shears the grit.

--nathan
 
It depends what kind of knife I'm making. There is a difference between field and kitchen knives. My field and chore knives get ground with 50 Blaze, 220 Gator before HT, and post HT cleanup with 220 and then 400 Gator before hand sanding. Knives with conventional plunges get 220 Jflex after bevels are at 90%, knives with swept plunge go from 97% or so at 50 Blaze up to just a little cleanup with 220 gator, then HT.

Kitchen knives get roughed in with 36 or 50 Blaze until the grind is about 80%. The spine will be finished thickness, and the edge will need another 20-30 thou off after HT.

After HT if there is any warp left it gets ground out, I take the edge down to finish size with 50, then 120 Blaze, refine with 220 Gator, then hand sand.

I've been playing with my belt selection for kitchen knives since I do more grinding post HT. I find the 120 Blaze to be a good belt to finish grind hardened steel with. Then the 220 gator has a lot less work to do, I find that they suck for hardened steel.

That's just my trajectory as of now.
 
Wow! I always amazed how much knifemakers are generous in sharing their knowhow. Some good stuff here. Thanks! :thumbup:
 
Does anyone else notice gator belts work much better at higher speeds . How do you tell when your 36 or 50 grit Blaze belts are to worn?
 
Duffy if you run your hand over them, regardless of how gritty they look and they don't "feel" sharp like sand paper, they're not cutting. It doesn't mean they're dead, blaze belts have a bad problem with glazing imho at hand pressures. Running a single point diamond dresser across them lightly while the belt is running will help to expose fresh abrasive.
 
I'm not in the same league as most of the folks who've answered, but...
I do the vast majority, probably 75-90% of my metal removal with 36 grit. From there it's generally 60, 120, 220.... That was the progression with my old grinder. With the new one I haven't gotten any 36 grit belts yet, they're in the mail, but I did a few blades with the 50 grit replacing it. MUCH slower and wore out the belt with less work done, but I skipped straight to 80 grit and barely touched with the 120 before moving on to 220. Which way's better for me? I don't know, that's one of the things I'm trying out with the new machine. In the past I'd get it in the ballpark with the 36 but not worry about it being perfectly even, just don't get so close to the final shape that it's tough to line it up with the 60 grit. With the ones I used the 50 grit on as my starting belt I took things much closer because it was much less of a ragged scratch pattern and the scratches were that much shallower so I had less to remove to clean them up as I worked down the grits. I think I'm likely to start using both methods, starting at 50 (or 60, depending on belt product line) for the thinner stuff and 36 for the thicker stock and doing initial profiling. The 50 grit could go direct to 120 grit if I wanted to take a little more time there, but I'll probably still hit it with the 80. It requires keeping a few extra belts on hand, but it's not like I'll be wearing out those intermediate grits very quickly.

I do almost all grinding pre-heat treat, just cleanup/decarb and then going to the desired finish grit. I usually start with 120 or 180 for cleanup and decarb but haven't tested with the new grinder and belts yet so I'm not sure what I'll wind up choosing.

The 50 and 80's I've been playing with are cubitron 967 belts. I got 5 small to mid sized knives out of one 50 grit but I probably should have stopped at 3, it was starting to run significantly hotter. That includes using it to clean up profiles though. I profiled another one but since I hadn't even finished the bevel work on the 5th due to belt wear I decided to stop there. This is on aldo's 1084, mostly 1/8". I'll probably plan on 2 blades beveled then use it for profiling for a few more, so I'll have one fresh and one old in use for each blade.
 
Duffy, like javand, I usually run the back of my hand over the belt. It really helps is the belt is running at the same speed you grind with. If the 36 grit belt cuts straight to the bone of my MCP joint in less than 1/2 a second, I consider it still sharp. If it takes a full second or more to reach bone, it's time for a new belt. For some reason, I'm only able to make about 10 knives before taking a 4-5 month break. ;)

On a serious note, if they don't feel sharp, a dresser works well to break up the glaze a bit as javand suggested. I don't have a diamond point dresser, so I use one of those star-wheel dressers with firm pressure.

--nathan
 
The 36 grit Blaze belts scared me a bit at first, so I used the 40 and 50 grit for a while. I have gone back to 36's now, but I will tell you that for follow up grinding, the 80 and 120 Blaze belts are some great stuff!!! Having that thick backing at 120 grit really allows you to get some hard work done that you can't do with thin backing AO belts..........that is, unless you want to use a few of them.:D
 
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