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Marten Sitic

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Marten Sitic last won the day on October 1

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  • Gender
    Male
  • Location
    San Joaquin Valley, CA
  • Interests
    Hunting, fishing, camping, smithing, hanging out with the family.

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  1. Marten Sitic

    My latest hunter, an experiment with copper.

    Cool, I am all for following your muse and doing something different just because! And I agree with using it for a nice contrast on a Damascus blade that has some “topography” to it.
  2. Marten Sitic

    More Hamons

    Beautiful! As Alan asked, all hand work polishing, or was there some belt-Jitsu utilized?
  3. Marten Sitic

    A good belt grinder under 300$ ?

    AJ, correct, much work can be done with tools that have limitations, whether that’s a belt sander or disc grinder.Not having one, or the funds for one, shouldn’t stop a person from pursuing this homie/craft. There are many ways to skin a cat and get equivalent results, some take more money, others more skill, and others more time and perseverance. At the same time folks should learn what their extra money will get them, and it is a lot (although not a pre requisite to doing quality work). A true belt grinder, not belt sander, will have a minimum true 3/4 HP motor, 1-2 HP being best, and I mean not using the new fangled method of rating - motors at twice their actual power and duty cycle. A belt grinder HOGS off metal when needed to, something a belt sander cannot. If you have limited shop time for your hobbies, or it’s done to pay the bills, one needs that extra oomph. Of course as you spend more on sanders or grinders you get other things, more stable bases and work rests, better platens, better belt tracking assemblies.
  4. Marten Sitic

    Forge Press Design Help

    Phil, you’re welcome. Geoffs link also has a GPM/bore size calculator for travel speed, I could walk you through the volumetric measurements and ratios but it’s really not necessary at this point. Plug in your variables and move to next step. Geoff, Brian and others that have built for this exact application will be your huckleberries, just because I have general hydraulics experience I haven’t built a forging press specifically. Keep these things in mind though, in general. The bigger the volume and speed of your pump, the faster your ram moves and more work you can do. Larger reservoirs prevent over heating (pressure creates heat, too much breaks down oil and parts), use filter through out, use the biggest motor reasonable that your electrical source can power, and use the recommended motor speed for a given pump- don’t assume that a half speed motor WILL do half the work, may or may not depending on how it works. Make sure whatever you do as proper pressure regulation and every part can handle the pressure it will be exposed to. Keep hoses protected from incidental contact with work pieces or slag that could damage them, and sheet metal shields are not a bad idea, pressurized oil can cut off body parts, and when it doesn’t it still can kill you via trauma and poisoning you. That last parts no joke, if you aren’t careful/competent/knowledgeable/skilled enough to set this up, move on. I don’t mean that meanly, it’s truly a word of kindness, be brutally honest with yourself. Best Steve Miller, aka Marten Sitic
  5. James we use a metric fecal ton of small rare earth magnets at work, I will see if I can find our sources. I work at a start up so we originally bought in small quantities, so they might be a source for you. My experience with the magnets is that eventually the nickel will chip/peel if they experience direct impact with other magnets or steel. A very thin piece of anything compliant between the two clasping pieces will save them.
  6. Marten Sitic

    Forge Press Design Help

    What Geoff posted is a great resource. I won’t go into GPM an piston speed, etc, I’m tired! Ok, let’s talk force. Force ( not velocity, etc) from a hydraulic system is ultimately determined/limited by two things: pressure produced by your pump (highest pressure and max gpm then determines motor size/speed required, again that’s for later) and the bore diameter of your cylinder. Ok, the pressurized oil enters the cylinder and “pushes” on top of the piston head. The flat surface of the piston head is circular, so you need to determine its surface area the pressurized oil will “push” agagainst (we will then multiply that area in “square inches” by incoming oil pressure in pounds per “square inch”. The formula for that is Pi (3.141) multiplied times the radius of the piston squared. In your situation your piston diameter is same as the bore diameter, so 3.25”. 3.141x (1.625x1.625)=8.294 square inches, now multiply that by the cylinder’s maximum rated inlet pressure, yours is 3000 psi. 3000psi*8.294 inches squared=24,882 pounds of force exerted to push the piston. 24,882 divided by 2000 (US ton)= 12.441 tons. That is theoretical max, there is oil shear and friction which drop it slightly, then small losses in any friction from your ram guides etc. If your cylinder needs to do work while retracting, you need to determine the cross sectional area of the piston rod and subtract that from the pistons surface area (where the rod connects to the piston the pressurized oil can’t apply pressure to push it forward).
  7. Marten Sitic

    Forge Press Design Help

    I can’t help on those questions, I’m sorry. However, you definitely are looking at a 12.5 ton press with that cylinder, I do a lot of (or did) pneumatic and air oil systems. The physics and rules are the same. Max pressure allowance of the lowest rated part in your system (you only have your hydraulic cylinder) times the surface area of the top of your piston. There will be frictional and mechanical losses so actual tonnage will be slightly less. There is NO way your current cylinder gets you safely above that, the 16 tons quoted is out of the question
  8. Marten Sitic

    D2?

    Jeremy, as to what to make from the barrels? I’ve seen original tomahawk heads from colonial and fur trade era made of scrapped octagonal rifle barrels, I will see if I can find some pictures for you.
  9. Marten Sitic

    Fetter Lane Sword No2

    Unbelievable craftsmanship in this piece, as one stated, truly fit for a king! I am awestruck by its beauty! I can only imagine in days of old, the king being presented with such a piece, or more so, a lesser lord or warrior obtaining such a thing of beauty from a battlefield.
  10. Marten Sitic

    D2?

    Most current carbon steel barrels now are 4140, higher quality ones are 4150. Nickel steel like 4340 is used by some custom makers for their actions, but not generally for barrels. Stainless are usually 416 but some makers use 410. Best Steve
  11. Marten Sitic

    A good belt grinder under 300$ ?

    Good tips given for sure! As for things being so expensive these days, good tools have unfortunately always been expensive. 35 years ago a Wilton Square Wheel belt grinder was already $1000, and it was cheaper than Bader and the alternatives at the time. You either need to learn to do with out as you save up, make your own with outhitting all the bells and whistles, etc.
  12. Marten Sitic

    Design of small urban EDCs

    Seems they’d get the job done, the handles look to lock the hand in place, and I like pointy straight edged knives for daily chores like opening packages and stripping wire (and I imagine opening attackers as well). However, I don’t like sharp points on the spine wher my thumb or fingers may need to rest for some tasks (some of your designs have a sharp point at the peak of the thumb ramps). Thanks for sharing
  13. Marten Sitic

    Opinions on grain size, and 1050 in general.

    Again, thanks for the gentle correction and the further education, it s much appreciated. Dumb non related question for the mods, I’d be happy to change my screen name to meet the current rules, I’ve had this one for four score and seven years before real names were required. Best, Steve
  14. Marten Sitic

    Epona - a La Tène period Celtic sword

    I really love the construction/composition of this blade. The central core showing the straight on-edge laminations, with the swirling randomness of the edges and tip. I particularly like that the edge lamination at the tip is quite a bit wider than on the two side edges, it really sets it apart from many other blades.
  15. Marten Sitic

    Finally a place I can call my own!!!

    Jeremy, just saw this! Congrats! That’s a really nice place you have gotten your family. I wish I had some acreage when raising my 4 monkey butts, they are all legitimate adults now.
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