Having issues with a coaxial indicator

Discussion in 'Tools' started by Michael Tod, Jul 5, 2018.

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  1. Jul 5, 2018 #1

    Michael Tod

    Michael Tod

    Michael Tod

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    I picked up a coaxial indicator to dial in the center of a steam engine cylinder on my mill.
    Using the short straight probe and running the mill at about 300 rpm it seems to be spinning but the indicator does not register any fluctuation as I would expect.

    I'm not sure what I'm doing wrong but it looks like the only way it would move the indicator is by leveraging the friction lever.

    But with the straight probe there is no way to create a pre-load on the indicator.

    [​IMG]

    I'm hoping that someone maybe able to give some insight to what is wrong.

    Thanks

    Mike
     
  2. Jul 5, 2018 #2

    rklopp

    rklopp

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    On a real Blake Co-Ax the probe is adjustable via a friction joint. You should be able to push the probe to the end of travel, and then keep going to slip the joint.
     
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  3. Jul 5, 2018 #3

    Michael Tod

    Michael Tod

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    Thanks for the response.

    The friction joint if I have that right swings free should it be tight?
    It's at the point where the probe connects to the bottom of the indicator.


    Mike
     
  4. Jul 5, 2018 #4

    Scott_M

    Scott_M

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    Use the bent probes, you need to "load" the indicator to some degree when you put it in the hole.
    The straight probes are for external bosses.
    Scott
     
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  5. Jul 5, 2018 #5

    Cogsy

    Cogsy

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    You can use the straight probes but you have to adjust the indicator slightly to do it. Loosen the nut and bolt at the bottom which attaches the probe mounting point and you can then change the angle at which the probe attaches, then retighten of course. I normally use straight probes for internal bores and the bent ones for outside features.
     
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  6. Jul 5, 2018 #6

    Michael Tod

    Michael Tod

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    Thanks for the help.

    Looks like the key is to have it adjusted then tighten it down.
     
  7. Jul 5, 2018 #7

    Chiptosser

    Chiptosser

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    Hello,
    Don't spin the indicator with the motor running!
    Turn the spindle by hand- gently. The cheapeze replica of a Blake is not as accurate as a Blake.
    I have both and I am not impressed with the copy. The only reason that I have both , is that I was given the copy.
    Both units are very delicate and can be bent easily. If you see run out while spinning the unit with out the tip touching anything, it is bent. If you have a new cheapeze , clean the heavy lube off from the shaft and lube it with light oil. It will not work properly with the heavy lube.
     
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  8. Jul 5, 2018 #8

    ignator

    ignator

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    This is a case for using youtube as your friend, search for Coaxial indicator instructions, I found this near the top, which gets into the usage by 1.5 minutes in.

    Hope you have high speed internet where you are at.
     
  9. Jul 5, 2018 #9

    Blogwitch

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    I have had the cheapo version for a few years now, and straight out of the box has worked perfectly and accurately since I have bought it.

    I have had to make a few shortened probes, even though I have a fairly large mill, just to get it to read when setting up tall components.

    It sounds as though your friction joint at the bottom is a little loose. if it was mine, I would just 'tweak' up the friction joint.

    For internal use swing the probe so that it sits just outside and above the hole, then gently push on the probe tip while inserting it into the hole, you should now have a reading on your your dial. I run mine at about 100 rpm, then just move your x & y until you get a non deflecting reading.

    BTW, you can also use this tool to align your lathe tailstock.


    John
     
  10. Jul 5, 2018 #10

    SmithDoor

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    It sounds like has gummy oil or if a use one it may coolant gum
    I have use alcohol and WD40 to clean
    I use mind for 40 years and had to clean too

    Dave
     
  11. Jul 5, 2018 #11

    Voltar1

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    Protector ring removed?
     
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  12. Jul 5, 2018 #12

    ICEpeter

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    Yeah, as a first step take the plastic ring off at the top that restricts the probes vertical movement.
     
  13. Jul 6, 2018 #13

    retailer

    retailer

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    When mounting in your mill use a collet instead of a drill chuck - any run out in the mounting is too much. I have a Chinese knock off as well and no longer spin mine but use a similar method to centering in a 4 jaw chuck, 2 Y readings (fore and aft) 180deg apart and move the table 1/2 the amount indicated, then do the same for X readings (sideways) - repeat this 2 or 3 times. If the indicator is spun in the spindle there is always a small amount of drag between the probe tip and workpiece, this can cause a few thou jitter in the needle which makes it impossible to get on centre.
     
  14. Jul 6, 2018 #14

    ShopShoe

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    "When mounting in your mill use a collet instead of a drill chuck"

    Absolutely True. I use a collet when I use mine. And I use a collet whenever mounting any other indicator to the spindle.

    For my knockoff coaxial indicator, I found I needed to get a 10mm R8 collet to attach mine. the inch collets I had did not fit.

    I have had mine "stick" from non-use and have had to tinker with the mechanism to free it up. I hesitate to recommend this to others, but mine allows easy access to the actual indicator mounting screws and the "interface" between the probe and the indicator stem. My shop is unheated and the last time I used the coax indicator last winter I cleaned out the lube I had used and replaced it with Tri-Flow: a lube that works to lower temperatures and that I was made aware of several years ago by a locksmith. (Disclaimer: I had a good experience, but I do not guarantee your results and I have no relationship with the makers of any product mentioned.)
     
  15. Aug 12, 2018 at 3:09 PM #15

    Brian40

    Brian40

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    I strongly disagree with the statement that a collet is required for accurate results . the co ax takes its reference from the quill bearings . any thing in between is irrelevant.
    to prove this I set up my face plate on the mill and clocked it to within half a division with the co ax
    then changed the chuck for my boring head and offset the indicator by 110 tho surely more than any bad chuck.
    the result was no change in the reading .
    . even though the indicator was gyrating wildly at 80 rpm
    Brian. co ax.JPG
     
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  16. Aug 13, 2018 at 3:52 PM #16

    backyard_cnc

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    Some have mentioned accuracy with regards to this device and it’s my understanding that it is a “relative indicating device” and not a “measuring device” . I use mine frequently to find the center of bores and also stuff like ensuring my lathe tailstock is perfectly centered. Any actual measurement indicated on the dial is not important for these sorts of tasks only that the point of minimum deflection be found. The actual measurement displayed on the dial is affected by the length of the probe and if you are attempting to use this measurement in some fashion than correction factors must be applied to obtain “accurate” results. Despite this a coaxial indicator even a cheap one is a very useful device!
     
  17. Aug 14, 2018 at 7:55 AM #17

    Cogsy

    Cogsy

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    I love mine, which is the cheapest I could find to buy. I don't use it very often but if I dropped it on the floor and smashed it I'd buy another one straight away. For finding centres and bores it gives me the most accuracy by far of all my tooling.
     
  18. Aug 14, 2018 at 12:02 PM #18

    BaronJ

    BaronJ

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    Hi Guys,

    I prefer a laser centre finder for this job. Just hit the edge of the hole and your there.

    01022015-001.jpg

    This is a picture of mine.
     

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