ATOMA 140 for flattening - break-in necessary?

Discussion in 'Maintenance, Tinkering & Embellishment' started by crowley213, Jul 13, 2020.

  1. crowley213

    crowley213

    38
    Jun 15, 2020
    All,

    Based on the recommendations from another thread I purchased the ATOMA 140 for flattening my SG stones (500/2000/16000).

    My question now: Is a break-in necessary to use the ATOMA 140 for flattening? If so, what is the best procedure for such a break-in?

    Herbert
     
  2. ToddS

    ToddS Basic Member Basic Member

    379
    Jan 15, 2015
    Probably the best way is to lap the 500 glass stone. I've had mine for 7 or 8 years and I still find it too aggressive for anything but lapping coarse stones - they don't seem to break in the way DMT plates do.
     
    Diemaker likes this.
  3. Bill3152

    Bill3152

    301
    Nov 27, 2018
    The 140 is a beast. It saves time when lapping but is extremely aggressive. For heavy work though sic powder is a better choice imo. I don't see a reason to use the 140 unless you have a seriously dished very hard stone. Before you drive in and spend more money get some wet/dry sandpaper. That's my .02.
     
  4. crowley213

    crowley213

    38
    Jun 15, 2020
    Hmm, doesn’t really answer my questions, but nevertheless thanks for your replies.

    Herbert
     
  5. Diemaker

    Diemaker KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    609
    Apr 28, 2017
    I believe ToddS did answer your question, but I would add that I think the 140 is too coarse for your 500 let alone your finer stones. It is good for flattening if your stones are really dished but some loose 60-100 grit sic powder on a flat surface is best to dress your stones for sharpening. The cutting action is totally different between a plate with abrasive stuck to it vs the abrasive rolling around between your stone and plate.
     
    ToddS likes this.
  6. ToddS

    ToddS Basic Member Basic Member

    379
    Jan 15, 2015
    The finer Shapton Glass stones I've analyzed contained both the nominal sized abrasive plus some very large (100 micron) aluminum oxide particles. My educated guess is that those large particles are there to increase the hardness and to burnish the steel to produce the characteristic shiny bevel that Shapton Glass stone are known for. Of course it's also possible I have a defective set of stones....

    I've observed that when I lap, those large particles are fractured and produce some very fast abrasion for maybe 20-50 passes after lapping, and then they slow down to the "normal" rate. My guess is that those large particles will prevent the 140 from damaging the finer stones.

    Although I own a complete set of Atoma plates, I only use the 400 for lapping my 2,4,8,16k SG stones.
     
  7. crowley213

    crowley213

    38
    Jun 15, 2020
    @Diemaker @ToddS

    Thank you very much for the posted information, it’s definitely helpful for me as a rookie.
    Nevertheless I dare to repeat myself, means my original questions have not been answered.

    1.) Using the ATOMA 140 for flattening, is a break-in of the ATOMA plate necessary before using the plate for flattening?
    2.) If a break-in is necessary / makes sense, what is the recommended method / procedure for the break-in?

    Herbert
     
  8. Diemaker

    Diemaker KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    609
    Apr 28, 2017
    Second sentence of the second post?

    Some of this depends on your Atoma plate. Sometimes you can get "hangers" or diamonds and bond that are abnormally proud. Let's hope not since it sounds like the Atoma bond is good enough to make it very difficult to fix that.
     
  9. ToddS

    ToddS Basic Member Basic Member

    379
    Jan 15, 2015
    In plain English, I believe it was poor advice for you to buy an Atoma 140 to lap those Shapton Glass stones.

    I don't know if your Atoma 140 is the same as the one I purchased 8 years ago, but I have spent (cumulatively) several hours lapping my Shapton Pro 320 and Sigma Pro 240 and the plate is still too aggressive for lapping a 16k Shapton Glass. My suggestion is to flatten your Shapton 500 first, and that should remove and egregious high points (which there probably are not).

    Now, we can make a semantic distinction between flattening and lapping, with lapping meaning before every use (as Shapton Glass stones really require to function efficiently) and flattening meaning you never lap, only flatten to remove dishing once every 20+ knives. In that sense, it's probably fine for flattening, but you would need to condition the surface with a nagura or something similar before use. The preferred way, which is what most people do, is to lap them before every use with an Atoma 400 or equivalent, and never let them get dished.
     
  10. crowley213

    crowley213

    38
    Jun 15, 2020
    @ToddS

    Thank you very much for the explanations, this time it is really informative and helpful for me. A rookie in sharpening and English not my native language maybe makes it sometimes a little difficult for me to understand.

    By the way, the person who recommended the ATOMA 140 to me (@Jason B.) also stated that he uses a Nagura stone to condition the stones, so that´s what I also ordered. He also stated that the ATOMA 400 is a good choice, but in case you don´t want to spend too much money in the beginning the ATOMA 140 plus Nagura stone is the more economical solution. So let´s see how it works for me and if necessary or it makes really sense then I have no problem also to spend the money for the ATOMA 400.

    Herbert
     
  11. Jason B.

    Jason B. KnifeMaker / Craftsman / Service Provider Knifemaker / Craftsman / Service Provider

    Jun 13, 2007
    The Atoma 140 is fine to lap SG stones, works better than the near $400 Shapton DGLP and is faster. Too coarse for a 16k? maybe but I've never had an issue. The SG stones are very hard so its not like you can simply grind away massive amounts of stone material.

    There is no Break-in for a lapping plate and if there is I have never noticed it. I've wore out several Atoma 140 Plates using them to lap and while it may be aggressive from the very start it will quickly level off, which is more of just the diamonds dulling form lapping duties. My only complaint with the Atoma is durability, they work best for lapping but in my experience a DMT plate will last years longer with the same abuse.

    IMO, the Atoma 140 is too aggressive for sharpening and that is the reason I mainly recommend it for lapping, even though you will need to replace it more often (maybe) it is far more efficient at the task.
     

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