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  1. #1
    Join Date
    Mar 2014
    Location
    Alexandria
    Posts
    8

    Default box joint a little loose

    I just had a disaster in the workshop. I tried to tighten up the joint by following the instructions in red. The result is a another finger about 1/8" and a gap between each joint. I thought the silver knob was for kiss calibration.

    I have made MANY MANY boxes and didnt want to adjust the fit in the middle of a project.....but today I was feeling HOLY....

    Does anyone have any ideas as to what went wrong?

    +++++++++++++
    The short answer is that it's normal to use the silver micro adjust knob to tighten the fit (turning the knob clockwise tightens the next joint cut). The jigs are manufactured to produce a setup that's slightly loose, typically 0.010" to 0.020", to allow the user to dial in the desired fit.

    If you're using a stack dado, this is a one-time adjustment because the kiss calibration isn't redone when changing cutter widths…each time you get the jig off the shelf, you'll just make a test cut at the desired dado width and spread the pin plates to fill the test cut using the red knob.

    The longer answer is that the operator's "touch" during each of the three setup steps can produce a pretty wide range of tightness...there's no right and wrong, but each user will be a little different. If the setup is consistently loose, there are likely a few ways to tighten it when doing the setup-

    - In the first step, bring the pin plates into solid contact with each other with the red knob. Not cranked tight like a bolt, but until you feel resistance at the knob.

    - When "kiss" calibrating against the cutter, put a piece of paper between the inner pin plate and the cutter, then advance the pin plates just until you feel some drag as you try to slide the paper. I find that it's easy to inadvertently let the pin plates press against the cutter when doing this only by eye, loosening the joint in the process.

    - After making the test cut, expand the pin plates with the red knob far enough to get some decent resistance when fitting the test cut over the pin plates.

    If you have a set of calipers that read in thousandths of an inch, you can measure the pin width and the cut width and go directly to the proper fit with the silver mike knob. Whatever the difference in the measurements is, dial it out using the graduations on the red knob (thousandths of an inch) and the red pointer on the silver knob. I like the pins to be 0.001" - 0.002" shy of the groove width, maybe ha hair more on wide boards.


    If I'm redoing the kiss calibration for some reason, instead of jumping into a full joint, I'll make the first two full cuts into a corner of two pieces of scrap and check the fit by flipping the boards around to assemble just the cuts at these corners. Number the corners of each board 1 through 4. Make 3-4 cuts into corner #1 on both boards, flip them around and check the fit. Micro adjust if necessary, then cut into corner #2 on both boards and so on. The reason for numbering the corners is that the test cuts can't be mixed and matched.

  2. #2
    Join Date
    Mar 2014
    Location
    Alexandria
    Posts
    8

    Default

    If one needs to tighten a finger joint do you use the silver know to do this as described below?

    Does anyone have any ideas as to what went wrong?
    CUSTOMER SERVICE FAILED TO INCLUDE IN THE INSTRUTIONS THAT ONE HAS TO HOLD THE RED KNOB WHILE MICRO ADUSTING>>>>> THANKS FOR NUTTING!!!

    +++++++++++++
    The short answer is that it's normal to use the silver micro adjust knob to tighten the fit (turning the knob clockwise tightens the next joint cut). The jigs are manufactured to produce a setup that's slightly loose, typically 0.010" to 0.020", to allow the user to dial in the desired fit.

  3. #3
    Join Date
    May 2015
    Location
    Brisbane
    Posts
    772

    Default

    I set mine up this morning and found that i had to go over the process 3 times before i got it satisfactory. I find the pins are not rigid enough and there is no real firm adjustment. Can i assume that the firmer you kiss the pins to the blade the tighter the join will be ?. I made my first box as per the attached photo and the spacing of the cut outs turned out nothing like the calculations suggested. Again, can i assume that this has something to do with the 1/8th you move the pins from the blade at setup.

    I'm interested in your thoughts.


  4. #4
    Join Date
    Mar 2014
    Location
    Alexandria
    Posts
    8

    Default

    Kiss calibration is done once and you don't have to think about this again. You should watch the video on the I-Box at the 3:45 mark: https://www.youtube.com/watch?v=3QESurntvaE

    https://www.youtube.com/watch?v=VK4JYV2YZbA
    http://www.incra.com/manuals/INCRA_I...ual_150dpi.pdf ===#4.p.9 -----then on page 12 will address the image above.


    The #1 most important thing you have to do every time you change dado blades or your setup is to do a TEST CUT. then adjust your pins so that they are snug in THAT test cut.....but before that, you raise your blades until " they just cut through your work piece", as mentioned in the video and instructions.

    okay I am not an expert but I've made many many hive boxes and looking at your picture I think I see a couple of hall marks of imprecision .

    Your blade depth may be just a bit too deep and that's why the fingers are a fraction too long?
    After your test cut, your pin adjustment may have been too loose.
    finally, I am not sure if I see wobble or if it is the camera angle/shadow but precise placement of the material on the stock ledge squarely is critical. the only time I clamp is for the first cut on the second set, the rest I eyeball the line I drew on page 12 and proceed.

    I divide length of the material by the width of the dado and see what kind of fraction I get. half a finger wont be noticeable , but small fingers can be a disaster. i consider going to a smaller or larger width and checking the math. What is the length of your board and what width dado did you use.....i want to see what the fraction was to explain the "little finger" at the end.

    Personally, I need to work on adjusting the fit using the silver knob. I burned through 12 feet of lumber last weekend by not holding down the red knob when I moved the silver knob.

    ALSO: because I am so afraid of fking up lumber i routinely add one of the shims: 0.020 but in the morning I will play around with the silve knob. Last week, I moved the silver knob and apparently didn't hold the red and royally RUINED the project with unsalvageable joints . Let us know what you figure out because when you figure stuff out and share-everyone benefits! hope this helps.

  5. #5
    Join Date
    May 2015
    Location
    Brisbane
    Posts
    772

    Default

    After posting I went and did a little checking. The small finger came from me converting imperial to metric so from now on I will just work in imperial and only convert when I am preparing stock. I have a lot of stock of varying widths so I will be able to machine widths to get precise finger sizes.

    The box I made was very small at 55mm high x 90mm x 90mm x 12mm thick and the dado was set at 3/8". I found the gaps were worse on the test pieces when I was holding the stock by hand so when I cut the box I clamped each cut but I feel that with wider stock I will be able to control the cut better and the height I can adjust.

    It was my first try so all in all I'm happy and I learned a lot so tomorrow's example should be of a much higher quality

  6. #6
    Join Date
    May 2015
    Location
    Brisbane
    Posts
    772

    Default

    This morning without realising i did exactly what you did in your original post, and it indeed screwed everything up. So after finally getting it back right i realise that my cut is 10mm and the fingers are 9. something, so i added .008 of spacers to the dado stack and adjusted the pins so that they fit very tight in the cut. All is good now and i have nice tight joins.


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