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DIY 5" sine bar

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  • DIY 5" sine bar

    There has been a lot of discussions over time regarding the use, need and cost of a sine bar and the seeming need for a 81-piece set of NIST certified "slip guages" (aka "jo blocks").

    Some have them and use them, others have them and don't user them (much) and other either don't need them, can't afford them, have never used them or would like to make or try one.

    This post is directed to those that would like to make one and try it.

    I've had this in mind for a while but a couple of recent "accuracy"-related threads got me going with it.

    I knocked out the following very rough "sketch"? ("mud-map"?) that is at the end of this post in about 10 minutes at the Kitchen table.

    It might surprise you how accurate it can be - certainly to within +/- 3 to 5 arc minutes which is as good a most rotary table, dividing head and protractors (vernier and digital).

    I have not specified any material. What-ever is handy will do - I'd suggest aluminium - for the Sine Bar (SB) body.

    Other than where I have put a tolerance the sizes and shapes are what-ever suits you. Of course the nearer you are to size the better.

    Finish is not all that important either - just do as well as you can.

    The tolerances should be readily achievable in a small HSM shop with a small mill or "3-in-1" machine.

    I have deliberately used 3 precision steel balls instead of the traditional bars/rods as it will cancel out the need for high accuracy in the bars being parallel to each other, plus 3 "legs" are inherently stable and will not "rock" as would be the if bars were used and were not parallel.

    The "super" magnets use magnetic force to attract them to the balls. They are recessed into the SB body and fixed with a suitable adhesive (normal "Building/Construction" or others at a hardware store) will do.

    The sizing of the "guage block" is given in a small sketch at mid left. The height of the "guage block" required is 5 x Sine of the angle required.

    The block is placed under the single ball - the other 2 balls rest on the table.

    The "guage block" for the angle you need can be made from anything handy and suitable in your shop but should be no more than 0.001" from the height required. A bolt/screw in a nut will do - but use a lock nut. I'd suggest facing off the "guage" ends to size and parallel in your lathe.

    I've put a lot of "to suit" stuff/sizes on the sketch. They are of no real importance so you can please yourself.


  • #2
    The sine bar shown above is an excellent expedient and will within the accuracy to which it was made deternine angles into arc second country.

    Many times I've pushed dowel pins through the holes in 1-2-3 blocks and after recording some measurements used the block as a sine bar. Same goes with a handy piece of rectangular cold rolled steel with a couple of holes drilled and reamed for dowel pins or some steps milled in the edge as is traditional.

    There is no real need in these days of omnipresent trig capable calculators for the pin centers to be dead nuts on a nominal dimeension - or even super parallel to the reference face. If you know the errors present you can mathematically compensate for them.

    So the message here is that a sine bar doesn't have to be a glistening work of the toolmaker's art. With some as-built measurements and a little shop math you can use something quick and dirty to obtain surprisingly accurate results.

    Chances are the home shop machinist will never have a need for a sine bar in his tooling inventory but should the need arise Oldtiffle's sketch should be kept in mind. Print it out and put it into the looseleaf notebook you keep on your library shelf next to "Machinery's Handbook" and other references.
    Last edited by Forrest Addy; 02-16-2008, 04:10 AM.

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    • #3
      Revision 1 - already!!

      Thanks Forrest.

      As it pleases you it sure does please me - and with a big sigh of relief.

      I have got to "Revision 1" already.

      I suggested the body be aluminium so that it had no magnetic qualities (or distractions) as I guess you knew. I just did not want to prescribe it in case some-one with something else would feel that he couldn't do it.

      I had second thoughts about the fixing of the magnets and so I revised the sketch to include a set-screw (with the contact end "squared off") and lock-nut in a counter-bored hole or "ledge"/bevel.

      Any effective other alternative that the maker chooses to use is OK.

      I just wanted to define the under-lying principles and let the maker do as he liked to suit himself with everything else. A job with "you" in it is something to show (off?) to others - particularly with a good aluminium finish and the shiny steel balls that works and is of use.

      I deliberately did it a "rough" sketch that might be done in the shop. I did not want it to be an intimidating CAD or other formal drawing.

      You are quite correct as regards the accuracy (or lack of it) in the centre-distance between the two ball axes. That figure can be substituted for the (now nominal?) 5" C/C distance and use a calculator.

      My usual method (as 5 = 10/2) is to use trig tables, shift the decimal point right by one postion (multiply by 10) and then divide by 2 (10/2 = 5).

      I thought it was about time that there was a project for a HSM-er by a HSM-er that would be of use, is not too difficult and uses a lot of machine skill.

      I did think of machining a 60 or 90 degree "V" along the back/top face centre-line as a sort of "V" block to locate anything cylindrical.

      I have included three pics:
      - the revised sketch (coloured);
      - 2 of the general principles and applications of a sine bar.

      You might recall the latter 2 as I withdrew them after Marv Klotz's protractor used as or in lieu a sine bar was "trashed" and "rubbished" badly by some. I was really "pi**ed off" at that and perhaps said some things that I shouldn't have.

      Anyway.

      Many thanks for your kind comments as they are very appreciated as I, as do many others, hold your skills and opinion in very high regard.





      Comment


      • #4
        While we are on alternatives.......

        If you are one of the great unwashed who don't have gage blocks, (which I would also be if I hadn't lucked into some).....

        If you own a micrometer, and you obtain a couple sizes of adjustable parallels, you have "instant gage blocks"...... any size you want, to any practical accuracy you care to adjust for (within the basic flatness, etc of the parallel).

        Sounds like a good match to the sine bar above.
        CNC machines only go through the motions

        Comment


        • #5
          Originally posted by J Tiers
          While we are on alternatives.......

          If you are one of the great unwashed who don't have gage blocks, (which I would also be if I hadn't lucked into some).....

          If you own a micrometer, and you obtain a couple sizes of adjustable parallels, you have "instant gage blocks"...... any size you want, to any practical accuracy you care to adjust for (within the basic flatness, etc of the parallel).

          Sounds like a good match to the sine bar above.
          Second time I've heard this trick (probably the first was also you JTiers).

          I like it!

          Oldtiffie, can't wait to see your build photos. Looks like a fun project.

          For those who may want a little inspiration in the department of what to do with a sine bar, I present one of Widgitmaster's (regular CNCZone contributor) many fine setups, this time with a sine bar:



          He's making the support arm for a CNC gantry router.

          Cheers,

          BW
          ---------------------------------------------------

          http://www.cnccookbook.com/index.htm
          Try G-Wizard Machinist's Calculator for free:
          http://www.cnccookbook.com/CCGWizard.html

          Comment


          • #6
            Guys...this is a great thread! I've never used a sine bar and always wondered how you used them in different applications.
            Tiffie...the drawings etc. explain a lot.
            Bob... nice example of how to use these.
            Anyone else have any more pics of different setups?
            Thanks!
            Russ
            I have tools I don't even know I own...

            Comment


            • #7
              The Compound Version Ball Sine Plate.

              Old Tiffie,

              Nice unit, You have there. Here's a 5.000" single or compound version, very useful on the inspection side (light), tricky to use on a machine, but I have done some strange one offs with it over the years.






              Les H.
              The Impossible Takes Just A Little Bit Longer!

              Comment


              • #8
                Quite so.

                Originally posted by J Tiers
                While we are on alternatives.......

                If you are one of the great unwashed who don't have gage blocks, (which I would also be if I hadn't lucked into some).....

                If you own a micrometer, and you obtain a couple sizes of adjustable parallels, you have "instant gage blocks"...... any size you want, to any practical accuracy you care to adjust for (within the basic flatness, etc of the parallel).

                Sounds like a good match to the sine bar above.
                Thanks JT - right on as usual.

                Items referred to by JT are at:
                http://cdcotools.com/item.php?itemid=14

                US$35 might seem a bit steep but they are a good tool to have.

                There are other sites including Littlemachineshop.com and eBay of course.

                I have a set and they get a lot of work. They are ideal as proxies for slip guages in the right setting.

                They are "Chinese" - of course - and a I had a minor "easing" job to do but they now slide beautifully and are surprisingly accurate.

                I find them very handy indeed for measuring gaps and slots etc. Once you have the "feel" for them they are very accurate - +/- 0.0005" is not out of the question and +/- 0.001" is relatively easy.

                Comment


                • #9
                  A great tool

                  Originally posted by LES A W HARRIS
                  Old Tiffie,

                  Nice unit, You have there. Here's a 5.000" single or compound version, very useful on the inspection side (light), tricky to use on a machine, but I have done some strange one offs with it over the years.






                  Thanks Les.

                  A very nice variation on a theme - very nice indeed.

                  And a brilliant application of the sine bar principle in a compound angle application with the "three ball" set-up - using 3 different height guages/blocks - which you sure can't do with a conventional sine bar with rollers.

                  That set-up effectively cancels out the use of a second conventional sine bar mounted on the first.

                  Put that 3-ball sine bar tool of yours on a rotary table and you can do magic things with it - just get the required surface "flat" with a TDI and read-off the blocks/guages (1 to 3 as required) on the sine bar and the rotation of the rotab.

                  Comment


                  • #10
                    Good use of tools

                    Originally posted by BobWarfield
                    Second time I've heard this trick (probably the first was also you JTiers).

                    I like it!

                    Oldtiffie, can't wait to see your build photos. Looks like a fun project.

                    For those who may want a little inspiration in the department of what to do with a sine bar, I present one of Widgitmaster's (regular CNCZone contributor) many fine setups, this time with a sine bar:



                    He's making the support arm for a CNC gantry router.

                    Cheers,

                    BW
                    Thanks Bob.

                    I won't be making it any time soon as I have a fairly complete kit in that regard.

                    I only sketched it in case some one wanted to either know how one was used or to make one in a HSM shop.

                    I actually had it in mind to use it in an angle-plate set-up for compound angles similar to Les Harris's set-up. I would have drilled and tapped the top of the angle plate in a similar manner to a 1-2-3 or 3-4-5 etc. block for obvious reasons. I've seen a lot of odd angles and faces on computer modeling screens which the designer approved without any regard as to how the machinist is going to or can make it.

                    I really did like that set-up you showed using a sine bar and 2-3-4 (or what-ever) blocks and good clamping. The set-up of the sine-bar (to be removed prior to machining?) will soon tell if the set-up has moved under clamping.

                    I might have at least considered doing the jog on a rotary table - but I can see that it would take a good-sized rotab to incorporate the clamping.

                    This is a truly great thread - particularly with posts like yours - and hopefully more coming!!

                    Comment


                    • #11
                      Originally posted by oldtiffie
                      US$35 might seem a bit steep but they are a good tool to have.
                      That made me giggle. Go see what a Starrett set costs - $175 for a set of six.

                      And oh, one of the most useful gizmos I've come across for Sinebars is this gizmo - admittedly it's overpriced, but it's easy enough to make with a surface grinder. Let's face it, most of the time, we're using angles that are common - 45, 30, 15, 22.5, etc.


                      HTRN
                      EGO partum , proinde EGO sum

                      Comment


                      • #12
                        This is a great thread.

                        Comment


                        • #13
                          The tool I made for cutting tapers has two .5 holes 5 inchs apart to set
                          taper . Like a cheap sine plate built in. In pic the two holes are used to swivle on a 5 inch arc to set angle.
                          jims





                          Comment


                          • #14
                            Good post Tiffie,I made a simple sine bar a long time ago,it was just a section of cold rolled square with two 3/4" dia. half round notches milled in the sides at 5"C-C and the corners trimmed off.Worked good for everything I used it for.It went missing a couple years ago and I was just about to plunk down some cash and buy new when I checked ebay.Found them in droves cheap.I landed a 5" and a 10" NIB made in Japan for $18 and shipping,yes I was that lucky

                            HTRN,never noticed those blocks before,one of those is diffinately on the to do list.
                            I just need one more tool,just one!

                            Comment


                            • #15
                              Right

                              Originally posted by HTRN
                              That made me giggle. Go see what a Starrett set costs - $175 for a set of six.

                              And oh, one of the most useful gizmos I've come across for Sinebars is this gizmo - admittedly it's overpriced, but it's easy enough to make with a surface grinder. Let's face it, most of the time, we're using angles that are common - 45, 30, 15, 22.5, etc.


                              HTRN
                              Thanks HTRN.

                              I won't "rubbish" "Starret" as is was (and hopefully still is) one of the world's "gold standard" makers of machine tools - MituToyo, Brown(e?) and Sharp and several UK (Moore and Wright etc.) and European names are similar.

                              But I can say that the "Starret equivalent" that I've bought in the US are as good as Starret for my purposes.

                              That "gismo" is a marvelous idea. First I've seen it - it is so damned obvious when I saw it - a set of spacer blocks all in one tool. But a set of spacer blocks made in the HSM shop will do the job too - +/- 0.001" or better will do for most HSM jobs and that tolerance is quite achievable.

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