plane blade grinding question

[David Wadstrup]

Hello,

I've just begun using a powered bench grinder to regrind my plane blades back to their primary bevel. It's amazingly fast, and with the set-up I have(will post about that separately,) I am able to do it without the slightest bit of fear of overheating the blade. My question is about accuracy. I use a tool rest, but not a grinding jig. I was able to get a pretty even bevel the full width of the blade, but not perfect. That it was not perfect was really noticeable after having finished up with a jig on waterstones -- the micro-bevel was quite wavy. So, to those of you who use bench grinders for this purpose: is this normal? does the waviness effect blade performance at all? is there something I should be doing differently? is free-handing it ever give absolutely perfect results?

PS I should mention that I use a One-Way Tool Rest, and because of the large platform surface, no blade holding jig I know of would work.

Thanks!

[Prashun Patel]

Is it the leading (cutting) or trailing edge that has the wave? The primary bevel is there just to remove a lot of the steel so that the real, cutting angle can be easily and quickly established and refreshed. If your cutting edge is square and honing the edge is easy for you, and your blade cuts as you like it, then there's no reason to change your method.

If the cutting edge has the wave even after honing, then are there concavities, or is it just a convex camber?

[David Weaver]

Hello,

I've just begun using a powered bench grinder to regrind my plane blades back to their primary bevel. It's amazingly fast, and with the set-up I have(will post about that separately,) I am able to do it without the slightest bit of fear of overheating the blade. My question is about accuracy. I use a tool rest, but not a grinding jig. I was able to get a pretty even bevel the full width of the blade, but not perfect. That it was not perfect was really noticeable after having finished up with a jig on waterstones -- the micro-bevel was quite wavy. So, to those of you who use bench grinders for this purpose: is this normal? does the waviness effect blade performance at all? is there something I should be doing differently? is free-handing it ever give absolutely perfect results?

PS I should mention that I use a One-Way Tool Rest, and because of the large platform surface, no blade holding jig I know of would work.

Thanks!

It makes no difference other than cosmetic as long as the entire edge is honed once you hone it. just keep grinding and you'll quickly find that your grinds are a lot more uniform from repetition and method (you'll figure out what works for you with method).

No jigs or any of that stuff, it's a waste of time and money. Your hands and your brain will allow you to grind anything short of a fingernail grind on a gouge, and you can even do that freehand with a decent belt grinder and a fine belt.

[Chris Griggs]

As long as you have a full straight,uniform polish at the cutting edge that is what matters. Any time I grind all the way to the edge I have a little out of straightness that I end up honing out on the stones. I typically deliberately grind EVER SO SLIGHTLY concave (for blades I want straight or very near straight) just because I find that makes sit easier to hone out on the stones (as opposed to waviness or unwanted camber).

What you will find is that when you go back to refresh the hollow, the polish, which is straight assuming your stones are flat, will guide your grinding. Unless you need to grind out a chip, when you regrind, grind as close to the edge as you can w/o fully grinding the last bit of polish away. At that point, if the polished line is straight your grind is straight. Again, it doesn't matter if it isn't perfect anyway as long as you hone properly, but maintaining a straight grind does give you less work on the stones, since you won't need to continually hone out an imperfect grind.

And yes, like Dave said, the more you grind free hand the better you'll get at it. When I first got my grinder, my edges were always real wonky of the grinder and I often had to spend a good bit of time fixing them on stones. But after just a bit of practice they came off the grinder straight or vary close to straight more often than not, and any imperfections hone out with just a couple strokes on the 1k.

[Hilton Ralphs]

Is the wavy micro-bevel not caused by the stone needing a good Rogering? I mean dressing the wheel with a diamond tool.

You can get one @ Lee Valley.

[David Weaver]

Not caused by a stone needing Rogering (that's a new word for me). If a stone is in need of dressing, it will instead skip on the bevel and when you stop the grinder, you'll find only one part of the grinding wheel is wearing. But other than being annoying, it doesn't create any ill effects on grinding. Literally just not grinding the same amount in every spot is the issue that the OP has, and experience makes it go away whether you try or not. That's one of the lovely things about repetition sometimes, you can get better just because it's easier to do some things more consistently.

[Hilton Ralphs]

Thanks David. 'Rogering' is what Kevin Bacon did to the boys in the movie 'Sleepers'.

[george wilson]

Take a little C clamp. Clamp a straight piece of metal straight across the upper part of the plane iron,beneath the plane iron,so that the piece of metal runs against the outside edge of the tool rest. Adjust the tool rest or the piece of metal so that the bevel you want to grind rests on the wheel at the angle you want to achieve. Then,you can slide the piece of metal sideways against the tool rest,and grind a perfectly straight across bevel on your plane iron.

I have also used the C clamp when grinding chisels,and even when grinding gouges. I rest the clamp against the tool rest and roll the gouge around while grinding it. It works great,giving you a super accurate bevel with no "facets"in it.

Sometimes,I am just able to rest the bolster of a chisel against the tool rest to grind.

I like my old,flat front Craftsman grinders because they have a 2 piece tool rest. You can loosen the bolts and pull the tool rest way out for resting the bolsters of chisels on. I haven't seen any of the new import grinders that have the 2 piece tool rests. i like the flat fronts of my old grinders too. they don't stick out and get in the way when grinding draw knives. Round motor grinders do get in the way. At least the 6" grinders do.

[lowell holmes]

I'm confused.

Is the grinder a typical bench grinder with a wheel?

If it is you will get a hollow grind. If that's the case, why is a secondary or back bevel needed?

I don't hollow grind because I keep a diamond plate and a mdf hone on the bench all the time.

[David Barnett]

Not caused by a stone needing Rogering (that's a new word for me).

http://a2.ec-images.myspacecdn.com/images02/66/2ad4795146954726a045775544d1df40/l.jpg

"Well, now, I have a work order here which specifies that I am to roger you roundly 'til 6:15 tomorrow morning. Mrs. Potter."

Dan Akroyd as Fred Garvin to Margot Kidder in a memorable SNL sketch. Haven't heard it employed euphemistically for tool adjustment, maintenance or flattening until now, as in "The Atoma 140—now that's a pretty good rogering plate for waterstones!"

[Steve Voigt]

http://a2.ec-images.myspacecdn.com/images02/66/2ad4795146954726a045775544d1df40/l.jpg

"Well, now, I have a work order here which specifies that I am to roger you roundly 'til 6:15 tomorrow morning. Mrs. Potter."

Dan Akroyd as Fred Garvin to Margot Kidder in a memorable SNL sketch. Haven't heard it employed euphemistically for tool adjustment, maintenance or flattening until now, as in "The Atoma 140—now that's a pretty good rogering plate for waterstones!"

Ha! I remember that! Shows how old I am.
In season 2 of The West Wing, during a flashback, the future President tells an unhappy constituent "you got Rogered, but good."

[Don Dorn]

I tend to agree about free hand sharpening and now that I use Paul Sellers method, I don't have to grind very often at all. However, when it's necessary, I still revert to my old method which is Ian Kirby's. It's fast, cheap and works every time. A few months ago, someone wanted some details so I did a video rather than try and write it all out.

http://s111.photobucket.com/user/djdorn/media/Grindingplaneiron.mp4.html