Old window for sharpening base?

[Chip Olson]

I picked up Rockler's "sharpening system" today, the one that's a slab of plate glass, a honing guide and a packet of sandpaper. It was cheaper than what a local glass place quoted me for the glass alone.

Then I realized that I might be an idiot (and not for the first time, either), because I've got a couple of old windows sitting in my basement. Is there any reason, like the glass maybe being too thin or unflat, why I couldn't cut one of the panes down and use that as a base for sharpening with sandpaper?

[Jeff Gorman]

Thinness can be accommodated by supporting the glass on a sheet of MDF or whatever.

The flatness is unimportant. Glass is usually chosen because of its smoothness. Supporting abrasive paper on a lumpy surface would lead to the lumps being planed by the edge as it is worked forwards.

Jeff G

[Charlie Self]

Chip Olson asks:

I can't comment on Rockler's kit, but I've got the Lee Valley glass, and there is very little glass that thick included in ANY window you or I are likely to get our hands on.

You could probably use standard window glass, but it is too thin in most cases. It breaks easily, and is not tempered, so when it breaks, you may get cut.

Charlie Self "It is inaccurate to say that I hate everything. I am strongly in favor of common sense, common honesty, and common decency. This makes me forever ineligible for public office." H. L. Mencken

[Chip Olson]

Yeah, I took another look at those windows after posting, and I'd forgotten that they're double-glazed vinyl windows, so the glass is probably somnething like 1/8" thick. :-(

[J]

1/4" glass resting on a reasonably flat surface will be just fine. Granite tiles also work. Anything that gives a true reflection (no bending or warping) will work.

-j

[Juergen Hannappel]

[...]

A quiet pool of water?

[Doug Winterburn]

Frozen - possibly.

-Doug

[Lawrence Wasserman]

Really old window glass may not be flat, modern glass is flat enough but a typical window has thin glass that may flex. This possibly could be minimized by gluing the glass to something like a piece of MDF. I use a marble tile, available for a few $ for a 12X12 from Home Depot or Lowes.

[Charlie Self]

Larry Wasserman responds:

All true, but you can also use plain old MDF, dry. McFeely's sells a kit based on that idea.

Charlie Self "It is inaccurate to say that I hate everything. I am strongly in favor of common sense, common honesty, and common decency. This makes me forever ineligible for public office." H. L. Mencken

[Larry Jaques]

On Fri, 12 Nov 2004 18:29:31 +0100, Juergen Hannappel calmly ranted:

Only if you're into Zen sharpening, Juergen.

- - - - - - - - - - - - - - - - - If God approved of nudity, we all would have been born naked. ----- ----- ----- ----- ----- -----

Your Wild & Woody Website Wonk

[J]

Even the Japanese wait until the water turns into a stone.

-j

[Michael Baglio]

Might want to check the box stores. Lowe's is in the middle of a country-wide remodeling upgrade, and there's a lot of 12X12 marble tile in odd quantities out there going for $1 apiece.

Michael Baglio

[patrick conroy]

I was paging thru a "Jigs and Fixtures" book a few days ago. A well published writer (Engler? Nick Engler?) said he invested in a marble slab used for cookie dough from a kitchen supply store for his scary sharp sharpening. His thought was it was plenty thick, plenty stable and cheeeep!

[rcook5]

The glass is both too thin and not as flat as plate glass. Plate glass is made by a special process that produces an extremely flat surface. I would also be worried about the window glass breaking under the pressure of sharpening, even with appriopriate backing.

Stick with plate glass. It's cheap enough in size pieces you need.

--RC That which does not kill us makes us stronger. --Friedrich Nietzsche Never get your philosophy from some guy who ended up in the looney bin. -- Wiz Zumwalt

[James Main]

I disagree-flatness is THE key feature. Smoothness is a by product of that.

[J]

Flatness and smoothness are not always the same. You can have a smooth ball which is not flat at all. Therefore it is not a by-product of flatness. Think about it.

[Ray Aldridge]

True, but since we're talking about planes, not spheres, this is irrelevant. A plane is both flat and smooth, by definition.

[J]

No it is not irrelevant. And, since you are diving into semantics, anyone who thinks that glass is a plane is wrong too. A plane has no thickness.

-j

[Dave Hinz]

Hey everybody, it's "word-games time". The one side of the glass being used to flatten a plane fits the definition of a plane well enough to be accurate. Yes, the glass itself has volume, but the meaning here is, ahem, plain.

[bridger]

if the diameter of you smooth ball is large enough it will produce a smooth edge on your tool which is within tolerance for straightness.

it's just a matter of what tolerances you hold your tools to and how big your balls are...