tailstock zero??

J

JDR

Guest
hello:can anyone tell me how to put the tailstock on the same center axis as the four jaw chuck when you center the barrel bore to prefection? my lath has a left and right ajustment but i am not sure how to do the up and down part. are lath buttons the best way to check it? having it on the same axis would seem to me the best way to hold a reamer in a dead center to chamber the barrel. thanks jerry
 
theres not any up and down adjustment for tailstocks. unless it's down and you wanted to take apart and shim.
 
tailstock

please tell some one that outside taper does not have anything to do with inside bore reaming. both operations are sun up to sun down in meaning.
 
I had actually toyed with the idea of incorporating a vertical adjustment into my lathe's tailstock but decided not to. Unless worn, most lathes will have a tailstock which sits a bit high when the headstock is cold. When the headstock warms up, vertical alignment is good.
In the end, this is one reason for not using a center to support the reamer on the tailstock. It could also be considered a reason for chambering in the steady reast. Just another one of those little challenges! Regards, Bill.
 
Jerry, are you in favor or against the Manson Floating reamer holder? I ask because it is the only one that I have used (borrowed), and I had no particular problem with it. If there is something better, however, I am open. I have been looking to buy something soon.

Clemson
 
Worked for me

Had a worn out SB Heavy 10. The TS had been, could be, shimmed vertical. I tried every way I knew of, but ended up centering a dial indicator rod in the4 jaw. Set the TS where you would normally use it to ream the bbl. (my bed was so worn, TS changed inch by inch). Indicate the TS (dial indicator on the center) as you turn the chuck. You might have to hang from the ceiling to see what's happening, but this will tell you which way to move TS to center. Real smith's may have a better way, or tell me this will not work, but I managed to ream a chamber with much less over-base size after I got it set up this way. Ron.
 
Last edited by a moderator:
Clemson said:
Jerry, are you in favor or against the Manson Floating reamer holder? I ask because it is the only one that I have used (borrowed), and I had no particular problem with it. If there is something better, however, I am open. I have been looking to buy something soon.

Clemson
Click to expand...

Clemson and Roy D, I have used 3 different design floating reamer holders. In each design, on some chambers, the floating holder doesn't float as it should and the chamber comes out 0.002"-0.004" oversize especially at the back.

I used a link to Dave Manson's reamer in Brownell's just as an example. No criticism of this particular holder. I've never tired this one but it looks just like many of the others.

I have been involved in machine shop tooling design, application and purchasing since 1969. I have only seen one floating holder that works as it should when used horizontally as in reaming a chamber. Warner & Swasey made one for turret lathes in the -70's that would truly float. At the time it cost over $400.

I much prefer a floating pusher. I have never had an oversize chamber with a floating pusher.
 
short300 said:
Had a worn out SB Heavy 10. The TS had been, could be, shimmed vertical. I tried every way I knew of, but ended up centering a dial indicator rod in the4 jaw. Set the TS where you would normally use it to ream the bbl. (my bed was so worn, TS changed inch by inch). Indicate the TS (dial indicator on the center) as you turn the chuck. You might have to hang from the ceiling to see what's happening, but this will tell you which way to move TS to center. Real smith's may have a better way, or tell me this will not work, but I managed to ream a chamber with much less over-base size after I got it set up this way. Ron.
Click to expand...

What you are doing is not a bad way to indicate the tailstock. You ought to indicate it at both of the extremes of the T.S. spindle travel that you intend to use, though. Don't risk hanging from the ceiling, just hold a small mirror under the indicator so you can see it as it faces away from you. BTW, you don't have to center the indicator on the chuck. It is turning on the spindle centerline........you could stick a magnetic base on the chuck or duct tape it on there (so long as it is rigid) and it'll give just as good a reading.

-Dave-:)
 
I think the floating reamer holder may get a bad rap because of the way the torque is taken on the reamer. If you take the torque at a 9 o’clock position on a lathe (9 o’clock being facing the operator) the torque will want to bend the reamer down at the 6 o’clock position. In my business we find the best way to take the torque is with a gimbal fixture. A gimbal will float and take equal torque at 9 and 3 o’clock. One will cancel out the other and the tool stays straight. If the reamer is bending a .001 the chamber will be .002 bigger at the back.

Dave
 
thank you gentlemen for you replys and help. I have watched gordys tape and he goes to a lot of means to get the bore and reamer true he talks about tens of thousands run out but does not measure the tailstock for axis truing only that he is consistant in tighting the hold down each time on the tailstock i could assume there could be some axis missalinment that could be several thousands anyway i would guess more than a few tens i would think that would not show up in the dial when checking the run out of the chamber but i think would cause the back or the chamber to be a little over size if the reamer is held with a dead center type reamer hoder any way i am no expert thanks jerry
 
Before I started cutting and shimming I'd get a precision machine level and level the lathe. I don't mean one from Home Depot I mean a Starrett.If the bed is in a twist you are about to embark on the longest tail chase ever. After you line it up as best you can put the level back on it and check it didn't move. I set my Monarch EE on isolators. They give you 2"-3"more height and my ancient back needs that.

Good Luck;

Mike Swartz
 
Jerry, I do get the lathe set up so the bed is perfectly true and level and then I make absolutely sure the centerline of the tailstock aligns dead true to the centerline of the headstock vertically as well as horizontally - this is extremely important!! Mike is so right - it takes a high quality machine level to really get a lathe leveled properly.

Hopefully the lathe will come this close already but they don't always - especially if they are a lower quality lathe or if they aren't being specified that exact during manufacture. Then you have to either scrape the tailstock (better know what you're doing before you attempt this) to lower it, or build it up to raise it. When Shiraz at Grizzly started to make the Gunsmith's lathes he specified all this so the factory has all this set up already.

The torque wrench setting then is where it exactly aligns vertically and this makes sure it gets to the same place every time.

I've tried a lot of different reamer holders out there and the one I like to use best is Greg Tannel's (GTR Tooling) reamer holders, which uses a spring loaded collar to hold the reamer against the center. This does away with a handle out the side and eliminates any torquing this can cause - they work great! Your lathe must be perfectly level and true to use this though.

When I'm done chambering the barrel, the chamber is never oversized and the reamer is such a close fit it has no side play whatsoever in the finished chamber like you can get when your lathe isn't set up perfectly or when using floating holders.

Gordy Gritters
 
gordy; thanks for the reply. i will not be buying a new grizzly this year but i am going to check the level of mine.do you feel the best way to check the tailstock is to use lath buttons or to use a test rod centered in a four jaw chuck and in the tailstock then testing along the top and the side of the rod for out of line thanks jerry
 
Be advised, if you scrape the tailstock to lower it when the lathe is cold, it will sit too low when the headstock has warmed up. The tailstock on a 13 inch swing lathe will usually sit about .003" high when the lathe is cold. After the machine has run for 20 minutes or so (depending on ambient temperature), the height will be closer to equal.
I have not seen a floating holder which did not cut to center (the holder's center, that is) when under load.
On one lathe I used, the tailstock was seriously worn and sat low. Since the bed was also worn so that no two places were the same, I decided shimming wouldn't work all that well. I set up center in a boring head and put it into the tailstock so it adjusted vertically and I could adjust my center to fit any occasion.
The use of a steady when chambering can eliminate any such problem as well. A spider on the barrel runs in the steady and is adjusted to eliminate runout. The steady holds the barrel at the same height as the tailstock. This is why the steady rest is so valuable when working with a worn machine. Regards, Bill.
 
tailstock height

MSC sells or at least did adjustable centers for tail stocks. Can be adjusted for both horizontal as well as vertical misalignment. Bill is right, as the lathe warms up alignment will change. Also when indicating tail stock centers always use a magnetic base that attaches indicator very close to lathe chuck. Do not use an indicator extended off of any type of arm. It will flex enough from top position to bottom to give you a false reading. Also remember that the tail stock quill's axis may not be in alignment with the axis of the headstock. A lot of though must be given to what can go wrong with the tail stock pushing on a damned reamer. Most tail stock quill's have a very small amount of flex or clearance so you kinda sorta have a built in floating holder:eek:. Jackie said it best: about the worst way to make a perfect hole in anything is with a reamer but it's all we have. Given the way these rifles shoot these days maybe it ain't all that bad. How much difference does all this make? Probably on how good the shooter reads the flags..Regards...Herb Coates
 
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