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  • What cutter bit to use

    I want to make inch scale markings on a degree wheel of sorts. The dial would be about 2" in diameter. I have a rotary table but I just don't know how to make the small graduated lines that would be my indicators. What type of cutter would be needed. Can I purchase a book that might explain the process and the rotary table. I'am real old and real new at this, but I do have time on my hands. Thank You.

  • #2
    I would grind a small, thin cutting tool to fit the spindle and then use the quill to scrape the lines.
    Michael

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    • #3
      I think Michael Az is on the right track. Grind up something like a lathe "V" tool with about a 30 degree included angle, maybe a bit less, and scribe the lines with it by using the quill downfeed. Use the quill stop to control the length of the lines. Exactly how you mount this toolbit in the spindle is an exercise for the user.... :-)
      Note that you probably don't actually want anything that remotely resembles a square lathe toolbit; you may want to mill the shape on the end of the piece of drill rod, with a little back taper for relief, harden it, and hold the result in a collet. You'll also want to lock the spindle against rotation.

      Having done this a couple of times, I've found that it's very important to get the dial or whatever EXACTLY centered on the rotary table, so the lines come out the same depth all around when you scribe them. One thing I've done is clamp the part, then use an end mill to take a very light pass all around by turning the work with the rotary table. Then you know the o.d. is truly concentric with the rotary table's rotation.

      I think Guy Lautard talks about graduating dials in his first "Machinist Bedside Reader." It's also discussed in Dennis Chaddock's book about building the Quorn tool and cutter grinder, and I think in George Thomas's Model Engineer's Workshop Handbook.


      [This message has been edited by SGW (edited 02-15-2003).]
      ----------
      Try to make a living, not a killing. -- Utah Phillips
      Don't believe everything you know. -- Bumper sticker
      Everybody is ignorant, only on different subjects. -- Will Rogers
      There are lots of people who mistake their imagination for their memory. - Josh Billings
      Law of Logical Argument - Anything is possible if you don't know what you are talking about.
      Don't own anything you have to feed or paint. - Hood River Blackie

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      • #4
        If you have access to a cylindrical grinder, just use an old center drill, dowel pin, or drill blank and grind it to a sharp point then scribe your lines. If you do not have a cylindrical grinder here is a little tip. Chuck up whatever you are going to use in a cordless drill or a corded drill, turn it on and use a pedestal grinder or belt sander. This will keep it true instead of trying to grind it by hand.

        Kevin
        If it's not good enough for you, it's sure not good enough for anyone else.

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        • #5
          Hmm...dunno. You need a cutting edge, not a round point. I don't think trying to scribe the lines with a round point will work very well.

          If you grind it round, then grind off slightly more than 1/2 the diameter so you have some cutting edges, that's something else again.
          ----------
          Try to make a living, not a killing. -- Utah Phillips
          Don't believe everything you know. -- Bumper sticker
          Everybody is ignorant, only on different subjects. -- Will Rogers
          There are lots of people who mistake their imagination for their memory. - Josh Billings
          Law of Logical Argument - Anything is possible if you don't know what you are talking about.
          Don't own anything you have to feed or paint. - Hood River Blackie

          Comment


          • #6
            The 2002 Airgas/Rutland catalog lists engraving tools (#2041 8220--8230) of various point angles and shank diameters 1/8" to 1/2".

            I have made my own from old end mill shanks. Just index and grind three angled flats on the point so that it looks like a three faceted pencil point.
            O

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            • #7
              Soooooooooo, My thinking was off by a mile. I had it in my mind that I would be using the mills rotation to cut these lines, marks ect. into the dials circumference. Everyones help has shed a whole new light on my dilemma. Now I know what direction to focus my attention. This has helped so much. This being my first entry; I had thought a great deal about how to enter my question to avoid embarrassment for being so thick. Thanks to All, jim

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              • #8
                In this forum the only stupid questions are the ones that don't get asked. So...ask away.

                You could use an engraving cutter, as per crypto, which is along the lines of what you were thinking. That's certainly another approach, and it probably work satisfactorily. Personally, I think scribing the lines is probably easier/faster, but crypto, being used to his methods, might disagree.

                For nearly all this stuff, there is no single way, or even one "best" way, to do a job. A lot depends on the tools at hand and personal experience.
                ----------
                Try to make a living, not a killing. -- Utah Phillips
                Don't believe everything you know. -- Bumper sticker
                Everybody is ignorant, only on different subjects. -- Will Rogers
                There are lots of people who mistake their imagination for their memory. - Josh Billings
                Law of Logical Argument - Anything is possible if you don't know what you are talking about.
                Don't own anything you have to feed or paint. - Hood River Blackie

                Comment


                • #9
                  SGW,

                  As a matter of fact I have thought some more about this. It depends on the desired width of the scribed line and perhaps cutting is not the way to go. Possibly a "drag diamond" cutter might be the best. It doesn't rotate just scribes fine lines. They can be purchased from suppliers of tools for engravers. I recall that the cutter (I used Gorton machine and cutters) had to be ground very accurately or else a burr would be left on the line or on the engraved letter. Sharpening a cutter took a bit of time and so if the job permitted it we would just go ahead and use a dull cutter and just rub off the burr with a piece of emery cloth wrapped around a small block of wood or steel or whatever was at hand. This was common practice, after all an engraved arrow indicating open or close on a valve handle was not precision engraving.

                  Engraving presentation gifts, firearms, placques, etc. that was when one HAD to have a sharp tool. I believe Michael's suggestion might be the most practical for you.
                  O

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                  • #10
                    Jim

                    Hey, don't worry about making an ass of your self, I have done it lots of times - they just whisper "Oh, he's from CANADA...don't feed him raw meat!"

                    Actually you can use a mill if you like. I use a carbide dental burr in my foredom flexshaft to carve a shallow groove - which I then fill with contrasting paint (usually white on black anodized or oxidized). BTW, I get them free from my dentist. At first He did not want to give them to me (I might get aides or space herpes 10 or something) - I told him to relax, that I would blowtorch them first to sterilize them. Then he said OK.

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                    • #11
                      I just finished making a division wheel of sorts, I took a section of tape from a tape measure and cut a length (10 inches in my case) I started from just before the 10 inch mark, ended at just before the 20 inch mark, ground the cut ends to fit perfectly spaced, and taped it into a hoop. I machined a disc about 3.14 in diameter, till the hoop would press onto it snugly, with the taped ends still touching. Glued the tape in place, now every 1/16 is 1/160 , every 1/8 is 1/80, etc. Starting at 10 inches is ok, as 11 in is marked as 1, so the scale reads from 0 to 10, repeating. I am about to try using a flexible stainless ruler with it's etched markings similarly, If I can find one marked in tenths instead of eights and sixteenths. I also have made similar using 25 inches of tape measure, on a wooden disc 8 in dia. Using that I etched a disc in 1/100ths to replace the sloppily made one on the mill.
                      I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

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                      • #12
                        darryl, Reid Tool Supply www.reidtool.com sells stick-on flexible tapes in a variety of styles, including some graduated in tenths. I don't think any of them are metal (the ones I've gotten are Mylar-covered plastic), but they may be something you could use. They're pretty cheap.
                        ----------
                        Try to make a living, not a killing. -- Utah Phillips
                        Don't believe everything you know. -- Bumper sticker
                        Everybody is ignorant, only on different subjects. -- Will Rogers
                        There are lots of people who mistake their imagination for their memory. - Josh Billings
                        Law of Logical Argument - Anything is possible if you don't know what you are talking about.
                        Don't own anything you have to feed or paint. - Hood River Blackie

                        Comment


                        • #13
                          darryl:
                          www.leevalley.com has these as well (may be different form reid's)

                          Comment


                          • #14
                            Thanks for the sources SGW and Thrud. I have a Lee Valley near me and I remember now that's where I saw the rule graduated in decimal. I used the only one I had years ago to make an indexable mount to use on the unimat. That machine still in with me, and I use it now to keep the dust off a small part of the workbench.
                            Just for interest, I scribed grooves recently on a plastic disc to replace an inaccurately made one on the mill. I used a felt pen to fill in the grooves, and wiped the surface with a cloth to remove excess, filling the grooves more in doing so. Very quick and neat, but marking the numbers by hand with a dremel made it look cheesy. I don't care 'cause I know the markings are accurate. I made a spin casting table years ago, and dug it out to test the existing dials on the mill. It can be set to rotate very evenly, and at any slow speed, so it was easy to synchronize the markings using a fluorescent light. I centered the dial on the table, dialled in the speed to 'stop' the markings, and laughed as I saw the markings wobbulate out by about 1 thou. I didn't expect this, but subsequent testing of other dials showed some were good, some were poor. The new disc I made had no visible unevenness. It certainly makes me wonder what other inaccuracies I've yet to discover with the asian mill. By the way, I used the lathe to hold the disc, indexed the spindle, and 'dug' the grooves using a flexible shaft tool on the cross slide, with a sharply pointed 'd' bit. This was made from a hss drill bit, but I would use a carbide bit next time, due to the wear I saw on the bit through the grooving process, even in the plastic I used for the disc (lexan).



                            [This message has been edited by darryl (edited 02-17-2003).]
                            I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

                            Comment


                            • #15
                              There is an alternative to an expensive engraving tool, one that most machinists have in their very own supplies on hand. A #1 centerdrill makes a great engraver. Run a new or barely used one at .003 to .005 depth. Works great. Learned it from one of the best milling technicians I ever knew, who incidently, is a regional technician for tooling and engineering for kennemetal (he is very good). I have done this for years now, and when programming in engraving for a company I worked for, showed them this trick (again, he worked there to start, they kind of forgot this until I brought it back, thought it was common practice there?).

                              I use these commonly for engraving in the school shop, very forgiving. They do some very intricate engraving.

                              I also use 1/8 inch shank carbide engraving tools for some work, but the cost is prohibitive for normal use where I can buy ten CD's for the cost of one micrograin or less 1/8 inch x 60 degree engraver.

                              As for the graduations, I learned a trick fom the famous magazine Home shop machinist I believe, ormight have been projects in metal. If you have a cad system, you can lay this out to size, and create the graduations. You of course need to know the circumfrence and the total movement per turn, but after this, lay it out in the cad system, and set the printer to print to the right length (circumference). Did this on an inch conversion to metric wheel set I made for a learning tool - made four wheels for my emco cross feeds to temporaily replace my inch graduation wheels. They were accurare to .002 in three turns (normally .125 per turn). There was more to this than what I mention, but it was almost as easy as taping on and go to engrave. No I did not have a real neat indexing head at the time, so this was my best bet, did this off a spin jig holding the wheel on an arbor.

                              Just some real quick ideas. The main one was for the engraving process.
                              CCBW, MAH

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