Belt Sander Setup

HeavyHanded said:
CasePeanut CasePeanut

Will have to wait till Monday for a proof of concept, but pretty sure I've come up with an accurate and repeatable way to address the paper wheel that is unlike the Tormek approach.

It should work with all my current jigs, so hopefully by Tues I'll have some feedback. Honestly I expect edge finish quality to be pretty high, just need to make it play well with the rest of the gang.
Click to expand...
Ok! Post up some pictures please!
 
Sharpening serrations form the back side is what Ben Dale or Edge Pro teaches too. When you think about it there is a lot of life in the serration grind as you can keep sharpening (from the back) until the edge moves all the way to the top of the serrations before they would need to be recut. By that point most people would consider the knife worn out anyway.
 
Mr.Wizard said:
Sharpening serrations form the back side is what Ben Dale or Edge Pro teaches too. When you think about it there is a lot of life in the serration grind as you can keep sharpening (from the back) until the edge moves all the way to the top of the serrations before they would need to be recut. By that point most people would consider the knife worn out anyway.
Click to expand...

Yes and no. As you move up the back you're making the angle larger. Also since the edge dulls from both sides the grind side should ideally be hit as well.

Hitting the back is a great way to touch them up.
 
Valid caveat, but if you grind the entire back face or bevel (flat or sabre grind respectively)—i.e. thin the knife—the angle doesn't change. That's a lot of grinding but it doesn't require the special equipment needed to recut serrations. The edge moves off center but serrated edges are often not centered to begin with. The serration-side does of course need to be deburred.
 
HeavyHanded said:
Yes and no. As you move up the back you're making the angle larger. Also since the edge dulls from both sides the grind side should ideally be hit as well.
Click to expand...

If I had more patience and more skill, I'd use something like a tapered conical file to hit each serration individually, trying to reshape the scallops to their exact factory geometry, and restoring the points completely. But I'm kinda lazy and not super skilled.

Do you have a preferred method of hitting the scallops that works well but doesn't require crazy patience or crazy skills?

I've actually found that going from the flat side seems to restore more of the points than going from the front with the Sharpmaker since there's no rounding involved. So even with extremely dull serrated blades, this method has worked pretty well for me so far.

Brian.
 
B bgentry If the front side hasn't been damaged grinding from the back will perfectly restore the original serration profile as you'll be cutting up into the pristine part of the serration grind. If it has been damaged and needs to be recut Josh's work is the nicest I've seen; I would have thought those had been cut with an industrial serration profile wheel if he hadn't told us otherwise.
 
bgentry said:
If I had more patience and more skill, I'd use something like a tapered conical file to hit each serration individually, trying to reshape the scallops to their exact factory geometry, and restoring the points completely. But I'm kinda lazy and not super skilled.

Do you have a preferred method of hitting the scallops that works well but doesn't require crazy patience or crazy skills?

I've actually found that going from the flat side seems to restore more of the points than going from the front with the Sharpmaker since there's no rounding involved. So even with extremely dull serrated blades, this method has worked pretty well for me so far.

Brian.
Click to expand...

The best I can do is with a clamp and bar to guide the conical diamond rods. And that needs to be done with an additional guide on the bar to keep the rod from changing grind angle.

For a quick touchup I use the rod on the backside to raise a burr and take a bunch of card stock/heavy paper, maybe a dozen layers presented edgewise with compound, used on the grind side. The paper separates at the transitions and you can minimize the rounding/smoothing of the teeth.

So far I haven't found a best practices, everything is a trade-off of quality for speed. Once I get setup on my homebrew guide it goes pretty fast.
 
M Mr.Wizard
CasePeanut CasePeanut

Here's the paper wheel solution vs the rapid change stone solution. The guide rod height needs to be adjusted for both when coming off the belt, but the stone holder has advantage that it is always the same shift - thickness of the holder and stone plus about a 1/4" to create the microbevel. Had to swap out a flat clamp guide for the usual rounded one to make the paper wheel option work. My formerly top-secret MAGUKC (MultiAngleGuideUniversalKnifeClamp - it ain't magic!) clamp, also allows for regrinds, guided work on any stone, and the same clamp can be chucked directly into a rig for doing serrations. Tracks around the belly better than any other widget I've tried.

Off the paper wheels following 220 grit Norton Bluefire belt (nice finish! Pics are with a 120 Blaze belt) was able to create a very good edge, shave armhair, pushcut copy paper. By my calculations the micro should have been about +2 degrees/side. As long as one keeps good contact on the platen the angle stays consistent, slide it around to always present the edge perpendicular to the wheel.

Using a 1200 grit diamond plate with guide and a few passes on a Washboard freehand the edge was treetopping hair and still very catchy.

Am going to continue to experiment with the paper wheels, but as a follow-up to the belt grinder is actually slower than the stone option coming and going. Freehand will be another ballgame and I suspect/have suspected from the get-go that paper wheels are best used freehand with nothing more than a visual indicator for angle reference.
Pics:
1 plain belt
2 paper wheel option
3 stone holder on belt grinder platen

PSSh6Cgl.jpg


lxl0l3ol.jpg

7fyWPnBl.jpg
 
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A while back in some thread about paper wheels, someone showed how holding the blade level with the floor allowed for a specific angle on the paper wheel. If you hold the blade level and touch the top of the wheel, that's essentially zero degrees. If you touch the part of the wheel that "sticks out the furthest" that's 90 degrees. In between you can vary your angle to whatever you want. Just mark the edge using a protractor (with the wheel stopped!) and you have a reference. But how do you find this mark with the wheel moving?

A laser level! This person showed how he used the angle mark on the side and then lined up his laser level to touch the wheel at the exact spot to yield the angle he wanted on the blade. Then all he had to do was hold the blade level and touch the wheel on the laser line.

I thought that was brilliant.

Brian.
 
bgentry said:
A while back in some thread about paper wheels, someone showed how holding the blade level with the floor allowed for a specific angle on the paper wheel. If you hold the blade level and touch the top of the wheel, that's essentially zero degrees. If you touch the part of the wheel that "sticks out the furthest" that's 90 degrees. In between you can vary your angle to whatever you want. Just mark the edge using a protractor (with the wheel stopped!) and you have a reference. But how do you find this mark with the wheel moving?

A laser level! This person showed how he used the angle mark on the side and then lined up his laser level to touch the wheel at the exact spot to yield the angle he wanted on the blade. Then all he had to do was hold the blade level and touch the wheel on the laser line.

I thought that was brilliant.

Brian.
Click to expand...
That's a great idea.
 
Furthermore, you can also just use the very top of the wheel (with it running away from you), hold the blade at a 45° oblique to the wheel, and set your angle like you would on a bench stone relative to the plane of the floor/tabletop. It's how I grind scythe blades, actually.
 
FortyTwoBlades said:
Furthermore, you can also just use the very top of the wheel (with it running away from you), hold the blade at a 45° oblique to the wheel, and set your angle like you would on a bench stone relative to the plane of the floor/tabletop. It's how I grind scythe blades, actually.
Click to expand...
I never used a laser. You doing that by eye or laser? I think the laser is foolproof. But after a while I don't think you need anything.
 
Bill3152 said:
I never used a laser. You doing that by eye or laser? I think the laser is foolproof. But after a while I don't think you need anything.
Click to expand...

No laser; all freehand. The angle used on scythe blades is only ~7-9° per side, so just a touch above dead level.
 
KnifeGrinders.com.au also teaches sharpening serrations from the back side, with deburring from the front.

 
HeavyHanded said:
M Mr.Wizard
CasePeanut CasePeanut

Here's the paper wheel solution vs the rapid change stone solution. The guide rod height needs to be adjusted for both when coming off the belt, but the stone holder has advantage that it is always the same shift - thickness of the holder and stone plus about a 1/4" to create the microbevel. Had to swap out a flat clamp guide for the usual rounded one to make the paper wheel option work. My formerly top-secret MAGUKC (MultiAngleGuideUniversalKnifeClamp - it ain't magic!) clamp, also allows for regrinds, guided work on any stone, and the same clamp can be chucked directly into a rig for doing serrations. Tracks around the belly better than any other widget I've tried.

Off the paper wheels following 220 grit Norton Bluefire belt (nice finish! Pics are with a 120 Blaze belt) was able to create a very good edge, shave armhair, pushcut copy paper. By my calculations the micro should have been about +2 degrees/side. As long as one keeps good contact on the platen the angle stays consistent, slide it around to always present the edge perpendicular to the wheel.

Using a 1200 grit diamond plate with guide and a few passes on a Washboard freehand the edge was treetopping hair and still very catchy.

Am going to continue to experiment with the paper wheels, but as a follow-up to the belt grinder is actually slower than the stone option coming and going. Freehand will be another ballgame and I suspect/have suspected from the get-go that paper wheels are best used freehand with nothing more than a visual indicator for angle reference.
Pics:
1 plain belt
2 paper wheel option
3 stone holder on belt grinder platen

PSSh6Cgl.jpg


lxl0l3ol.jpg

7fyWPnBl.jpg
Click to expand...
Thanks so much for the pics! The belt and paper wheel mounted on the same motor seems like a great combo. I agree that it should be very fast if you are doing it all freehand.

I’ve experimented with the laser levels but found it pretty fiddly, especially since I don’t have a dedicated spot for my grinder and needed to setup the whole contraption each time.
 
Mr.Wizard said:
KnifeGrinders.com.au also teaches sharpening serrations from the back side, with deburring from the front.

Click to expand...

That guy is amazing. His first test off of the serrated side produced an edge sharper than anything I've tested on my own tester so far. I've seen a 135 on one of my blades. He got a 110. Then he stropped it again and got a 65! A double edged razor blade for face shaving scores somewhere in the 45 to 60 range. Wow.

Brian.
 
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