Powered Deburring for Toothy Edges

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bgentry

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Aug 3, 2009
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I've had my belt sander setup for several months now and have done a fair number of blades. I can, fairly easily, produce a polished (not mirror) edge by going from ~600 grit belt to green compound on smooth leather. This cleanly deburrs the blade and polishes it quite a bit in the process. These edges measure really impressively on the BESS tester. My last one, a ZDP-189 Delica, measured 90 to 105, which is really, really sharp.

But these edges have no bite. They aren't all that great at everyday tasks. I really do like an edge that's more like 220 to 400 grit, cleanly deburred without extra polish. In search of that edge, I've been following advice from someone on the BESS forums who recommends:

1. Grind with 180 grit belt to produce as small a burr as possible. (Mine tend to be larger than smaller, but not huge)
2. Wipe off the burr using medium (blue) ScotchBrite belt. This takes many passes and sometimes will not remove all of the burr. I often get a little bit of rounding doing this.
3. Finish with bare rough leather to remove the last little bits of burr.
4. (Optional) repeat 2 and 3 as required to get all of the burr.

I find that I end up with "welded on burr" or LOW (Line Of Weld) very often. I'll end up having to use increased angle or increased pressure, or both in step 2 above. This is time consuming and not super fun.

It occurs to me that there might be an in between way of doing this that might be faster and more reliable. Something like #1 (180 grit) followed by diamond compound on linen or leather. I know Jason B. Jason B. likes 1 micron diamond for finishing. But is it good for deburring? The burr left over by a 180 grit belt is kinda big and nasty and requires a good bit of work.

Anyone have a favorite method for making a toothy edge with a belt sander that leaves you with a nice clean deburred edge?

Brian.
 
Best way to remove the burr on a machine is to either manually remove it on a stationary belt with a few leading passes or run it slowly in reverse.

Have also found it helps to repeatedly run the edge across some endgrain wood between passes - am not sure why this helps in this case or manually, but when working edge trailing it def makes a difference. When I use the finish belt, contact is extremely light, barely dancing on the belt across the highest points, as fast as the machine will run. The edge just has a glint along the apex a la microbevel - I don't do the entire flat.

Having tried it I can advise against using the Scotchbrite to deburr an edge - it works great on tooled/machined parts but is too aggressive for a cutting edge. Anyone who has had success plz chime in with specifics.

Otherwise I set in the grind with the belt and finish manually on a stone/strop.
 
Option 1: Try spraying the 180 belt with WD40 (or another light oil), and have the solvent evaporate a few minutes before use.
Besides the cooling effect on the edge the oil will also make the grit cut cleaner and the burr easier to remove (within limits)
The type of oil can make a difference too.

Option 2: on even more stubborn burrs) get a diamond file with the same grit rating as your belt, and use that to remove the burr edge leading as much as possible.
Due to the diamonds the file cuts practically without any pressure, not even the weight of the file itself is enough for this.
I use various Chinese diamond files from the bay (120/180/300 grit) for manual regrinding certain blades, plus to make coarse edges and also remove (most of) the thick burrs.
The small burr remnants left are then easily stropped off on leather or cardboard with some 1.0 micron diamond paste.

Examples in this thread (also page 2): https://www.bladeforums.com/threads/finetuning-a-couple-of-condors.1662592/#post-19015639
 
I've actually had good success with the ScotchBrite, but it's inconsistent for me. Some days it works well. Other days not as well. It's probably a matter of my patience and attention to detail. Thus I'm looking for something that's easier.

Interesting that you should mention diamond files. Just a few days ago I went from a 280 grit belt to a DMT Coarse plate. Manually deburred on the plate. Which took WAY more strokes than I expected. But when I was done it was quite clean and really nice and toothy. Gave it a few passes on the powered leather belt (bare) and it seemed to improve marginally.

Still, I'd kinda like to do everything on the belts if I can. If.

Brian.
 
180 grit belt to paper wheel creates an edge that is hard to beat imo. Plenty of tooth. No reason to overdo it, just remove the bur.
 
bgentry said:
I've actually had good success with the ScotchBrite, but it's inconsistent for me. Some days it works well. Other days not as well. It's probably a matter of my patience and attention to detail. Thus I'm looking for something that's easier.

Interesting that you should mention diamond files. Just a few days ago I went from a 280 grit belt to a DMT Coarse plate. Manually deburred on the plate. Which took WAY more strokes than I expected. But when I was done it was quite clean and really nice and toothy. Gave it a few passes on the powered leather belt (bare) and it seemed to improve marginally.

Still, I'd kinda like to do everything on the belts if I can. If.

Brian.
Click to expand...

If you can keep the burr real small, a light touch on the belt can do it. I've also pulled it off on the sisal wheel but that degrades the edge a little. Still pretty good.

My experience with a belt at high speed, or paper wheel made very similar edges. Both work great if the burr is small. Bigger ones can be trouble no matter what you do.
 
bgentry said:
I've had my belt sander setup for several months now and have done a fair number of blades. I can, fairly easily, produce a polished (not mirror) edge by going from ~600 grit belt to green compound on smooth leather. This cleanly deburrs the blade and polishes it quite a bit in the process. These edges measure really impressively on the BESS tester. My last one, a ZDP-189 Delica, measured 90 to 105, which is really, really sharp.

But these edges have no bite. They aren't all that great at everyday tasks. I really do like an edge that's more like 220 to 400 grit, cleanly deburred without extra polish. In search of that edge, I've been following advice from someone on the BESS forums who recommends:

1. Grind with 180 grit belt to produce as small a burr as possible. (Mine tend to be larger than smaller, but not huge)
2. Wipe off the burr using medium (blue) ScotchBrite belt. This takes many passes and sometimes will not remove all of the burr. I often get a little bit of rounding doing this.
3. Finish with bare rough leather to remove the last little bits of burr.
4. (Optional) repeat 2 and 3 as required to get all of the burr.

I find that I end up with "welded on burr" or LOW (Line Of Weld) very often. I'll end up having to use increased angle or increased pressure, or both in step 2 above. This is time consuming and not super fun.

It occurs to me that there might be an in between way of doing this that might be faster and more reliable. Something like #1 (180 grit) followed by diamond compound on linen or leather. I know Jason B. Jason B. likes 1 micron diamond for finishing. But is it good for deburring? The burr left over by a 180 grit belt is kinda big and nasty and requires a good bit of work.

Anyone have a favorite method for making a toothy edge with a belt sander that leaves you with a nice clean deburred edge?

Brian.
Click to expand...
Brian - I defer to you and the BESS crowd as far more knowledgeable, but aren’t the Blue scotchbrite belts “very fine” grit? Seems like a coarser belt could help deburr the LOW with fewer passes.

a more obtuse angle than the sharpening angle can be helpful in deburring as well. Some good info on Bessex forum about that.
 
The critical element is to keep applied pressure VERY light, and contact speed as high as possible. In this case it doesn't hurt to elevate the angle slightly as well.

When I do this with the belt I'm using a guide, not very confident I could make this work as well freehand without a ton of practice. The edge is just barely touching the belt or paper wheel as it skips along. The burr has to come off without folding and without dubbing the apex. The ability to inspect and come back at the exact same angle is a biggie.
 
CasePeanut said:
Brian - I defer to you and the BESS crowd as far more knowledgeable, but aren’t the Blue scotchbrite belts “very fine” grit? Seems like a coarser belt could help deburr the LOW with fewer passes.
Click to expand...

Excellent question. That's actually exactly what I assumed when I first heard about ScotchBrite for deburring. So I ordered the Medium (maroon) belt. I was then told that it didn't work that well, but I was free to try it. So I tried it. It didn't work all that well. :P

I then ordered the very fine (Blue) and super fine (Gray) to play with. The Blue seems to be the ticket as far as burr removal. But still difficult. The Gray is nice to have for general smoothing and (rough) polishing, but I don't use it for deburring.

Brian.
 
HeavyHanded said:
The critical element is to keep applied pressure VERY light, and contact speed as high as possible. In this case it doesn't hurt to elevate the angle slightly as well.

When I do this with the belt I'm using a guide, not very confident I could make this work as well freehand without a ton of practice. The edge is just barely touching the belt or paper wheel as it skips along. The burr has to come off without folding and without dubbing the apex. The ability to inspect and come back at the exact same angle is a biggie.
Click to expand...

Hmm. I use the KallyRest angle guide on my Kalamazoo. But for deburring I tend to do it freehand. The ScotchBrite belts are a very thick woven material and are not super consistent in thickness. So getting the guide right up to almost kiss the belt is problematic. Therefore I've just done it freehand. I need to try it with the guide as close as I can get it, so I can try out your method.

Thanks for the ideas.

Brian.
 
You need to get a Fine Scotchbrite WHEEL. Get at least a medium or a hard version. Scotchbrite belts are for surface finishing and will cause too much rounding at the edge for a good sharpening, thus the reason for the harder wheel.

The idea of the Soctchbrite is to soften the Burr not remove it. This allows the polishing stage to cleanly remove the burr and yield a sharp edge. Though I would still be using power polishing methods on the final step. Its the same rules that apply when hand sharpening. You don't want to go to your strop with a big'ol burr because its just going to scrape your strop all to hell. The tough burr left by the belt needs to at the least be "softened" up a bit so its not so tough on the polishing tools .

FYI, I use 1 micron diamond on leather or balsa is to use after Hand sharpening, I do not use it in my power sharpening methods. I like the Koyo Green compound, some of the higher grade white compounds and Flexcut gold, In that order. The polishing compound you use will work best on a prepped wheel or belt. If the wheel or belt is built up with compound and removed metal the polishing of the edge will be inconsistent and sharpness will suffer. Clean with a diamond spur and apply fresh compound every 5-10 blades or as needed.

I use a 120 grit norton blaze for grinding, a Fine/hard Scotchbrite wheel for burr reduction and a Leather Surgisharp wheel for polishing. I have sharpened Mountains of knives this way and for besides being sharp that are all consistently sharp. I also only make one light pass per side on the Scotchbrite.
 
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