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Making hold down clamp for v-block

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  • Making hold down clamp for v-block

    Got a homemade v-block at the flea market but does not have any clamps to hold stock. V-block has a 3/8" X 3/16" milled channel about 1" below top surface of block on either side. Any suggestions as to how to make a clamp?
    Thanks Paul

  • #2
    Hmm I'll be curious to see what others suggest. The problem with the clamps is that it requires alot of material removal if you start from solid. Much more efficient to cast it.

    Since most of us don't have access to a foundry ... how about welding one up? Some square stock, layout like an A-frame, weld it up, then machine it to suit. Just need to whack the top of the A off ... drill and tap...

    I dunno, just thinkin' out loud.


    • #3
      I made a couple for a set of B&S blocks I picked up.

      I started with 1/2" cold rolled 4140 square stock,heated it red and formed it around a mandrel to form a U shape.After trimming the legs off even I drilled and tapped for the clamp screw then clamped the U in the mill vise and used a woodruff keyseat cutter to mill the tangs in the ends of the arms.

      I had thought about laying it out on a piece of flatstock and just milling out the whole profile,but decided the other method would be faster.
      I just need one more tool,just one!


      • #4
        imo this is a simple forging job - and that's from someone without forge, anvil or much forging experience (but some).

        pick some suitable stock, using the vise to hold the bar and vise grips to bend it, heat bright red where you want the bent and have it. file the two indented bits to accurately fit the V block and drill and tap. with a bit of care a very workmanlike job can be done with a torch, vise and vise grips and finally a file

        ah, weird beat me to it! i'd be more grass roots though and finish it on the bench without mill

        here;s some pics...set up for bending a split'll bend where the heat is, so control actually isn't that hard. I just held up a cardboard template with the radius i wanted and tweaked until it looked good.


        Last edited by Mcgyver; 01-07-2009, 11:48 PM.


        • #5
          Yep - I hadn't even thought of forging it. Ironically I just came in from doing some old school blacksmithing work in a charcoal forge. I make my own charcoal so my forge is always smokey. (i.e. I reduce the wood around the edges of the forge and feed the charcoal into the heart) I smell like a campfire!


          • #6

            I had a similar problem, V blocks and no Clamp. I thought about it for a few minutes and the ordered replacement ones. It is not worth the time to make them unless you need something special.

            But you can always start with a big block of material and cut away everything that does not look like a clamp



            • #7
              I made this V Block a while back. The clamp is just a 1/4x1" bar stock bent to a U with the tangs welded on and cleaned up. The wings are not fixed to the block. Works great and the little birds mouth really keeps round stock locked up. I use this in the shaper and on the band saw weekly.

              Wow... where did the time go. I could of swore I was only out there for an hour.


              • #8

                Bloody hell - I can't get stuff as round as that using a lathe, let alone a set of locking pliers and a gas torch...

                Well done!

                All of the gear, no idea...


                • #9
                  V-block clamp

                  I made a v-block clamp from an old flaring tool clamp. See details


                  • #10
                    Originally posted by Ian B

                    Bloody hell - I can't get stuff as round as that using a lathe, let alone a set of locking pliers and a gas torch...

                    Well done!

                    I agree. At this stage in my machining career, the only way I would have been able to produce those pictures would be to buy a split ring, take a picture, then pry it apart for the before picture.
                    Esoteric Garage


                    • #11
                      Geez, Really nice work guys!!!!!!!!!!!!!!!!!!!

                      (Mcgyver--- is that vise by chance a "Rae" made in Barrie Ont.) ?


                      • #12
                        How about getting them laser cut? Probably a $7.00 job if cut from 1/2" 44W plate.


                        • #13
                          I made a couple of clamps from 1/2 inch gage stock. Band saw cut them out, then finished them with a woodruff key cutter.

                          Lot of cutting but it was good experience in precision cutting on a band saw. This was early in my apprenticeship.

                          I posted pictures in the "shop made tools" thread. Probably in the first hundred posts.

                          Some other good ideas mentioned here also.

                          OPEN EYES, OPEN EARS, OPEN MIND

                          THINK HARDER


                          MY NAME IS BRIAN AND I AM A TOOLOHOLIC


                          • #14
                            That could be a job for a bender and flat bar. There will be four bends- two for the tabs, and two to make the U shape. When you bend for the tabs, leave extra length so the bender can handle it, then trim those to allow the sides of the U to be close to the V block. I would make these bends a little over 90. Then make the other two bends. You might have to stop these short of 90 degrees until you see how tightly they can be bent in the machine. If you can bring them both to 90, great. Otherwise one extra step is needed, and that is to reverse-bend the flat bar at the center of its length before you bend the two corners. When the corners are at 90, place the piece in the bender again and press the center bend flat. The end result is a U shape in flat bar with tabs to fit the slots in the V block. The last step is to drill and tap for one or preferably two hold-down bolts. If the flat bar is wide enough, there will be enough material left for strength after drilling and tapping the two holes.

                            While you're at it, you would probably make a few of these in different heights to accommodate different diameters of workpieces. What I don't like about the typical clamp is that it sticks up too high. For smaller diameter stock, I'd prefer a lower profile clamp.

                            After all this, you can make any suitable 'end-piece' for the clamping bolt that you would like. I like the bird-mouth one, and I'd also like a short angle iron one. The clamping bolt would bottom out in a hole in the corner of the angle iron, so it wouldn't press on the workpiece itself.

                            In the time it has taken me to type this, I could probably have made one U shaped piece by now. I think I'd be inclined to start with a 3/16 x 1 inch flat bar- maybe using just one clamp bolt, and I'd also want to make one wider using two bolts.
                            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-


                            • #15
                              Plasma cut

                              Why not get someone to plasma cut the blanks and machine the cut edges smooth ,drill and tap for a bolt .
                              It would be easy to get extras made , 1/2 inch plate would be adequate .
                              No worries with hard areas with plasma either.