Align drill press table to drill precise holes reliably?

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  • Align drill press table to drill precise holes reliably?

    I am contemplating building a modular model railroad layout. By that I mean sections with fixed dimension end plates that can be locked together.

    The idea is that that each bed played with have an alignment pin and and alignment pin receiver, and any module can be mate with any other module as long as the end pieces fit precisely together. For example, suppose all of then end pieces have 3/4” holes precisely 2” inches from the top of the end piece and 8” apart, precisely in the center of the end piece - then any module can be jointed to any other module.

    I have a dill press, and I plan to make jig to drill these holes - and that I can use my BT3100 to cut the end pieces to the same size.

    What I don’t understand is how to align the drill press table laterally - around the drill press post. For example, suppose that I make a set of end pieces today, and then need to make another set next summer.

    If the drill press table has rotated a couple of degrees around the post goes from the motor to the stand, I don’t know that I could detect that.

    I may be able to align the table by inserted a drill but into the chuck and then aligning it with a reference hole in a piece of wood used only for that purpose.

    But I wonder if there is some simpler better way to do this that has not occurred to me?

    I would think that this is a common problem for woodworkers, but I really haven’t found any solutions with various web searches.

  • #2
    I would make a drilling jig that can be entered from either side and aligned to the end of the railroad module.
    You can drill the holes as accurately as you can on the jig which then becomes an alignment and template all in one.
    Holes in hardwood can use used a few times, if you are going to be using more than 10 times You can get either metal insert bushings or make the center piece of aluminum or even steel.

    The jig has two internal three sided corners. One corner is for the left side of the module and the other for the right side. In both positions the center piece with the holes should lay against the side of the module and the long side should lay on the top of the module and the short piece should be in contact with the front of the module so that the holes will register the exact same distance from the front edge and from the top of the module road bed and the holes will be exactly 8" apart.

    You are going to want to make the center piece thick (I suggest at least 3/4") while the top and end pieces of the jig can be like thin plywood or masonite. Having a thick center piece will keep the drill somewhat straight even when handheld. You of course should drill the jig on a drill press to ensure the holes in it are perpendicular to the face.

    I assume your modules are going to be about 24 inches wide. So its hard to stand up on a drill press table. You can probably drill with a hand drill once you've clamped the jig to the end of the table. Flip the jig so that the front is registered to the front of the module and then drill from the other side of the jig.
    Have you thought about how you are going to line the track up to the end?
    There are modular section standards for N and HO and other gauge modular model railroads.

    If this doesn't make sense let me know. A drawing of your modular standard dimensions will help or at least a web page link.

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    Last edited by LCHIEN; 03-15-2022, 09:07 PM.
    Loring in Katy, TX USA
    If your only tool is a hammer, you tend to treat all problems as if they were nails.
    BT3 FAQ -


    • #3
      As Loring said, that is what jigs do with the tools. The jig determines the alignment, and makes the alignment precise and repeatable.

      I may be able to align the table by inserted a drill but into the chuck and then aligning it with a reference hole in a piece of wood used only for that purpose.
      Yes, That is the purpose of a jig.
      Last edited by leehljp; 03-16-2022, 07:35 AM.
      Hank Lee

      Experience is what you get when you don't get what you wanted!


      • #4
        It been a few decades since I was into model railroading, and I recall an article that was in Model Railroading regarding modular table assemblies. That was way back in the very early 70's IIRC and I no longer have that magazine. As I recall it wasn't overly complicated, basically setting up each top section with an alignment block that was glued and screwed to the bottom surface to precisely align with the mating table section. A template was used in the article so that each table section could be aligned or even juxtapositioned, if that was desired.

        Basically the blocks were made and then fastened into position using a jig to ensure alignment.

        Here are a few pictures I made of making something similar using dowel centering pins and an edge centering guide jig that is quite easy to make. You can then use a drill guide to properly drill the holes horizontally. Much easier than using a drill press, unless you can guarantee perfect vertical alignment of your stock under the drill press.

        The edge centering guide, is just a wood scrap, marked with a compass to provide a center hole and two equally spaced holes from the center in which to locate dowels. Once you make your alignment blocks you simply fasten them to the mating tables. I used this process when building multiple bookcases for my library, making a template first to ensure alignment of all sides, supports, and shelves.

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        I hope this helps,


        Think it Through Before You Do!


        • #5
          Thanks to all for the thoughts. I realized while reading those that there was a simplification available.

          I am not building to anyone else’s module standard - in part because I plan to run live overhead catenary with both rails on the track electrically connected to each other. For those who aren’t into model railroading arcana, that means my modules will not connect with with anyone else’s modules - or at east any standards I’ve ever head of.

          Since my modules only ever need to be able to connect to each other, I should be able to build the jig, lock the drill press table in place, and cut and drill 20 or 30 end pieces over a weekend without shifting the drill press table.

          I figure that if they are all made with same jig in a fixed location, they will all mate with each other.

          Since each module requires 2 end plates, 30 end plates - or maybe even 20 would be lifetime supply.

          I had thought of creating a separate “centering” jig - a jig I clamp the table with a reference hole that I adjust to be right under a bit in the chuck of the press - I just don’t know how accurate that would be.

          Thanks to all.


          • #6
            Here is a typical jig I use to make uniform holes repeatedly in say a post leg.

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            The center piece is a 2x4 cutoff, with holes drilled 3/4" from the top and 3/4" from the front and 2 inches center to center.

            The top and end pieces are just thin scraps to align with the post along the arrows; these pieces extend over the other side as well so that the jig can be used to drill holes on either side of the post for right and left side use..

            You can either use a 1/8 drill and this piece as a drill guide. to start the holes. Or you can use an inexpensive and very useful transfer punch set. These punches are .005" undersized so that they can slip in a hole and transfer the hole location to mark the center for drilling. Use just hand pressure or a gentle tap of a small hammer.
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            If you drill the wood directly using the drill it will be good for one project maybe ten times, but the straight and perpendicular hole you drilled with the drill press will be saved in you use a hand drill. I say ten times because the drill will somewhat open the hole a little each use. If your bit is short for the jig, you can start the holes using the jig, then remove the jig and complete to depth.

            A transfer punch will locate well but it you want perfectly square holes you need to transfer the marked piece to a drill press to drill. The other good thing is it will allow you to use different sized bits than the bit used for the jig.

            Either way the use of a drill press in making the jig will accurately transfer the holes to the opposite side of the jig and make sure the holes are square to the surface. And consistent from piece to piece.

            The width/thickness of the center piece of the jig can be 3/4" or 1.5" depending on you preference. 1.5 will give the straightest most perpendicular guide but may be inconveniently thick.

            Keep the jig in a box and you can make matched parts for years if need be.

            Obviously you can add holes, and scale it up to 18 inches long or more to locate holes on the right and left side (by flipping) of modular RR sections.
            Last edited by LCHIEN; 04-29-2023, 11:43 AM.
            Loring in Katy, TX USA
            If your only tool is a hammer, you tend to treat all problems as if they were nails.
            BT3 FAQ -


            • LCHIEN
              LCHIEN commented
              Editing a comment
              re-reading this a year later, I have some add'l comments.
              1. Wood grain often makes drill bits walk off a little if the bit contacts at the ridge of the hardest part of the grain.
              2. Using the jig directly as a drill guide prevents walking off best.
              3. Drilling a smaller pilot hole can help, as will a punch and
              4. Use brad point bits to locate the precise hole location and get the bit started.

          • #7
            Aligning the drill press table is essential for consistent hole accuracy when using a drill press. To achieve this, first release the locking handle on the table, and then set the table to the desired height. Once the table is level, you can use a square to ensure that it is properly aligned with the drill press's column. If the table isn't completely square, move the chairs around until they are. Finally, lock the table in place by turning the handle. Once you've aligned the table of your drill press, you can rest assured that it will consistently and accurately bore holes to your specifications.


            • dbhost

              Editing a comment
              Please explain what you mean by "move the chairs around until they are."

          • #8
            Many yrs. ago I had a project that required many hundreds of pieces that had interconnecting holes. This job went on several weeks and used a shared drill press so the table was in a different position every time I went to use it. Rather than messing with re-setting the table I built a jig with a half round cut out that nested against the round drill press column. All that was required was to position the table so the drill bit went through the table hole and set its height and lock it down. With the jig against the column I located the jig with the drill bit and clamped the jig to the table. No messing and fussing with setting up the table. If there is a question about whether the table is level, just put a small level or angle gauge on the drill press post to check the machines level, the set the table to level.