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I have a Suehiro 20k, shapton glass lapping plate and a DMT 325. I am running into a wall trying to lap this stone :banghead: I am wondering if getting an Atoma 140 or Atoma 400 would greatly improve the ease of lapping this particular stone? Or is there not going to be much of a difference from what I already have? Otherwise I am going to sell this stone. Thanks Gentleman
What issue are you running into? Is it just taking a long time or not lapping at all?
Well, I would say the time it takes to lap it would seam like it isn't lapping the stone at all.Quote:
Originally Posted by dinnermint
IME when you go to lap the Suehiro 20k for the first time you need to bring your lunch. :)
Been posted that the 20k can strip diamonds off of the Atoma 1200 but the 400, or the 120 is good to lap it with. I imagine the DMT 325 is also alright, if used under a trickle of running water. The DMT is nowhere near as efficient as the Atoma IME. It will get the deed done, but it will take longer. :gl:
When you say the atoma diamond plates are more efficient, what would you say the amount of time saved is?Quote:
Originally Posted by JimmyHAD
I have a Shapton lapping plate and it uses Silicon Carbide as grit. It makes quick work of anything period.
It is unbelievable. the Atoma's diamonds are situated, for lack of a better word, differently than the DMT. They are just way more aggressive. The time advantage is worth the $ AFAIC. I've got the DMTs in various flavors, the Shapton DGLP, and an Atoma 1200. The 1200 just rips through the toughest stuff like Grant took Richmond. That is the 1200, which I now know isn't recommended for the 20k. I don't have a 400 .......... yet ........ but I imagine it would be even more efficient than the 1200.Quote:
Originally Posted by dshaves
Is that the same as the Shapton glass lapping plate, because mine just skims over the stone and removes nothing!Quote:
Originally Posted by thebigspendur
Yes this is what I am looking for and awesome reference too, thank you.Quote:
Originally Posted by JimmyHAD
That is the one. I have it, and what I used to do was use the DMT for the grunt work, and then finish with the Shapton. They are both 325, but the Shapton being so much more expensive, I figured it would last longer if I only finished the lapping with it.Quote:
Originally Posted by dshaves
Eventually it became worn through use, and it still cuts, but not as it did when new. I have used the Atoma 1200 in the same way. Grunt work with the DMT and/or the Shapton, and finish with the 1200. Maybe that is why my 1200 didn't suffer any loss of diamonds on the 20k.
The owner of Japan Tools has come out and said the 1200 should not be used to lap the 20k. As far as how well any plate works, it is like a set of tires. We can both have a set of Michlens on the same model vehicle.. How many miles, the type of road surface, and the fellow behind the wheel, all determine how many miles the tires will last. Same with lapping plates, and with hones for that matter.
I shudder at the thought of lapping ANY hard hone/stone with a diamond plate.... I almost ruined my DMT 325 lapping plate on a couple of super hard barber hones back in the day. I stopped before I completely wore out the DMT, and it still works fine (but slowly) on typical man made hones like the Naniwa and Shapton Glass series, but I would not use it on a hard hone like the Zulu Grey and in this case it sounds like the Suehiro 20K is in the same league.
thebigspendur mentions the Shapton lapping plate, not to be confused with the Glass Diamond lapping plate or their other reference diamond lapping plate. It is just a flat piece of cast iron with a pattern in the surface and is meant to be used with loose SiC powders. This is the tried, tested and true lapping method machinists are familiar with. It's inexpensive and gets the job done, but it is messier than using a diamond embedded plate.
For simple/cheap, a flat concrete floor, a cookie sheet to contain the mess, some SiC particles and a bit of water will get the job done, saving your expensive diamond plates for what they do best, cleaning between honing razors on soft hones that load up with swarf.
DMT vs Atoma. I've used and own both.... I prefer the Atoma brand diamond plates. The difference is that while DMT evenly spreads their diamonds over the entire surface of their plates. Atoma makes little piles or buttons of the diamonds leaving empty space between them. Atoma plates suffer less from suction in use when flattening/cleaning hones.
I recently flattened the backside of my Zulu Grey 8" x 3" hone.... that is one hard rock and I promptly put away my diamond plates and brought out the lapping gear with loose SiC grit. I use the glass plate with plastic cover sheets from Lee Valley Tools. You could use just the glass plate, but you eventually dish it from lapping... By using the inexpensive plastic sheets, when it wears through, I just stop and replace it, but they are quite durable. I also mark the glass with a felt marker as to what grit I use on that side, then cover with the plastic and I don't have to worry about an occasional errant grit embedded in the plastic as it will always be the same size. But rest assured, even using SiC grit, that Zulu Grey hone took quite a while to flatten.
I don't worry about the finish of my hones..... the stria in the surface is just negative space and has no effect on the razors edge, unless it's super deep and at a 90 degree angle to the length of the hone. If the stria on the surface are large enough and deep enough to affect the edge of the razor, the hone would have to look like coarse metal file. I know some swear by "polishing" the surface of a hone, but that means you are knocking the tops off the grit in an attempt to reduce it's cutting effect. This is the method used with barber hones of yesteryear and today's Tormek water wheel grinder. The Tormek system uses a SiC two sided hone. The coarse side is used to rough up the surface of the wheel and expose fresh grit, and the fine side of the SiC stone is used to burnish and flatten the grit of the wheel without tearing the grit out of the surface, emulating a finer grit wheel. For what the Tormek is used for... it works fine, but for razors.... I dunno.... it's like taking a 1K Naniwa Chosera and after burnishing the surface claiming it is a 10K hone.... That just does not work for me.
So.... If it were me, I'd put the diamond embedded hones away, and instead grab some cheap loose SiC grit and lap that stone the old fashioned way.... I'm sure there are many sources for SiC grit, but if you are in a bind to find some, Lee Valley runs a internet mail order service and ships to the USA as well as in Canada. Shapton's loose grits are the same thing.... if you have a supplier of those, that's fine too. The only thing I would watch out for is the lapping compounds sold for lapping automotive cylinder head valves. It's the same grit, but it's mixed with mineral oil/grease to make it into a paste. You want the dry powder type and you want to use water for lubrication so it doesn't ruin your hone.
Regards
Christian
I have to be honest here, for me the 16k SG and the nani 12k ss get the edge right where I want it. With the fact that I live in a nice apt with no work space it and the lapping process for this Suehiro I would prefer someone to get the stone at a great price that would love to use it or need it for that matter. Do these Suehiro 20ks re sell well?
No, this is a very heavy and dense steel plate.Quote:
Originally Posted by dshaves
I would say it is a niche market. Speaking generally. There are not lines of people waiting to spend north of $200 on a synthetic hone to finish straight razors. Of course we are talking theoretically, because we both know that it is not allowed to offer items for sale on the forum.Quote:
Originally Posted by dshaves
The classifieds 'strops & hones' section would be the place to offer a 20k for sale, should anyone ever want to. :rolleyes:
Yup, before you spend a bunch more money on a lapping plate, spend $15 from GotGrit.com and get an assortment of grits 60 -500.
A dollar cookie sheet, like the Kaptian said, and put it on the floor, a tablespoon or grit, squirt of water and 15-20 min will get it flat.
The SG20 is hard, they will pull out diamonds, and that will cause you more problems, cause then you got to polish them out.
It is the next step up from the 12 and 16k. I refresh mine with an Ark. And if you get into Naturals, your all set for lapping...
You might try the other side, before you give up on it.
To satisfy my curiosity, could you do a pencil grid then do a quick 10 second lapping? Then post a pic on here.
You & I thinking the same thing here ? Stone is warped & he's trying to lap the convex side... which ain't gonna happen anytime soon :pQuote:
Originally Posted by dinnermint
Not to say that the recommendations mentioned are wrong, but my experience is different. I've used a dmt325, and only a dmt325 to lap all of my natural and synthetic stones. I have had zero problems whatsoever. The 20k was a pain and took longer, but it doesn't have to be "perfectly" flat. Just look at an old barbers coticule, most of them are probably picking up HBO they are so dished out.
+1 on the diamond plate. I'm willing to try new and different stuff, but for the past 8 years the plates have been my lapping mainstay. DMT, Shapton, and finally the Atoma.Quote:
Originally Posted by prodigy
I'm wondering how loose grit can be used and be uniform enough, under the stone, to do an accurate flattening ? I'm not gainsaying, particularly since I haven't tried it. When I picture the procedure in my mind's eye it just seems that some areas would have more grit collecting under the stone than others ?
As far as the 20k, here is mine long time ago. Still not much changed with that one corner that never got flat in spite of many bouts with the plates. There is adequate honing area, so if it never gets dead flat, no worries .............. :)
Attachment 250512
A quick quote from Wikipedia and yes, I know it's NOT the ultimate source of knowledge, but lapping has been done for a long time.... it's nothing new.
The topic "Lapping" on Wikipedia appears to be well written and accurate as far as I can tell, and is a far more interesting read than I can write!Quote:
Taken to the ultimate limit, with the aid of accurate interferometry and specialized polishing machines or skilled hand polishing, lensmakers can produce surfaces that are flat to better than 30 nanometers. This is one twentieth of the wavelength of light from the commonly used 632.8 nm helium neon laser light source. Surfaces this flat can be molecularly bonded (optically contacted) by bringing them together under the right conditions. (This is not the same as the wringing effect of Johansson blocks, although it is similar).
Regards
Kaptain "Ouch.... tripped over another word again....<sigh>" Zero
[Edit]
Yes, it does collect in hollow areas, but it only removes material where required and not where it's not required. Grit is sorted by sieving.... nothing larger than the holes in the sieve will get through. Smaller particles that do fall through, will have no effect on the lapping until the larger particles have worn down to the same size. Using a softer material for a lap allows the grit to grab hold and not wear the lap away as fast as what is being lapped. It IS important to remember that there is a skill involved to obtain a *flat* surface, no matter the tools. Highly accurate diamond plates do not guarantee the hone you are flattening will become perfectly flat. Using poor technique, you can create a convex or twisted surface quite easily. This of course applies for lapping with loose grit and a lap as well.Quote:
I'm wondering how loose grit can be used and be uniform enough, under the stone, to do an accurate flattening ? I'm not gainsaying, particularly since I haven't tried it. When I picture the procedure in my mind's eye it just seems that some areas would have more grit collecting under the stone than others ?
And just to clarify, it's not all that messy really, but it IS messier than using a diamond plate. And... you can use a flat counter top in the kitchen with that baking sheet. All that cookie sheet needs is a firm flat surface as by itself it's rather flexible.
A lap can be quite soft, such as the thin plastic self adhesive sheet I use on glass plates. Lead is also often used for a lap against steel, as is brass.... This may seem odd at first, but remember that wet/dry sandpaper is only a paper substrate with grit attached to it with glue, and yet you can sand away steel with it!
The SG20k is a pretty hard (tightly bonded) hone. A new diamond plate of 325 grit or thereabouts will flatten it very quickly, but it will slow the plate down some afterward due to diamond wear. An old diamond plate that's got worn diamonds will take a dog's age to flatten the SG20k. Personally I find the best approach for flattening very hard stones/hones is - as already mentioned by several fellows - to use loose grit. You can take the stone/hone down to flat pretty rapidly this way, then give it a quick scuff with your preferred grit diamond plate to smooth it.
Another point I'd like to make is that there is some misconception about the "negative space" not doing any honing that I've seen mentioned by several fellows that isn't really completely accurate and isn't being thought through very well. Using a coarse grit to lap a hard stone can be bad news in terms of the finish that will be imparted by the stone afterward.
The "negative space" implication is that the surface of the hone is quite flat but has furrows plowed in that surface that are lower than the mean average surface height. This isn't really the case - in reality there are those furrows but there are also pointed peaks created as well - which break off easily during honing and create an auto-slurry which creates a coarser surface finish on the item being honed. Eventually this wears down to that flatter surface with "negative space" furrows, but until it does it is to the detriment of the created surface finish. This is much worse on harder hones (they take longer to wear down) and it's far worse of an effect when new diamond plates are used for lapping - they create deeper furrows and higher peaks than worn-in plates.
At 60 grit, you are hogging off material. On a hard stone like an Ark a tablespoon with water will get to flat quickly. The Silicon Carbide will thin out to a single layer of grit and abrade surprisingly flat and quickly.
Then it is just matter of polishing and refining. You can finish on Wet & Dry or a diamond plate if needed, on a SG20, 500 grit is plenty smooth and flat.
After 60 grit, the subsequent grits polish quickly. Just a few minutes, you can feel the smoothness of each grit.
You can get a ¼ pound of 60, 80, 120, 220, 320, 500 each for about $15, enough to do many stones.
It is much like honing on slurry.
If you think it's the diamonds getting "worn" I'd like to understand how and why with evidence. Diamonds are the hardest material known to man and I really don't think rubbing them on a stone is wearing them one bit. Now the steel plate holding the diamonds might be wearing out, and losing its hold on the diamonds, but the diamonds themselves are not being "worn".
Why buy all the stuff you don't need? Multiple types of loose SiC powders, a cookie sheet, a flat piece of tile etc? All you need is one dmt 325. Mine was purchased not long after I joined this site, so it's 3 years old and has never once been a problem. I think I paid $46 on amazon.save ypurself the time, money, mess etc and get a atoma or dmt diamond plate. You will never look back.
I'm also thinking that since so few laps are needed, just having a 4" or 5" area of flat should be more than sufficient to get the 20k finish on a razor. Might be a let down to use so little of an expensive hone. However, you're still getting the intended finish.Quote:
Originally Posted by onimaru55
JimmyHAD's photo was exactly what I was trying to find (in vain).
That was my thinking too. Eventually, if I live long enough, and hone enough razors, I'll continue lapping it and maybe even get down to flattening that corner. In the meanwhile it does the job it is supposed to do as is.Quote:
Originally Posted by dinnermint
Thanks everyone, I decided to try and flip the process and put the DMT-325 in the hold and rub the stone on the plate. Wow what a difference....it cleaned up the stone super quick vs plate pushing into stone. I don't push super hard in to the stone or vise versa I learned my lesson with my Super stones warping the stone. I learned a lot here, really thank you for sharing!!!
Oh yea, I always use the stone holder for the dmt. I learned the hard way with that, getting blisters in awkward places on both hands trying to hold the dmt. Glad you got it figured out.Quote:
Originally Posted by dshaves
Oops...diamonds., like any other physical substance is subject to wear and tear. They WILL flatten and become less effective in a grinding environment. The hardness of the material is no never mind.... Yes, they will resist wear longer than other materials, but they WILL eventually wear down.
“The diamonds likely aren't fracturing in the application of flattening stones, at least not after its been broken in. “
Of course, they wear, and pull out from the binder. They are hard, but not unbreakable.
They do fracture/wear, ask any good jeweler that looks at a lot of diamonds. People scratch glass with rings and fracture the edges and corners of Diamonds, all the time.
Most folks just don’t ever look at their rings with magnification to see how damaged they are.
Diamonds like any rock or gem are filled with inclusions, especially the lower clarity, use in industrial applications. Here is a quote from an article on Diamond Fracture Filling, a process used to drill out impurities/inclusions from Jewelry quality diamonds to improve clarity, so they can be sold for higher prices.
“Fractures are very common inside diamonds and are created during the diamond's creation in the earth's crust. As the rough diamond travels up from the earth's crust through volcanic pipes it comes under extreme stresses and pressures, and during this travel tiny fractures can form inside the diamond. If these fractures are visible and damaging to the beauty of the diamond, it will have much lower demand and won't be as salable to jewelers and the public, making them candidates for fracture filling and thus visually improve the appearance of the diamond.”
As many of us can attest, they do wear and an Ark, or other hard stones can trash a new Diamond plate in a hurry. So, call it micro fracturing or eroding, they do wear.
Diamonds and how we look and think of them, are in large part a result of an aggressive and successful marketing campaign. Diamonds are not as rare or indestructible as the De Beers, would have you think.
Well, that's my point. They do erode, but no one will be around in 1 billion years to measure the .00000001 millimeter that goes missing....Quote:
Originally Posted by Magpie
New thread created here for those who want to discuss the life of diamonds:
http://straightrazorpalace.com/advan...onds-wear.html
:gaah: .......... :matrix:.......:whipped:............. :deadhorse:............ :popcorn:Quote:
Originally Posted by onimaru55
