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  • Annular cutter questions

    I'd like to cut some 1" diameter holes in some 1/4"-thick structural steel.

    I'm considering getting one of these annular cutters to do the job:

    http://www.buyweld.com/cc100.html

    Some questions:

    1) It looks like it has a 3/4" shank, however there appear to be several flats on the shank - are they there in order to fit a particular style of chuck or drill, or can I use the cutter in a regular drill chuck or in a collet or end mill holder? If this cutter is intended for a specialized chuck only, are there other styles of annular cutters that would work in a regular chuck, collet, or holder?

    2) The description refers to a pilot pin, however I do not see a photo or details about the pilot pin. Is it simply a pin that is axially aligned with the shank and for which I must drill a pilot hole?

    3) Once you have used the annular cutter to drill a hole, how do you remove the material from the center of the cutter? Are there holes in the top of the cutter that you can use to insert a punch and tap out the material?

    4) What is the expected lifetime (number of holes) of these bits? Can they be resharpened easily, or would I need to take it to a professional to get it resharpened?

  • #2
    I have used them in a mill with r-8 collets for coping steel tubing. Light cuts only, If it spins in the collet you could trash the collet.

    You dont need the pin.

    The piece usually falls out the bottom, they dont stick like hole saws.

    They must be sharpened professionally.

    Hougen makes arbor adapters to hold them properly in drill presses or mills.

    http://www.hougen.com/cutters/magdri...cessories.html

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    • #3
      Originally posted by doorknob View Post

      Some questions:

      1) It looks like it has a 3/4" shank, however there appear to be several flats on the shank - are they there in order to fit a particular style of chuck or drill, or can I use the cutter in a regular drill chuck or in a collet or end mill holder? If this cutter is intended for a specialized chuck only, are there other styles of annular cutters that would work in a regular chuck, collet, or holder?
      We've used cutters like this for years. I'd stay away from collets as they do have a tendency to slip, especially as cutter size increases. For each machine that we've used them in we simply bought a cheap 3/4" endmill holder and shortened it a bit--so that the setscrew lines up with the flats. Works like a charm.

      2) The description refers to a pilot pin, however I do not see a photo or details about the pilot pin. Is it simply a pin that is axially aligned with the shank and for which I must drill a pilot hole?
      The pin is pointed and is designed to slide inside the shank of the cutter. If you're working from centre-punch marks you need it to line things up.

      3) Once you have used the annular cutter to drill a hole, how do you remove the material from the center of the cutter? Are there holes in the top of the cutter that you can use to insert a punch and tap out the material?
      As mentioned, the slugs normally drop out. On the rare occasion that they don't you must remove the cutter from the holder and knock the slug out by pushing through the pilot hole with a small screwdriver or other available tool.

      4) What is the expected lifetime (number of holes) of these bits? Can they be resharpened easily, or would I need to take it to a professional to get it resharpened?
      How many holes depends on the material and the quality of the cutter. Genuine Hougen cutters are more expensive but we generally found that they lasted longer. Roto-broaches are much more durable than holesaws if you look after them. Be sure to use lots of coolant type lube--flooding is best. Oil works but it doesn't flush the chips out of the cut which seems to have a big effect on the life of the cutter. They do need to be professionally sharpened but if you do it regularly and don't chip the cutters they'll last for years. I have some that have been around for at least 25 years...
      Keith
      __________________________
      Just one project too many--that's what finally got him...

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      • #4
        If I had the need - which I don't at present - I'd seriously consider one of these drills so that the drilling is not limited to the mill or pedestal drill:

        http://www.buyweld.com/power-tools-m...ll-preses.html

        http://www.machineryhouse.com.au/D900

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        • #5
          Lots of useful info, thanks all!

          Comment


          • #6
            I use them in the mill all the time. If you want a round hole on size they are the ticket. I used a 1/2 inch one to "birdsmouth some 1/2 inch stainless tube. The fit was tight enough to silver braze without any rework.
            If you have a lot of holes to do, there is an adaptor for a mill that combines a spring loaded ejector pin and coolant. The pin turn on the coolant when the pin touches the part and shuts it off when it ejects the blank.

            I do not use the ones over 1-1/4 in a collet and I am very carefull to lock the mill travel as well as tighten the daylights out of the vise.

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            • #7
              I'm surprised at how inexpensive those are. Might consider that in future...

              thanks!

              doug

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              • #8
                Why not step drill with silver and deeming drill bits? HF sells a set 1/2 to 1" for the price of that cutter. And they can be sharpened by bench grinder. Maybe I missed something. Would not be the first time.

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                • #9
                  There are several reasons to not step drill. 1) Annular cutters make round holes. Drills as a rule unless sharpened really well make somewhat round holes. 2) annular cutters can make 1/2 holes as well as overlapping holes. Drills can't do either without some creative tooling. 3) Annular cutters use much less horsepower than drills of equal size. 4) With an Annular cutter the hole is done in one pass not by stepping up with Silver & Deming drills.

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                  • #10
                    and... annular work a heck of a lot better in thin material than big drills.

                    Comparing HF S&D drills to a quality cutter? lol... I have a set of those drills in 1/64th ... pretty bad...

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                    • #11
                      Plus step drilling rarely leaves a hole concentric to the intended center point.

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                      • #12
                        Ok, ok... now I see the light.

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                        • #13
                          Consider seriously the Hougen RotaCuts (you don't need and probably won't want the extra length of the Rotabroach configuration). They screw onto an arbor which has a shank with 3 flats, making it easy to grip in a drill press or milling machine chuck. Each arbor - there is a larger one and a smaller one - will take a number of different diameter cutters. Extending just past the teeth of the cutter is a spring loaded pointed pilot. It is part of the arbor, and extends coaxially from it. A tiny prick punch dimple is all you need to drill a hole. You lower the spring loaded point down into the hole, which centers the cutter, and then just keep lowering the quill until the cutter teeth contact and then cut through the work. Quick, accurate, easy, no step drilling, good finish. The cutters are worth what you pay for them.

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