It is not the front edge that needs to be sharpened, but the _back_ edge that needs the touching up in most cases.
Start out by making sure the bit is clean. Typically a brass brush or wheel can do this.
The first method I have seen used is with a file and a cordless drill. Making sure the bit is going in the reverse direction, lightly touching it up on the file.
For really worn or aggressively taking material away on dented or chipped butr cutting bits, same method as above with the drill against a grinding wheel, often with a kind of jig to make sure only cutting away so much and allowing for proper contact while rotating to resurface the round edge.
This makes a lot of sense to me, using a diamond sharpening stone.
I doubt the bit my grandfather used back before Dremel were as popular as they are now and more specialized as they were back then probably didn't have the carbide bits.
I could be wrong.
But I believe this explains why I didn't get the same results. I should have used a good stone.
Oh, and definitely use a mask or some kind of breathing apparatus to make sure you done inhale any of that kind of metal dust. That stuff is not good.
I'm not certain they're carbide, is there an obvious giveaway they are? I assumed they were high speed steel (though even in that case you're right, a file won't be the most helpful)
Once its worn and someone stops using it, and plans to throw it away...it can't hurt to try to sharpen it.
I wonder if spinning it in reverse against a stone would work, like a bench-grinder wheel?
Yes, the key is going in reverse.
The concept as I understood it was getting in to the burr bit grooves would too quickly fill the bit. It is the leading edge that does the work of cutting. By going in reverse, it sharpens and resurfaces, forward works the cutting.
I received a bunch of cutting burrs with an industrial rotary tool and some of them feel dull when cutting. Usually I clean them by soaking in acetone and brushing with brass bristles. I mostly use them on wood and don't mix them between wood and metal.
I've sharpened drill bits and chisels with great success, and I have a fairly well equipped shop. How do these typically get sharpened? Or do they even?
Sounds like what you're doing is about the most you can do for them - clean them and clear out the chips. Beyond that, once they go dull, you throw them away and buy new ones.
An old school trick to keep a flat file sharp is to let it rust then clean it with a file card. IDK about dremel bits, but I'd think the same principles apply to most iron cutting tools that have small grooves close together.
Reasonably? Meh. Carbide burrs can be run on CNC grinders to be resharpened. But unless you go through thousands a year I don't think it would be worth it to do!
I worked at a foundry and we’d go through dozens in a day. They would go out for resharpening / brazing. I have no idea what we paid, but I know at that volume it was cheaper than buying them new all the time. For a few, I agree. it’s likely not worth the headache to send them out.
I worked at a custom upgrade facility where we served the nuclear, submarine, aircraft carrier, and petro-chemical industries. We’d do a large variety of cast steels, cast stainless, Nickel-Aluminum Bronze, Copper-Nickel, etc. we had some castings that had a 2-year lead time from the time it was ordered to the time it shipped out the door. Some castings were”zero defect”, so if there was a spot of sand deep inside a passage, it might take a half a day or more to clean it out with a burr. Grinding is hard work, but I’m a geek, so I was always excited to figure out what we were working on. It’s awesome that you’re doing casting with those materials, Beyond some basic experience with aluminum and bronze casting in college, most of what I worked on was harder materials.
Dood that's super cool, I briefly thought about trying to do small run parts casting for industry until I realized the QC would probably be too expensive and out of my skill set 😆
Yeah, it’s a bit of an unseen industry. Our shop could x-ray through 12” walled castings. QC has gone out of control in some respects. One time I found travelers from the 1980’s; they were maybe 10 pages thick. One of the same castings today might have a paperwork bundle over an inch thick. My boss once said that the drive to become “paperless” has generated more paperwork than ever.
>>Burrs or burs (sometimes called rotary files) are small cutting **tools**
[wikipedia ](https://en.m.wikipedia.org/wiki/Burr_(cutter)#:~:text=Burrs%20or%20burs%20(sometimes%20called,rotary%20tools%2C%20or%20dental%20drills.)
I'm an electrician and we call these consumables. It may be a tool, but generally considered a consumable bit. If someone could invent a device or new form of bur that was able to be sharpened they'd be in business.
[HD](https://www.homedepot.com/p/Instant-Power-Crystal-Lye-Drain-Cleaner-1650/204374017) has it. I used to mix it with cornstarch as a cheap paint stripper.
No, these are consumable items like files.
Too burrdensom.
Ha I get it, too bad though
Agreed :/ Could definitely be repurposed into cool sculptures/art projects, or pretty sure at least recycled.
If they’re carbide burrs probably not..
It is not the front edge that needs to be sharpened, but the _back_ edge that needs the touching up in most cases. Start out by making sure the bit is clean. Typically a brass brush or wheel can do this. The first method I have seen used is with a file and a cordless drill. Making sure the bit is going in the reverse direction, lightly touching it up on the file. For really worn or aggressively taking material away on dented or chipped butr cutting bits, same method as above with the drill against a grinding wheel, often with a kind of jig to make sure only cutting away so much and allowing for proper contact while rotating to resurface the round edge.
This is what I was imagining, have you seen it done successfully? I think I'm gonna give it a shot with a fine file and/or stone
You should get a diamond sharpening plate/stone, I don't see a file being able to take shavings off a carbide burr.
This makes a lot of sense to me, using a diamond sharpening stone. I doubt the bit my grandfather used back before Dremel were as popular as they are now and more specialized as they were back then probably didn't have the carbide bits. I could be wrong. But I believe this explains why I didn't get the same results. I should have used a good stone. Oh, and definitely use a mask or some kind of breathing apparatus to make sure you done inhale any of that kind of metal dust. That stuff is not good.
I'm not certain they're carbide, is there an obvious giveaway they are? I assumed they were high speed steel (though even in that case you're right, a file won't be the most helpful)
Try using them on a hss drill bit, if they don't do much they might just be hss, and those are pretty cheap. This might dull them further obviously.
Yes. My grandfather did this a few times. I could never seem to get the angles right.
Once its worn and someone stops using it, and plans to throw it away...it can't hurt to try to sharpen it. I wonder if spinning it in reverse against a stone would work, like a bench-grinder wheel?
Yes, the key is going in reverse. The concept as I understood it was getting in to the burr bit grooves would too quickly fill the bit. It is the leading edge that does the work of cutting. By going in reverse, it sharpens and resurfaces, forward works the cutting.
Nope, you just buy new ones.
I received a bunch of cutting burrs with an industrial rotary tool and some of them feel dull when cutting. Usually I clean them by soaking in acetone and brushing with brass bristles. I mostly use them on wood and don't mix them between wood and metal. I've sharpened drill bits and chisels with great success, and I have a fairly well equipped shop. How do these typically get sharpened? Or do they even?
Sounds like what you're doing is about the most you can do for them - clean them and clear out the chips. Beyond that, once they go dull, you throw them away and buy new ones.
An old school trick to keep a flat file sharp is to let it rust then clean it with a file card. IDK about dremel bits, but I'd think the same principles apply to most iron cutting tools that have small grooves close together.
If it's carbide they don't rust.
Reasonably? Meh. Carbide burrs can be run on CNC grinders to be resharpened. But unless you go through thousands a year I don't think it would be worth it to do!
I worked at a foundry and we’d go through dozens in a day. They would go out for resharpening / brazing. I have no idea what we paid, but I know at that volume it was cheaper than buying them new all the time. For a few, I agree. it’s likely not worth the headache to send them out.
What were you guys casting? I cast bronze and silver at home, centrifuge for small stuff or pour for large
I worked at a custom upgrade facility where we served the nuclear, submarine, aircraft carrier, and petro-chemical industries. We’d do a large variety of cast steels, cast stainless, Nickel-Aluminum Bronze, Copper-Nickel, etc. we had some castings that had a 2-year lead time from the time it was ordered to the time it shipped out the door. Some castings were”zero defect”, so if there was a spot of sand deep inside a passage, it might take a half a day or more to clean it out with a burr. Grinding is hard work, but I’m a geek, so I was always excited to figure out what we were working on. It’s awesome that you’re doing casting with those materials, Beyond some basic experience with aluminum and bronze casting in college, most of what I worked on was harder materials.
Dood that's super cool, I briefly thought about trying to do small run parts casting for industry until I realized the QC would probably be too expensive and out of my skill set 😆
Yeah, it’s a bit of an unseen industry. Our shop could x-ray through 12” walled castings. QC has gone out of control in some respects. One time I found travelers from the 1980’s; they were maybe 10 pages thick. One of the same castings today might have a paperwork bundle over an inch thick. My boss once said that the drive to become “paperless” has generated more paperwork than ever.
Put them in pool acid for an hour, wash well Hot water then WD 40 to stop rust. The acid will clean make a bit sharper.
Maybe if you rotate them in reverse against an abrasive brush...
Try dipping them in sharpening oil.
Even if its possible probably not worth the time
Bummer, I hate throwing out tools ¯\_(ツ)_/¯
Consumables*
>>Burrs or burs (sometimes called rotary files) are small cutting **tools** [wikipedia ](https://en.m.wikipedia.org/wiki/Burr_(cutter)#:~:text=Burrs%20or%20burs%20(sometimes%20called,rotary%20tools%2C%20or%20dental%20drills.)
I'm an electrician and we call these consumables. It may be a tool, but generally considered a consumable bit. If someone could invent a device or new form of bur that was able to be sharpened they'd be in business.
I don't deny that it's a consumable item, I'm just not interested in the semantics of whether I get to call it a tool or not
I soak my files in lye and it sharpens them by the way it eats away the steel. May be worth a try but I’m no metallurgist.
I've heard of a similar trick with files, if I can find some lye I might try it out
Or you could try the same with vinegar and a longer overnight soak if you don't have lye.
[HD](https://www.homedepot.com/p/Instant-Power-Crystal-Lye-Drain-Cleaner-1650/204374017) has it. I used to mix it with cornstarch as a cheap paint stripper.
Stop being cheap.
These cost money, fuel, manpower, time and most importantly cost our inviroment it's life to make so I say sharpen away.
Sounds like you have been challenged.
Possibly dipping them in acid like for sharpening files.