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  1. #11
    Quote Originally Posted by Noplace View Post
    very nice, just curious how much would it cost to build one if you were willing to build in the future to sell it?
    Difficult thing to say at this stage. But the KMG grinder sells for 1800$ and can not flip to horizontal. The best one sells for 3000$ and can flip and more . The ebay clones made from box section or/and 6mm laser cut pieces go for 800-1000. That without the wheels especially made for knife making.

    On my prototypes all parts are milled/for now/ , so i have still to decide which ones are to be milled and which to be laser cut. Have in mind the price of the VFD and the 1.5kw 3 phase motor. Also welding things aligned precisely takes its time, so still not sure where to weld and where to bolt.

    But the way i see it i want to have one model at ~1000euro /+30% if-when sold legally as a company / that beats all basic models around. But it may be high end 2000euro .

    Cause its very simple. You want to make knifes, you need a grinder.You need a knife grinder. Thats it. FIY one way or another even if you totally DIY you will spend 500-800 euro on the complete machine. If you have lathe and mill and mig welder ~400euro at least.

    By the way its a very useful machine even if you dont intend to make knifes.

    So my idea is to make it accessible priced but not sure for now if it will be easily achieved. I started making changes on the drawing even while i am welding it together for this and that reason. So as i said this is a prototype to study whats working on the market and eventually make something better.
    project 1 , 2, Dust Shoe ...

  2. #12
    Quote Originally Posted by Boyan Silyavski View Post
    So as i said this is a prototype to study whats working on the market and eventually make something better.
    Surprised you have made 3 identical when it's still in prototype. I Prototype lots of stuff and first version nearly always gets changed or improved in some way. Hell with my little router design I see ways to improve or make building easier just about every time I make one.

    Surely would have made more sense to build one and test then improve second and test again etc.?
    Last edited by JAZZCNC; 07-02-2016 at 04:01 PM.

  3. #13
    Quote Originally Posted by JAZZCNC View Post
    Surprised you have made 3 identical when it's still in prototype. I Prototype lots of stuff and first version nearly always gets changed or improved in some way. Hell with my little router design I see ways to improve or make building easier just about every time I make one.

    Surely would have made more sense to build one and test then improve second and test again etc.?

    I make one small wooden musical instrument as a side hobby and every now and then i have a whole day or 2 day, when i do sanding all day long. So the faster the better.

    I needed a serious sander also for all the steel projects. I have a nice DIY 12" sander but what i am making here is a "grinder" not "sander" meanung it will have very serious surface speed with 120mm OD wheel at he motor spinning at 300rpm / 4 pole 3 phase 1420 rpm motor with VFD/

    The other thing is that i have a knife project where i am at the stage of needing the grinder. I made the prototypes using small bench sander but as i am using one of the bad ass tool steels its very difficult to grind with belt sander to shape.

    Plus as i found the typical paradox- " To make a grinder you need a grinder"


    The design is more or less clear, a lot of DIY copies of the KMG grinder with plans in internet. The KMG is also a copy of an older machine, so i understood while looking at the plans that these are not just copies, but a concept proven through the years of abuse, that works. So i directly started building on it knowing that it will work.

    Jeff needed a grinder, all of the above+ that they sell material in 6m, packets of 10, etc., so doing 3 machines at once made sense to me.


    The next step from here is next week machine is ready, i continue my knife project and while having actual experience using it for knifes, i will meditate upon a much more brave design.


    In fact Dean next step would be directly producing them by the 10, cause of the fixtures on the mill and the lathe is makes sense to make 10 pieces at once.

    Needless to say that the experience from building CNCs till the moment helped in in such way that the only error till now was just 1 spot weld not at the right place.
    project 1 , 2, Dust Shoe ...

  4. #14
    Quote Originally Posted by Boyan Silyavski View Post
    Needless to say that the experience from building CNCs till the moment helped in in such way that the only error till now was just 1 spot weld not at the right place.
    Erm I'd say the error was the spot welding.! . . . Doesn't look good or strong. Great for proto typing but not for real thing. It needs proper welds to give it credabilty as industrial strength tool.!

  5. #15
    Quote Originally Posted by JAZZCNC View Post
    Erm I'd say the error was the spot welding.! . . . Doesn't look good or strong. Great for proto typing but not for real thing. It needs proper welds to give it credabilty as industrial strength tool.!
    I feel that too. Nothing will go out from here that could be broken by hand and a hammer. And you are absolutely right, now i could take the hammer and certain pieces could be broken apart for seconds. When all belts are spinning and i see everything is working correctly there would be proper welds where necessary. The other thing i will do is blacken all bare steel heating it with the gas torch to 315C.
    project 1 , 2, Dust Shoe ...

  6. #16
    toomast's Avatar
    Lives in Tartu, Estonia. Last Activity: 14 Hours Ago Has been a member for 4-5 years. Has a total post count of 79.
    Quote Originally Posted by Boyan Silyavski View Post
    ...The other thing i will do is blacken all bare steel heating it with the gas torch to 315C.
    What do you mean by that?

  7. #17
    Quote Originally Posted by toomast View Post
    What do you mean by that?
    There is a way to treat low carb steel / mild steel/ . You heat it at 315C, keep it there a couple of minutes, thin oxide layer forms in black, then you brush it with some oil and it goes even blacker. Result is much tougher part, even if not a high carbon steel. Black oxide layer is not real anti rust though it gives some protection


    bellow you could compare bare cold drawn steel bar and treated.


    Click image for larger version. 

Name:	cold drawn steel.jpg 
Views:	132 
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ID:	17546
    project 1 , 2, Dust Shoe ...

  8. The Following User Says Thank You to Boyan Silyavski For This Useful Post:


  9. #18
    toomast's Avatar
    Lives in Tartu, Estonia. Last Activity: 14 Hours Ago Has been a member for 4-5 years. Has a total post count of 79.
    Quote Originally Posted by Boyan Silyavski View Post
    There is a way to treat low carb steel / mild steel/ . You heat it at 315C, keep it there a couple of minutes, thin oxide layer forms in black, then you brush it with some oil and it goes even blacker. Result is much tougher part, even if not a high carbon steel. Black oxide layer is not real anti rust though it gives some protection


    bellow you could compare bare cold drawn steel bar and treated.


    Click image for larger version. 

Name:	cold drawn steel.jpg 
Views:	132 
Size:	304.5 KB 
ID:	17546
    Interesting. What is the "official" name of this process?

  10. #19
    Quote Originally Posted by Boyan Silyavski View Post
    When all belts are spinning and i see everything is working correctly there would be proper welds where necessary.
    Well next time do your self a favor and grind Chamfers on the edges will give stronger nicer welds. Created your self lot of grinding now or ugly proud welds.

  11. #20
    Quote Originally Posted by JAZZCNC View Post
    Well next time do your self a favor and grind Chamfers on the edges will give stronger nicer welds. Created your self lot of grinding now or ugly proud welds.
    Where was important and i was sure that will not need to break it apart its done like you say. The machine is still not finished.
    project 1 , 2, Dust Shoe ...

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