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Grinder plans

Discussion in 'Shop Talk - BladeSmith Questions and Answers' started by Kevin McGovern, Mar 20, 2017.

  1. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    I can see how my current configuration can be applied to the left tool arm plate by adding a raised tab to it and putting the semi circular track and pivot hole in that tab. I was having trouble trying to make an add on as you suggested since the alignment would be off. I'll crack at it again tomorrow.
     
  2. mike-E

    mike-E

    399
    Mar 2, 2013
    i had trouble working around the tracking hinge on my grinder too. i cant mount my spring upside down the way i would like. i could be wrong about the spring weight, though 100lbs is what grimsmo and strider use on their grinders with the OCC set up in a similar way. idk what AR customs uses. dont be too concerned about being out of horizontal. the grinders that had problems were probably 45 degrees or more elevated. mine sits about 5 or 10 degrees up and the tracking works awesome. i understand about wanting it to be as easy as possible for the end builder to assemble. i think the hardest part to do and easiest to mess up will be drilling the hole straight in the tracking hinge. if that hole is out by 1 or 2 degrees the tracking will be out from the get-go.
     
  3. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    I hear you on the tracking hinge hole. Luckily, I have a pretty precise drilling set up. Circa WW II.
     
  4. mike-E

    mike-E

    399
    Mar 2, 2013
    I made a quick sketch of the parts I was trying to describe. This might be more helpful than typed words.
    [​IMG]
     
    Last edited: Mar 21, 2017
  5. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    That does clarify a lot of what you were describing. Three questions:
    1. why a hole in each corner of the "tombstone"? just options? I'm thinking i only need one stop pin.
    2. does it really need a set screw? My thinking is if it freely rotates, who cares? Since one it is at the bottom of the cam stroke, it's not going anywhere.
    3. can the hole for that you show tapped 5/16"-18 be 1/4"-20? I have taps, but I'm trying to keep it simple for others. I already require 3 tap sizes for the current build. Just a thought.


    Thanks for all the input. It's a pretty slick set-up. I think others will get a kick out of it, if I can post a good video showing how it works and the exploded views to see how simple it is. I am kind of disapointed that the other idea is not likely to work, since i had it layed out that you wouldn't see the cam slot, at all and the only thing on the left you'd see is the arm to actuate the cam stroke.
     
  6. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    My CAD guy is following this thread, and I'm turning him into a knife grinder expert. How long before he asks me if he can make a kirambit out of a railroad spike?
     
  7. mike-E

    mike-E

    399
    Mar 2, 2013
    the two holes are not needed. you could always take that piece off and flip it around depending if you wanted to push or pull to compress the spring. you definitely need the set screw. it will lock the rotating piece to a 1/2'' bolt that will stick out on the left side of the grinder that a handle can be attached to. the 5/16-18 is the thread size of the ball end gas spring mounts.(much easier to mount and lower profile) i tried to link you to the mcmaster carr listing but couldnt get it to work. thats why i suggested changing the size of the hole at the end of the arm to a 1/4''. that is tap size for 5/16-18. if i could make one more suggestion it would be to do away with the work rest mounting bar and make that the handle. if you have a two pocket grinder you wont need that piece anyway.
     
  8. Jesse Latham

    Jesse Latham

    698
    Jul 4, 2010
    It seems if the angle of the shock is an issue there seems to be enough room on the steel plate to change the profile of the tracking upright to include a landing spot farther forward for the cam.
     
  9. tommywoh

    tommywoh

    43
    Oct 17, 2014
  10. kuraki

    kuraki Fimbulvetr Knifeworks

    Jun 17, 2016
    That looks good but no reason for a wrench rather than another dog leg with a handle.
     
  11. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    Mike-E is suggesting the lever on the end of the "axle" on the left side. I like this, as I won't have to worry about it interfiering with the throw. I'm thinking this: https://www.mcmaster.com/#91044a033/=16v4yqt on the end of the axle bolt. on the left side. Also, I could then set the handle at any position I like. thoughts?
     
    Last edited: Mar 22, 2017
  12. kuraki

    kuraki Fimbulvetr Knifeworks

    Jun 17, 2016
    I was referring to the design Tommy posted a link to, I don't quite follow what you're describing.
     
  13. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    Oh. Got it
     
  14. tommywoh

    tommywoh

    43
    Oct 17, 2014
    Sorry I posted that to closely show how it was put together but later on he added a handle to it and it looks much slicker
    https://instagram.com/p/_Ct25Izb4U/


    Sent from my iPhone using Tapatalk
     
  15. kuraki

    kuraki Fimbulvetr Knifeworks

    Jun 17, 2016
    Yeah. I'm going to make parts to convert mine to do that no question about it.
     
  16. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    I for one will appreciate it when I'm old, like Kuraki.
     
  17. mike-E

    mike-E

    399
    Mar 2, 2013
    yes, you can put the handle in any position.(edit): that swedish dudes grinder is sweet, but i think he's got it mounted on a pretty narrow table. his motor could only be about 6'' long to pivot horizontal.
     
    Last edited: Mar 22, 2017
  18. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    We figured out (well, my partner, the smart one) that a #75 shock will give the same tension my current grinder has. I am going with the original design with an #80 shock. I like that it keeps everything out of the way, is easy to use, and the cam action is sheilded on both sides when installed. I will post up drawings when they are ready.
     
  19. mike-E

    mike-E

    399
    Mar 2, 2013
    cool, cant wait to see a finished grinder. you dont have to be old to appreciate easy belt and tool changes. it can save quite a bit of time and frustration on every knife. notice on that swedish dudes video he installs the wheel with the belt pulled tight. you dont want to do that. you want there to be slack for changing belts. that is why i mark my tool arms and install the same distance into the pocket.
     
  20. Kevin McGovern

    Kevin McGovern

    Jul 31, 2015
    I'm just messing with my boy. I updated the files and links. I'll let you know when I get all the steel cut.
     

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