Lathe leveling and Tailstock Alignment
Host Bill VanOrden
January 22nd 2005
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Members in Attendance
Bill Van Orden
The meeting was held at Bill VanOrden's shop in Tempe. Thanks for letting us to invade! Thanks go to Earla Marshall for making a goodie run for sodas and stuff for the post meeting weenie roast.
Here are some of the attendees (L to R), Jerry Hine, Bob Sanders (blue sleeve hiding), Neil Peters (red shirt hiding), Doug Endrud, Tom Davis and Bob Harbour.
A general discussion of lathe placement and basic leveling and mounting strategies started out the meeting with Bob Sanders at the helm. He mentioned that the best way to test the accuracy and adjustment of a level is to place in on a stable surface and take a reading. Then reverse the level end for end and take another reading. If the level is adjusted correctly it will read the same both ways. Also noted was to let the level stabilize before taking the reading. The level may take 6-10 second to stabilize.
Equipment used in this demonstration:
Precision level 12” long and accurate to .0005” per foot
123 blocks 2 setsCo-axial indicator
Here we see two levels resting on the lathe. The better placement uses a set of 1-2-3 blocks and places them on the flat parts of the bed which are more precisely machined.. The alternative placement is on the tops of the V's of the bed. Nicks and dings of the top of the V's and the fact that the flat portion is machined more accurately make the placement with the 1-2-3 blocks the preferred setup.
The level is then placed at the tail stock end of the bed and another reading is taken. The feet are then adjusted to make both readings the same. It is not critical that the lathe be leveled lengthwise as this will not affect the turning process. Deviations in the readings taken at either end, with the level placed crosswise to the bed, will result in twist of the bed and inaccurate turning. Having no les than 3 machinist's levels at the meeting we just placed two and did away with moving the level.
Aligning the tailstock came next. Discussed were two ways to test and adjust the tailstock.
The first method used a co-axial indicator. The model shown here is from Enco and is a reproduction of the Blake Co-Ax Indicator. The indicator is fitted to the headstock using a collet fixture. Beevo's lathe uses 4C collets, so if you have any you want to get rid of email him! The indicator is set up to sweep the inside of the ram on the tailstock. The indicator has a rod sticking out of the side to prevent it from rotating when the lathe is turned by hand when testing the alignment of the tailstock.
The second method involves making a test bar and measuring it between the centers.
First step is to face off and center drill the two ends of the bar. Here Beevo faces off the 1" x 12" piece of steel used as our test bar.
Now the ends get center drilled.
(image Doug Endrud)
Now a smaller piece of steel is turned to a point having a 60° angle. This was done because Beevo had some lathe dogs but didn't have a faceplate to drive them with. Bob's years of experience came into play as he explained that turning a center in the 3 jaw chuck gives you a perfectly aligned center and the dog can catch one of the jaws. "We don't need no steenkin' face plate....."
With the needed fixtures in place the previously faced and center drilled test bar is turned true for about an inch on one end. Here we are using a live center in the tail stock and our home made center with dog held in the 3 jaw chuck.
A brief intermission ensued while Marty and Beevo (with Tom Davis looking on) tried to find a decent tool bit to turn the test bar. Obviously Beevo didn't run home after the last meeting and sharpen all (or any) of his tool bits. A sort of decent bit was found and the turning re-commenced.
Marty sets up a dial indicator on the carriage of the lathe.
The test bar, with one end now turned true, is placed between the centers without the lathe dog. The indicator is placed against the turned part of the bar an the dial zeroed.
Now without changing anything on the carriage, the bar is reversed so the turned portion is at the tailstock and the carriage is moved down to take a reading again. If the tailstock is properly adjusted the reading will be identical.
If not, and they never seem to be, you adjust the position of the tailstock. Bob and Marty make the needed changes. When making adjustments the two screws on the base of the assembly need to be kept in tension. As you tighten one, you need to loosen the other, just enough to allow the adjustment to be made but not allow any slop in the assembly. Before retesting you need to make sure the tailstock is locked down and the ram lock is on.
Here Marty sets up the indicator to test the vertical alignment of the tailstock. The test bar is measured on the top surface at the tailstock end.
Then the bar is reversed and the carriage moved to measure at the headstock end. Any changes to be made here require machining or shimming the tailstock!
Tom Davis compiled these Hot Tips:
Removal of the chuck from the headstock spindle may impact the leveling of the machine.
With the curved end on the indicator check run-out inside the tail stock. Rotate the headstock by hand and monitor the gage for run-out measurement. Make adjustments as needed to eliminate the run-out.
The adjustment screws at the bottom of the tailstock assembly move it perpendicular to the lathe bed from front to back.
Vertical mis-alignment will require shimming under the tailstock to correct.
We used a live center in the tail stock for this demo. If you use a live center, be sure to check it for play before you try to correct for run-out.
Bill Van Orden (Beevo) showed us a great clamp on lamp available at the new IKEA store for $8.00
With the technical part of the meeting adjourned some members stayed to help toast and consume hotdogs and discuss various machining and non-machining subjects. CAD programs were discussed briefly and Beevo passed around a new book he recently purchased on using the 2D portion of TurboCAD. The book is available from CAD Course and authored by Kevin Doucette, it's called Mastering TurboCAD V9 2D.
Show & Tell
Beevo (aka Bill VanOrden) brought the group up to date on his ongoing stepper drive conversion to the Meade LX50 Telescope. The main housing with half of the stepper drive is on the bench in the foreground.
This conversion is planned to be offered to the astronomy hobbyist as a complete conversion, parts kit or informational package. To save club bandwidth, follow this link.
Neil brought a picture of his hit 'n miss engine project. He is making it from commercial castings and it looks like it will be running soon! It has 6” diameter flywheels, 1.125” bore, and 1.750” stroke.
Except where noted all images by Neil Butterfield
Meeting notes & Hot Tips by Tom Davis.
Page text by Bill VanOrden