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Finger Plate small part holder/drill jig

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  • Finger Plate small part holder/drill jig

    I just had to make somethin' in the shop between family events over the 3-day holiday weekend. I've been eyeing John Moran's (Gadget Builder) "Finger Plate" small part holding drill jig for quite some time and decided to whup one out.

    I made mine a little bigger. The base plate is 2-7/8" x 4-1/8" x 5/8" and the clamp arm is 3/8" thick instead of the 1/4" thick as on John's. I had a chunk of cast iron left over from a butchered angle plate and wanted a little more mass to help hold it down by hand on the drill press table. I think John's was 2-1/2" x 3" x 1/2"

    I got to use a couple of other recently finished projects which really helped. I used the mill table travel stops to set the endpoints of the slot on the clamp arm and also the tilting angle table set at 90 deg. with a spindexer clamped on to mill the flutes on the knob. They both worked great! Sir John's recent spindexer vernier explanation really helped and I ended up with 8 evenly spaced flutes rather than 7, or 9 or 8.5 like I previously would have.


    The other thing I tried was turning a small drill bushing from 5/16" drill rod. I heated it up to a dull red and swished it around in a pan of oil. It came out hard as a....well a file won't grab it anyway, so I guess it's OK.
    Milton

    "Accuracy is the sum total of your compensating mistakes."

    "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

  • #2
    I did a couple of trial runs, one spotting a cotter pin hole on a piece of 1/4" round and the other I drilled a small hole in the end of a .030" x 1/4" brass strap. Both are normally clumsy jobs but came out perfect using the new tool.

    Milton

    "Accuracy is the sum total of your compensating mistakes."

    "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

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    • #3
      Nice, I like it and can see the everyday use this jig can be useful for.

      .
      .

      Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



      Comment


      • #4
        nice

        I drill a lot of small holes in tiny sewing machine parts
        Would come in handy!
        please visit my webpage:
        http://motorworks88.webs.com/

        Comment


        • #5
          A really good and useful job

          A really good useful job well done in good time.

          You could leave that on the coffee table as a "conversation piece" as there are no "holes to pick" in that - especially as regards the finish - and the complete answer to the inevitable "Nice - but what do you use it for?".

          It's that well finished that (even) your wife will show off what you've made!!! And, no, I'm serious. I don't joke about good work.

          And it has nicely solved a few nagging problems that come up on several forums - accurately and easily drilling "cross holes" in "round" sections and using the "vee" to keep a drill in place.

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          • #6
            they are handy to have buried in the bottom a draw, I like the use of the spin indexer to make the knob....next we'll guys making them on their rose lathes
            .

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            • #7
              I've always seen those things with the v-slot in the base. I like this much better! It would be so much easier to line things up for cross drilling.

              I do have a suggestion though, bear with me here. When I made the clamp set for my mini-mill I used jack bolts in lue of the fancy step blocks that the comercial clamp sets use to adjust height. However I used plain old hex head bolts, head down to the table. I think that spreads the load over a bigger footprint and prevents marring the table. I think that may be helpful here, although you will probably have to counter-sink the clamp and maybe even thin the head of the bolt to hold the realy small stuff.

              I had good luck just putting the threads of the bolts in the three jaw chuck and facing the lettering off the heads of the bolts. If you are only taking light cuts you don't have to tighten enough to damage the threads.

              Again, I like it! I've been going to make one of these for a long time. Now I know what I've been waiting for.

              Rick

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              • #8
                Thanks for the kind words fellers. One of these days I hope I'll have a "eureka!" moment and make something really nifty of my own design rather than just copying or modifying other folks' stuff.

                Rick, next time I'm out in the shop, I'm going to drill the end of the jack screw and press in a brass tip to reduce the marring on the plate....just like Mr. Moran did on the his. He thinks of everything!

                Tiff, wifey did say it was one of the prettiest little gizmos that she doesn't have a clue what it's for that she's ever seen. I spent an extra 10 min. or so on my poor man's surface grinder purtying-up the clamp and ran the knob across a wire wheel for a bit to make it look better. (Poor man's surface grinder = sheet of 120 grit wet/dry paper on a piece of plate glass)

                No offers to store it on the coffee table though.
                Milton

                "Accuracy is the sum total of your compensating mistakes."

                "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

                Comment


                • #9
                  Glad you liked the finger plate but realize it isn't my design. Like you, I copy nifty items I come across; finger plates were developed long ago, where each machinist added little details appropriate for his work.

                  I added the little brass end on the bolt and rounded it slightly so the edges wouldn't dig in. Unfortunately, this merely makes the divots in the plate round - it really needs to be flat with a larger contact area. In retrospect, this really would benefit from a miniature loose end like the one often seen on C clamps.

                  John

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                  • #10
                    looks neat but as a manufacturing engineer that is also a gage and fixture designer I have some questions...

                    1) How do you align the drill bushing with the spindle so the drill and the bushing have the same true position center line? Wouldn't it require being set up on a surface plate to get the bushing plate parallel with the bottom plate? (Assuming the c'line of the bushing and bushing plate are running perpendicular.)

                    1a) What's the tolerance between your bushing and the drill? Becuase getting the bushing lined up dead nuts gets real critical the tighter the tolerance. Or is this for getting the hole "sortta kinda on the center line" and the tolerance is loose enough to not matter a whole lot?

                    2) Do you change the bushing between the center drill and through drill? Or is it just for spotting the hole?

                    3) I understand the "fish tail", but couldn't same thing be accomplished with a through hole and a deep c'bore? This would allow a visual centering with the through hole while not having to worry about bumping the fixture with the side of the drill.
                    Ignorance is curable through education.

                    Comment


                    • #11
                      Nice job Gadget - Here's a similar one made from the details in an article by Cdr.W.T.Barker S.M.E.E. in Model Engineer Vol.104 (1951) pp268.

                      Funny thing - used it and a thin-piece vice this morning to file up a 1/16" x 3/32" x 1/4" key for a current project.
                      This one's a bit scruffy having been around in the workshop for what seems like forever !
                      Mark
                      What you say & what people hear is not always the same thing.
                      www.remark.me.uk

                      Comment


                      • #12
                        Here's my less traditional take on the finger plate.



                        The block is sized to fit into the milling machine vise in all possible orientations. Removable fences allow the part to be aligned to the block while it is clamped. (Removable so that, after clamping, one can access the edges of the part for drilling, etc. if so required.) A movable, bolt-on stop allows repetitive positioning in the milling machine vise.

                        Not shown is a collection of specialty clamps, miniature V-blocks, etc. that increase the utility of the fixture.

                        While I use this fixture like a finger plate for freehand drilling of small parts, its primary use is as a set of "clamp-on reference surfaces" for small engine castings and the like. It makes the job of establishing initial orthogonal reference surfaces on the castings much easier.
                        Regards, Marv

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

                        Comment


                        • #13
                          Rusty I didn't plan on using it clamped down in my mill's vice and aligning it precisely to the spindle. It'll be used for freehand "quickey" projects on my drill press table. Holding it down by hand will allow a little movement and so far it's worked a treat.

                          The 1/8" I.D. drill bushing is used to align the #1 center drill (body is 1/8") to start the hole and then finish up with a 1/8" screw-machine length bit. I really hadn't thought about larger drill sizes.

                          0-b-uk....yours looks like it was designed to be aligned to the spindle, clamped down to the table and then the round stock clamped in the v-groove to be drilled?

                          Wow Marv, yours is the pièce de résistance of the finger plate world! I"m going to add some removable fences to mine for repetitive ops. That's a great idea.
                          Milton

                          "Accuracy is the sum total of your compensating mistakes."

                          "The thing I hate about an argument is that it always interrupts a discussion." G. K. Chesterton

                          Comment


                          • #14
                            Originally posted by Rusty Marlin
                            looks neat but as a manufacturing engineer that is also a gage and fixture designer I have some questions...

                            1) How do you align the drill bushing with the spindle so the drill and the bushing have the same true position center line? Wouldn't it require being set up on a surface plate to get the bushing plate parallel with the bottom plate? (Assuming the c'line of the bushing and bushing plate are running perpendicular.)

                            1a) What's the tolerance between your bushing and the drill? Becuase getting the bushing lined up dead nuts gets real critical the tighter the tolerance. Or is this for getting the hole "sortta kinda on the center line" and the tolerance is loose enough to not matter a whole lot?

                            2) Do you change the bushing between the center drill and through drill? Or is it just for spotting the hole?

                            3) I understand the "fish tail", but couldn't same thing be accomplished with a through hole and a deep c'bore? This would allow a visual centering with the through hole while not having to worry about bumping the fixture with the side of the drill.

                            As a non-machinist, I use the finger plate on the drill press - which in my hands is not a precision drilling tool.

                            I made the bushing hole 0.128 with the idea of using a 1/8" center drill to start holes so I don't change bushings. The finger is set parallel to the base using a square against the edge of the plate; this ensures the drill doesn't bind in the bush. Overall, not a precision setup but quick and adequate for many if not most jobs. For precision centering I use the mill, pick up the edge, etc., a much longer process.

                            If a hole larger than 1/8" is needed I spot with the 1/8" center drill, through drill with a 1/16" or so drill, move the work to the drill press vise and align the spindle to the hole using the small drill as a guide while clamping. Then drill with the desired size. Again, not precision location but adequate for many tasks.

                            The center drilling aid and fish tail are optional. Finger plates are simply clamps that the owner can easily customize for specific applications as desired. Its easy to make more fingers for other uses or with different goals.

                            John

                            Edit to add link: http://www.gadgetbuilder.com/FingerPlate.html
                            Last edited by GadgetBuilder; 05-29-2007, 04:10 PM.

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                            • #15
                              Finger Plate

                              Originally posted by Airhead

                              I had good luck just putting the threads of the bolts in the three jaw chuck and facing the lettering off the heads of the bolts. If you are only taking light cuts you don't have to tighten enough to damage the threads.



                              Rick
                              Airhead, if you ever need to clamp down tight on the bolt's threads, just take a nut of the appropriate size ( a coupler nut works really well, gives lots of surface for the jaws to engage) and slit it across one of the six sides with a hack saw or dremel tool. The bolt will thread into it, and the lathe chuck jaws squeeze it down tight onto the threads without damaging them. You can either run the bolt head up tight against the nut, or use two such nuts in a jam nut configuration to keep the bolt solidly positioned.

                              Steve
                              Steve
                              NRA Life Member

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