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  • #16
    Originally posted by Dan Dubeau View Post
    you want knobs? jwwinco They got knobs.

    Have you thought about machining a steel mold and casting aluminum around the head of a cap screw? I've always wanted to try that. Few year back I made a mold for casting lead dead blow faces like that and that's when I got the idea for casting aluminum hand knobs too.
    I am not really setup to cast aluminum, but its on my list of things I want to do "for fun" down the road some day. Mine is a hybrid application. I make the knob, drill, and tap it, and then use a cheap(ish) stainless socket head machine screw that is fully threaded. If I tried to make a one piece knob like that out of solid stock it would never be cost effective, but by making a hybrid screw its not to bad.

    I'll take a look at J W Winco. I'd rather buy than make if I can. McMaster does NOT have a unit that is exactly what I want and those that are close are currently in the $9-15 per unit price range. For that price I can make them myself, and get something closer to what I want.

    A quick check shows a finished product (that still has to be modified) just 1-2 dollars cheaper than McMaster. Not a big savings, but an option if I got excessively busy. Thanks. If I make some bigger compromises I think I could get it down a little from them.
    Last edited by Bob La Londe; 02-27-2020, 06:55 PM.
    *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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    • #17
      carr lane is another we source fixture components from. Not sure the specific size you're looking for, but I just checked a 1/4"-20 x 1.5" (assuming it's close to what you're using) long knob and it was $6.95.

      We also use Jergens sometimes, but they're always more money.

      Another train of thought is to just use a tapped knob and some all thread loctited into the mold half. If would sure spin on faster than a stud for quicker demolding, and would be easier to produce. You could use the same knob for many different mold thicknesses and not have to worry about having different lengths of capscrews on hand. Just cut the all thread to whatever length you need at the time.

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      • #18
        Originally posted by Dan Dubeau View Post
        carr lane is another we source fixture components from. Not sure the specific size you're looking for, but I just checked a 1/4"-20 x 1.5" (assuming it's close to what you're using) long knob and it was $6.95.

        We also use Jergens sometimes, but they're always more money.

        Another train of thought is to just use a tapped knob and some all thread loctited into the mold half. If would sure spin on faster than a stud for quicker demolding, and would be easier to produce. You could use the same knob for many different mold thicknesses and not have to worry about having different lengths of capscrews on hand. Just cut the all thread to whatever length you need at the time.
        A semi mass produced stock design mold that sells for around $100 (give or take) with 6 knobs at $7 plus markup each would price itself out of the market. (I do custom (starts at 10X and goes up) and stock design work.) Studs are a non starter because customers would damage the molds and blame me for the design causing them to scar the molds with the studs during assembly. Studs and knobs are still an order of magnitude more expensive (and more work) than simple stainless steel socket head screws that I buy in 100ct boxes cheap. The screws are so cheap I always throw in a couple extras and a hex key that fits whatever screws were used in the mold. (Hex keys are cheap in 100ct too.) Most customers don't even use the screws that ARE included with the molds. They use bar clamps, welding clamps, c-clamps, and in some cases a pneumatic vise. In my opinion short bar clamps are the easiest thing to use and cost less than knobs of any kind, but I put clamping screws in all molds for safety. If they choose to clamp it some other way then its on them. I already went down this path. I really am not looking for an alternative. I'm really not trying to be a smart ass when I say I covered this adequately in post 1.

        I'm neither bragging nor asking for help. I posted this as a maybe bit of help or push for people who are always looking for something to make and sell. Its not worth it for you to make one (1) knob for anybody, but if you find somebody who needs small quantities and you can make 10-20 at a time you can pay yourself a fair wage for standing in front of your lathe.
        Functionally doubling the cost of a mold is a non starter. The shoulder bolt knobs are an after purchase OPTION ONLY for those customers who want them. I can make them and make my shop rate for about the same as purchasing them, and those I have found so far do not exactly fit my needs. $100-150 additional cost in knobs for a custom mold that is in the 500-2000 range is still a significant add-on. Typically much more into a mold than that and clamping is not an issue as its made to go into an automatic injection machine, and the machine closes and holds the mold closed.

        The other part I am making may benefit from some alternatives, but they still need shoulder bolts with a knob head to make it easy to grasp and easy to tighten.

        One thing you mentioned is sort of already what I do. I make a thru threaded nob... and USE ANY LENGTH SCREW IN IT I NEED so I only have to make one knob for most thicknesses of molds. Well two knobs. I use two sizes of screws fairly often depending on the application. I am pretty sure I described that process in post 1 also.

        I found the easiest way to make them was to make an aluminum knob with a knurled head and a shoulder below, then drill, counter bore and tap the knob. This made it easy for me to run in a stainless socket head screw of whatever length was suitable for the particular mold.
        The whole point of the post was to point out that a part that can be made cheaply is often not sold cheaply. It was to inspire other members of this forum to make things and look for opportunities to make things. It was never intended to be a lesson in mold making or treatise on clamping methods. LOL.


        *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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        • #19
          Originally posted by Bob La Londe View Post

          The whole point of the post was to point out that a part that can be made cheaply is often not sold cheaply. It was to inspire other members of this forum to make things and look for opportunities to make things. It was never intended to be a lesson in mold making or treatise on clamping methods. LOL.
          Thanks, I wasn't sure -- mold making is a black art to me. However I've been wondering about the economics of small parts for a long time -- what can I make that people would want? Eventually I would like to sell to home shop guys becoming an advertiser, and maybe small shops. Right now I have all the time in the world, but its not always going to be that way.

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          • #20
            Originally posted by nickel-city-fab View Post

            Thanks, I wasn't sure -- mold making is a black art to me. However I've been wondering about the economics of small parts for a long time -- what can I make that people would want? Eventually I would like to sell to home shop guys becoming an advertiser, and maybe small shops. Right now I have all the time in the world, but its not always going to be that way.
            Mold making doesn't have to be a dark art. There are a lot of ways to make molds and lot to it, but people often try to make more of it than it is. I certainly couldn't tell you everything there is to know about mold making, because most of what there is to know I don't. Don't get me wrong. I think I am decent in the niche market where I do most of my work, but there is a lot more to know than that. Some guys try to make it sound like a dark art, but if you can learn to use a CAD program and a CAM program you can learn to do what I do. It might be easier for you or it might be harder for you, but if you can learn the first two things and work at it you can learn the rest.

            I personally think the guy who hand carves a master, and uses it to cast or pour a mold out of silicone, plaster of paris, or some other media is just as much of a mold maker as I am and he knows things and has skills I don't. The guy who builds a form out of plywood 2x4s, fillets it with resin and wood flour, and coats it with wax, so somebody can spray a bass boat into it out of his fiberglass chopper gun is a mold maker too. Another mold maker that knows things and has skills I don't.

            Even closer to what I do there are lots of side branches where I would have to learn it as I did it. High pressure injection, various types of casting, different mold materials and media. There is a lot, but you don't need to know it all to be a mold maker. Just enough to make the types of molds you want to make. Some things cross over and other things don't.

            Primarily I make low pressure injection molds and gravity casting molds out of aluminum flat bar. Sometimes I make press dies out of steel. I've made a couple high pressure injection molds for small desktop machines, but its not really my area.

            The pictures show some generic knobs I made for various applications in the shop, the turret I use in the tail stock of the small lathe for drilling and tapping knobs, and some soft plastic bait molds I've made.
            Attached Files
            *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

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            • #21
              I make knobs using a very simple method,more like woodworking than machining. I use a bandsaw and cut a template out, then I can make more from sheet stock and a router with a template following cutter. I only make knobs for my own projects and use wood, but I bet some black plastic could make real professional looking 5-star knobs.

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              • #22
                We used to make knobs for socket head screws using the punch on the ironworker. First shot we punched out circles. Punch left a dimple that centered a smaller punch that made a hole we pressed the socket head capscrew into.

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                • #23
                  One thing I always enjoyed about machining , after you did it once, you could almost always find a better quicker way.. and tbat is satisfying..

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                  • #24
                    Originally posted by garyhlucas View Post
                    We used to make knobs for socket head screws using the punch on the ironworker. First shot we punched out circles. Punch left a dimple that centered a smaller punch that made a hole we pressed the socket head capscrew into.
                    DANG-IT GARY !!! Now I want an iron worker. LOL
                    *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

                    Comment


                    • #25
                      Originally posted by Bob La Londe View Post

                      DANG-IT GARY !!! Now I want an iron worker. LOL
                      You know, you can probably just *buy* a bucket full of the punchings from steel distributors and large shops. CHEAP. Because they consider them to be scrap. But yeah, thats one hell of an idea. I used to throw those punchings in the scrap bin, or save them for capping the ends of handrails.

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                      • #26
                        Originally posted by nickel-city-fab View Post

                        You know, you can probably just *buy* a bucket full of the punchings from steel distributors and large shops. CHEAP. Because they consider them to be scrap. But yeah, thats one hell of an idea. I used to throw those punchings in the scrap bin, or save them for capping the ends of handrails.
                        I've got a buddy who makes a his own version of hobby welder tungsten grinder who has buckets of aluminum off cuts. He would always push them off on me whenever I visited his shop. I made a fair number of knobs out of them. Then about the same time I started selling "speed screws" for molds he found a use for those off cuts. LOL.
                        *** I always wanted a welding stinger that looked like the north end of a south bound chicken. Often my welds look like somebody pointed the wrong end of a chicken at the joint and squeezed until something came out. Might as well look the part.

                        Comment


                        • #27
                          They call them slugs, usually easy to buy, just pay a bit more than scrap price. They won't however sort them usually..

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