Press Drill & center finder ?
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  1. #1
    Join Date
    Feb 2012
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    237

    Press Drill & center finder ?

    Today at work i had a job that's need to be almost accurate as a machine shop job, some holes in small steel pieces, even if my measuring, scriber, and center punch skills are good enough, when it come to the press drill work bench and allign with the 5/16 Dia twist drills was a bit harder, i made a jig that i fixed hard on the table under the drills, but i had to change my set up 2 or 3 times to be right in the center.

    After couple of time i had an idea, i have a carbide scriber that the point as been machined like a pencil, i put the scriber in the chuck (as if i want to put a drill) tight the chuck and allign with it, its works great, now i found a starrett tool which i think its made for that but im not sure!

    so how should i use this tool,and why its look like a mobile parts ? the center parts look like moving and i don't understand why???
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  2. #2
    Join Date
    Feb 2008
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    Rome GA. (NW GA.)
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    Re: Press Drill & center finder ?

    That is an edge finder/center finder. You can chuck it up in a drill chuck in a milling machine and start it up. Make sure that the end is turning offset (wobbleing) ease it up against the side of the part and watch it as the wobble gets less and less until its gone. At the point it loses all the wobble it will slip a little sideways you are at the exact side. Lift the edge finder above the part. If you have a edge finder that has an end that is .200 (like the one you have pictured) move it in .100 and you are at the center of the chuck on the exact edge of the material. Some edge finders have an end that is .500, you have to move those in .250 to get the center line of the chuck over the edge of the part. It would be hard to use in a drill press unless you have a mill type table on it.
    Making as much progress as a one legged duck in the middle of a pond, just going in circles.

  3. #3
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    Feb 2008
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    Rome GA. (NW GA.)
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    762

    Re: Press Drill & center finder ?

    here is a video that explains it.
    Making as much progress as a one legged duck in the middle of a pond, just going in circles.

  4. #4
    Join Date
    Jun 2011
    Location
    WV
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    89

    Re: Press Drill & center finder ?

    I think this is probable more of what you are looking for. http://www.rockford-industrial.com/I...-bar-vise.HTML

  5. #5
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    Oct 2010
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    western kentucky
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    4,392

    Re: Press Drill & center finder ?

    you might be more interested in a "wiggler" in a drill press...

    a spring loaded tap guide would probably work...

    edge finder might be a little more than you need, but you can get those cheap too, I wouldnt buy a starret edge finder to put in a drill press..

    If you have to get pretty close you could always make a jig..

  6. #6
    Join Date
    Feb 2012
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    237

    Re: Press Drill & center finder ?

    Quote Originally Posted by brucer View Post
    you might be more interested in a "wiggler" in a drill press...

    a spring loaded tap guide would probably work...

    edge finder might be a little more than you need, but you can get those cheap too, I wouldnt buy a starret edge finder to put in a drill press..

    If you have to get pretty close you could always make a jig..
    That's EXACTLY what i need, i was just searching for some keywords, Wiggler, i googled it, youtube it, exactly what i need thanks a lot!

    Now its time to Ebay It!
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  7. #7
    Join Date
    Jul 2011
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    Melbourne, Australia.
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    815

    Re: Press Drill & center finder ?

    Hi, you can't use a wiggler or edge finder on a drill press unless you have a co-ordinate table to move the job, like in a mill.

    There is a set of Wigglers that comprise a pointy one for picking the centre of a cross marked drilling location, a .200" diam edge finder one, one with a ball on the end for similar purpose and a device for mounting a small dial indicator.

    On a drill press the simplest device is a "sticky pin", simply a ball of modelling clay, (Plasticine), and a sharp pointed needle or pin.

    You stick the lump of clay with the pin sticking out of it onto the end of the drill and run the drill at about 200 rpm.......the needle sticking out of the clay will be running all wobbly.

    You use a 6 " ruler held on it's side to slowly touch the side of the revolving needle until it runs true....then you position your job under the needle point (don't touch it, just get very close to the X scribed line) and allign the needle point to the X spot co ordinates.

    You can also use a pointed piece of welding rod, but the average drill chuck never runs true enough for the point to run dead true.

    If you want to get "dead accurate", same as in a milling XY table co-ordinate movement, you will need a mill or a cordinate table with vice etc made to fit on a drill table.

    BTW, the Starret double ended edge finder/centre locator shown in post #1 can be used to locate the drill centre on the drill, (an expensive method), but it is a manual method of locating a centre mark using the pointed end, and is always used for work that has been marked out with X marks and centre pops for drilling.....the other plain cylindrical small end is for edge finding on a mill only.

    Holding the body of the finder in the drill chuck with the pointed end sticking out, run the drill at about 200 rpm, and hold the edge of a 6" rule against the side of the parallel part LIGHTLY behind the point, until it runs true.......the drill chuck does not have to be in good condition and as they always run out from useage, the point on the finder will be able to be made to run true no matter what the chuck condition.....the drill bit will not run true, but that's a problem you can't fix if the chuck is knackered or the drill spindle is too.
    Ian.
    Last edited by puddytat; 07-18-2012 at 08:32 PM.

  8. #8
    Join Date
    Feb 2012
    Posts
    237

    Re: Press Drill & center finder ?

    Thanks for those explanations, first of all i'll try to explain my issues in better words (even if im not very good to write english)

    The press drill that i use at work is not a press drill powered by strap, is powered by gears, so im not a machinist at all, but there is a huge difference in accuracy and quality of work, those gear powered press drill doesn't shake like those cheap strap running one's, for me and for some of the work i do its work great!

    When i have to pierce holes in mild steel that doesn't need to be dead accurate (concrete anchor or wood flooring anchor) i use the crappy press drill, the work i have to do was some railling parts made of Stainless Steel, 2 plate bolted together back to back with countersink, i don't want to give lesson to no ones by saying this but its really need to be accurate because in Stainless you'll see if something is not square or the 2 bolted plates are not prefect matched with the others!

    also, the ''gear powered'' press drill that we have (can someone tell if there is a right name for those press drill?) as a small vice that move right and left , back and forth but i didn't use this vice for the job i did!


    At the end, my big problem was more about the fact that i found it hard to allign the point of the drill to my center punch because how its shaped, and anyway the drills is supposed to cut the metal, so im a little bit off center, it will cut off the center and not in my center punch!

    That's why i find the second ''wiggler'' perfect for what im doing!

    am i the only one who had hard time to allign perfectly press drill and center punch layout ???
    Last edited by LayoutMan; 07-18-2012 at 10:56 PM.
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  9. #9
    Join Date
    Jul 2011
    Location
    Melbourne, Australia.
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    815

    Re: Press Drill & center finder ?

    Hi, you can drill holes with a vee belt drive drill press or a geared head drill press, or a mill drill, or a milling machine....they all rotate the drill bit and enable you to drill holes accurately.....PROVIDED the job is secured in a vice (bolted down) or clamped to the drill machine table.

    Drilling holes in metal by holding the job down with your hand to stop it moving is very dangerous.

    Once you have marked the centre of the hole with two cross lines on the job, you take your dividers and mark a circle the same size as the finished hole on the job......then you lightly centre pop four places opposite one another round the circle......this will tell you when you have drilled the hole that the hole is in the centre of the marking and you will see 4 half round pop marks to prove it.

    This method is used when you have a few holes that must be in an exact position, and is only really suitable for holes about 12mm diam and up.

    Once you have located the centre of the hole to be drilled under the drill spindle, you use a centre drill to make the first location small hole to guide the next drill accurately.

    If you wanted to drill a 12mm diam hole accurately, you would drill the centre drilled hole first then a 3mm hole, followed by a 11.5 mm hole and finally with a 12mm drill to get size.

    There are other easier ways, but essay writing is too tedious, and you will learn by experience to get good.

    The Wiggler with a point is only really used for marked out work, whereas on a mill you would use the edge finder and X & Y axis co-ordinates of the milling machine to position your drill, but the multi drilling method gives you accurate sized holes without the drill wandering off position or going oversize.
    Ian.
    Last edited by puddytat; 07-20-2012 at 12:41 AM.

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