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'Wide head' socket cap screws?

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  • 'Wide head' socket cap screws?

    I'd like to find a socket head cap screw with a 3/8-inch diameter shank, but with a larger than standard diameter head. The lower bearing surface on a standard 3/8-inch head isn't much bigger than the shank, but I'm limited by the application to a narrow shank/thread. Standard height head is fine.

    A 1/2-inch head on a 3/8-shank would be just about perfect. Hardened preferred, 2-1/2 inch length, either hex or Torx ... does such a beast exist? I've check online with Grainger and Fastenall, and at the local hardware stores without any luck.

    Plan 'B' is a 12-point flange bolt, but I'd prefer to stick with a cap screw. The head will be countersunk.

    Thanks in advance for any suggestions,

    Bob

  • #2
    Would a shoulder bolt work? It would require two diameters to be drilled.
    Jim H.

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    • #3
      Isn't this what washers are for? They do sell grade 8 washers. Probably higher grades as well if you search. Or roll your own.
      Paul A.
      SE Texas

      Make it fit.
      You can't win and there IS a penalty for trying!

      Comment


      • #4
        Originally posted by Bob Farr
        I'd like to find a socket head cap screw with a 3/8-inch diameter shank, but with a larger than standard diameter head. The lower bearing surface on a standard 3/8-inch head isn't much bigger than the shank, but I'm limited by the application to a narrow shank/thread. Standard height head is fine.

        A 1/2-inch head on a 3/8-shank would be just about perfect. Hardened preferred, 2-1/2 inch length, either hex or Torx ... does such a beast exist? I've check online with Grainger and Fastenall, and at the local hardware stores without any luck.

        Plan 'B' is a 12-point flange bolt, but I'd prefer to stick with a cap screw. The head will be countersunk.

        Thanks in advance for any suggestions,

        Bob
        I must be misinterpreting - the head diameter on a 3/8 socket head cap screw is already larger than 1/2 (it's 9/16). You could also go with a button head socket cap screw, the head diameter is 5/8 for a 3/8 screw.

        Cheers,
        Randy C

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        • #5
          wide head socket cap screws

          randyc, I know that heavy duty hex head cap screws do exist. The standard 3/8 hex cap screw has a 9/16 head while the heavy duty one has a 5/8 head.

          Comment


          • #6
            Originally posted by randyc
            I must be misinterpreting *** Cheers,
            Randy C
            No Randy, you have it right, but I'm guilty of violating the 'measure twice, post once' rule. A 3/8-inch shank socket head cap screw does indeed have a 9/16-inch head diameter. My mistake. Here's one that I sourced locally:



            The closeup photo messes up the perspective a bit, but this is a standard 3/8-shank socket head cap screw. With a standard 9/16-inch head that only leaves me with 3/16 total difference in the O.D.'s. There is a 1/32-inch inside radius between the head and the shank, so I'm left with a mere 1/16-inch bearing surface of head around the outside of the shank. That's not much, or at least not as much as I'd like. Here's the application:



            It's a little wedge-action split vise I'm working on. Randy is familiar with the project. Paul's right, I would normally go with a washer, but I want to closely countersink the heads to leave as little space as possible for swarf to work its way in.

            Studentjim's 'heavy-duty' socket head cap screw with a 5/8-inch head might help. If I cut away any inside radius that would give me 1/8-inch bearing surface remaining on the head around the outside of the shank, doubling what I had before. I would probably take Paul's advise and roll my own special washer just to have something 'sacrificial' and easily replacable between the head of the bolt and the body of the vise. Studentjim, where do you source the HD cap screws?

            JCHannum, your shoulder bolt suggestion has some possibilities. I'll slip into the hardware store in the morning and check it out.

            Any other suggestions?

            Thanks,

            Bob

            Comment


            • #7
              Clamp

              Bob - You may want to make your bolt in the clamp part straight up and down like the other one. Then again , maybe not. Just a thought.
              Kansas City area

              Comment


              • #8
                Thanks for the suggestion ToolGuy. I wish I could but I can't fit a swiveling pin (like a screwless/grinding/toolmaker's vise) inside the t-slot and a straight bolt would be subject to a side load during clamping because of the wedge action. Here's the original thread for a bit more context:

                http://bbs.homeshopmachinist.net/showthread.php?t=44835

                I'd love to hear any alternative suggestions you might have!

                Bob

                Comment


                • #9
                  Clamp

                  Any side loads will be negligible in the amount of movement involved going from snug to tight. However, if you are concerned about that you can make a ball depression in the top of the clamp and radius the bottom of the SHCS to match. Then make 1 of your T nuts with a slight radius on the part that contacts the underside of the T slot.
                  Kansas City area

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                  • #10
                    Hey, thanks for sharing the idea ToolGuy! A t-nut which is a OD segment of a large diameter swiveling pin would work. Do you think the loss of clamping surface between the forward t-nut and the t-slot would be a problem? I'd be really disappointed if snugging down the jaw only resulted in scooting the vise backward away from the work. The body is small and only has one other clamping bolt so there's not a lot of 'grip' on the table.

                    Bob

                    Comment


                    • #11
                      Clamp

                      The rear bolt will provide a lot of anti-scooting stability, but the other one will too. Together they will work as well as any other similar design.
                      Kansas City area

                      Comment


                      • #12
                        How many are you looking for? Some shell mill holder screws have very big heads, I know I have couple that have 3/8-24 thread and around 1" head.

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                        • #13
                          I believe that the style of head you're looking for is called "cheese head"

                          I have a few here that were salvaged from something or other. Seems like they are machine screw size, like 10-32 or so. Don't know if they're available in bigger sizes.

                          The socket head that holds my face mill onto the arbor is a prime example of what a cheese head looks like. Maybe it's a specialty screw, when I buggerd one, they certainly charged plenty for a new one.

                          TC
                          I cut it off twice; it's still too short
                          Oregon, USA

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                          • #14
                            http://www1.mscdirect.com/Shell-Mill...002010808.HTML

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                            • #15
                              The ones you may or may not have seen could be "Stripper Plate Bolts" used in press tool industry. Thet have a ground shank with an enlarged head and a smaller than shank diameter thread.

                              Regards Ian
                              You might not like what I say,but that doesn't mean I'm wrong.

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