Using jig on abrasive...

[David Ragan]

It has occurred to me while using my LV sharpening jig (Veritas Mark II honing guide, etc) that perhaps the wheel/bearing surface is dulling my abrasive. Seems to be the case with the Klingspor abrasive sheets on glass.

No problem, I just change out paper, be more methodical with my strokes, etc. I could even shorten the abrasive paper where the roller wheel doesn't ride on the abrasive at all. Not likely to shorten my stroke-go to all that trouble.

So, while using some diamond plates, the Odate plates, and some others we have available........do you all think that the roller wheel on the jig dulls/wears out the diamond surface? Is this something I should be concerned about?

[Jim Koepke]

do you all think that the roller wheel on the jig dulls/wears out the diamond surface? Is this something I should be concerned about?

By the laws of physics my answer would be yes. The real question is, how much?

The answer is likely not enough about which to be concerned.

jtk

[Hilton Ralphs]

do you all think that the roller wheel on the jig dulls/wears out the diamond surface?

By the laws of physics my answer would be yes.

I think the opposite is true. Why would a brass wheel which a relatively soft alloy wear out the diamond coating made from the hardest substance known to man?

In fact, Lee Valley even sells a replacement roller because the brass bit wears out.

That's how I see it.

The other thing to consider is that most diamond impregnated sharpening surfaces do show initial signs of wear but then it beds down and life goes on.

[Andrae Covington]

I have chewed up the brass roller on my MKII guide on coarse abrasives. So much so that I've almost completely abandoned it in favor of the relatively-unscathed cambered roller, even when I don't want a camber. I'm just careful about side pressure when I don't want the camber (e.g. for chisels). The extra-extra-coarse DMT plate slowly took a toll, but the real culprit was a short-lived experiment with very coarse loose-grit silicon carbide. First of all, what a mess! But it also did a number on the brass roller; the once-smooth surface feels and looks like brass-colored sandpaper now.

[Jim Koepke]

I think the opposite is true. Why would a brass wheel which a relatively soft alloy wear out the diamond coating made from the hardest substance known to man?

Even a soft element can cause wear to a hard element over time. If this were not the case, how is it that working soft pine can cause wear to my blades made of a much harder material?

Of course the softer material will wear faster than the harder material. Over time, the harder material will show wear, however minimal.

jtk

[Pat Barry]

Even a soft element can cause wear to a hard element over time. If this were not the case, how is it that working soft pine can cause wear to my blades made of a much harder material?

Of course the softer material will wear faster than the harder material. Over time, the harder material will show wear, however minimal.

jtk

I suspect the culprit is that the very edge of the tool is relatively weak since there isn't a lot of supoort material there thus the force from the cutting process causes the edge to roll over eever so slightly and then the required cutting force goes up and so does the resulting effect on the dge, etc, etc. Also, there may be some minerals in the wood that act very abrasively.

For the roller going over the abrasive, I think its much more likely that the wheel will get gnarly and worn out than the diamond plate

[Jim Koepke]

I suspect the culprit is that the very edge of the tool is relatively weak since there isn't a lot of supoort material there thus the force from the cutting process causes the edge to roll over eever so slightly and then the required cutting force goes up and so does the resulting effect on the dge, etc, etc. Also, there may be some minerals in the wood that act very abrasively.

For the roller going over the abrasive, I think its much more likely that the wheel will get gnarly and worn out than the diamond plate

Of course the softer material will show more wear. One might need an electron microscope to see any wear to the diamond plate. The wear may be on the level of less than an angstrom unit. Just the same, it is still wear and as stated in my answer to the OP not enough to cause any concern.

jtk

[David Ragan]

Of course the softer material will show more wear. One might need an electron microscope to see any wear to the diamond plate. The wear may be on the level of less than an angstrom unit. Just the same, it is still wear and as stated in my answer to the OP not enough to cause any concern.

jtk

Well that is reassuring
i had one Odate plate that they exchanged cause the diamond stuff come a loose
your point about soft substances is well made tho cause of the effect of water on rocks

[Winton Applegate]

cause of the effect of water on rocks

The water has very small fragments of the rock suspended in it. That is the thing wearing away the rock.
See water jet cutting tools.

Coooool Stuff !
at up to 90,000 psi
capable of attaining accuracies down to 0.005″ (0.13 mm) and repeatabilities down to 0.001″ (0.025 mm)
Cuts: rubber, foam, plastics, leather, composites, stone, tile, metals
over eighteen inches (45 cm) thick. ! ! ! !

The only problem is explaining to SWMBO why I absolutely need one for my shop.
Maybe I will start a new thread asking for strategies with that.

AND
I can see how the brass wheel could pick up grit in its soft surface and use the grit against what ever "stone" we are running the jig over.

[Joe Bailey]

In fact, Lee Valley even sells a replacement roller because the brass bit wears out.

I'm pretty familiar with the LV catalog, but that is news to me -- can you point me to it?

[Hilton Ralphs]

I'm pretty familiar with the LV catalog, but that is news to me -- can you point me to it?

It's hidden but Vic has your answer.

[Joe Bailey]

Thanks Hilton.

[David Ragan]

The only problem is explaining to SWMBO why I absolutely need one for my shop.
Maybe I will start a new thread asking for strategies with that.

AND
I can see how the brass wheel could pick up grit in its soft surface and use the grit against what ever "stone" we are running the jig over.

My strategy is simple-timing is everything.

Excellent point about the brass picking up grit and transferring to another surface.

[Hilton Ralphs]

I was thinking about this roller issue last night. It would be solved if you could somehow strengthen the base and have two rollers on the outside of the path of the blade instead of one big one following the blade. The gap just needs to be as wide as the jig can handle. You could even run the wheels/rollers in a track of sorts on UHMW strips to lessen any friction.