Flattening Glass Plate....

I thought that float glass plate was reasonably flat. I was wrong. I picked up 4-¼ inch glass plates (3" x 11") from a local glass/mirror place and lapped them on my DMT lapping plate. All four were certainly not flat but flattened easily with some effort on the lapping plate. I did it dry. I got these plates in anticipation of receiving some lapping films to evaluate how the new lapping films compare to stones, cubic boron nitride slurries on various substrate, and strops.

All four plates needed flattening. Two plates has several high spots that required significant work to flatten them (about 30 minutes of lapping). The other two, while needing flattening as well, had minor high spots that leveled off within about 10 minutes of lapping. The DMT metal lapping plate works well at flattening glass.

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Originally Posted by DoctorSaul

I thought that float glass plate was reasonably flat. I was wrong. I picked up 4-¼ inch glass plates (3" x 11") from a local glass/mirror place and lapped them on my DMT lapping plate. All four were certainly not flat but flattened easily with some effort on the lapping plate. I did it dry. I got these plates in anticipation of receiving some lapping films to evaluate how the new lapping films compare to stones, cubic boron nitride slurries on various substrate, and strops.

All four plates needed flattening. Two plates has several high spots that required significant work to flatten them (about 30 minutes of lapping). The other two, while needing flattening as well, had minor high spots that leveled off within about 10 minutes of lapping. The DMT metal lapping plate works well at flattening glass.

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Thanks for sharing. I was honestly not aware of this. I have never used such a thick piece of glass, though.

The great advantage of glass over sharpening stones, is that you can check it easily. Just hold it near your eyes, at a tangent angle, and it should reflect a straight image, not a wavy one. Very high-grit stones might do the same; mines don't (up to 8000, Norton brand). Most stones just don't reflect an image at all.

I had good luck with 12x12 marble tile being flat...works great for a sheet of sandpaper.

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Originally Posted by shooter74743

I had good luck with 12x12 marble tile being flat...works great for a sheet of sandpaper.

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+1

Same here the shops surface polish the marble so the chances are much higher of "Flat"

I'd do a search on "lapping film" before starting a whole new topic on reinventing a method that has already been discussed at large on the forum.

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Originally Posted by MT4

Thanks for sharing. I was honestly not aware of this. I have never used such a thick piece of glass, though.

The great advantage of glass over sharpening stones, is that you can check it easily. Just hold it near your eyes, at a tangent angle, and it should reflect a straight image, not a wavy one. Very high-grit stones might do the same; mines don't (up to 8000, Norton brand). Most stones just don't reflect an image at all.

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They're not that thick. I should have written it as "four ¼ inch thick plates". Not the way the post reads. I did price ½ inch plates, but they were $30 each. The ¼ inch plates were $8 each. Big difference, so I went with the ¼ inch plates. Intuitively, the ½ inch plates should be more stable in terms of flatness, but I don't really think there would be a significant difference in varying from flatness due to instability (flow) in my lifetime.

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Originally Posted by mainaman

I'd do a search on "lapping film" before starting a whole new topic on reinventing a method that has already been discussed at large on the forum.

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Have to agree with Stefan here

Film has a few followers, but it also has many others that just won't use it

IME it really comes down to the razors that you are honing, Film works just fine with straight edged, harder steel, and is a bit lacking when used on others..

Not better or worse just more limited then hones..

But yes there is quite a bit of info on here by simply searching "Lapping Film"

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Originally Posted by mainaman

I'd do a search on "lapping film" before starting a whole new topic on reinventing a method that has already been discussed at large on the forum.

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Thanks for the advice, Stefan. I've been reading up on lapping films (my thanks to Euclid440) and want to try them out myself, just for fun. I needed a very flat substrate, which is the reason why I bought the four glass plates and lapped them to flatness.

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Originally Posted by MT4

Thanks for sharing. I was honestly not aware of this. I have never used such a thick piece of glass, though.

The great advantage of glass over sharpening stones, is that you can check it easily. Just hold it near your eyes, at a tangent angle, and it should reflect a straight image, not a wavy one. Very high-grit stones might do the same; mines don't (up to 8000, Norton brand). Most stones just don't reflect an image at all.

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The glass plates are not that thick. I bought four glass plates locally. They were ¼ inch thick, and measured 3 inches x 11 inches. I should have spelled out "four" to avoid the misread.

Here in Bulgaria there is no lapping films , and i whant to try them so badly . Where can i order them , the best quality at the best prise . I have heard only good words for the lapping films .
And 30 $ for a glass plate , wow bwtwr buy a sharpening stone or cut your self a piece of domestic glass .
Glass with paste on it works fine , a little bit slow but fine .

It is best that you don't have films there in Bulgaria, have you ever noticed any of the regular honers using films? NO

Yes, it is a way to get into honing cheaply, but it is also a way for more frustration and you will still have to learn to hone on a stone if you wish to have repeatable results.

Basically, you are just cheating yourself and your face. Yes, I tried films years ago and forgot about them as quickly.

I am a coffee guy and films remind me of instant coffee...not too good compared to fresh ground coffee bean.

Thorlabs.com, buy Aluminum Oxide film, works just as well as diamond for a fraction of the cost. About $1.50 per sheet but you get 4 pieces from a sheet.

Any piece of glass will work even a 1/8 in thick piece, as will any marble or granite tile lapped flat with a diamond plate.

Glass tile is popular now here in the US, and a 3X11 tile is about 5 bucks.

I have even lapped Ceramic 3X8 tiles with great results.

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Originally Posted by RusenBG

Here in Bulgaria there is no lapping films , and i whant to try them so badly . Where can i order them , the best quality at the best prise . I have heard only good words for the lapping films .
And 30 $ for a glass plate , wow bwtwr buy a sharpening stone or cut your self a piece of domestic glass .
Glass with paste on it works fine , a little bit slow but fine .

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Try garrettwade.com for lapping films. I don't know if they ship outside of the United States, but you should ask. I think just doing a google search for lapping films should turn up sources that you could order from.

You are right regarding the glass plates. It is much cheaper to buy a large piece of float glass, ¼ inch thick, and cut it to the size(s) needed. Glass cuts easy with a glass scoring tool, some instruction, and some care. I think you'll still need to flatten the glass plates. The easiest way to do this is with a DMT diamond lapping plate, or if you succeed in getting lapping films, mounting a 400 grit or so on a known flat surface could be used to flatten the glass plate. I think you'll be surprised how much float glass is not flat, I was.

What I did learn since the original post, is that ¼ inch float glass works well. There is no reason to buy ½ inch glass, and the price difference is enormous for the thicker glass. Like $30 US for ½ inch 3" x 11", compared to $8 US for the ¼ inch. You can buy a large sheet of ¼ inch float glass plate locally here for about $25 that will yield about twelve 3"x11" pieces that you cut yourself from it. That makes it a little more than $2 for each plate, quite reasonable.

I'm fairly sure that you should be able to source 3M lapping films in Europe. Probably Germany is the best bet for sourcing there, since hand work hobbies are a big thing there. You probably know more about how to search for material in Europe than I do. Is there an equivalent of Google there? Going to the 3M international website may also yield some vendors in Europe. Good luck finding the films.... they are fun to work with and yield surprising results when honing razors.

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It is best that you don't have films there in Bulgaria, have you ever noticed any of the regular honers using films? NO

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Thats why i love stones as they give conctant results , if used properly. We have here fine sandpaper up to 3 000 grit but it clugs and the cuting power goes doun with every stroke ,even cleaned properly it is a chep way to hone a single rasor, i was hopping that lapping films are more durable and wear resistant,just my curiosity and my HAD were activated.

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Originally Posted by RusenBG

Here in Bulgaria there is no lapping films , and i whant to try them so badly . Where can i order them , the best quality at the best prise . I have heard only good words for the lapping films . .

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Another really good source for lapping films is bestsharpeningstones.com. I don't know if they ship internationally, but you may want to ask.

I'm curious about 2 things.

1/ How does one flatten a 3x11 glass tile with a 3x8 diamond plate ?
2/ Did you check the DMT for flatness ?

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Originally Posted by onimaru55

I'm curious about 2 things.

1/ How does one flatten a 3x11 glass tile with a 3x8 diamond plate ?
2/ Did you check the DMT for flatness ?

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1. It is surprisingly easy to flatten a glass tile with a 3" x 8" DMT diamond plate. I've done it dry or with water, and it works well with either. I mark the glass tile with a permanent marker so you can see the high/low spots when you begin to flatten with the DMT plate. I have flattened using the DMT plate moving on top of the stationary glass tile, or the reverse, both ways work well.

2. The DMT plate is made of steel impregnated with diamond dust. If you read the blurb on the DMT website they claim that the 3" x 8" plate is "flat" to their specification which seems quite "flat" to me. I doubt that this level of flatness will change with use, after all it is a steel plate. One could also buy the larger DMT lapping plate, which sells for around $170 that has guaranteed "flatness" to, I believe, 0.05% variation from flat. This plate, too, should not change much during use, since it too is a steel plate.

I did not check my DMT steel plates for flatness. I am comfortable going by the manufacturers claim and guarantee.

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Added later: regarding the Dia-Flat lapping plate, from the manufacturers website:

"..hand certified flat to +/- 0.0005”, the Dia-Flat™ Lapping Plate assures precise results when flattening stones."

I believe that the point he is trying to make is that if the item being flattened is larger than the item doing the flattening you probably aren't getting it flat. He would be correct. I tried the same thing with the same size glass and diamond plate and checked with a straight edge. Didn't get very flat. Closer than it came, but not flat enough to be acceptable to me.

It does not have to be, the film is only 9 inches long and while you lap the glass to get the film to stick better, it works even if you don’t lap it flat.

It is not like lapping a stone where a low spot may not be as smooth as the lapped surface, the flim is already smooth and uniform, you just will not be using the film to the fullest potential.

Yes, that is true if you do your full progression on film. But I thought the question was whether it's getting flat, not does it need to be.

You guys are overkilling things. Plate glass is flat, if you are honing properly...your blade will never know if the stone or whatever you are using is a few hundredths off. Pressure and "feel" is what you should be worrying about...

That is not true in many cases. I have had pieces of glass that look like motocross whoops. They need to be at least fairly uniform and without abrupt dips and/or twists or you will really mess up a razor. If it ever gets taken to a flat stone or film and flat glass plate afterward there will be a lot of work to do.

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Originally Posted by eKretz

That is not true in many cases. I have had pieces of glass that look like motocross whoops. They need to be at least fairly uniform and without abrupt dips and/or twists or you will really mess up a razor. If it ever gets taken to a flat stone or film and flat glass plate afterward there will be a lot of work to do.

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I agree. As I described in my post, several of the glass plates were basically ok and required very little lapping to flatness. A few however were really quite bad and required about a half hour of work getting the glass surface reasonably flat. Seems to make sense to me that trying to hone on a surface that is not flat is not a good idea. I'm not talking about a surface that is "...a few hundredths of an inch" out of being flat, but a surface that you can visibly see "hills and valleys" with the naked eye. I've certainly seen some glass plates that have visible hills and valleys.

What's nice about using glass or ceramic plates and lapping films, is that once you flatten the plate(s) you do not need to re-flatten them since they won't change in terms of flatness with use, unlike manmade and natural stones. I've picked out a particularly nice flattened glass plate of the ones I've processed and basically use that one with both adhesive and non-adhesive films for honing. I could get by with just that one glass plate, but, as you would expect I have about a dozen glass plates..... What can I say... I'm weak.

If you have a lapping plate, why wouldn't you just put the lapping film on the back of it?

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Originally Posted by edhewitt

If you have a lapping plate, who wouldn't you just put the lapping film on the back of it?

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He-he... of course you could, as long as you made sure that the backside was clean. What's nice about the glass plate, or ceramic plate, is that is is dedicated to use with the films. If you use the lapping plate for other uses, you may have to stop a honing progression in order to use the plate to flatten a stone or lap a knife, or whatever.

If you really wanted to, you could use the surface of an iPad as a substrate for the lapping film..... it seems reasonably flat to me. But, again, if you had plans to use the iPad at the same time as you wanted to use it with lapping film, you have a problem. I think it better to have a dedicated flat surface to use with lapping film.

I agree Shooter. Are we talking about wet shaving or lenses for the Hubble? Abe Lincoln was probably in office when my best shaving razor was made. I enjoy the history and use of straight razors, but these guys need to get a life.

Have you ever even lapped a piece of glass to use for lapping film? Have you even checked a few to see if they were reasonably flat? I thought not. Maybe you should limit your utterances to subjects you actually have experience with rather than insults to people you don't even know.

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Originally Posted by eKretz

Have you ever even lapped a piece of glass to use for lapping film? Have you even checked a few to see if they were reasonably flat? I thought not. Maybe you should limit your utterances to subjects you actually have experience with rather than insults to people you don't even know.

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You sir are funny & you gave me a chuckle. Thank you:rofl2: My first impulse was to put you in check with your vast knowledge of honing, but then I would be bringing myself to your level.

Remember, for everyone you THINK you are smarter than...there are 10 who are smarter & more experienced than you.

Seriously? First, no one is claiming to be smarter than anyone here except I guess you. Knowing something that someone else doesn't does not make a person any smarter than any other, only more well informed. There is a big difference between intelligence and knowledge.

Second, your vast self-proclaimed knowledge of honing qualifies you as an expert on every piece of glass ever made also? If you honestly think that all glass, including the aforementioned glass tiles from big box hardware stores are flat enough to hone razors on without being lapped/flattened you should really go buy some and see for yourself. I'm telling you, they aren't. I've bought several. It's about half and half judging from the ones I've gotten, which is similar to what the OP found. If you guys want to hone on hilly surfaces go for it, I'll stick with flat. Just don't go proclaiming that all glass is flat enough for honing when it isn't so, for newbs' sake. Plate glass cut from larger sheets MAY be better, but that's not the point. The point is, check and flatten if necessary. A few hundredths of an inch - this is .030" BTW - is WAY farther out of flat than I would ever consider acceptable. By an order of magnitude.

Third, I don't care who you are or what you may or may not know, there's no call to be insulting here for any reason. Defending that behavior is as bad as participating in it, IMO.

To the newbs who may be reading this, the takeaway from all of this would be to check your honing surface before blindly believing what anyone may say, one way or the other.

If you ever wish to have any honing lessons or anything to do with a straight razor, please contact me.

Now you're making me chuckle. Chortle even.

Just some food for thought here really don't have a dog in this fight,, Don't really like Films all that much :)

It is an accepted practice to insert a sheet of paper under the final finish film or even the last two..

Seems to me that this would negate the entire theory of "How Flat is Flat" when you are intentionally introducing "Cushion / Flex" into the equation to attain a smoother edge..

:p

Although I see where you're both coming from, not really in this specific case, as the amount that the "bad" glass plates were out of flat was far more than the thickness of a sheet of paper. Mine were close to .008" out as well as being very twisty. And the .03" - or almost 1mm (.039") that was mentioned as acceptable is nearly 10x the thickness of the average sheet of paper. For me, a .005" out of flat surface is the maximum deviation from flatness I would consider acceptable for honing a razor on, and only if it was a regular curve, not twisted or undulating.

Personally I don't much care for film edges either, but I did try them for quite some time just to give them a fair shake. Flatness is certainly more critical on stones if one must go from stone to stone in a progression. Otherwise the stone won't contact the blade in the same place as you switch stones. Not super critical on the coarse stones but more so on the fine stones that don't have the cutting power to reshape the steel. As the honing surface remains the same throughout a film progression it is certainly less critical but still not something I would ignore. Especially if the razor will ever be honed later on a stone, or as I mentioned earlier, there may be a good bit of extra work to do straightening things out.

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Originally Posted by eKretz

Have you ever even lapped a piece of glass to use for lapping film? Have you even checked a few to see if they were reasonably flat? I thought not. Maybe you should limit your utterances to subjects you actually have experience with rather than insults to people you don't even know.

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Hey eK
You are absolutely right. I have never lapped glass (unless it held booze). I shave with an old razor and hone it with an even older hone. I'm certainly ignorant on the topic of honing which is why I read about it on the forum; it is interesting. My remarks were snide and uncalled for. I apologize.

Hmmmm not really

I understand the idea of "Flat" and some people's OCD about it honest I do, if any one understands being obsessive it is me :)

But unless you are doing the exact same stroke straight down the hone/plate (You can't, it's physically impossible) the amounts of absolute you are discussing mean nothing...

Think it through before you disagree, the unevenness of a human honing stroke, and the FACT that you are not honing over the exact same spot every time negates the the minor unevenness of the Stone/Hone/Plate Don't take this to reductio ad absurdum I am not talking dished hone here I am saying Flat enough, is Flat enough...

This is one reason why we use the X-stroke in the first place, it helps to keeps the bevel even between three imperfect things

1. The human error
2. The hone error
3. The razor error


ps: By adjusting the stroke and the pressure you can easily hone on a Rounded Dished hone, but I agree the most flat it is the easier it is

I don't disagree with any of that. But the glass in question was not a regular and uniform dished shape. If it were it wouldn't be as much of an issue, agreed. My main issue is I like to be able to go from hone to film to whatever medium without adding extra work for myself.

In a case such as the pieces of glass that I got, they did not come close to hitting uniformly across an edge that was finished on a flat stone - that's how I found that the glass was so far out in the first place. Initial honing on a 12u film only hit in a few places, and at differing parts of the bevel. Like many others, I had assumed the glass would be flat enough as is. It wasn't, so I flattened it. I could have done a non standard stroke to hit all along the edge also, but that's not the way I do things unless I have to. Say on a razor that has a bent spine, et. al.

You agree that it's less effort and work as well as easier to hone on a flat surface - that subsequent honing on a flat surface like a stone would be easier and less work if the glass was flat is all I was saying in the first place. I mentioned that in my first or second post in this thread IIRC.