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Post by parfive on Apr 26, 2021 17:14:35 GMT -5
If you’re happy just letting it settle, fine.
Otoh, the paper bag routine’ll get you that gallon of clean oil overnight.
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Post by Bob on Apr 26, 2021 18:55:45 GMT -5
Thanks Henry on the oil.
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Post by Rockoonz on Apr 27, 2021 12:54:29 GMT -5
If you’re happy just letting it settle, fine. Otoh, the paper bag routine’ll get you that gallon of clean oil overnight. I generally do both. But I buy it 55g at a time to pay well under $10 per gallon, including Kevin delivering it. I really need to locate some steel pails with lids so I can set up a brown bag filter setup at our new place. In the meantime I'm hoarding grocery bags in anticipation of the greenies outlawing them.
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Post by Peruano on Apr 27, 2021 13:41:36 GMT -5
In terms of draining slabs when they come off of the saw. Its mostly to reduce the amount of oil going into the oil/dri (cat litter if you go that way) rather than trying to recover oil. Often an overnight slanted drain on a saw table will result in a slab more or less dry to the touch -- then it can go to oil/dri granules or directly into dawn liquid. Either way its cleaner and less oily than with no drain. True I throw preforms into the oil/dri but large slabs or end cuts always drain. I drain my oil through paper bags but realize that most of the oil to be recovered will be in the first few days. After that its a bit now and a bit later. You have obviously discovered that most of the mess that most folks fear can be avoided by careful oil management. The problems of controlling water causing rust and sediments on stones, make me use oil for just about all processes. I do have 6" saw in which I use water, but only when I have a special stone, or am lazy about getting oil on my glasses.
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Post by Bob on Apr 29, 2021 10:59:04 GMT -5
It puzzles me how that dry to the touch thing can happen, which I have noticed. I googled "can mineral oil evaporate" and the answer online is no. Yet it seems to me that is it happening. On a rock, I can see it might gradually soak in. Yet even on the saw itself, it seems like after a week, some surfaces are dry which seems weird.
What is it that wears out on a lapidary blade? I figured the "teeth" would decrease to nothing over time. I think they are 4mm high new, and even with all the freehand sawing I've been doing, I bet I've still got 3.5mm left, so hardly anything has changed on the diamond bearing area of the rim. However, it seems to me that the blade might be getting thinner. It seems a bit floppier and more flexible. Is that where is will fail, on the core the perimeter is welded to?
I've thought about how this core might be wearing and maybe the large rocks I saw pressing against it cause a little wear due to tiny diamond dust that might be in the oil from the tank. It certainly sounds scary to think a blade might fail upon getting too thin. I can also mic it to check, but from the feel of it I'm just sure it's happening.
Perhaps instead of the MK-301 #166068 10" x .040" blade I'm using, I should have instead tried the MK-303 #157180 10" .060" blade, which obviously would be much stiffer. I'm guessing that stiffness would really help on freehand trimming like I'm doing. Although the MK-303 comes in several blade thicknesses, the MK-301 comes in only that one.
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Post by Peruano on Apr 29, 2021 13:33:17 GMT -5
The diamond bearing part of the blade is wider(the kerf) than the rest of the saw blade core. Hence all wear will be on the perimeter and or the extreme circumference of the blade and not the rest of the blade. That wider outer rim reduces friction with the rest of the saw surface. Blades that are dished radically or flex alot can crack probably most frequently at the perimeter of the flange washer. The blade has no teeth (I know you know that), but the projecting diamonds are harder than anything and hence don't really wear much. I have a 12" slab saw blade (MK 225) that I've been using for years (bought used from an RTH member) and it still cuts away and shows no wear what so ever. Ideally as a blade wears, I would expect that narrow band around the extreme perimeter of the blade to be narrower (i.e. the circumference of the blade should be reduced), but thats just the way I envision the wear and I could be full of beans. Feeding by hand and trying to avoid crowding the blade and slowing the rpms, is probably a good way of minimizing wear. Saws may cut better with clean oil, but it probably takes a lot of rock grunge to make a real difference unless you have an underpowered saw. You are grinding, not really sawing.
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Post by Bob on Apr 29, 2021 14:29:04 GMT -5
Thanks for that clarification.
What do you think of the following info? It's from a post on this forum from over a decade ago that turned up when I was searching about lapidary blades. It was written in a kind of sloppy way and I cleaned it up some.
One thing that really got to me was about needing to use the blade in both directions. The part about flattening the edge got my attention too, because I can tell that edge is no longer flat, it's either rounded or v shaped.
=================================== Jul 31, 2008 23:04:34 GMT -5 Jack, lapidaryrough said:
Never use a brick on a saw blade, Bricks well grind this thickness off where the diamonds are real fast, then you’ll have a blade that well not dress or sharpen the face of the diamonds.
Never use a grinding wheel coarser than 220 grit and only cut about 15 sq“s off the wheel. The very best material to dress a blade is OBSIDIAN only or 220 grit wheel.
Blades must be run in both directions un-less you’re using non-lapidary blades such as concrete/asphalt/green cement blades.
As a diamond blade cuts the diamond faces wear down and the matrix will expose more of them.
If you only cut in one direction the blade will glaze. Don’t be thinking “I need to dress the blade.” No, you need to remove the blade and run it in the other direction.
You can dress a blade with a piece Davis Creek Rainbow obsidian or Lassen Creek. Gold Sheen works fine to.
The cutting face and side edge of the blade is where the cut is made. The sides do more cutting of the rock then the face edge.
The cutting face of the blade MUST be square and a right angle to the blade, flat at the point it contacts rock. If the face is rounded--that's saw blade abuse. If that happens, mark the blade with a felt pen, so that you can take a large file and using it’s edge strike the blade each and every 1/8” to square up the edge.
Don’t hit hard, just enough to flatten the face. Each hit must be the same. Then dress with obsidian. Do not run the file across the blade, only flatten by hitting the blade. This will destroy some of the diamond particles, but the blade matrix will be fine. After dressing, saw a big Brazilian agate. Make two cuts, then reverse blade direction and make two more. ============================
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Post by Rockoonz on Apr 29, 2021 16:38:29 GMT -5
I'll try to answer inline, see if I remember PB HTML Thanks for that clarification. What do you think of the following info? It's from a post on this forum from over a decade ago that turned up when I was searching about lapidary blades. It was written in a kind of sloppy way and I cleaned it up some. One thing that really got to me was about needing to use the blade in both directions. The part about flattening the edge got my attention too, because I can tell that edge is no longer flat, it's either rounded or v shaped. =================================== Jul 31, 2008 23:04:34 GMT -5 Jack, lapidaryrough said:
Never use a brick on a saw blade, Bricks well grind this thickness off where the diamonds are real fast, then you’ll have a blade that well not dress or sharpen the face of the diamonds.
Never use a grinding wheel coarser than 220 grit and only cut about 15 sq“s off the wheel. The very best material to dress a blade is OBSIDIAN only or 220 grit wheel.
Blades must be run in both directions un-less you’re using non-lapidary blades such as concrete/asphalt/green cement blades.
works fine with non-sintered blades or the cheap crimped edge blades, but not with sintered blades. Barranca and MK put a direction arrow on their blades for a reason
As a diamond blade cuts the diamond faces wear down and the matrix will expose more of them.
If you only cut in one direction the blade will glaze. Don’t be thinking “I need to dress the blade.” No, you need to remove the blade and run it in the other direction.
look above, only do this with old style and crimped blades
You can dress a blade with a piece Davis Creek Rainbow obsidian or Lassen Creek. Gold Sheen works fine to.
nope, obsidian will clean residue from things like jade and soft stones, but will not dress. It's not abrasive.
The cutting face and side edge of the blade is where the cut is made. The sides do more cutting of the rock then the face edge.
that would be very bad, the kerf would get thinner and the blade would become useless quickly
The cutting face of the blade MUST be square and a right angle to the blade, flat at the point it contacts rock. If the face is rounded--that's saw blade abuse. If that happens, mark the blade with a felt pen, so that you can take a large file and using it’s edge strike the blade each and every 1/8” to square up the edge.
Don’t hit hard, just enough to flatten the face. Each hit must be the same. Then dress with obsidian. Do not run the file across the blade, only flatten by hitting the blade. This will destroy some of the diamond particles, but the blade matrix will be fine. After dressing, saw a big Brazilian agate. Make two cuts, then reverse blade direction and make two more. ============================On this last item, I call it swaging and I do it with a hammer, with the blade removed and flat on a table with the edge sticking out. The goal is to make the edge square and wider than the part to the inside. The edge of the blade should not be cutting, or the kerf would be getting thinner, not a good thing.
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Post by Bob on Apr 30, 2021 10:50:41 GMT -5
For wood saw blades, the direction arrow is almost always acid etched on the blade and remains there through years of use, even though the proper direction is obvious to most people due to slant of teeth. I was surprised that the direction arrow on my new Barranca blade was small and on a bit of paper that got worn away in the first few days of sawing. And there seems to be no directionality to the "turbo" edge. Seems like if lapidary blades are one directional that the makers would help out a bit more.
Are you saying that there really is one proper direction even though nothing directional can be seen with the naked eye in the way the edge is made? Or, it's not that, but that once wear begins, and the diamonds are exposed with the matrix behind each one etc. that the reversing the direction would merely accelerate the wear and be a dumb idea?
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Brian
fully equipped rock polisher
Member since July 2020
Posts: 1,507
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Post by Brian on Apr 30, 2021 11:04:50 GMT -5
Bob, I did a search on that last question myself because it didn’t make sense to have a direction indicated for a continuous blade.
Your last guess matches with the consensus I found. As it runs, the diamonds are exposed with a trail of matrix behind. Switching directions causes more wear of the matrix and can lead to slower cutting and vibration until the blade is “broken in” to the new direction. Switching directions does not seem to provide any benefit that I could find.
I also saw comments that the blades can be broken in at the factory, which provides the initial directionality.
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Post by Bob on Apr 30, 2021 14:08:43 GMT -5
Thanks Brian. www.mkdiamond.com/pdf/prop65/MK_blade_manual.pdf makes for some darn interesting reading on some aspects of all this. However, this seems to be written primarily for their non-lapidary blade series but I'll bet a lot of the info is still applicable. See "When a Blade Stops Cutting" on page 12. The cause of Undercutting on page 15. Toward the bottom the reasons for glaze over or close up are mentioned, which I bet I have caused. Page 25 2nd to last bullet point is very interesting to me because I'm seeing that described wobble and flutter, yet the RPM is factory correct. So I bet I have heated the core in my freehand cutting of large rocks in not holding the rock perfectly at times. One cut took almost 13 mins the other day. I think that heating is mentioned somewhere in this document as one cause of the wobble and flutter. Oh, I see it now on page 30. Several times is mentioned that a blade can be factory retensioned. I think I'd better 1) try buying a thicker, stiffer blade since my trimming is all freehand, and 2) contact MK about having this blade retensioned and what the cost would be if they even can do it.
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Post by Bob on May 3, 2021 12:04:55 GMT -5
I took off the blade, and cleaned it.
I mic'd it and found that core was about .030, a decrease of 25% from .040. OMG, that is scary! I mic'd it about 1" down from the rim in several places. I had not mic'd it new, so just assume the .040 was accurate. This shook me up so bad that I have already gone and ordered the MK-303 blade in the .060 version hoping for the stiffness.
When the blade is laid on a flat surface, it's obviously not planar any longer. It's curvy a bit like a potato chip. When laid like that, the worst part has perhaps 1.5 to 2.0mm of air under it.
Then I got under a lamp and really looked at the rim under 10x lens. Wow, never would have I expected to see all those faceted diamonds. As expected, many are backed by a matrix support just like the leeward side of a snowbank. There were also a lot of holes where diamonds used to be. I carefully looked for any structure or feature that indicated one blade rotation direction would matter, and I could not find one. I saw no evidence of "glazed over" diamonds, not that I know what it means. The edge though is definitely not a flat surface perpendicular to the side of the blades. It's worn down and rounded just like an old metal washer you had rubbed against sandpaper. There are of course diamonds on edge and sides of rim.
So I reversed the direction, figuring the worst that might happen is some diamonds might be lost quickly in first few cuts. The blade cut 2-3x fast, and did the entire session which was about 45 mins! This sudden increase in productivity didn't decrease, but remained the entire time. I have no idea why. I wish I had measured the height of the diamond rim before doing this, so I could compare after and see if reversing it might have caused a sudden loss of some of the rim. One might guess that doing this ripped off the "support" matrix that normally would back up the diamonds, but one might also guess that right after that some diamonds--now unsupported--might have been ripped out until new supports were created in the opposite direction.
Based upon this experience so far, reversing the blade had amazing benefits. Anyone reading this needs to know I'm only doing freehand work and not making slabs nor do I even have a drive mechanism on this saw. I'm cutting all kinds of size from the size of a grape up to cantaloupe. Most though are around golf ball to plum size.
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Post by HankRocks on May 3, 2021 12:23:08 GMT -5
I took off the blade, and cleaned it. I mic'd it and found that core was about .030, a decrease of 25% from .040. OMG, that is scary! I mic'd it about 1" down from the rim in several places. I had not mic'd it new, so just assume the .040 was accurate. When the blade is laid on a flat surface, it's obviously not planar any longer. It's curvy a bit like a potato chip. When laid like that, the worst part has perhaps 1.5 to 2.0mm of air under it. Then I got under a lamp and really looked at the rim under 10x lens. Wow, never would have I expected to see all those faceted diamonds. As expected, many are backed by a matrix support just like the leeward side of a snowbank. There were also a lot of holes where diamonds used to be. I carefully looked for any structure or feature that indicated one blade rotation direction would matter, and I could not find one. I saw no evidence of "glazed over" diamonds, not that I know what it means. The edge though is definitely not a flat surface perpendicular to the side of the blades. It's worn down and rounded just like an old metal washer you had rubbed against sandpaper. There are of course diamonds on edge and sides of rim. So I reversed the direction, figuring the worst that might happen is some diamonds might be lost quickly in first few cuts. Wow again, the blade cut 2-3x fast, and did the entire session which was about 45 mins! I had no idea why. I wish I had measured the height of the diamond rim before doing this, so I could compare after and see if reversing it might have caused a sudden loss of some of the rim. Based upon this experience so far, reversing the blade had amazing benefits. Anyone reading this needs to know I'm only doing freehand work and not making slabs nor do I even have a drive mechanism on this saw. I'm cutting all kinds of size from the size of a grape up to cantaloupe. Most though are around golf ball to plum size. Bob, I think the rated .040 is the thickness of the diamond edge, the kerf. The steel core will be less, probably around .030 . The core should not be worn down by cutting as the diamond kerf is wider than the steel core and the rock does not usually run against is if the rock is clamped and the run of the table is perpendicular to the blade. Even if the rock rubs against the steel core it's only going to push it over a slight bit. If the steel core was wearing as much as you measured, it would be a recipe for an eventual catastrophic failure of the blade which I have never seen happen.
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Post by Bob on May 3, 2021 13:21:22 GMT -5
HankRocks, you're right! I have no idea why I thought the core would vary in thickness like I did--was just on wrong track. I am not worried about safety thanks to your post.
Since I already ordered that .060 blade, I guess I will measure it's core when it arrives. If it's also .030, then it would not really be stiffer. Maybe it will be somewhere between .030 and .060.
MK hasn't yet replied to my website inquiry about retensioning the blade. I will call them this week if have to. If I am causing the out of planar problem, then I could potentially need to have one blade on while an alternate blade was being sent to them for retensioning.
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Post by Bob on May 4, 2021 12:07:19 GMT -5
Well, I mic'd the cutting rim last night and it's .050. So I guess the theory that the .040 specs on this blade refer to that are off in some way. Will be interesting to check both on that new thicker blade that is on the way.
I cut again last night on this reversed blade. Oddly, the cutting speed seems to be even better now than before. This is exactly the opposite of what I expected to happen. I thought the speed might be extra fast right after reversing it and then fall off. But I cut again for about 45 mins like the first time. And I'll just swear that it got a little better as I went along. Apparently there is a lot going on with these blades and many variables that are complicated.
Just arrived is a white MK Dressing Stick part #152792 for me to try also. I don't think I knew it when I ordered it, but on the back it says for "MK Tile Saws" and has multiple models listed. I think MK tile saw blades are different from their lapidary blades. But it wasn't expensive and I'll try it the next time this blade starts slowing down. The lights I have mounted are bright enough that I can inspect the blade easily while mounted on the saw with my 10x lens. So I will take a good look before and after I dress it to try to see what dressing it actually does.
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Post by Peruano on May 4, 2021 12:32:45 GMT -5
I cut a variety of material , but most of it is hard. I've never dressed a blade, nor have I ever beat on it to restore the perimeter profile. I cut a lot of slabs, but mostly using a slab saw that feeds slower than you would normally using hand feed. I'm still using the same trim saw blade that came to me used with the saw several years ago, and the same 12" slab saw blade that I installed more than 5 years ago. I realize some folks believe in higher maintenance, but I don't understand it unless its original quality of blade, or operator variance. We all develop our own techniques and biases and until proven wrong cling to them like incumbent politicians.
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Post by Bob on May 4, 2021 14:19:20 GMT -5
I can see how slabbing with a vise would be much easier on blades. To cut my rocks, I use a black marker pen to go all around the part to be cut, trying to keep the mark is what will be one plane as much as possible. Then I hold the rock in the position best suited to cut that plane while also having the max support on the saw table. But now and then, a rock won't behave or the shape is wonky and the blade gets strained at some point during the cut. So with that, I'm probably pushing the envelope a little and causing problems.
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Post by Bob on May 28, 2021 11:50:15 GMT -5
Got the Mk-303 blade a few days ago. The rim mic'd at .068, possibly more than the .060 spec because of the little diamond bits sticking out. The core is .045, just a bit more than that other blade. But overall I can tell the blade is much stiffer. I will mount it soon and see how to goes compared to the Mk-301.
It does have a directional arrow on both the paper and on the blade itself. The one on the blade appears to have been made with an electric arc and probably will last through side wear pretty good. When I examined the rim for any directional construction, I saw none, other than the diamond bits are already backed up in one direction as if the manufacturing process does that.
The wobble in my 301 blade is pretty bad now. It makes hand cutting rocks larger than an egg a bit challenging because if I don't have things positioned just right, the blade will wear against the side of the table slot under a rock when I can't see it. But with smaller rocks, it's still okay and easy to control. So I may start dividing up my rocks to be sawn into small and large, and just do the small ones with the 301 blade and hope the 303 blade which is stiffer will be better for the large rocks.
Oddly, the label on this new blade said it was designed to be used with water-based coolant. Surprised it didn't water or oil.
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Post by Bob on Jul 1, 2021 13:42:27 GMT -5
Well, finally got around to mounting the MK-303 blade a few days ago. The saw runs so much quieter, perhaps due to lack of "serrations" on rim or lack of blade wobble. It cuts significantly faster on anything lemon size or smaller. On larger, about the same or slightly faster. On cutting a large rock the size of an apple or larger, the other thinner blade would never bog down the motor, but this blade will bog down and slow down the motor perhaps due to overall amount of surface area in contact with rock due to it's greater width and rim. So I have to be careful with my feed pressure.
But the stiffness of the blade is wonderful. I don't have to worry about bending the blade and the blade touching the saw's throat slot. With a very odd-shaped rock with the cut starting on an angled side, with the thin blade I had to first turn the rock so that the blade could get a kerf started, then turn the rock into proper position to proceed with the cut. But with this stiff blade, I can start the cut about anywhere without such manipulations. Also, the side of the blade can be used as a grinder to some extent to touch up this or that after the cut. The other blade was too thin and flexible for that.
It does remove more material and the cut edges are slightly rougher and slightly chipped out. I found my face shield being impacted by tiny pieces of rock debris that had never happened with the thinner blade.
It makes more of a cutting sound than the thin blade did. Perhaps the diamonds protrude more from the matrix. I can literally sense the cutting being done in my fingers when holding the rock. In that way, it feels more productive than the thinner blade. The cut face is slightly more rough, not that it matters for tumbling as I'm not making slabs to polish. The cut face is sure super flat due to the stiff blade. The cut face with the thin blade had more undulations as the blade shifted now and then during the cut.
My conclusion is this is the blade of choice for general hand trimming like I'm doing. However, I may start dividing my rocks to be trimmed into two piles. Most would be for this blade, probably 90% or more. But for pieces for which I want to absolutely minimize the material lost in the cut, or the chipped out edges at beginning or end of the cut, such as a some small pieces of psilomelane, chrysoprase, amethyst, obsidian, etc.--I would save to use only after changing back to that thinner blade. Not that I want to change blades very often, because it's a lot of work involving removing the shaft arbor held down by multiple Allen head screws and some other things to deal with. I would prefer to only change blades maybe once per year.
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Post by Bob on Nov 10, 2021 12:41:34 GMT -5
I have a comment and a question. At this point, I've probably hand sawn close to 1,000 lbs.
The comment is that boy have I learned to not saw a piece of hematite until the last one of the batch! Once that red dust gets in the oil--you can't see anything--your marks on the rock, the saw table, etc.
My question: This MK-303 blade is a real workhorse. I reverse it's direction once/month and it starts cutting again great. I have done the bastard file edge peening which also greatly increased cutting ability again. But, gradually it has warped such that the blade moves back and forth maybe 1/8". This is a royal pain to deal with.
I have 4 ideas on what might have happened to cause this warpage and solicit reactions from you saw hand sawing experts:
1. Does it just happen when you saw a lot by hand including of large rocks? I'm cutting small rocks grape size all the way up to cantaloupe. Some of these rocks are long in cutting, and I try very hard to prevent any wobble or the material but it happens sometimes.
2. It means I'm doing something wrong, feeding too fast, or not right in some other way. Is it heat that caused it? I typically saw 45 to 60 mins on evenings. I stop when my hands are tired, or the oil feels very hot which tells me the motor also has to be getting very hot, or the motor housing is so hot it hurts to touch, or the oil becomes sludgy and difficult to see through so I know it needs to either be cleaned out or allowed to settle for a couple of days.
3. My saw table is an aluminum surface with a blade slot wide enough that there is maybe 1.5 to 2.0mm on either side of the blade. I've had maybe 3-4 jams, where a thin slice of rock will come off and slide down and stop or almost stop the saw. I turn the saw off immediately, reverse the blade, and these come right back out easily. Do these jams warp a blade?
4. There is breakout at the end of a cut--sometime minor and sometimes major. If the blade was so stiff that it didn't flex when pressed, one can avoid these breakouts, or rather easily trim the resulting protrusion off after it happens, by cutting that protrusion bulge off. However, because the blade will flex when doing this, I've adopted a different method. If I'm sawing a rock in half, such that both halves are on each side of the blade when the cut is being finished, I sort of hold those two halves against the blade on each side as that last part is breaking and right after to clean up the protrusion that is almost always on one side. This takes maybe 2-4 seconds and works pretty well because the depth of the diamond sintered part is pretty deep--maybe 3/8". But, if instead I'm cutting say a corner off of a very large rock, to support the blade sideways at the very end of the cut, I'll pick up a grape size cut piece of something else to hold in my other hand to back up the blade on the other side of the blade in that last part of the cut. The film of oil works pretty well I guess because it works and seems to slide on the blade just fine, which I press against the outer part of the blade blank just inside of the sintered part. Could this cause the warping damage?
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