Lathe setup?

[TRECustom]

My lathe is a 12" swing over the ways and can take 60" between centers. Overall, it's about 8' long. It weighs about 2000 lbs and has jack bolts under the drive end and under the tailstock end. I have been trying to align the tailstock quill and the spindle to be in perfect alignment with no success. It dawned on me that the first thing I need to do is to be sure the lathe is flat and level with no torque on the bed. It's on my concrete garage floor with a 24" square 1/4" thick steel plate under each end. I used the jack bolts and a machinists level to level each end across the ways and then to adjust the tail end to bring the bed into level lengthways.

Question #1, Is there a better way to make it sit level and flat on what I have?

Question #2, What's a good system for aligning the tailstock with the spindle?

Any suggestions will be very much appreciated.

Thanks, Tom

 

[rider_hunter]

if your lathe is close to level it is fine if you have centers for spindle and tail stock get a piece of round stock and drill centers in both ends if not center one end and clamp the other in your chuck it is best to have about 12'' of bar exposed to turn start your lathe up take a few light cuta tell every thing is trued up measure thw tailstock end and the headstock end if there is any difference put an indicator on the spindle of your tailstock and move it half the distance of the difference in your reading and turn the piece a couple more times and remeasure any more questions feal free to ask

 

[holstil]

That's a good size lathe. It might be a good idea to get it leveled up and anchored. I'm not saying you have to, but I like things bolted down myself.
I use a sight level for such things. You can rent them, and they are easy to use. The related TTS's or theodolites on the other hand would require more training. A good machinist's level will do the job also.
First remove any soft foot from the feet. done by filling any existing gaps. I'm guessing you got big feet on that, plus you'll want to use at least 5/8" anchors, so B shim (quick shim) would work.

Next identify the high point of the ways four corners.
Then add shim to the other three where needed till its level at all four points. You can do front to back first, then end to end, or vice verse. You may decide to just do end to end.
Double check for any soft foot. Done.
As far as tail stock to head stock, rider has it covered.
I used a rotalign, only cause I had access to one and I was curios.
What I found was that you could get er perfect side to side at the front point, however the angle was off a touch. No big deal, as the tail is pointed (centers) for everything I'll be doing. Also, as the manufacturer states, You can torque the hold down bolt to the tail stock to achieve up to .003" crush for top to bottom offset adj. Again though, the angular misalignment was about the same for top to bottom as side to side. I ran it two times with varying results telling me the amount of flex and or play in the ways and tails stock frame.
This, like chambering a barrel, can be whipped to death having the same outcome.
Jim

 

[rider_hunter]

also when you are leveling try to keep equal torq on the feet so there is no built up tension in your lathe

 

[TRECustom]

Rider and Holstil, I look forward to doing the alignment now. At least I won't be guessing, and will have some confidence when I'm done. I used a Starret 9" machinists level, but have access to a precision spirit level that is so sensitive that it is almost impossible to adjust between the lines. The vial is almost straight. I'll look into the sight level. I like the idea of shooting the corners individually. Rider, point well taken about balancing individual torque. Holstil, you're right about the size of the machine, so I'm going to first try just getting it as near perfect as I can, and use its own weight to keep it steady. Sort of free-float? I don't do any heavy work or heavy work pieces, so it's worth a try. Also, being timid, I take light cuts. It's been about 6 yrs since I set the lathe up. I will go back using your suggestions and do it over. Then I can recheck it with confidence from time to time with the same method.

On the tailstock, I discovered that I could set the live center point so that it centered in the horizontal plane, but when I ran the tailstock spindle (quill?) out, pushing the tailstock back, and locking it down again, the point had moved off true, so I knew the tailstock was angled. I bought a #3 male morse to a #4 female morse reamer extension about 9" long and popped it into the tailstock spindle, and then set a dial indicator on the chuck face and rotated the chuck. That took hours to bring the end of the extension into concentricity with the drive spindle, then travel an indicator on the carriage along the side and top of the extension body, and find that it was not true again, then go back and repeat the chuck indicator setup. I never got it true both ways so finally gave up. I now also have access to a 13" long precision alignment bar, and will use it with the tailstock spindle retracted, and then with it extended. Sounds much simpler than what I was doing, and more accurate.

I'm going to do this stuff before I take another cut on anything, so will post results when I've finished.

Thanks to you both. Tom

 

[TRECustom]

Jim, I forgot to ask. What's a rotalign?

Thanks, Tom

 

[GLZ]

Laser alignment system. The Pro or new Ultra are Bad A$$ for shaft alignment.
http://www.pruftechnik.com/en/alignment-systems/products/shaft-alignment/product/rotalign-pro-ex.html

 

[TRECustom]

Results of testing:

The bed is very close to square and level. So close that I left it alone.

The tailstock is not close at all. Using a 13" long 1" diameter alignment bar from P.T. & G. with an indicator mounted on the carriage, riding on top of the bar and traveling away from the chuck end, the bar rises from zero at the chuck to .002" high at the point of the live center with the quill retracted. With the quill extended 5", the rise doesn't change from the .002" reading. The quill is parallel with the ways, but .002" high. I'm going to call a good friend who owns an industrial machine shop and see what he recommends. I'm thinking that having the top of the baseplate surface ground .002" makes sense. Maybe even having .003"-.005" ground off, and then shimming the tailstock body on top of it to bring it into perfect vertical alignment. I'll see what he recommends though. ON EDIT: DISREGARD THE RESULTS OF THE VERTICAL TEST IN THIS PARAGRAPH. SEE MY REPLY # 12. TOM

In the horizontal plane, from zero at the chuck, the bar displaces to the front of the lathe.0015" at the point of the live center, with the quill retracted. With the quill extended 5", the displacement increases to .003". The tailstock is offset and angularly misaligned too. I know from experience that the lateral and angular adjustment between the tailstock baseplate and the tailstock body is crude as hell, and very hard to bring in to zero offset and zero angularity, but with patience, it can be done. Once it's there, I think I'll drill, ream, and set 2 taper pins so that it'll stay in place and be easier to bring back if I have to kick it off.

Any comments or suggested alternatives will be most welcome.

Thanks, Tom

 

[holstil]

There should be no tension issue with regards to torque if you have all the soft foot removed. At least none to worry about (that's the purpose of removing soft foot).
Sounds like you found the same angular misalignment I found. I was going to set my tail coincident to the head till I found out how tedious that was. I new pretty quickly that I was in need of a good floating reamer holder. Kinda makes ya not want to run that bad boy out too far don't it?
There are a few other laser alignment devices out there. Ours is accurate to 2 microns? I think. Follow the given link, that should tell you all about it.

 

[holstil]

We posted same time.
Yeah, you may want to hold off on grinding anything just yet. Some machines have torque value on the tail stock hold down (mine has .003"). Someone pointed out to me that they felt as though that was deliberate for wear on the ways??
Jim

 

[TRECustom]

Jim, I hadn't thought about wear, but it seems like wear on the ways would be much worse in the 10-20" right in front of the headstock. The tailstock don't spend much time there. In the meantime, the high tailstock causes error.

I use a floating reamer holder, but I don't like to feel it shift.

Not to worry, I'm not going to do anything until I chew on it awhile.

On edit: I'll indicate the tailstock vertical and horizontal again and be sure to lock it down first. I'm not positive that I did the first go-around.

Thanks for the heads-up, Tom

 

[rider_hunter]

when I am doing percision work I have a torq wrench on my tail stock on my lathe if you just bump the handle tight but not really tight the tailstock will read .0015 but if you really torq it down in reality too tight it will read -.0009 so that is why I use a torq wrench ever though I can get my lathe perfect center I still always use a floating reamer holder something you might do that I did is take your tailstock apart were it slides parrallel to the cross slide when I got my lathe it was .004 high and when I took that appart there was grease in there that was making it too high you might clean it out and use a light oil

 

[TRECustom]

Holstil and Rider, Going back and checking the tailstock lockdown paid off. All the time I've been using the lathe, I've just been pulling up on the tailstock locking lever (not very hard). This morning, at Jim's suggestion, I indicated the bar again. Same result, but when I locked the tailstock down hard, it indicated to within .0002" flat over the 13". I'm not good enough to work that close on purpose, so alignment in the vertical plane just became a non-issue. Thank goodness!

About 6 months ago, I pulled the tailstock off and block sanded the mating surfaces of the base and the body of the tailstock very very lightly with 600 grit emery paper, just enough to be sure that there were no dings or hickeys on either. I then solvent cleaned everything and wiped the bare surfaces with a light oil so that there was no visible residue.

I couldn't stand the bubble being off on the level, even though it was the same on both ends, so I spent about an hour this morning bringing it in. Now I'm happy.

Using the bar, I'll take as long as I need to, and bring in the horizontal alignment. It's "cut and try", but I can get there.

I always use the floating reamer holder unless it's a little bitty reamer. Then I hold the reamer with a bar type tapping handle, but I still use the tailstock to control the back of the reamer.

What do ya'll think about installing taper pins or dowels when I get through aligning the tailstock?

Thanks again, Tom

 

[holstil]

I'm in the air on the pinning thing for this application. If you do decide to pin, I suggest that you do so at precise 90deg. angles. Just in case you decide to move something later due to wear or what ever. You don't want want a block of Swiss cheese with pin holes and a crank hanging out the back.
I would monitor and adj. accordingly, let the reamer holder work. If you go to a collet, or the like, for holding the reamer, that's a different story.
Opinions may vary.
Jim