Toolgal Posted July 19, 2018 Share Posted July 19, 2018 This one should be easy to figure out, but I can't find an exact match so I am, as always looking for answers in all the right places. It is a double ended bit, one end has a slight point, which I suspect is a nail starter hole tip, the opposite end has no such tip. Each end has what looks like a small channel in it that makes me think that the bit removes the wood as the it turns, somewhat like an auger. Because it can be flipped around to use either end I am tending toward an electric drill bit, but I really need more of a name. Any BIT of info would be appreciated. Tool Gal Link to comment Share on other sites More sharing options...
Daswulf Posted July 19, 2018 Share Posted July 19, 2018 I have a bunch from my grandfather and other places but im no machinist. I'd say double sided countersinking drill bit. Link to comment Share on other sites More sharing options...
1forgeur Posted July 19, 2018 Share Posted July 19, 2018 Center drill for a lathe Link to comment Share on other sites More sharing options...
SLAG Posted July 19, 2018 Share Posted July 19, 2018 I think that Herr Daswulf is on the right track. It looks like a drill bit with a base portion that would widen (chamfer) the hole drilled. The hole now can receive a screw and the head of that screw would be flush with surface, (or below said surface), of the wood or metal. The widened portion of the drill bit has a groove in order to clear the cuttings. I would surmise that the tool would cut (drill) a partial hole. The screw would then deepen the hole, and be very snug. A thought just came to mind. I have some of those bits and they are used for drilling rivet holes. The rivet head would fit flush with the metal, (of one piece), and the other rivet end is peined, (mushroomed) That rivet end passes through the other metal piece in order to join the pieces together. The bits came with my pop rivet set kit. I used the word chafer, countersink is the better term. (thanks Das). The metal I alluded to are generally sheet metal. SLAG. Link to comment Share on other sites More sharing options...
Marc1 Posted July 19, 2018 Share Posted July 19, 2018 Although that tool can be used in different ways, it is a lathe centre drill. CENTREDRILLS Link to comment Share on other sites More sharing options...
BIGGUNDOCTOR Posted July 19, 2018 Share Posted July 19, 2018 I always call them center drills as they are used to drill a pocket for the lathe's live or dead center to sit in. I have seen them listed as combined drill and countersink in some catalogs. The countersink part is 60 degrees though and flathead screws and bolts are 82 degree, and hole chamfers are usually a 45. Where I do use them for chamfering is when I am tapping a hole as the 60 degree matches the 60 degree thread angle. I use center drills in the milling machine as well when I need to start a twist drill in an exact location. Use the center drill to put a starting hole in the part that helps to center the twist drill better than a center punch will. They also work great for removing broken bolts when using an easy out. Being as rigid as they are they will stay on center (when in a mill or lathe) and won't walk like a twist drill will on an uneven surface like a broken bolt. Again, it is used just to get a good starting point for the twist drill that follows. They come in graduated sizes like shown above so you can match them up with the drill, or the center being used. The one I used the most was a #4. Link to comment Share on other sites More sharing options...
Toolgal Posted July 22, 2018 Author Share Posted July 22, 2018 I was going to have to make a big decision, was it a center drill, like Biggundoctor and others said, or was it a countersink bit, like Das Wulf and others said? Two pretty worthy camps to have to choose from. Thank heavens Marc1 spoke up and confirmed my belief that bits can be used for a variety of things. I took my image and added a countersink bit and a center drill, and it's pretty hard to tell the difference. I have a few tools called Screw Hammer Wrenches, so perhaps this will be called a Countersink Center Drill? Take a look at the three bits together. If you see a difference between them please let me know so I can differentiate. That leads to a question I still feel comfortable asking due to my Newbie status - why are some bits called drills? To me a bit is not much good unless it is attached to the drill. Why are some bits called drills? Link to comment Share on other sites More sharing options...
SLAG Posted July 22, 2018 Share Posted July 22, 2018 Madame Gal, They are called drills because, (among other things) they can be chucked into a lathe. That set-up is ideal for horizontally drilling holes in wood turnings. For example drilling the center of a turned lamp "standard". And yes I found them in the riveting kit that I bought ages ago. (in other words they have more uses than for solely lathes.) Regards, SLAG. Link to comment Share on other sites More sharing options...
Marc1 Posted July 22, 2018 Share Posted July 22, 2018 i am afraid it is not that simple. I have used large drill bits to countersunk a predrilled hole, but a drill is not a countersink tool, and the fact I used one for that purpose does not make it such. Why? it's all in the angle. Real countersink tools come in a variety of angles and consist of a conical cutter with several flutes. The idea is to either clean the burr left by the drill, or to allow for a screw head to be flush with the surface, sunk in the counter ..., hence the counter-sunk name. The process of drilling with a drill bit and cutting a conical hole to allow for a screw to sit flush can be done with a drill and countersunk combination tool. Most have a drill bit that can slide for different depth and others have fixed drill bits. Your picture shows a tool that has a different purpose, and that is to drill a shallow hole and a conical recess to accomodate the centre of a lathe. A lathe cone has 60 degrees and rarely 70 degrees angle, A countersink screw has angles that range from 80 to 120 degrees. Drill bits have an angle of 118 ( or should have) If that tool came with a pop rivet tool, it surely can perform the task required for a pop rivet operation ... that is besides drilling the hole ... well nothing! A pop rivet does not need countersinking, just needs a hole. Scratching away the burr is usually a luxury when it comes to pop rivets, but even with that in mind, the tool is and remains a centre point drill for lathes. it can be used for a multitude of task? ... sure. Link to comment Share on other sites More sharing options...
iron woodrow Posted July 22, 2018 Share Posted July 22, 2018 Show that to any fitter, turner or machininst, and you will get the same answer. Centre drill. They are able to be used as other things, but a centre drill by any other name is a centre drill. Similarly, my grandfather used a hammer as a doorstop. Is it a hammer or is it a doorstop? Link to comment Share on other sites More sharing options...
Marc1 Posted July 22, 2018 Share Posted July 22, 2018 That reminds me the time I worked at Qantas. The baggage master office had a door stop that looked like a brick all wrapped up in newspaper. For years we kicked it back and forth to keep the heavy steel door open or close it. Eventually someone kicked it hard enough for the many layers of paper to come off and show what was inside. it was not a brick but a large gold bar. It was common for gold bars to be transported in a box bolted inside the baggage container. One must have come out somehow and whoever found it hid it in plain view but was then not game to take it with him. It was a door stopper for us ... Link to comment Share on other sites More sharing options...
Will Taylor Posted July 22, 2018 Share Posted July 22, 2018 .....and they are used to uniform primer pockets on cartridge brass Link to comment Share on other sites More sharing options...
DuEulear Posted July 22, 2018 Share Posted July 22, 2018 It is most diffinitly a center drill but why limit yourself to lathe operation? If ever you are having trouble with small diamiter drillbits walking ( dispite center punching the hole first) they are great in a drill press or mill to spot the holes before drilling the final hole as the thick crosssection behind the buisness end keeps the tool right where you want it. Dead on center . Just don’t drill to far if you don’t want the countersink. du Link to comment Share on other sites More sharing options...
iron woodrow Posted July 22, 2018 Share Posted July 22, 2018 1 hour ago, DuEulear said: It is most diffinitly a center drill but why limit yourself to lathe operation? No one said to not use it for other operation. The question was "what is it?" and that was the answer. One could use it to clean ones nose if one desired. Link to comment Share on other sites More sharing options...
Daswulf Posted July 22, 2018 Share Posted July 22, 2018 I yield to the rightful name of Center Drill that was mentioned by the more knowledgable here. Glad to know the proper name now. If you look up or as for a center drill that is what you will get. If you look up or ask for a countersink bit you would get something different anso those would be different for wood and metal. ( which I also have some of each) so yeah. Proof is in the proper name. Even if it can be used for multiple purposes. Link to comment Share on other sites More sharing options...
PaperPatched Posted July 22, 2018 Share Posted July 22, 2018 2 hours ago, Will Taylor said: .....and they are used to uniform primer pockets on cartridge brass I would not go anywhere near a primer pocket with a center drill. Primer pocket uniforming tools come sized specifically for primer pockets (large and small), are flat bottomed, and have a shoulder to control the depth of cut. Link to comment Share on other sites More sharing options...
Will Taylor Posted July 22, 2018 Share Posted July 22, 2018 yes and you are correct. I meant to say flash hole,I have one ( I don't actually use it,other tools for that) that is the correct size. Link to comment Share on other sites More sharing options...
stevomiller Posted July 23, 2018 Share Posted July 23, 2018 16 hours ago, DuEulear said: It is most diffinitly a center drill but why limit yourself to lathe operation? If ever you are having trouble with small diamiter drillbits walking ( dispite center punching the hole first) they are great in a drill press or mill to spot the holes before drilling the final hole as the thick crosssection behind the buisness end keeps the tool right where you want it. Dead on center. They are indeed technically called center drills, but as stated above they make a great spot drill. As a matter of fact, I’ve heard mill operators (as opposed to lathe operators or full blown machinists) call them “ Spot Drills”. Link to comment Share on other sites More sharing options...
DuEulear Posted July 23, 2018 Share Posted July 23, 2018 Woodrow that sounds extrodinarilly bad for ones sinuses just throwing out one of my favorite uses Link to comment Share on other sites More sharing options...
Toolgal Posted July 25, 2018 Author Share Posted July 25, 2018 On 7/22/2018 at 5:21 AM, iron woodrow said: Is it a hammer or is it a doorstop? Depends on if it is on the floor or on the workbench. Great discussion guys! Yes, the proper name is always what I am looking for but picking up all the other info is a bonus! Link to comment Share on other sites More sharing options...
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