How flat does the substrate have to be when using the Scary Sharp method? I have checked some MDF for flatness with a steel ruler. None of it is perfectly flat because you can see a sliver of light underneath the ruler. I don’t have feeler guages so I do not know the depth of the gap. i would estimate it is about the thickness of a piece of notebook paper. Maybe two? Is that too much gap for sharpening plane irons and chisels?
Replies
How flat is Flat?
Surface irregularities can lead to the iron or chisel "hopping". Plate glass is often preferred.
Makes Sense!
Thanks for the reply Ralph. It seems to make the most sense when you think about it. I'm a little apprehensive about having a piece of glass in my shop. Maybe I can come up with a jig to hold it (safely). That would be a good use for all of the MDF scraps I have.
Granite Surface Plates
come in a variety of sizes and can be very, very flat.
Granite plates
Compared to MDF, wouldn't a granite surface plate be very, very, very, very flat? ;-)
Compared to MDF???
After reading your reply to my original post I went down to my shop and pull a chisel across each of my MDF honing blocks. I pulled slowly and deliberately paid attention to the sensations in my finger tips. You are correct - bump, bump, bump! Subtle but bumpy. I went to great lengths to make sure the MDF and the PSA backing were clean before I put them together. I'm done with those until I can get a nice piece of glass.
Thanks VAM!
I've heard mixed reviews about the granite slabs sold in the woodworking supply stores. Cracks and lack of flatness being the chief complaints. If I went the granite route I would probably get a cut-off from my local retailer and ask him to bevel or round the edges for me.
Frame it
A piece of MDF as a backer board and a frame around the edges would do the trick. A hinged piece of hardboard (Masonite) as a cover would add extra protection.
Your local glass shop should have 5/16" or 3/8" - thick enough not to flex.
Many Thanks!
Thanks to your input I've decided to go with a piece of 3/8" glass. The MDF backer and frame are also a great idea. I've also done business with the local glass shop. They are friendly and reliable. I'm sure they have a piece they could cut and bevel for me.
Feelerless Fellow
I just called THE International Bureau of Weights and Measures based at the Pavillon de Breteuil in Sevres, France. They said , and I have had a premonition for some time this late breaking development would come to pass soon ; (some times these things just come to me (( but I am not psychic or anything)) that they were working on a new precision measurement unit that every one has on hand.
so . . . let me get a breath here . . . I am just so excited . . . . anyway they said . . .
are you ready for this ?
They said it is OK . . . to use your note book paper as a feeler gauge (or even two stacked together). They used to send out unit police to stop this kind of behavior, and the penalties and fines could get quite brutal I can assure you, but have now reversed their policies and embrace paper thickness unit use. I know this is what has been stopping you but you are free now. Your pressing needs and desires for paper unit use are FINALLY on the right side of the law .
So . . .
go on . . .
be bold . . .
slip that paper sheet (or two if you dare) under that straight edge.
Give us a full report on how it goes and any injuries incurred.
It isn't official and I am probably risking censorship by divulging this but the average note book paper sheet unit is on the order of three thousandths of an inch (.076 millimeter). You know how the metric crowd frowns on converting back and forth. Just use the easy one they cry (the easy one being the metric one). In this case the single note book paper unit. The SNBP unit. Silly metric user people . . . they just don't know how much fun adversity can be ( once you get used to it and build up some calluses ).
HP Color Inkjet printer paper is .00445 inch (.113 millimeter)
The HPCI unit
The cover of the latest Fine Woodworking magazine is .005 inch (.127 mm)
The FWWC unit
If you want to go for extreme precision and be all nerdy and sheet one of the pages inside the magazine is .00255 inch (.064mm)
The FWWPI unit. Wow ! (in the spirit of Ralph I am not going to tell you which one : ) )
So there you have it . . . a veritable arsenal of measuring devices ready to hand
If the unit police bang on your door don't blame me. You don't know me SEE ? !
: )
PS: Oh and I almost forgot . . . if you want to sharpen plane blades and stuff use stones and flatten them on one of these :
http://www.amazon.com/DMT-W250CXNB-10-Inch-DuoSharp-Extra-Coarse/dp/B00004WFUL/ref=sr_1_5?s=hi&ie=UTF8&qid=1349638733&sr=1-5&keywords=dmt+coarse+extra+coarse
Here are the best stones I have found and the best place to buy them:
http://www.craftsmanstudio.com/html_p/Q!0P0000.htm
but I am not opinionated or any thing
: )
Thanks roc
Your posts and replies are always entertaining. Believe me, I've looked at the stones you mentioned, discussed the possibilities with my wife/financial diciplinarian and was advised that if I sold a kidney I could do whatever I wish with the proceeds. However, I would not be allowed to skip work or use vacation time to undergo the procedure. I was also told that undergoing such a procedure and its associated recovery time would not alleviate my responsibilities toward the accomplishment of my household chores - that must be completed prior to (ahem) "playing" in my work shop. Therefore, I'm going with honing film on glass. Don't bother with the long term investment vs. short term outlay argument either. I lost that one months ago. I lose most arguments. My wife is a lawyer. She makes her living arguing with other people who make their living arguing with other people who... Get the picture? It's either honing film on glass or my tools get sold on eBay and the workshop gets turned into (another) storage room. Which would you choose?
That is one tight spot you'r in.
> responsibilities toward the accomplishment of my household chores - that must be completed prior to (ahem) "playing" in my work shop.<
Hmmmmmm
That general phrasing and tone sounds so , so familiar . . . I swear I just heard an echo in another part of the house where I am at saying that very same thing.
You could open with the price of the stones etc. are about the price of a tune up on HER BMW and you will still have your sharpening stones when she is eyeing the new models a few years form now.
You could try that tack . . .
Tune ups on Hondas / much cheeper . . . that sort of thing.
You may have to sell a piece of furniture that the stones helped produce. Then they suddenly become "ESSENTIAL" to your lively hood and all that baloney.
OK, Ok . . . I got it ! Sell your car, ride your bicycle to work like I do and then you have all that capital and savings for wood tools.
Nah huh ?
Hey I tried.
I could discuss with her just how little they actually do during one of those BMW tune ups . . . 'corse she would come back with isn't it essential to protecting her investment and I would have to say wellllllll yeeeeeeesssss.
Sell your body and pay cash for everything so there are no credit card slips and charges etc..
Yep that is what you are going to have to do.
Ah ! Another woodworking problem solved.
PS: thought you might like some tool porn . . . see photos. Oh Yah !
Have you tried . . .
. . . the POS (pair of shoes) argument? As in, "This stone is only 0.6 POS."
On second thought, that probably won't work, either. Her shoes are essential to her law practice, while shop stuff is completely non-essential. ;-)
Another approach is to save spare change . . . in a place that isn't likely to be discovered, like in a bag behind the rose bush. You make deposits while weeding and tilling the soil, so it's not obvious. Once you've saved up enough to make a purchase, you have it shipped to your friend George's house. Later, when she sees the item in your shop and asks, "Where did that come from?", you can reply, "Oh, George gave that to me." One point, though. George needs to be single. Otherwise, his wife will snitch on you.
It is not easy being the Insignificant Other
Queenmasteroftheuniverseandbabybunnytrainer just "let" me help her in the kitchen a bit ago. We are having salmon paddies.
I asked her "why do you let me help you in the kitchen now but used to be against my helping". She said "I had to teach you who was the boss first . . . in the kitchen. She threw in the "in the kitchen" bit right at the end to soften the effect a bit.
Annnnnywaaaaaay . . .
POS units. I like that. Hey don't broadcast the roseexnae in the gardennaye. They listen and look in from time to time you know.
OK Ok "kidding" aside I can make one more useful suggestion :
If you don't like the idea of glass in the shop, which I can totally relate to, then consider getting a length of aluminum plate that is fairly thick. That is what Mike Dunbar uses and he is one of if not theee guy who started Scary Sharp. Extruded aluminum plate in good, from the plant, new, condition is extremely flat !
You have no idea who you are dealing with...
Hide something? From MY wife? You know not of which you speak.
Chuckle
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