PDA

View Full Version : how to align headstock on lathe



andy_b
03-11-2005, 10:54 PM
i found a lot of threads where folks ask about removing their headstock to transport a lathe, but i didn't find a lot of good answers on realigning it once assembled. on that big LeBlond i got, i had to take the headstock off to lift the lathe out of my truck. the headstock sets on one flat surface, and one inverted V. i got the lathe bed moved into place today so i put the headstock back on. it seemed to set right into place, and the V looks like it aligned everything (in fact, i don't see how it could NOT be aligned). so my question is, how do i check if it is aligned?

andy b.

smurph
03-11-2005, 11:21 PM
Chuck up a 24" ground round bar and use a test indicator mounted on the tool post. Test the top and side of the test bar along it's length and align accordinly.

[This message has been edited by smurph (edited 03-11-2005).]

andy_b
03-11-2005, 11:52 PM
how do i know if the head is out of alignment, or the chuck?
http://bbs.homeshopmachinist.net//smile.gif

andy b.

BillH
03-12-2005, 01:00 AM
hmm, you could get a test bar made with integral taper to fit inside the spindle of your lathe, or use collets

hammerhead74000
03-12-2005, 02:08 AM
Spin the bar/chuck/spindle assembly while your dial indicator is on it at the far end from the headstock -- if the reading does not change as it is being rotated, then the deviation is from the headstock alignment to the bed, if it does change during rotation, then it's from runout or misalignment of the chuck, spindle, and bar assembly, or the bar is bowed.

Forrest Addy
03-12-2005, 02:12 AM
This is how I used to check lathe headstocks under re-build.

If you meticulously precision leveled the bed before you mounted the headstock,

- if you glided a slip stone over the mating surfaces and found no raised metal,

- if you appied a petroleum based metal preservative on the mating surfaces beforehand,

- if you re-mounted your headstock with scrupulous attention to cleanliness:

if you successfully did all that, you'll never get it any closer than the factory's final install. But you want to make sure.

The best check is with a test mandrel which if factory made is damn expensive but you can make one for yourself.

You're testing for spindle axis aligment with the carriage motion. Making a test mandrel that runs near perfectly concentric out of the spindle eliminates any present in the workholding.

Grab with the 4 jaw a hunk of sch 40 pipe large enough to just clear the cross slide. Make it about 3 pipe diameters long. Relieve the pipe's diameter 1/16" smaller than the clean-up size except for the 1/2" at the tailstock end and the inch in front of the chuck jaws.

If the pipe rings and chatters place a suitable scrap of 1/2" plywood between the center and the end of the pipe and apply a little tention. This plywood will damp the chatter but because there is only friction to hold it, it has little effect on conentricity. With the plywood the pipe is free to move with cutting forces to the limits of its elasticity.

Machine two diameters equal size within 0.0005" on the remaining unmachined portions. Give it a fine tool finish. Polish them lightly for convenience in using ther indicatior. Check for concentricity and diameter as a final machining step.

This is your test mandrel. It took you 20 minutes to make it and it's as accurate and far stiffer than any taper mounted factory mandrel ever thought of being.

Mentally divide the pipe into two planes horizontal and vertical. Mount an indicator on the carriage and check the top and side of the test mandrel. If you got zero on the side and zero to 0.001" rising to the tailstock you're right on the money.

If you get different but consistant readings cranking right compared to cranking left, congratulations! your saddle ways on the bed need attention. Correct this error before you attempt any correction on the headstock alignment.


[This message has been edited by Forrest Addy (edited 03-12-2005).]

sauer38h
03-12-2005, 11:55 AM
Not to worry - the question gets exposure because some of the Chinese lathes don't locate properly on a V and a flat - they use some wretched system with adjustment screws.

Hendeys have proper Vs and flats. Your head will align itself on those just fine, or at least the alignment will be as good as it was before you took it off. You are right, you can't NOT align it properly (unless you clamp some crud in there in between the head and the ways).

To check alignment, do the usual checks you'd do to see if the bed isn't twisted - test bars, etc.

andy_b
03-12-2005, 09:23 PM
thanks for all the replies!!!!
i have to admit, this time i actually did what "seemed" correct, and it looks like it was. i did exactly what Forrest said (before i knew he said it though). i cleaned, smoothed, cleaned, oiled, cleaned and mounted the headstock. i will get some schedule 40 pipe to check it, but i would guess it is as good as it was from the factory.

andy b.

.RC.
03-12-2005, 10:12 PM
<font face="Verdana, Arial" size="2">Originally posted by sauer38h:
Not to worry - the question gets exposure because some of the Chinese lathes don't locate properly on a V and a flat - they use some wretched system with adjustment screws.

</font>


My lathe is like that and it is not that bad...At least if something does go wrong it is possible to realign it something impossible to do easily on a lathe with V alignment..

dalesvp
03-02-2007, 02:22 PM
Got an alignment issue on my Victor lathe and I'm not sure where the problem is. When reaming a short piece of brass (1/2" x 3" brass tube held in 3-jaw chuck; reamer held in headstock chuck) there is a visible wobble. In checking with a round (pin gauge) held in the headstock chuck and indicator held in the 3-jaw chuck there is an "up" error of .007-.009" which seems like a lot to me.

My question is how does one lower the headstock chuck til it aligns with the center of the 3-jaw chuck? Or is that the solution at all? Maybe there is something else not quite right....

DICKEYBIRD
03-02-2007, 02:35 PM
The "Rollie's Dad" method works very well, regardless of chuck/test bar condition. It worked well for me.

http://www.john-wasser.com/NEMES/RDMLatheAlignment.html

Steph dexter
02-18-2016, 11:09 AM
Im a new member and new lathe user.

I had a terrible accident this afternoon when testing my Chinese lathe, the cutter bumped to my chuck and causing the spindle missed alignment.
A local service suggesting to replace the spindle bearing and charging high price for his service. But Im not convinced 100%...

Hope i can get guidance to fix my lathe spindle.

btw can i post a video of my spindle to dial indicator here?

Carm
02-18-2016, 11:35 AM
Im a new member and new lathe user.

I had a terrible accident this afternoon when testing my Chinese lathe, the cutter bumped to my chuck and causing the spindle missed alignment.
A local service suggesting to replace the spindle bearing and charging high price for his service. But Im not convinced 100%...

Hope i can get guidance to fix my lathe spindle.

btw can i post a video of my spindle to dial indicator here?

Start a new thread. Yes, you will get help here.

RichR
02-18-2016, 11:36 AM
Welcome to the forum. You can post a link to a video but it must be hosted elsewhere.

boslab
02-18-2016, 11:45 AM
Sorry you had to arrive under such circumstances, it's fixable
Welcome
Mark

Steph dexter
02-18-2016, 12:02 PM
I will, thanks Carm & RichR