flattening plane blade backs

[Robert Culver]

I have been working on flattening a couple hock bench plan blades for a number 5 and number 7 it seems that it is taking quite a while to get them right I have switched from my 1000 grit shapton pro to 220 wet dry paper on glass im wondering if I should step up to 100 grit or 80 grit then work my way through the process again or if I should just go to the ruler trick and call it good enough!

[David Weaver]

An iron needs to be flat to the edge more or less for a ruler trick to be applicable.

100 or 80 grit norton 3x is the best paper to use if you're going to use paper. The PSA al-ox rolls from mirka (the gold ones) or something equivalent from 3m is also good. Stick to the aluminum oxide and don't waste your money on any of the blue or purple paper. Whatever durability is added to the abrasive is for high speed work. It doesn't translate at low speed - plain old sharp aluminum oxide is still the best. Silicon carbide is second best, but its friability is a little counter productive.

[David Weaver]

By the way, make yourself a holder like andrew fleck showed in another thread. It will literally save more time than it takes to make on the first iron. if you want to be extremely lazy, you don't even need to put handles on it, just take a section of 2x4 about 14 inches long and drill two holes in it and run bolts through it.

[Robert Culver]

I will have to give that a shot looks like a finger saver and anything that saves time is welcome in my book thanks for the tip !!

[david charlesworth]

I like to use double sided sellotape to stick a small handle touching the heel of the bevel. This handle is about 1/2" less wide than the blade and 3/4" X 3/8" in section. Sharp corners removed for comfort.

This allows me a much better grip, and makes it possible to exert much more downward force. This speeds metal removal.

When flat, near the edge, on an 800 grit or equivalent stone, I can go straight to the ruler on a polishing stone. Something like 6,000, 8,000 or 10,000 grit.

Best wishes,
David Charlesworth

[Jim Koepke]

My 4' granite slab with full length strip of 80 grit will fix that blade real quick.

If you're coming out west, shoot me a PM.

jtk

[Noah Wagener]

I put a blade on the side of a grinder wheel to get below pitting on a blade back. A hand cranked grinder. Besides loose grit or paper on a flat substrate, what are some other methods? I have a coarse diamond plate that is molasses and some 90 grit silicon that is quickly ineffective. What was the traditional method? They have sandstone wheels, did they have benchstones as well? Would it dish too fast? Are there any super coarse Naguras you could use on a harder stone to get an aggressive slurry?

[David Weaver]

A sandstone grinder is probably OK as long as it's flat enough to not do too much damage. Things I have tried that don't work that well:
* loose paper or new sanding belts (dubbing creates a lot of extra work - and on top of it, the stuff belts are made of is not intended to take repeat high pressure use)
* Stones (not diamond plates) - any type. The most aggressive types are the crystolon and other not too hard silicon carbide stones - as long as they're new - the old ones bonds have hardened and they're worthless. Stones go between several different problems, from being fast enough but too soft to being hard enough and loading. Coarse stones are good for bevel work (maintenance grinding, or more of an iron is thin and soft enough), but not good for any signficant amount of flattening.
* Coarse diamond hones - good for a little bit or if doing basic tools, but not good for heavy removal of pitting
* Loose aluminum oxide and loose silicon carbide - silicon carbide crushes right away under low speed high pressure and becomes fairly worthless, making a huge amount of fine sludge. If you have to remove a small amount of material and want a decent finish, it works well. Aluminum oxide, the same except that it doesn't break down quite as fast, it's just not as durable as diamonds, nor as sharp cutting ,but it's cheap. I guess if you had a big enough area you could make use of it (soap supply places sell 100 grit al-ox cheaply - like $6 for a pound or two).


What does work well:
* a long run of al-ox PSA stick down paper (like mirka gold) on a flat surface - could be a jointer table, could be a long glass shelf. Expect that the paper won't last forever (it's probably intended for a lot of high speed low pressure work and not low speed high pressure) and you can still do some damage if you don't keep things flat. Works best if you have a holder of some type.
* Loose diamonds on cast iron or mild steel (also requires a holder for the iron). 100 grit diamonds can be had for about 25 cents a carat now, and I'd imagine that for your 25 bucks, you could flatten a couple of hundred irons that are just a little out or probably 25-50 pitted irons. The surface MUST be flat (the flattening plate that LV sold with the grooves is pretty pointless for flattening backs of anything), so either a milled mild steel plate, a kanaban, or a piece of rigid flat cast off of an old machine or a plane bottom, etc.

If you work the whole surface of a piece of cast or steel, you can keep it flat (which means that something 2" wide or so is better than something bigger). If you don't work the whole surface, it will get hollow in the middle over time, which leaves more work for you to do following that.

[Robert Culver]

I have thought about the 3m roll but have a though time spilling out the 40.00 might have to give it a shot

[David Weaver]

Presume those are 25 (or more) yard rolls 2 1/2 inches wide or so? They'd work well. The initial outlay is annoying, but it wouldn't take more than a couple of yards of 80 grit to knock the pitting out of a vintage iron. Couple of bucks.

In terms of the diamonds, I've probably been through about 25 carats of 100 grit diamond in 6 years, which includes on and off again use when I get the bug to buy a bunch of planes (esp the vintage type that have pitting but plenty of thickness to remove the pitting). That's probably 40-50 irons worth to burn through those 25 carats, with 10 or so of them being badly pitted.

Even if you're very liberal with the diamonds (and it's nice to be if you have a lot to remove), it'd be really hard to go through more than a dollar or so's worth of diamonds in a single iron. For some reason, I'm on a glut of old woodies right now. The entire planes, save one very nice example, have averaged less than $20 per and have at least 1 1/2 inches or more of iron left on them that just needs a little flattening. It's almost like getting something for nothing. I have to believe the planes are cheap because of the irons, and because of the wide open mouths. The diamonds take care of the iron and proper use of the cap iron eliminates any need for the mouth to be really tight.

[Noah Wagener]

Thank you.

Are loose diamonds only to be had via mail order?

As a "what the hey?" i bought a 50 lb bag of fine sand and put it on top of a Japanese natural stone i just bought. It worked ok but was pretty messy. I would have to wait for summer to do that again. It roughed up the stone pretty bad but the stone was like a slow 1,000 grit though i do enjoy using it. I bought it because of the infectious enthusiasm of that guy 330mate. Good for oire nomi!!!! make for disrespect the rust! make steels happy!

I was going to send you a link to some stones from a Chinese seller that i was sure you had not tried. They looked like gemstones and one looked like a translucent Arkansas. I did a search to see if they (Agate and Jade) were common as hones and the first link was a forum thread with you discussing one at length.

Do you know anything about Morty the Knife Man brand Arkansas stones? Could i send you some links to stones on auction to get your opinion?

[David Weaver]

Send me the links on the morty the knife man stones. Arkansas stones are variable, and I'm of the opinion that a vintage pike washita and a good finisher (can be a newer stone if a good one) are all you need, perhaps with the exception of adding a synthetic oilstone if you tend to chip edges for some reason.

I do have one of the green jade/agate stones. They aren't cheap, but they're not ungodly expensive (actually, they are all over the place depending on who the seller is - they can be had for about $90). They have a place purely as a burnisher, but not really anything else, and are not close to being the equal of a good hard arkansas stone for woodworking. You can entertain yourself with one, but it would get on your nerves if you had no other finisher and you were trying to use it in place of a faster stone.

The washita can wear two hats - if you let it settle in, it will rival the finish from a translucent stone. It won't equal it, but it will still be fast enough to use without any other stone and you can get an edge off of it that is paring sharp with no issue, and more easily. Or, you can abrade the surface and it will cut fast with bite.

The trouble with the washitas is that a lot of stones that aren't pike mine stones are called washitas, and they don't have the ability to go fine like the pike stones do - they are a lot more one dimensional. And when you do find a genuine pike, they've gone nutty in price. I like the pike labeled stones the best, though, maybe out of any stone of any type. They are easy to use for a freehander and give you a whole lot of flexibility if you can make a good clean grind and minimize the amount of metal removal you do with your stones. (Of course, grinding on coarse stone is fine, too, as long as you set up geometry well. I find it easier and faster to do it with a bench grinder, but it may just be because I don't do it without one very often).

[David Weaver]

Btw...yes to the diamonds being a mail order good. Ebay, some seller's got a name yuri something or other yuriy06 or something like that.

I just looked up morty the knife man stones, and I'm not sure exactly what they are. The one I see a picture of doesn't look like a pike washita, and it's also not pore free like a good finisher will generally be.

They look like a fairly common "hard" stone as stones are marketed now, which are not equivalent to vintage "hard" stones, which were pore free stones like a black arkansas finisher or a translucent.

Money no object, I'd look to find a vintage pike lily white and a dan's HTA or black (dan's stones are the closest modern things I've seen to the good vintage stones - I only like the trans better because it lets me see what the stone's doing when I'm fiddling with a new tool). IF you're freehanding, 8x2 size is a really nice size to have, it's easier to keep flat than wider stones.

I'd avoid modern norton stones unless they're cheaper, IME they are decent stones, and less expensive than dan's, but they are not as fine as dan's stones and leave me sort of unimpressed, and I do have a big one (HTA) still in a tri hone in case I think I'm misremembering something about them. I liked the black ark better than their trans ark, but it wasn't as fine as a vintage black ark - it has more of a favorable combination of speed and fineness. The dan's black is finer, though (and more expensive).

It gets a little harder every year to find any good vintage stones for an inexpensive price, the market for them is getting bigger between the woodworkers and shavers. Once shavers latch on to a certain type of stone, until they're not fascinated with it any longer, it's almost impossible to get a decent deal on one.

[David Weaver]

Thank you.
As a "what the hey?" i bought a 50 lb bag of fine sand and put it on top of a Japanese natural stone i just bought. It worked ok but was pretty messy. I would have to wait for summer to do that again. It roughed up the stone pretty bad but the stone was like a slow 1,000 grit though i do enjoy using it. I bought it because of the infectious enthusiasm of that guy 330mate. Good for oire nomi!!!! make for disrespect the rust! make steels happy!


Presume that the stone you're referring to is one of his iyo nagura type stones, white or whitish orange? I've never used one, but stones like that have to be constantly slurried to work well, and if you use another stone of the same type that's as hard, they will grade each other. One has to be soft and the other hard. They do work well to remove rust, like he says. I have a scrap of that type as a nagura, but no full size stone. I'm wary that even the best of them (which are a couple of hundred bucks) might not be better than the cheap ones.

[David Weaver]

Yet one more addendum to what I put above - I just went out to peebay and see that even a no 1 washita is over a hundred bucks (one of which I got with label on and Chris G still has - for about 40 or 45 bucks not that long ago). To me that is unreasonably high, and I don't know who drives that kind of thing. I paid $90 for a lilywhite less than a year ago, and have learned to spot likely unlabeled washita stones that aren't called "washita" on ebay, most of those being about $25-$40 each, and I'm 4 for 5 guessing so far.

Anyone who calls their stone "pike" without there being a label on, and then prices it like a pike - I would avoid. Those might be very good stones, but like many older stones, half the value or more is in the label, and a stone without a label should be priced to reflect it.

The trouble with learning to spot a true washita is that you have to see some stones that are or aren't washita, and the only way I know of to do that is trial and error. Once you know what to look for, you really don't need more stones. Once you find one decent one, you really don't.

Mechanic's Friend, Carpenter's friend and woodworker's delight or whatever all of those old labeled stones are called are pike type washitas. They can be had cheaply sometimes and are good. I wouldn't give an arm and a leg for one, though, because they don't seem to get the $$ respect that the pike stones do.