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Re: [taigtools] Mach. square recommendations please! :)

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  • Tom Benedict
    I ve been lusting after a Starrett combo square for some time, but just haven t laid down the cash yet. Good to know that the PEC is that far off. I ve seen
    Message 1 of 7 , Sep 3, 2002
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      I've been lusting after a Starrett combo square for some time, but just
      haven't laid down the cash yet. Good to know that the PEC is that far
      off.

      I've seen center finders that are dedicated center finders. Not sure how
      close they are, but they're not $120. For finding the center of a round,
      that might fit the bill.

      There's one I find in wood shops all the time. (Remember, this is for
      woodworking.) It's one you bolt to the wall. It's got a v-groove in it
      with a fairly dull blade bisecting the V. You put your stock in it, smack
      the other end with a mallet, rotate 90 degrees, smack with a mallet.
      Voila, you've got an X at the end of your round.

      I'm guessing that's not what you're looking for...

      Tom

      On Tue, 3 Sep 2002, penitent75 wrote:

      > Hey all,
      > Just got my first order from Enco and am in heaven, except for one
      > thing: the 4 piece machinists square set I got sucks! I got the PEC
      > one, thinking that for $80 it had to be reasonably decent, but the
      > center finder head on it is worthless, off by a mile! Maybe not that
      > far, but is painfully evident, even by eyeball.
      > So I would like to know, who makes an accurate machinists square?
      > I really am mainly interested in the center finder, is there a
      > cheaper way to find center on a rod than with a $120 ruler? ;)
      > Thanks again for all of your help!
      >
      >
      >
      > To Post a message, send it to: taigtools@...
      >
      > To Unsubscribe, send a blank message to: taigtools-unsubscribe@...
      >
      >
      >
      > Let the chips fly!
      >
      >
      > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
      >
      >
    • Stan Stocker
      Greetings; You might want to take a look at the slot for the rule in that center finder head, it isn t too rare to find a bit of swarf or crud stuck in the
      Message 2 of 7 , Sep 3, 2002
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        Greetings;

        You might want to take a look at the slot for the rule in that center
        finder head, it isn't too rare to find a bit of swarf or crud stuck in
        the bottom of the slot on these.

        Using these can be a bit of a trick, as the width and form of the
        scriber point used can throw the results off wildly. I use a fine
        scriber, and run the point down the edge of the rule against the work.
        I then move 90 degrees around the shaft and scribe, as expected. Then
        go another 90 degrees, scribe, then go another 90 degrees. You'll
        either end up with only 2 lines (a minor miracle indicating a good head,
        fine scribing technique or good luck, and truly round shaft), or often 4
        lines, with a very small square in the middle. Center pop the center of
        the square and you're darn close.

        If I have to mark the true center of a shaft, the inspection grade V
        blocks and height gauge get used on a surface plate, after miking the
        shaft carefully. Be aware that a shaft may be something other than
        round, but mike dead on at all points. This used to be fairly common,
        although centerless grinders have improved to the point that this is
        rare. To verify "roundness", you either need a mike with a V anvil, or
        you need to rotate the shaft on V blocks while indicating with a tenths
        reading indicator.

        If I have to put a center hole in the end of a shaft to high precision,
        the shaft gets run in a steady rest and the 60 degree taper is bored
        with the shaft running on its perimeter.

        Interesting how putting a center hole in the center of a shaft isn't the
        simple thing it appears isn't it? :-)

        Cheers,
        Stan

        penitent75 wrote:
        >
        > Hey all,
        > Just got my first order from Enco and am in heaven, except for one
        > thing: the 4 piece machinists square set I got sucks! I got the PEC
        > one, thinking that for $80 it had to be reasonably decent, but the
        > center finder head on it is worthless, off by a mile! Maybe not that
        > far, but is painfully evident, even by eyeball.
        > So I would like to know, who makes an accurate machinists square?
        > I really am mainly interested in the center finder, is there a
        > cheaper way to find center on a rod than with a $120 ruler? ;)
        > Thanks again for all of your help!
        >
        >
        > To Post a message, send it to: taigtools@...
        >
        > To Unsubscribe, send a blank message to: taigtools-unsubscribe@...
        >
        > Let the chips fly!
        >
        >
        > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
      • penitent75
        Thanks all for the great advice! :) I turned some rod, and used the center finder on it, scribing once, then turning 90 and doing the same. Each mark was off
        Message 3 of 7 , Sep 3, 2002
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          Thanks all for the great advice! :) I turned some rod, and used the
          center finder on it, scribing once, then turning 90 and doing the
          same. Each mark was off center by almost 1/32 of an inch each time
          (center was easy to see, since the toolbit is too low and left a
          little nib in the center). Is this much inaccuracy normal?!?! I
          thought it would be more precise than that!
          If it is that far off, wouldn't it affect the lathe's ability to
          turn a straight cylinder? If it turned a true cylinder wouldn't you
          end up with a much smaller rod than you began with (since the lathe
          is taking more material off of one side, I think?)
          Regardless, I am returning it to Enco, since it isn't precise (and
          for $80 I would expect that!). As an aside, the folks at Enco were
          super nice about the return! I think the customer service was
          awesome, and they even answered the phone in less than a minute! I
          was pleasantly stunned, and will definitely be using them again :)
          Now to save up some extra bucks for a Starrett (THOSE are super
          accurate, aren't they???). Thanks again for the help!

          --- In taigtools@y..., Stan Stocker <skstocker@a...> wrote:
          > Greetings;
          >
          > You might want to take a look at the slot for the rule in that
          center
          > finder head, it isn't too rare to find a bit of swarf or crud stuck
          in
          > the bottom of the slot on these.
          >
          > Using these can be a bit of a trick, as the width and form of the
          > scriber point used can throw the results off wildly. I use a fine
          > scriber, and run the point down the edge of the rule against the
          work.
          > I then move 90 degrees around the shaft and scribe, as expected.
          Then
          > go another 90 degrees, scribe, then go another 90 degrees. You'll
          > either end up with only 2 lines (a minor miracle indicating a good
          head,
          > fine scribing technique or good luck, and truly round shaft), or
          often 4
          > lines, with a very small square in the middle. Center pop the
          center of
          > the square and you're darn close.
          >
          > If I have to mark the true center of a shaft, the inspection grade V
          > blocks and height gauge get used on a surface plate, after miking
          the
          > shaft carefully. Be aware that a shaft may be something other than
          > round, but mike dead on at all points. This used to be fairly
          common,
          > although centerless grinders have improved to the point that this is
          > rare. To verify "roundness", you either need a mike with a V
          anvil, or
          > you need to rotate the shaft on V blocks while indicating with a
          tenths
          > reading indicator.
          >
          > If I have to put a center hole in the end of a shaft to high
          precision,
          > the shaft gets run in a steady rest and the 60 degree taper is bored
          > with the shaft running on its perimeter.
          >
          > Interesting how putting a center hole in the center of a shaft
          isn't the
          > simple thing it appears isn't it? :-)
          >
          > Cheers,
          > Stan
          >
          > penitent75 wrote:
          > >
          > > Hey all,
          > > Just got my first order from Enco and am in heaven, except for one
          > > thing: the 4 piece machinists square set I got sucks! I got the
          PEC
          > > one, thinking that for $80 it had to be reasonably decent, but the
          > > center finder head on it is worthless, off by a mile! Maybe not
          that
          > > far, but is painfully evident, even by eyeball.
          > > So I would like to know, who makes an accurate machinists
          square?
          > > I really am mainly interested in the center finder, is there a
          > > cheaper way to find center on a rod than with a $120 ruler? ;)
          > > Thanks again for all of your help!
          > >
          > >
          > > To Post a message, send it to: taigtools@e...
          > >
          > > To Unsubscribe, send a blank message to: taigtools-
          unsubscribe@e...
          > >
          > > Let the chips fly!
          > >
          > >
          > > Your use of Yahoo! Groups is subject to
          http://docs.yahoo.com/info/terms/
        • Stan Stocker
          Greetings; Any chance the pip was the source of the inaccuracy? It seems the rule couldn t lay flat if the end of bar isn t flat. If the rule is up in the
          Message 4 of 7 , Sep 3, 2002
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            Greetings;

            Any chance the pip was the source of the inaccuracy? It seems the rule
            couldn't lay flat if the end of bar isn't flat. If the rule is up in
            the air, the scriber will tend to wander. The center finder head will
            tend to provide a supporting point of contact on one leg, the other leg
            could be out in the air, but it could feel solid if the rule is hard
            against the pip giving the second point of contact. The pip is only at
            the center of rotation, there is no automatic assurance the pip is at
            the center of the shaft, unless you verified zero runout at the end of
            the bar prior to facing.

            I'm not saying the unit isn't defective, just that having a pip makes it
            a lot harder to get the results you're after, and the pip location may
            not be where you think it is. Roll the bar on a flat surface and see if
            the pip is wobbling or dead steady. If it wobbles, it isn't on center.

            You are correct that the cylinder would be smaller than it has to be if
            the goal is simply to turn off the outer surface between centers.
            Usually turning between centers is reserved for cases where full access
            end to end is required (you'll have to flip the stock end for end and
            move the dog), the ability to remount the work precisely is required,
            you're generating a taper via set over, or extreme accuracy in terms of
            no allowable taper comes into play. Simply cutting off the crust on a
            long shaft is usually done holding in a chuck with tailstock support.
            In this case, you usually press hard against the tailstock while
            snugging the chuck, just to allow for a bit of error in the center hole
            position - it needs to be close, but not dead on in this case.

            As to Starrett being great - I've heard a lot of rumbling lately about
            poor customer support and defective goods out of the box lately. I have
            very little new Starrett stuff, although I have quite a bit of their old
            stuff and like it a lot. I have one of their old protractor heads, a
            center head, and several rules. The heads were a bit rough (peeled
            paint, surface rusting and such) but when cleaned up and repainted have
            given good service.

            Cheers,
            Stan

            penitent75 wrote:
            >
            > Thanks all for the great advice! :) I turned some rod, and used the
            > center finder on it, scribing once, then turning 90 and doing the
            > same. Each mark was off center by almost 1/32 of an inch each time
            > (center was easy to see, since the toolbit is too low and left a
            > little nib in the center). Is this much inaccuracy normal?!?! I
            > thought it would be more precise than that!
            > If it is that far off, wouldn't it affect the lathe's ability to
            > turn a straight cylinder? If it turned a true cylinder wouldn't you
            > end up with a much smaller rod than you began with (since the lathe
            > is taking more material off of one side, I think?)
            > Regardless, I am returning it to Enco, since it isn't precise (and
            > for $80 I would expect that!). As an aside, the folks at Enco were
            > super nice about the return! I think the customer service was
            > awesome, and they even answered the phone in less than a minute! I
            > was pleasantly stunned, and will definitely be using them again :)
            > Now to save up some extra bucks for a Starrett (THOSE are super
            > accurate, aren't they???). Thanks again for the help!
            >
            <snipped>
          • Nicholas Carter and Felice Luftschein
            I would check Ebay, they seem to go for $25-50 for a complete conbination square set. Mitutoyo, Starrett, Sher-Tumico, Brown and Sharp, all are great brands.
            Message 5 of 7 , Sep 3, 2002
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              I would check Ebay, they seem to go for $25-50 for a complete conbination
              square set.
              Mitutoyo, Starrett, Sher-Tumico, Brown and Sharp, all are great brands. Not
              much goes bad on these, just make sure its not too rusty.
              felice@... is Felice Luftschein and Nicholas Carter. See our web pages
              http://www.cartertools.com/nfhome.html
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