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  1. #1
    jroberts1968's Avatar
    jroberts1968 is offline Plastic
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    Default brownells lathe centering bar

    Anyone have experience with one of these.


    LATHE CENTERING BAR - Brownells

  2. #2
    CalG is offline Titanium
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    Default No, If I question the tail stock alignment I can dial it in

    Quote Originally Posted by jroberts1968 View Post
    Anyone have experience with one of these.


    LATHE CENTERING BAR - Brownells
    Or take a couple of cuts on a length of bar out of the scrap box.

    But if you are into shiny "tools" (tooling bars even) go for it. I think it's a bit spendy for my needs

  3. #3
    hickstick_10 is online now Stainless
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    Default

    you MUCH need more practice on your lathe if you think you need that.

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    Default

    Well its 8 inches of ground 1 inch material that's been faced and center drilled at each end. I can see $84.21 there. Some where. I guess. But I think you could make one for $10.00 if you have a center drill, lathe and a place that sells ground stock.

    This sort of does the same thing and Fisher edge / center finders are only $12.00.

    Chamber reaming between centres

    Just saying.

  5. #5
    wesg is offline Stainless
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    Sure, but that only tells you if your tailstock is aligned when it's up close to the headstock. This bar tells you it's aligned when your centers are exactly 8" apart. And that must be important or else they wouldn't be selling these, right?

  6. #6
    hickstick_10 is online now Stainless
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    if your tailstocks not aligned at different distances your lathe is likely not properly levelled. Screwing with the tailstock will not help you here.

    They're are people out to screw you for every dime you have, especially with the new craze crop of basement machinists. Some of the tools out there serve no purpose other then to seperate man from his dollar.

  7. #7
    johara1 is offline Aluminum
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    I got sucked in on one, if you want to buy cheap i'll sell it. I ran the mic over it and it's not even round........junk.....jim

  8. #8
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    I was lucky. The first time I needed to re-center a tailstock, the guy I was working for told me that the book way to do it was to clamp a CoAxial indicator in the chuck and run it on the inside of the tailstock spindle. Then he told me to get an edge finder out of the tool crib and clamp one end in the chuck and the other end into the Jacobs chuck in the tailstock and measure the split, center it up, and stop costing him money by wasting time. The only man that I ever met that was grumpier than myself.

  9. #9
    keydiverfla's Avatar
    keydiverfla is offline Cast Iron
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    Quote Originally Posted by speerchucker30x3 View Post
    The only man that I ever met that was grumpier than myself.
    Is that possible? Just sayin', er askin'

  10. #10
    RifledAir is offline Plastic
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    Alright I confess. I use a shopmade version of the same that is 24" long made from 1" centerless ground. I find it a really fast and easy way to give everything a quick check just before I mount a barrel.

    And I don't care if I'm not the coolest kid in school

  11. #11
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    I was always taught that using an indicator on the apron and a pre-turned bar would not give an accurate reading in some cases. On most lathes the tailstock and the apron run on separate ways. As a rule the ways of the apron wear more than the ways of the tailstock. The ways on the tailstock actually wear very little as its seldom moved back and forth. The only truly accurate way to align the headstock and tailstock is to run a CoAxial indicator in the chuck with the indicator needle on the inside of the tailstock quill or to run 2 precision ground pieces of stock together, one in the headstock and one in the tail stock and measure across the split of the two parts. This eliminates any drift of the apron as you move it up and down the bed. Theoretically, the CoAxial indicator is the most accurate as the quill and the chuck used to hold the precision ground stock invariably add error to the system. However, its been my experience that worrying about such trivialities gives people ulcers and makes them goofy so I try not to give it much thought. But I do have a CoAxial indicator. Somewhere. LOL

  12. #12
    RifledAir is offline Plastic
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    Quote Originally Posted by speerchucker30x3 View Post
    I was always taught that using an indicator on the apron and a pre-turned bar would not give an accurate reading in some cases. On most lathes the tailstock and the apron run on separate ways. As a rule the ways of the apron wear more than the ways of the tailstock. The ways on the tailstock actually wear very little as its seldom moved back and forth. The only truly accurate way to align the headstock and tailstock is to run a CoAxial indicator in the chuck with the indicator needle on the inside of the tailstock quill or to run 2 precision ground pieces of stock together, one in the headstock and one in the tail stock and measure across the split of the two parts. This eliminates any drift of the apron as you move it up and down the bed. Theoretically, the CoAxial indicator is the most accurate as the quill and the chuck used to hold the precision ground stock invariably add error to the system. However, its been my experience that worrying about such trivialities gives people ulcers and makes them goofy so I try not to give it much thought. But I do have a CoAxial indicator. Somewhere. LOL
    I agree the tailstock and the carriage are on different ways, but that almost seems to be more of an argument in favor. Ultimately the toolbit is going to be in the same position as the indicator so what counts most is the carriage running parallel to the centerline.
    I guess the one caveat here is I only use the bar between centers not when using a chuck

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    Ultimately the toolbit is going to be in the same position as the indicator so what counts most is the carriage running parallel to the centerline.

    That's the whole problem. The carriage/indicator and the center line are on different planes. Whether you use a center or a chuck makes no difference. You can't use a bent path to check to see if the path next to it is straight. It can not be done. If you try the bent path will always be getting closer or father away from the straight path as you walk along it. The reality is that you can't even tell which path is bent. You simply have to assume that both paths started out as straight and the one with the most abuse is the bent one. But I don't think a thousandth or two makes a big difference in the big scheme of things. Besides even with more and possibly better micrometers than a lot of good machinists that I know have, I can't measure and cut much closer than + or - .001 inch and neither can my competition, despite their claims.

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    GGaskill is offline Stainless
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    I can cut to .001" but the problem is doing it every time. :-)

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    AH HA. A funnyman. My cuts always come within one tenth of one thousandths of an inch. The numbers to the left of that last number can however, be slightly erratic. he he

  16. #16
    gorrilla is offline Stainless
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    Quote Originally Posted by speerchucker30x3 View Post
    I was lucky. The first time I needed to re-center a tailstock, the guy I was working for told me that the book way to do it was to clamp a CoAxial indicator in the chuck and run it on the inside of the tailstock spindle. Then he told me to get an edge finder out of the tool crib and clamp one end in the chuck and the other end into the Jacobs chuck in the tailstock and measure the split, center it up, and stop costing him money by wasting time. The only man that I ever met that was grumpier than myself.
    I've always used a dial indicator. Mag base, stuck to the chuck. Swing it around the live(or dead) center, adjust the tailstock body to true. Need to check it out further. Clamp a fairly stiff bar in the chuck. Whether it's perfectly true or not is of no consequence, long as it's rigid and stable in any eccentricity it has. Stuck it out to the desired location, fasten the indicator to the bar, swing it in. Now, if it shows different numbers than it did up close, you likely have a leveling problem. Or the beds twisted. Or worn funny, up close likely. But that would be one worn out lathe. Get past all that, check your part for runout in the chuck, and Bob's your Uncle.
    Good dial indicator will tell you as much as the gadget. Gadget is for making it easier and quicker. But tells you nothing about the level, twist, or wear in your lathe. I've made something similar out of PGS(Precision Ground Shafting) mounted in a set of collets, centerdrilled(carefully), and pointed on one end to fit in a centerpunched mark. For centering odd shaped pieces up in a four jaw. Still have to have the tailstock centered up well. Probably wasn't accurate to the tenth, but accurate enough for the molds we were doing.

  17. #17
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    I make sure the machine is level, but I don't go beyond zeroing at the chuck with an edge finder, which is as accurate as the micrometer you measure the split with. I suppose one could over think and over check everything but I can't do anything about bed wear or warp so its pointless to worry about it. If it gets to the point where these things are an issue I would just buy a new machine. But I have never have had to do that yet and I don't expect I ever will. Admittedly, it took a while to figure it out for myself and except it, but as I was taught, anything beyond holding an edge finder in the tailstock and headstock is just an excuse to waste time. On top of that everyone that has a mill has an edge finder and if they don't they are only $14.00 for a top of the line model and about $7.00 for a Chinese knockoff. Setup time is as quick as you can run the tailstock down and clamp it in both chucks. Occam's razor always applies.

  18. #18
    precision tools is offline Hot Rolled
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    The only problem with using an edge finder in that manner is that it assumes the chucks are zero-zero. They will not be, particularly the lathe chuck if it is a three jaw.

    I do agree with not overthinking the alignment, you will endup chasing your tail. If it is critical, I take a light cut, check for taper and adjust the tailstock as needed.

  19. #19
    Rawleigh is offline Aluminum
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    Tubalcain has a good Youtube video on making an inexpensive alignment bar that you an make for the exact length you want your work piece to be.

    MACHINE SHOP TIPS #78 Aligning Lathe Centers pt 1 of 2 tubalcain - YouTube

  20. #20
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    Quote Originally Posted by precision tools View Post
    The only problem with using an edge finder in that manner is that it assumes the chucks are zero-zero. They will not be, particularly the lathe chuck if it is a three jaw.

    I do agree with not overthinking the alignment, you will endup chasing your tail. If it is critical, I take a light cut, check for taper and adjust the tailstock as needed.
    After you have both ends of the edge finder chucked up turn the chuck until you see and feel the high point on top. Then measure the split on the sides. If your scroll chuck runs out more than .003 inch you might want to knock it back in. Loosen the back plate so that the bolts are so/so snug, put a piece of precision ground stock in the chuck an run an indicator on it. Use a piece of babbit or a lead hammer to true it up and re-tighten the bolts.

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