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  1. #1
    Manual66 is offline Aluminum
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    Default Using a Steady Rest.

    Ive recently had to start using a steady rest on alot of jobs, and Im having diffculty using them. my biggest problem is trying to get the part (tubing, shafts, etc.) running concentric. this is a vital part of our machine shop, and im getting kinda tired of asking the other experienced machinists to help me out. any advice????

  2. #2
    johnoder's Avatar
    johnoder is online now Diamond
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    What you may mean is that you don't know where center is.

    My trick is to put the same dia (even if you have to cut it to the same dia) as a short piece in the chuck and set the SR jaws to that.

    Now you have some asurance when you move the SR down the bed it will fit AND CENTER what you are trying to do.

    John Oder

  3. #3
    willbird is offline Banned
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    Also in several lathes I have found adjusting the steady rest fingers by "feel" to not result in perfect alignment. If you are doing something that requires perfect alignment with the tailstock simply clamp an indicator on the workpiece (I use a hose clamp) and indicate the tailstock center, then move the steadyrest fingers until the work is perfectly concentric with the tailstock center.

    Bill

  4. #4
    knedvecki is offline Plastic
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    Like Johnoder says, " chuck up a piece of stock, turn it to the diameter of your work. Then adjust your steady rest to the machined diameter while it is still in the chuck with the SR clamped to the ways. Then open the SR, unclamp and slide it off of the machined diameter down the ways to where it is to be located on the work piece. Another alternative is to machine/bore or center grind a true/ concentric center in the work piece or in a false center, check the alignment of the tailstock as mentioned above, mount the work between centers, and adjust the SR to the work.

    Regards,

    Keith

  5. #5
    Manual66 is offline Aluminum
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    thanks for the advice guys... the only problem i would see with using a shorter piece of stock is that i am now using the steady rest to bore out 8 inch diameter tubing and larger. there isnt any spare material in that size large enough to use. we also use them to repair rolls that have bent shafts running through them. what we do is weld up the entire shaft up to the roll body and then turn the shaft to be concentri after we recenter the shafts. difficult when you first do it like me.

  6. #6
    johnoder's Avatar
    johnoder is online now Diamond
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    Make a cat head for the rough stuff. Just a heavy wall sleeve with four hefty set screws 90 apart near each end.

    You center it up on the rough shaft with your 6" scale.

    The OD of the sleeve is smooth and round for the steady rest.

    John Oder

  7. #7
    becksmachine is offline Cast Iron
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    A chuck, either 3 or 4 jaw, that can be mounted in the tailstock can be very handy in a situation like this.

    Also, looking to see what size circle a sharp center or center drill will scribe on the end of the part will tell you how far off you are.

    In other words, it SHOULDN'T scribe a circle at all, should be just a dot. If it is a circle, be fairly quick about stopping the spindle and adjusting because it is probably working it's way out of the jaws quickly. Very embarrassing when a light shaft starts waving around in the air, fairly destructive when a heavy shaft falls out of the chuck and breaks the steady rest.

    And learning to be vigilant about watching to see if the workpiece is working it's way out of the chuck jaws as the job progresses.

    Also, you didn't say what size workpieces you are dealing with. If it happens to be a size, say 6" dia. by 20' long, that will sag significantly between the steady rest and chuck. If it does you should use a second steady, or adjust the steady to run above center so the workpiece is square with the jaws at the chuck. All of which is accentuated by however much "bell mouth" the chuck jaws have. It can be a real PITA when you can't run a second steady and you have to put a center hole in the tailstock end. Dave

  8. #8
    becksmachine is offline Cast Iron
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    I type too slow. Dave

  9. #9
    Troup is offline Titanium
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    There's a cunning way of indicating I came across on this forum, but I can't remember who to credit. Sorry, whoever it was !

    Sometimes it's physically easier to arrange than clocking up the barrel of the tailstock, particularly if the workpiece is tubing and the steady's close to the end.

    If you clamp an indicator base to the face of the chuck, and touch the probe to the work some distance from the chuck, turning the spindle will produce a progressive once/rev deflection, if the work is not centered in the steady.

    Makes sense when you think about it, but it's probably not something I'd have thought to try

    Not that it's particularly helpful in practice, but: if the indicator reached as far as the steady (not advisable, as gravity will start to deflect the rod of the stand) the TIR would be twice the offset, half way back to the chuck it'll be the same as the offset of the steady.

  10. #10
    Troup is offline Titanium
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    I forgot to say: often, if the work is parallel, and you have it chucked truly, you can just get the steady approximately centered (run a clock from the carriage along front and top of the work)_ prop the work up with a V block on packers off the bed, and run the steady back as close to the chuck as you can (leapfrog the cross slide if that's practicable, although sounds like you're on a big machine) clamp it down temporarily and set it there (It's easier to do it by feel here where the work can't spring much), then take it back to the end of the work and reclamp it without fiddling with the settings.

    Works well on smaller lathes.

    For the 8" dia hollow workpiece : is there a big enough cone (pipe) centre in the shop? If so, but the bore isn't quite true to the OD and you need to true to the OD, you can temporarily use 3 or 4 bits of shim evenly spaced around the lip of the hole to get it true enough to set the steady.

  11. #11
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    rockfish is offline Titanium
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    Some very good ideas here.

    What I usually do (and this depends a lot on how long and heavy the stock is) is put the stock in the lathe and turn the chuck by hand smacking the stock around with a rubber hammer until it's fairly close to center by eye, then I use an indicator to dial it in closer. I try to get the stock running as close as possible BEFORE I put the steady rest on it. Of course, this doesn't work too well if you have extremely long and heavy pieces of stock, so you'll have to follow some of the suggestions other have come up with. Still, for most work, this is what I do.

  12. #12
    FlatBeltBob is offline Stainless
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    I use one of those attachments that lets you set 2 steel rules at 90deg angles.
    lay one scale across the ways , and slide the other scale up from the bottom to get the height above the ways . Transfer this to the part at the SR .
    Then I use the same jig to check the distance from the front of the ways , ( using a 6" scale ) to get the in/out distance , and transfer that to the SR . This takes a few trys , but gets you close enough for most work .
    I like the idea mentioned earlier that uses a mag indicator to tram around the tailstock quill .
    Excepting for deviations in the weight of the indicator itself , this seems to be a pretty accurate way to do it .
    FBB

  13. #13
    Peter S is offline Titanium
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    I thought I had come with an original idea, but I see Willbird has said much the same. How about simply putting your magnetic base directly onto the end of the drum nearest the tailstock, and clocking up the tailstock ram. Even easier than a hose clamp, though the mag base post may hit the bed on some lathes if you try to do a complete rotation....(This is a variation of the method I use to check tailstock alignment by putting magnetic base on chuck and clocking up the tail stock ram).

    A variation on this would be to put your magnetic base onto the revolving centre so you can rotate the centre to clock the end of the drum. It depends what sort of revolving centre you have - on the one we have at work the entire outer diameter of the centre revolves, not just the centre itself, so easy to attach a magnetic base and rotate. Otherwise use a tube centre and stick the magnetic base to the large centre itself? I haven't tried either of these methods, so tell me if I'm wrong....

    I suppose another variation of this would be to use a vee block-mounted indicator (even a mag base with magnet turned 'off'), hold it against the tailstock ram and rotate it around the ram while indicating the OD of the workpiece.

    I guess all these methods will not show up the fact that the tailstock may be sitting a bit below headstock centre after a few years wear...

    We were taught the method of setting the steady on a short dummy workpiece up at the chuck end, but I admit it isn't always practical, and some lathes don't allow the steady to go up near the chuck.

  14. #14
    willbird is offline Banned
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    Quote Originally Posted by FlatBeltBob View Post
    I use one of those attachments that lets you set 2 steel rules at 90deg angles.
    lay one scale across the ways , and slide the other scale up from the bottom to get the height above the ways . Transfer this to the part at the SR .
    Then I use the same jig to check the distance from the front of the ways , ( using a 6" scale ) to get the in/out distance , and transfer that to the SR . This takes a few trys , but gets you close enough for most work .
    I like the idea mentioned earlier that uses a mag indicator to tram around the tailstock quill .
    Excepting for deviations in the weight of the indicator itself , this seems to be a pretty accurate way to do it .
    FBB
    I just clamp an interrapid right on the work with a hose clamp....so the weight of the indicator really does not come into play, my work is typically 1.2" in dia :-)
    I guess all these methods will not show up the fact that the tailstock may be sitting a bit below headstock centre after a few years wear...

    We were taught the method of setting the steady on a short dummy workpiece up at the chuck end, but I admit it isn't always practical, and some lathes don't allow the steady to go up near the chuck.
    Well typically tailstocks ARE a bit high because the lathe is NEW, or maybe a bit low because it is OLD :-). BUT if you get the work aimed right at the tailstock center...any drilling or reaming you do will not have the tool off center to the work, and the alignment will be exactly as good (or just as bad) as if the part were between centers, so you will at least know what to expect based on past performance between centers.

    Bill

  15. #15
    Carl Darnell is offline Titanium
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    Manual66 here is how I do it. put the steady rest on the lathe where you need it and adjust the fingers to about the size of the shaft. Lay the shaft/tube in the chuck and on the steady rest and tighten the jaws till they touch the shaft/tube. Run the tailstock up to the end of the shaft/tube and adjust the fingers untill the tube/shaft is nearly centered and snug up the jaws as you center the shaft. I use a 6" scale to measure it with.

    Now, with a mag base indicator indicate the tube/shaft in at the chuck and snug the jaws. Leave the indicator at the chuck.

    I put a drill chuck in the tailstock and a split sleeve I made in the chuck. Then I put my Co-Ax indicator in the sleeve and snug the chuck untill there is a slight drag on the Co-Ax shaft. Put a indicator finger in the Co-Ax to rub the OD of the tube/shaft, hold the Co-Ax so you can watch the dial face and rotate the finger around to each finger area. Adjust the fingers to center the tube/shaft untill it is as close to "0" as you want.

    Go back and check the "0" at the chuck and adjust as needed. Recheck the tailstock indicator as needed. Tighten the chuck as needed to machine and tighten the steady rest on the lathe and the fingers and the top retainer bolt.

    After you have done it this way several times it will be easy and very accurate. As accurate as you are willing to get it anyway.

  16. #16
    drylakemachine is offline Cast Iron
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    Default steady rest

    Tape...On the tube put three pieces crossed @ 60 degrees,then bring the tailstock up close enough to use a pencil to mark a small circle, then adjust the steady with the lathe turning slowly to get the center in the center of the marked circle. this will also work for the welded shafts,also if the centers aren't welded to allow a new receneter,I use an end mill.<center cutting >to take out about 80% of the original center to minimize runout when you try to center drill it.Re check both ends TIR often.On the tube it's better to be just a hair above center witch alows the work piece to drift toward the chuck in stead of falling out of the chuck

    good luck jim

  17. #17
    RC99's Avatar
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    Some great advice here, I have recently had to do some internal threads on some 3" ID brass tube...I had hell trying to centre the fixed steady and even when I thought it was right the tube still started to walk out of the chuck...

  18. #18
    mattox85 is offline Aluminum
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    I am not an experienced machinist, but this could be something to try when centering a piece in the steady rest. You want the axis of your part parallel with the ways and the spindle axis. If you have a part with a straight (as opposed to tapered) OD and your part is centered correctly, then running an indicator along the length of the part on both the side and the top should give no runout. If your part has a taper on the OD this would have to be taken into account when checking. If the steady rest is not aligned with the spindle correctly then the part should have runout in either the horizontal or vertical direction or both. If this is not a good method Im sure someone will say!

    Jonathan

  19. #19
    Kyle Smith's Avatar
    Kyle Smith is online now Hot Rolled
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    Nothing wrong with that, keeping in mind a shaft will sag hanging out of the chuck. On large, heavy parts it is desirable to cheat the steady high so that the part walks back into the chuck face instead of walking out of the chuck jaws.

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