Lathe installation without a precision level?

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Tozguy

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When installing a lathe (13x40) it is important to avoid twist in the ways. Is there a trick to doing this without using a precision machinist's level?


I have access to granite surface plate and wonder if this can be layed upside down on the ways to detect any twist.

Thanks for your help.
 
Tozguy said:
When installing a lathe (13x40) it is important to avoid twist in the ways. Is there a trick to doing this without using a precision machinist's level?


I have access to granite surface plate and wonder if this can be layed upside down on the ways to detect any twist.

Thanks for your help.
Click to expand...


Interesting idea about the granite plate. I can see where if it doesn't rock you would be close.

Another way would be to install a long bar between centers and using the same number on the dial, turn down a small 25mm section on each end
to the same diameter (according to the dial). If you measure them both they should be the exact same size. It they are not, it's not level.

Imagine holding your lathe in your hands. One hand at each end of the lathe. Now twist the lathe in both directions. Twist more with your right
hand away from you and the tail stock end would turn larger. This visualization will help you to know which direction it needs to go to level it.
 
I used to level up my lathe without a level,the same way lathes on ships must be leveled. First,make certain your tailstock is exactly in line w/the headstock. Put a sharp,new center in each,and bring the tailstock right up to the headstock center. Look straight down with a loupe to see that the points are exactly in line. You can get them very close this way. Adjust the tailstock sideways till perfect. Then,and only then,you can take a long bar held between centers,and adjust the twist of the bed till the bar is turned the same diameter with light test cuts at both ends. This is a shortened version of what you can read about in "The Amateur's workshop" by Ian Fleming. Buy the book. It is a valuable resource.
 
Thanks for the replies. My concern is about what can be done to get the ways as good as possible before doing the tailstock alignment and turning test.
I plan to do the turning test as you folks have mentionned for fine tuning and repeat it again after the lathe settles in.
 
I see this as a 2 part answer, aligning the bed to turn a shaft straight without the tailstock and aligning the tail-stock so you can turn a shaft straight between centers. I don't think the plate test would work as granite will bend a slight amount and whos to say the top of the lathe V's are the same height?

First make sure the lathe is setting on all the leveling screws on the floor with an equal amount of pressure. The screws should be setting inside a leveling plate with a counter sunk or counter bored spot face in the center about 1/8 deep and a bigger diameter then the screw. . On a machine your size a 3/8 x 3" x 3" steel plate would work fine or a round 3" plate. Chuck up a 2" to 2 1/2" bar of alum, brass or leaded cold roll. A random length with about 8" sticking out. First face it, don't worry yet about the face alignment.

Then take a clean up cut of the OD, stop about 1" from chuck, You will want the turned area to be about 6 1/2 to 7" long. Then mark on the part 2 areas that we call collars or flange 1/4 to 3/8" wide on the extreme right end then measure 6" toward the chuck and mark another collar or flange 1/4 to 3/8 long, Then go to the right side and turn on the machine, turn clearance say .030" deep between the collars and in the space nearest the chuck to the left of the left collar. __TT________TT
I hope my crude drawing makes sense. That's the top half
of the shaft...Next go to the collars and take .002" cut, on right side .

After you clean up the right side disengage the feed lever DO NOT TOUCH THE CROSS-FEED or Compound. Let them stay at that position. then hand crank the saddle down to the left and engage the feed to clean up the collar next to the chuck. When the tool clears the edge of the 2nd collar stop the feed and turn off the spindle. Then slowly crank the saddle to the right, draging the tool across the collars.

Take a 2nd free cut or a cut that you do not change the cross feed dial. You may take off .0002" or so this will eliminate the push away factor. At the end of 2nd cut slowly crank it to the right again to the right and mic the collars. If the head-stock (HS) and bed are aligned it will be the same or slightly bigger .0001" in 6" on tail-stock end.
If it's out, raise the front or back leveling screw to align the bed. If the collar on the right is big, raise the tail-stock front leveling screw. You can mount a mag base on the cross-slide and a .001" indicator on the right collar, zero it. Raise the screw so it goes up the same amount it is off. You might think you only take 1/2, but take the same. The ratio of the end of collar to the spindle nose is 1 to 1.
You want the 2 collars to be the same or the right end .0002" bigger. Once you get that tighten the lock nuts on the leveling screws. Use 2 wrenches to do this so when you tighten the nut the screw doesn't turn too. Take a final .-002" cut now and see what it looks like. Then align the tails-stock. If you do not know an easy way I can write more later. Just let me know with a private message please. I will come back on this thread and write it. I align lathe beds using a level or the 2 collar test. You can also Google 2 collar test and it's written all over the net.
 
Try a piece of glass with a ball bearing. Lay the piece of glass on lathe ways, set the ball bearing onto the center of the glass and softly tap the glass. The ball bearing will roll down hill to what ever point is lowest, and adjust till the ball will just sit in the center. Then do a test bar cut, as already stated. The plate glass will get you very close. Of course this works if only the bed ways or the same height.
 
hobbygunsmith said:
Try a piece of glass with a ball bearing. Lay the piece of glass on lathe ways, set the ball bearing onto the center of the glass and softly tap the glass. The ball bearing will roll down hill to what ever point is lowest, and adjust till the ball will just sit in the center. Then do a test bar cut, as already stated. The plate glass will get you very close. Of course this works if only the bed ways or the same height.
Click to expand...

Another interesting approach! I have a thick piece of tempered glass and a big ball bearing that have been laying around doing nothing....up to now anyways! Do we know how flat and parallel glass is supposed to be?
 
Do you have a tool rental place anywhere near you? There is a place I can rent a machinist's level from for $30 day but you might as well just spend another $50 and buy one.
 
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