Tips for belt finished knives?

Tenebr0s said:
Stacy, are there special safety concerns with flap disks, or are they pretty much the same as for buffing wheels in general? I.e. they can rip a blade out of your hands and throw it before you even know what happened. I won't lie, when I've used them over here in my teacher's workshop, I had a healthy fear of them.
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Here's how I do it. Yes they can rip a blade out of ur hands and u must pay attention and not be distracted. The spine may catch but u sense it and feel it and u have a chance to correct. https://vimeo.com/173563798



Sent from my iPhone using Tapatalk
 
Nathan the Machinist said:
Also, I think it helps speed things up if you can change the angle of the grind a little. This keeps grit from falling in a previous scratch making it deeper.
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This. It also helps previous scratches stand out against the finer scratches.
Past 220 I use a lot of 400 grit greaseless on a stiff concentric wheel, hard felt or a worn 400 grit cork belt (depending on the blade grind and shape). It cuts well, doesn't chatter and leaves an almost crocus like finish itself.
After that, cut & color on a sisal wheel and then pink stainless compound if you want a mirror finish.
 
I know this thread is older, but I'm just getting started out and I was researching using a flap wheel sander instead of hand rubbing. Is there any issue with using small flap wheels on the finer grits with a 1/8" arbor (dremel tool size), or 1/4" arbor (hand held drill size)? I was thinking 120 and possibly 320 on the grinder, then cleaning up with small flap wheels along the blade to give a similar look to a hand sanded blade. I was also thinking about using dremel tool buffing wheels for the plunge line.

Thanks guys,
Paul
 
Using small wheels on a Dremel or flex shaft isn't the best way.The wheels are too small and can leave a rippled finish.

When you are new, don't look for a short cut. Master hand sanding and then you will know what methods will help speed things up. Seems every new maker wants a jig or machine to do the work for them before they know what the work is.

Another thing is no belt or polishing wheel will remove scratches left behind from unfinished previous steps. The blade should be perfectly smooth and shaped before any mechanical polishing steps are taken.

I find a Scotch Brite medium belt saves me a lot of time, but I didn't start that way.
 
kuraki said:
I apologize if this has been covered, I did try searching a bit, but I don't think I'm using the correct terminology.

I'm wondering if anyone could give me some tips for how to avoid hand finishing blades. I know that one might never achieve the same level results with a blade finished on their grinder that they can with a backer and paper, but I've a lot of requests from potential customers for knives that they would rather not pay for my time hand rubbing.

I am having my best results with slack belt grinding, but would like to figure out how to get a reasonably good looking blade off my flat platen. My current process is to forge or cut the profile depending on the knife, rough it in with a 36 grit ceramic or zirc belt, step up to 60, 120 ceramics, then to trizacts, I start with A300, then A160, then A45 and last A30. That gives me a pretty good looking bevel, and I could always get one or two steps finer with the trizact, but there will sometimes be perceptible waves in my bevel, or scratches that just won't seem to come out (I actually think the finer trizacts are causing these either because I contaminated them somehow or they have a bit of bigger grit in them).

Right now the best method I have to finish a knife as efficiently as possible is to grind it, blast it and parkerize it, which I personally really like, but not all people do. The blast profile hides a lot of stuff that shows on a polished blade I'd never let out of my shop with my name on it.

I'm not trying to get rich. I like doing this, that's why I do it, but in order for me to do it the way I'd like, I need to sell a few knives for cash to reinvest into abrasives if nothing else. And my customer base is not paying $250+ for a knife. And I can't bring myself to charge someone $100 for a knife that looks like hell, even if I have 4 hours of time plus materials into it.

One issue I know I have is the lack of a VFD. I feel like if I had that speed control I could slow things down and spend more time per pass with everything lined up correctly without worrying about overheating. I plan to build a second grinder with a VFD, but are there any other tips?

Maybe I just suck and need more practice :D It's definitely part of the equation.
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I'm in the same situation. The hours I have in a knife vs the $$ I can get just isn't that great. 6-8 hours in hand sanding just seems like wasted time for the money.
So I'm rethinking the finish. Seems like the sweat spot is $220-$250. I can't produce a finely finished knife for that kind of money. So yeah, I'm reading this thread with interest.
 
The highest finish I can achieve off the grinder is norax or gator belts up to a16. Then a well broken in cork belt loaded with compound. I get what I'd call a satin finish, almost a very low mirror maybe?
 
Paul Dal said:
I know this thread is older, but I'm just getting started out and I was researching using a flap wheel sander instead of hand rubbing. Is there any issue with using small flap wheels on the finer grits with a 1/8" arbor (dremel tool size), or 1/4" arbor (hand held drill size)? I was thinking 120 and possibly 320 on the grinder, then cleaning up with small flap wheels along the blade to give a similar look to a hand sanded blade. I was also thinking about using dremel tool buffing wheels for the plunge line.

Thanks guys,
Paul
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I don't think the dremel flap will be very useful and give you what you want.
also I think you asked a general question which is fine, but others can assist you better if you can be more specific.
For example, what kind of steel are you working with? what style blade? kitchen, outdoor ....
what grit finish do you want your blade to finish at?

I think the devil is in the details :D

personally I favor a satin, scotchbrite level finish.
 
So, to give further info, I'm using 1084 and making mostly outdoor "use" knives with a 400 grit finish or so, not show-pieces (at least not yet). My initial thought was that if I were to use a flap wheel sander in the same plane as hand sanding it might cut some time. It makes sense to me that the small diameter of a dremel might leave an uneven finish, but to use a buffer with a larger flap wheel like mentioned earlier in this thread, I think I would want to install a variable speed control on it first.

I'll give up that idea for now, and use finer grit belts, then hand finish.

I had been told that the joint on a finer grit belt could create issues as it thumps past the blade. Does anyone have experience with that, and if so, at what grit does it become an issue?

Thanks
 
Paul Dal said:
So, to give further info, I'm using 1084 and making mostly outdoor "use" knives with a 400 grit finish or so, not show-pieces (at least not yet). My initial thought was that if I were to use a flap wheel sander in the same plane as hand sanding it might cut some time. It makes sense to me that the small diameter of a dremel might leave an uneven finish, but to use a buffer with a larger flap wheel like mentioned earlier in this thread, I think I would want to install a variable speed control on it first.

I'll give up that idea for now, and use finer grit belts, then hand finish.

I had been told that the joint on a finer grit belt could create issues as it thumps past the blade. Does anyone have experience with that, and if so, at what grit does it become an issue?

Thanks
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Belt thump is why I recommended norax or gator belts.
 
H
HSC /// said:
Here's how I do it. Yes they can rip a blade out of ur hands and u must pay attention and not be distracted. The spine may catch but u sense it and feel it and u have a chance to correct.



Sent from my iPhone using Tapatalk
Click to expand...
HSC, the link doesn’t seem to work for the flap sanding video, but I’d really like to see it. Would you be able to repost or elaborate? Thanks for the tips!
 
kuraki said:
I apologize if this has been covered, I did try searching a bit, but I don't think I'm using the correct terminology.

I'm wondering if anyone could give me some tips for how to avoid hand finishing blades. I know that one might never achieve the same level results with a blade finished on their grinder that they can with a backer and paper, but I've a lot of requests from potential customers for knives that they would rather not pay for my time hand rubbing.

I am having my best results with slack belt grinding, but would like to figure out how to get a reasonably good looking blade off my flat platen. My current process is to forge or cut the profile depending on the knife, rough it in with a 36 grit ceramic or zirc belt, step up to 60, 120 ceramics, then to trizacts, I start with A300, then A160, then A45 and last A30. That gives me a pretty good looking bevel, and I could always get one or two steps finer with the trizact, but there will sometimes be perceptible waves in my bevel, or scratches that just won't seem to come out (I actually think the finer trizacts are causing these either because I contaminated them somehow or they have a bit of bigger grit in them).

Right now the best method I have to finish a knife as efficiently as possible is to grind it, blast it and parkerize it, which I personally really like, but not all people do. The blast profile hides a lot of stuff that shows on a polished blade I'd never let out of my shop with my name on it.

I'm not trying to get rich. I like doing this, that's why I do it, but in order for me to do it the way I'd like, I need to sell a few knives for cash to reinvest into abrasives if nothing else. And my customer base is not paying $250+ for a knife. And I can't bring myself to charge someone $100 for a knife that looks like hell, even if I have 4 hours of time plus materials into it.

One issue I know I have is the lack of a VFD. I feel like if I had that speed control I could slow things down and spend more time per pass with everything lined up correctly without worrying about overheating. I plan to build a second grinder with a VFD, but are there any other tips?

Maybe I just suck and need more practice :D It's definitely part of the equation.
Click to expand...

Long ago I had 2 KMG grinders run on step pulleys. Years later I bought a tw-90 with variable speed. Honestly I have no clue how I lived without it!! It may not be your problem. But it makes things SOOO much easier.
 
The Trizact belts can hold debris. Blow them out with shop air or touch the vacuum nozzle to it as it's running. They also need to be dressed sometimes. I use a file card for that, it seems to work great. If I want to end with a 600 grit finish I go to 800 grit first and then back to 600. I've found that gives me a more consistent finish.
 
One thing hit it with black compound on a sisal wheel after the 220 grit belt. It will clean up any scratch’s that have been camouflaged during the grind. Then you can proceed to remove the coarse grind marks you find.
 
Yes on that. Use the buffer to see what scratches you have missed. I tend to do it almost before every grit change. That goes for handles as well.

That 10 seconds on the buffer saves you 20 minutes dicking around getting a too coarse scratch out with a too high grit.

That and I have started wet sanding all of my handles. You know how well the paper cuts in the first 10 seconds? That's because it is not all loaded up with material. I wet sand from 120 grit on. Give that a try as well!
 
Saw nick wheeler post a video a while back where he used a scotchbrite belt, used a welding brush to clean it while it was running, then spray it with wd40. Looks great IMO
 
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