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  • speed bit or spade bit

    Had a question posed to me today- what's the difference, if any, between a speed bit and a spade bit? I have a hunch that north of the 49th it's called a speed bit, and south of that it's called a spade bit. There are also ones where the cutting edges have extended tips that first cut a circle before the meat is removed, to reduce splintering. Anyone know the real skinny on these woodworking bits?
    I seldom do anything within the scope of logical reason and calculated cost/benefit, etc- I'm following my passion-

  • #2
    I think they are the same, I've also heard them called "paddle bits".

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    • #3
      darryl,
      I call a spade a spade bit.
      The ones with the tips is called a forstner bit.
      I think thats how its spelled.
      jack

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      • #4
        There are spade bits with the spurs and spade bits without spurs. Either way they're spade bits. My good spade bits have spurs. My Craftsman spade bits don't have spurs. Figures!

        Forstner bits are a totally different animal. I wish I had a good set of Forstner bits. They make nice precision flat bottomed holes.

        Speed bits might be a manufacturer's name for their spade bits. Does Irwin call their spade bits speed bits?

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        • #5
          yup, your right. forstners have the tip in the middle.
          I need more coffee.
          jack

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          • #6
            Say what? Forstner bits are spiral bits with teeth at the outside circumference with an auger screw point, similar to a ship auger bit, but with the outside diameter cutting blades to slice the fiber for a clean cut. Spade bits are flat with a high positve rake cutting edge on either side of a central vee shaped cutting tip, quick and dirty. Good for drilling a hole in a stump to insert black powder...
            Free software for calculating bolt circles and similar: Click Here

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            • #7
              Evan:

              Not all Forstners have a screw tip ... at least down here. I have a set meant
              for use in a drill press where, for obvious reasons, a screw tip would be a
              disadvantage.

              Regards, Marv

              Home Shop Freeware - Tools for People Who Build Things
              http://www.geocities.com/mklotz.geo
              Regards, Marv

              Home Shop Freeware - Tools for People Who Build Things
              http://www.myvirtualnetwork.com/mklotz

              Location: LA, CA, USA

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              • #8
                My set of Irwin bits is called "Speedbor".
                Lynn (Huntsville, AL)

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                • #9
                  The Forstner bits with the saw teeth and screw(self-feeding)centers are plumbers bits,they are for rough work.
                  The true Forstners have a solid edge and a plain conical or four sided point.They were originally intended for gunstocks,piano and carrage work where precise holes were needed.

                  Spade or paddle bits are also for rough work,they came about with the advent of the electric drill.Before that were a self feeding type that were cheaper than the ship augers and double flutes of the time.

                  I personally use forstners and plumbers bits.I cringe everytime I see somebody use a spade bit in a drillpress(Norm and the other guy do it from time to time)keep waiting for one of them to have a spade snap off and go flying But I guess they edit out the blood splatter

                  Also Forstner bits are made to run slow,they work by slicing and shearing,not scraping.I bought a big set of Forstners from Grizzly,they are decent bits,even got one small set from the truckload-o-junk tool sale that works pretty good.

                  I would like to find a source for Forstners without the saw toothed edge on 1-1/2" plus diameters.

                  [This message has been edited by wierdscience (edited 12-24-2004).]
                  I just need one more tool,just one!

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                  • #10
                    One place I found that the spade bit (not to be confused with the Spade Drill) works well in the machine shop is blowing holes in the drill press on engineering plastics such as nylon, acetals or UHMW as long as the holes do not need to be close. The flat paddle shape of the bit hepls prevent the drill from over heating the plastic and getting stuck in the hole
                    Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

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                    • #11
                      Yep Spin,

                      I tried that as a test a year or so ago. A plain old spade bit with a high rake edge cuts nylatron easily and with suprising accuracy. It has plenty of room for chip clearance and doen't overheat. I never expected it to work as well as it does.

                      Free software for calculating bolt circles and similar: Click Here

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                      • #12
                        Hmmm...looks like we've got some disagreement on terminology here.

                        Evan, how can a "spade" bit have a high rake edge. Are you talking behind the cutting edge, like back rake?

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                        • #13
                          Evan I tried it when I had to make up some holders for Hardinge hardened and ground step collets. The boss did not want wood so we went with delrin. probably about the most expensive collet racks in history
                          Forty plus years and I still have ten toes, ten fingers and both eyes. I must be doing something right.

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                          • #14
                            High rake as in a steep angle behind the cutting edge of the flat part of the bit edge on either side of center. It works very well. Here is a piece of nylatron, 2" OD, with a 3/4" hole produced with a spade bit so ground.

                            Free software for calculating bolt circles and similar: Click Here

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                            • #15
                              Evan go to http://www.leevalley.com/home/main.asp they have two traditional types of forstner bits the smooth knife edge and saw tooth edge. The saw tooth form is normally used on larger holes, the knife edge type cut the cleanest holes. Lee Valley sells HSS forstner bits and the normal carbon steel as wellas carbide tipped. The HSS are the best ones . The also have repoind brad lipped HSS drills for holes smaller than the tradional 1/4" forstner bits thiss do not cut flat bottom holes like forstners but do cleanly cut the wood grain without tear out. I have both the HSS Brad lipped drills and the HSS Forstners and highly recommend them to anyone seeking better wood drills.

                              The bits you are reffering to are called "Auger bits" you can look them up on Lee Valleys site as well. Auger bits are self feeding and were designed originally for ship building - specificxally mortise & tenon hole cutting in oak beams of the old english ships. Since then they have been adopted by plumbers and electricians for pipe and wiring routing in buildings. These have - for the most part been replaced by the ubiquitous holesaw and the mighty "Milwuakee Magnum HoleHawg" the plumber & electritians best friend - and worst nightmare when it gets out of hand!

                              [This message has been edited by Thrud (edited 12-25-2004).]

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