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A Handy Fixture: Button V-Block

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  • A Handy Fixture: Button V-Block

    I got the idea from an Ed Dubosky article in one of the Metalworking Books:

    You can make them in various sizes and with various features. This one is optimized for making the connecting rods for a steam engine Team Build I'm involved with.

    Here it is in action:

    I use that Planer Gage to "flip" the part and keep alignment to the flats when I do the other side.

    Surface finish comes out very nice. It's just an easy facing operation on the lathe. When I get ready to bore the crank and wrist pin holes on the mill, I'll just slap this little guy in a 5C collet block and we'll be lined up and ready to go.

    Details on how I made mine are here:

    If you're fooling with little bitty parts, tooling like this is very helpful. So is my newly mounted collet chuck. Don't know how I ever left it sitting on a shelf for so long, but I made a backplate for it on this project and it has been a treat!


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  • #2
    One more item, while I'm talking about the collet chuck. Mine is a cheezy import, costing $150 on eBay. I actually got it to be extremely accurate by fussing over the backplate. I get 2.5 tenths runout, and its repeatable, which is pretty slick for what I do.

    However, it's a pain to switch collets--you have to wind a lot of turns in the key to get the old one out and a lot more to get the new one in. To make matters worse, this cheap key had no knurling to hold it in place, so I'd be spinning it like mad with my finger and suddenly it would fly across the shop.

    Very annoying!

    So I made this from a bearing and a piece of scrap brass I had laying around:

    That's one of those cheapy skate bearings. I got a bag of them off eBay for $20 or so. You can see my knurling to hold that end in place alongside the original useless knurling.

    The bearing is shrink fitted to the brass hub, then that piece is Loctited onto the chuck key. Now I can just grab the bearing like a knob and it spinds like crazy.


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    • #3
      Very cool Bob,

      I guess necessity is still the mother of inventions.

      This is one of those things that one should make right away because when you need it way down the road you won't remember, or is that just me



      • #4

        Very neat trick. I am always pleased to see new techniques and this one definitely is a good one. Of course now I will have to make one. Or perhaps it can wait till I have a part that requires it.

        I also appreciate the way you use the various tools in an integrated manner: 1-2-3 block, angle gauge, collet block, collet chuck, vises, planner height gauge, etc. I have seen questions here about the value of each of these items and you have illustrated all their values in making a single part.

        Bad luck on the broken tap. I would have to agree that it is often a waste of time to remove it if the part is easily reproduced.

        When I saw your ball bearing handle for the chuck key, an idea hit me. I have been working on plans for a collet chuck myself. Reading your comments made me realize that any keyed chuck for a threaded collet will require a lot of cranking. Anyway, my idea is to use an inexpensive, battery powered electric drill or screwdriver for this task. They can be purchased from various sources for $25 or even less. It would not need to have a lot of torque as the final tightening would be by hand and it should be very easy to make a square driver tip for the chuck. The tool could be kept on the charger by the lathe ready for instant use. Perhaps with additional accessories and one of those 1/4" hex quick change holders in the chuck, additional tips could be kept handy for other tasks at the lathe.

        Anyway, nice job and thanks for sharing.
        Paul A.

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


        • #5
          Originally posted by Ken_Shea
          This is one of those things that one should make right away because when you need it way down the road you won't remember, or is that just me.
          Yup, just you.

          The one that ALWAYS gets me though is the "Dang, I made a widget 2 years ago that will save me a ton of time making this part...if I could just FIND it!"

          "Accuracy is the sum total of your compensating mistakes."

          "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton


          • #6
            Bob I bought one of those 5c collet chucks with a D1-4" camlock fitting delivered for £99 it is very good value and pretty accurate too.I hear what your saying re tighhtening the collets but well worth the money.kindest regardsAlistair
            Please excuse my typing as I have a form of parkinsons disease


            • #7
              Great little fixture Bob! I'll have to remember that one.



              • #8
                Paul, the electric drill is a good idea. Another is to mill a 3/8" socket adapter. I have a little 1/4" air ratchet, and I got a 1/4" to 3/8" adapter for it that would be perfect. Would spin it nice. It needs milling because whatever size the key is (didn't measure it) is slightly smaller than 3/8" square on my collet chuck. I would've gone that route, but I needed the chuck key to quit falling apart for the final tightening anyway, so this seemed like more fun.

                BTW, the ultimate collet chuck IMHO is the one J King made from a planetary gear set from an automatic transmission:

                I wonder if they planetary gears would make changing collets faster too due to the gear ratio or just the reverse?

                Someday I'll try my hand at copying it, but for now these smaller bits of tooling are a bit more my speed!

                Paul, I am a sucker for gadgets, I must admit, but as you see, I do eventually manage to put most of them to work.



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                • #9
                  Nice work Bob. I love to look at your stuff, it looks real professional, unlike some of things I hash up. But I have every intention of getting to where you are at. Some day. Jay
                  "Just build it and be done"


                  • #10
                    Good tips come at the right time . I remember the article now .But have been scratching my head trying to figurer out how to hold some parts I need to make for a Miser Hot Air engine I am building . Talk about good timing. Will build one of those fixtures.
                    Every Mans Work Is A Portrait of Him Self