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Tramming the Router/Spindle

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  • Tramming the Router/Spindle

    I assume that Tramming is the right term. I've searched the forum for more information but I am really not finding enough detail laying out the process. Perhaps someone can point me to a thread or website specific to the Shark that will give me some instructions.

    I have a Shark HD3 that I purchased last year used and fully assembled though it was never used to my knowledge. I added an MDF spoilboard but never bothered to fly cut it to make sure that it was level until this week. I bought a 2" planing bit, setup a tool path and kicked it off to cut a .015 depth with 50% step over. My path was designed to move side-to-side in the X-axis and increment though the Y axis. After just about 3 rows, I noticed that there was a small step between the passes and stopped the operation. I created a new path turned at 90° so that it went in the Y direction and incremented in the X. Same result. This time I decided to let it completely surface the spoilboard and the step between the rows was consistent all the way across I realized that my problem is not that the table is not level (though it may not be) but instead, the plane of the spinning bit is not parallel to the plane formed by the X and Y axes so I need to tilt the router to get it parallel.

    My Router mount is the standard plastic one with 2 clamps sandwiching the shelf (for lack of a better term) that is attached to the gantry. I made a simple tramming device that attaches to a bit in the spindle with a bolt several inches out to measure how far off I am. I determined that the spindle is tilted diagonally (both and X and Y). The device measures just under 5" from spindle to the measuring point and with it just barely skimming the table at one point, it is over 0.050" out on the opposite side. Note that I removed the spoil board for this. Also note that I put a different router into the mount and it is out the same amount.

    My question is what is the best way to go about fixing this. I have tried to place shims between the clamps and the shelf. I have manged to get it closer but even putting a .050 washer under one corner of the top clamp and and another washer on top of the opposite corner of the bottom clamp didn't fully close the gap. It just doesn't seem like this approach is doing what I expected. Is there a better way to make this adjustment. I noticed in one topic discussing a similar problem that one of the pictures shows an aluminum mounting clamp sitting on top of the shelf with shims underneath it. Could I for example move both of the clamps to sit on top of the gantry shelf to make it easier to shim it? Is there another, hopefully better, way to do this? It is a little surprising to me that there is not a built in adjustment for this or detailed instructions somewhere on how to do this.

    BTW, I tried posting this of in the Sharktalk forum as well but there is something wrong with that forum. Every time I try to post something I get an error.

  • #2
    Hello NathanAu, first off, go with the KISS method. Keep It Simple Stupid. This isn't directed it you, it's just sounds like you are trying to do too much at once. Pick an Axis to adjust, usually the Y is the easiest so let us start there. Using your device, only measure the Y Axis, straight down the bed, and 180 degrees opposite of that toward you. Try to get as much, or as close as you can by loosening the gantry bolts and tilting it, my guess is it is leaning back away from the front of the bed. If so, use a board to wedge it up a bit and re tighten the gantry bolts. If this helped, try it again to see you if can correct the Y axis with this alone. If not, shim the remainder until it's level. Use two shims of equal size, one on each side, left and right, to tilt the router evenly as you adjust/shim it. Now you will need to tilt the router mount left or right to adjust the X axis. Loosen the mounting bracket bolts, this is also probably where you placed the shims for the Y Axis so take care not to let them drop out, there should be enough play to tilt the bracket to adjust it. If there is't enough play, you might have to take the mount off and enlargen the holes just a bit to make room to move it. Now using your measuring device, only measure the X axis on the far right and 180 degrees opposite to the left and move the mount until it is level. You can recheck the Y axis and readjust if needed, but don't get too carried away, a few thousands should be good, the spindle mounts on an HD3 and 4's aren't well known for their rigidity. Now flycut your spoilboard, there should very little to no lines. If lines do appear, and your measurements were good, try slowing the feed rate down, as I said, your spindle mount has a lot of flex, so slowing it down may help. Hope this helps!


    • #3
      Thanks nanoqx for the reply. With no one else replying, after 4 months I had pretty much given up hope on this forum.

      I had actually tried to concentrate on one axis at a time but with the approach I used, both X and Y really had to be done together. After getting one axis close, shimming the other would obviously change the other so I really had to work in both axis at the same time. That is when I posted this hoping to find a better way. Pretty amazing to me that there isn't information already out there in the NWA archives. I am aware that the HD3 is a rather lightweight machine, given all of the plastic in its structure but I am hoping that this will improve the quality of my results. Even when using a 1/2" end mill to cut a pocket with light passes, I can see and feel small steps in both X and Y axes between passes.

      I am not clear which bolts you are referring to when you say to loosen the "gantry bolts". To my brain that could be anything from where the gantry is attached to the carriage on the Y rails to where the router bracket is attached to the Z axis. Perhaps an explanation about where the shims would be placed (between what 2 surfaces) would help clarify?

      Same question regarding the "mounting bracket bolts". Not sure exactly which bolts and what surfaces I will be shimming.

      Thanks again for your reply. I am still climbing the learning curve but having a blast as I do.


      • #4
        Here are a couple of pictures, let me know if it helps, Chuck ?

        HD3.jpg HD3 router mounting bolts.jpg


        • #5
          Thanks. Sorry for the delay in responding. I've been out of town and haven't had a chance to check back until now. I will look through this and give it a try soon.