I have a Taiwanese manual 10x24 sold by Jet back in the 80s. It was new in the grease when I bought it in the late 90s. I'm still learning. I saw this setup video and put a 10" x 1 3/4" round 6061 piece and did as you showed. I feared the worst because I had disassembled it to get it in the basement in 2001. I don't recall any alignment keys when I put the headstock back on. A 1" test bar between centers helped align the tailstock. When I did your method today, the difference over 7 1/2" of the 6061 bar was 2/10000! Yes, 4 zeros. I think I have a nice little lathe. Thanks for the great video.
Great video, Tom. I remember finding all these papers after my uncle passed with all these different measurements. Later I would find out this is what he was doing. I never got the lesson from him but this is some primo knowledge. Thanks.
Hi Ryan, That is really cool you found your uncles measuring sheets. Do you still have them? It would be fun to look at them. Thanks for sharing. Cheers, Tom
thank you for the vid. I am buying my first lathe soon and was wondering how to level it properly. I grew up in a shop as both my grandfathers were engineers and looking forward to having my own. thank you for all the videos
Hi Duncan, I was wishing Chuck was around. Most of these things go better with a helper to read the instruments or make adjustments. Its also a lot more fun. Cheers, Tom
Thank you very much Tom for those references. Kind of you to take the trouble. I'll see if my import is anywhere at all near them! Much appreciated. Bob.
Thanks for the video to go with ice cream on this Sunday evening! You are right about twist and flexing bolt tensions and jack screw pressures and all the fun stuff that goes with adjusting the alignment. I love to talking to mechanics about alignments only being math problems, even though I have lived the experience of the for mentioned! I work alignments as a ratio, in addition to the two indicators you used, add two more at the jacking points. formula; using the length between forward and rear jack screws or jack screw span divided by double spindle indicator span equals ratio. Ratio times the movement needed on your choice of jack screws. When I tear down my carriage to make and install a new nut and screw I may take a look at my spindle alignment too! That was a great subject matter! Tom Cheers, Keith ;{)-----
Hey Keith, Thanks for the comment. The jacking arrangement on my lathe is lets just say jacked up. There is no good pivot point to help with the process. I ended up moving it away from the jack points so it could pivot enough to bring it into alignment. I tightened the snot out of the big holdown bolts in the hope I won't have to do it in the near future. The ratio approach makes a lot of sense. Looks like I need to buy a couple more indicator bases. Yipppee more tools. All the best. Tom
Hey Bill, Remember the pipe I use for the rod bender? Well that's the snot part of this operation. Guessing here at around 200 lb/ft with that arm. One oxpower was used which is equal to 5252 lb/ft min. Cheers, Tom
Hi Aw, If you had a known test bar and could hold it straight then it would work. The test cutting is by far the easiest and most foolproof method to check for lathe mis-alignments. After all we ultimately care how a machine cuts. How do you qualify a test bar in your shop? You need to check for straightness and cylindricity to understand where any measuring errors come from. You need to make sure you take your measurements along the centerline of the bar as well. Not always an easy thing to do. Cheers, Tom
oxtoolco We have a pretty decent inspection room here in our shop. I guess what I meant to ask is if your machine is cutting a taper how can you tell if it's out of level or if the head stock is out of square. BTW, I heard you mention Hayward in one of your videos. I work in Fairfield for the Ball Corporation :-) Thanks again. Sonny
Hi Sonny, I would start by precision leveling the machine to see if you can eliminate your taper problem. If you see little to no effect much like I did in the video then take a look at headstock alignment. The point it to be careful to not introduce another source of error from the wrong place. Cheers, Tom
Thank you!!! Your video helped me soo much. Second shift crashed my lathe and didn't tell anyone. After your video I was running in about 2 hours. Thanks again. Steve B
Great video Tom. It was very informative. This is the exact same adjustment I plan to do with my Victor, as I have had taper problems with it for a while now. I played with it once, but never tore into it completely to find out where all of the adjustments are made. Maybe some content for a future video. Thanks for sharing bud. Adam
Hey Adam, Let me know if you need to borrow a 14mm allen key or socket. I had to buy a couple for this one job. Yeah put that gopro on your head so the viewers get an idea how much you go back and forth. Talk to you soon. Tom
Hey Tom- I remember starting off woodworking where 1/16" was accurate... Then starting metalworking where we broke an inch into a thousand... Cool I thought- Then we are introduced to the thought of breaking an inch into ten thousand.. That's when humility kicks in and we stop using phrases like "perfect". Metalworking can indeed be very humbling... Thanks for another great lesson...
Hey John, Well I've been humbled by treewood a few times. It takes the same attention to detail to do good work in pretty much any trade. Tenths are pretty humbling chasing them about all day long. Cheers, Tom
A sixteenth is fine for carpentry. But when I do fine work, joints need to fit exactly. So I set my woodworking equipment up with my metalworking metrology tools. It’s a myth that fine woodworking is a lot sloppier than metalworking.
I've had to align a few 3 axis CNC machines in my day and I know how you feel when you talk about the mind bending frustration. You can start to get a little batty after a while. So how many hours did the whole process take you? And does the temperature in the shop effect any of the alignment? Great vid as always, Jay
Hi Jay, Total hours was maybe six. It took about a week because of needing some tools and other stuff I was working on. Temp is not an issue at this level. everything in my shop is about the same temperature so its kind of mute. Cheers, Tom
10:42 this meant no such thing as at this point you had no idea about the trueness of the rod. For all you knew it could have been bent only cutting on one side of one end like that.
Actually, you should loosen the jacking screws after you tighten the headstock bolts. You want the headstock to move if you ever have a crash. If things can move, they are less likely to break.
Hi Wes, If you loosen the jacking screws the headstock would shift. Its kind of a push pull arrangement. Its not designed as a safety measure for crashes. Thanks for the comment. Cheers, Tom
Yes, the push/pull screws are the ones I'm talking about. The headstock should have a center spud or hub that allows it to rotate in what would be the Y axis. There will be a pair of push/pull screws that let you adjust the rotation. Mazak and Mori call them "knock bolts". Other lathes have no spud and use 2 pairs of knock screws. I recommend that you leave them loose. The headstock bolts will hold the headstock in alignment. Like I said before, you want the headstock to move in the event of a crash. Every manual I have seen recommends leaving them loose after the alignment is achieved. Some lathes have jam screws that you can used to raise each corner to align the spindle in the vertical plane. Obviously you can't leave those loose. That's not a great design though since the bearing area of the jam screws is so small.
It doesn't matter. Some CNC lathes have no spud and use two sets of jacking bolts. I guess you're committed. It's your machine... You also need to realign the tailstock after moving the headstock.
Hi Wes, Its not that I don't believe what your saying is correct for some machines. The YAM manual clearly says "After obtaining the proper alignment, tighten the fixing bolts, then tighten the six hold down bolts" After screwing around with it for a few hours I'm not touching any of them. I'l risk any potential consequences from a crash. Thanks for the comment. Cheers, Tom
Hi Tom, Wow, not boring at all, highly informative, I would have had no idea what would be involved in that process, I can easily see how tedious and frustrating this could be. I think I would be afraid to do such a test on any of my lathes for fear of having to slog thru such a procedure, and in my case, excavating would be involved as well. Excellent informative video .... Mike
Hey Michael, You might save some work tunneling in from the outside. Come up right under the lathe to adjust the levelers. If it aint broke don't fix it is a good maxim here. Cheers, Tom
Hey Tom I did NOT enjoy this video because I was hoping to be there in person :(. assisting and learning...NOW with that said I know why I wasn't there because of the tedious work required and having me there would be a distraction not an assistance! Great video!...I have read many different articles on lathe leveling...the "Rollie method etc..... My worn lathe cuts a taper and my mentor Chui had showed me and assisted me in getting the best from my machine using this method that you showed. FYI...I had to tie down one of the tail stock feet to the concrete because when I pushed up for the twist the complete foot end of the lathe would lift, the attachment to the deck gave me that slight twist required. Thanks for showing....great instruction Chuck
Hey Chuck, You can bet I'm going to lure you up here the next time I need to do this. Beware if I say something like, Gee Chuck I have a whole bunch of extra tooling and material you might be interested in. If your smart you will be busy. Cheers, Tom
We should have measure beard growth! Did I count 6 different outfits?:-0) That stuff always starts out 'fun' and then makes you nuts! Very interesting though.
Hey Jim, Busted. I did this over about a week. I had to order some allen wrenches and then once I discovered the head was out just had to quit for the night. Cheers, Tom
Thanks for the video Tom. I happen to have one of those yee olde South Bend lathes from 1948 I'm playing with. I've been playing with it and trying to get it level and all the twist taken out of it so I can use it to repair some old tractor parts and make bushing drivers and the like. I don't have all the fancy dial indicators and high precision measuring devices, so knowing out to level it using a piece of round stock and some micrometers helps.
Hey Tom - great video as usual. I watched it through and I had a question - are you taking out the twist in your machine or rather preloading it to compensate for years of wear-and-tear? Also, when I did my lathe work at the tradeschool, we had a rule where the maximum material length stickout was 2x material diameter. I know the piece you were turning was really large, but is it possible that even a light cut can "push" the work away slightly, making the dimensions differ on different ends? Thanks!
Hi Job, For general turning you are right. I am only taking off maybe .001-.002 each pass. This is why you need a decent size bar and sharp tools. Anything below the measuring threshold we don't care about which in this case was something like .0001. Cheers, Tom
thanks again Professor Tom, i cant say enough for all of you who are taking the time to make these vids, and teaching those of us, 3000 miles away. great stuff for sure. the only question i have is what about your chuck? and may it be out of alignment? if so where would you start machine or chuck or would the tool cutting the piece negate that? just an fyi, im absolutely new to machining in general, and just 5 days ago, finally got my first lathe, and she needs all kinds of love. thanks again for everything!
Hi Dj, When you take a cut all the eccentricity that your workholding may have comes out. It cuts about the spindle rotation not the workholding axis. This is the reason for taking a cut. Thanks for the comment. Cheers, Tom
Monday: Spends 5 hours setting up lathe.... Tuesday: New arbor press arrives....you suddenly realize you have to shift the lathe 3 feet to the left....... Wednesday: Neighbors send cards and get well wishes as you recover in the ICU from head wounds sustained from banging your head with chuck key.
I have seen this bed ways alignment video and your tailstock alignment video but I dont see a headstock video. Is it titled a little off maybe? I have a lathe that is cutting about .0002 taper on 12" so happey there. But I'm getting a pretty bad .005 taper when facing. My thoughts were I need to adjust the head stock. Would love to see your take on it
Just thinking here about a method of confirming if the load on a pair of feet is equal and I've been thinking about this since I heard the ring when tapping on one of the feet. Long sentence but I wonder if the change in the ring is relative to frequency, load on foot, and if that change in frequency can be measured with an app. There's more to this but there must a long term stability benefit in carefully balancing the load. Thanks for the interesting video.
This is the equivalent of doing pump strains with a millwright. You move it, shim it and heat it and your flanges have to be perfectly aligned and the studs must pull out by hand. Then they have a shut down and totally ignore all of that and bolt it up tight and get it operational because "we are losing product."
Great information Tom. Newbie question most likely, how sensitive is this process to the chuck installed - I imagine your lathe is now 'calibrated' if you will to the 6 jaw. I imagine if you have a 6 jaw you are only likely to switch it out with a 4 jaw where you are going to have to dial in over the length anyway, but if you say had a collet chuck how close do you think your taper results would be?
Hi Steve, The workholding is not part of the test. We are measuring about the axis of rotation. Imagine if the test bar was running out .010. Once we cut it to a full cleanup that cylindrical surface is coaxial with the spindle rotation. I would not expect any difference in taper switching work holding gear. Cheers, Tom
Ok I understand the accuracy you're trying to achieve but for a backyard turning operation dose it really matter I mean what's the accuracy of the mating face?
the world runs on the nattering little details which cause out alignment issues with all precision instruments, correction of which takes much patience and time. That tends to be boring for bystanders but causes those of us whom practice precision works, to revel in the amelioration of
Your concern was unwarranted - this was not at all boring and may have saved me a great deal of trouble. I'm about to disassemble a new lathe and move it to the basement and wanted to check it it's before disassembly state of alignment so this was just the ticket.
Hi Tom, Very informative as always. From the numerous comments bemoaning the conditions of lathes, it seems certain a person could make a tidy living becoming a "machine tuner", much like a piano tuner. With experience usually comes proficiency, so instead of a machinist spending six or more hours the tuner could do it in half the time, or less. Also by spreading the cost out over numerous machines, the tuner can afford to have multiple precision levels, indicators, etc to make the job easier and quicker.
Hey Morris, With modern machines technicians from the factory to the fussy setup so the machine performs as advertised. There are quite few folks that make a good living doing machinery repair and troubleshooting. As a shop owner you rarely want your top machinists fooling around leveling machines or diagnosing electrical problems. Problem is these guys are always busy when you need them. Cheers, Tom
Hi Tom I feel your pain ! Im a projectoinist by trade - what you did there is what I do with really big video projectors . Imagine the headstock is the body of the projector and the chuck is the lens . I aim the whole unit at a screen - all the pixels are accounted for so I cant over shoot or under shoot and call it art . now this where it gets fun - there is a backup projector stacked on top of the primary projector. that projector is aimed at the screen , pixel accurate, to the primary and runs along with the primary with the same image being displayed ..... not done yet .... today's demands have pushed for more screen resolution - think really wide screens , with lots of picture in picture content over background thats also data / video content . the biggest one I have done so far is 230' by 30' and about six time the brightness of a movie playing at your local cinema . there was 41 stacks of projectors . - all for a 40 min presentation .... so how that is done is I take yet another stack(s) of Projectors and edge blend where there left stack shares part of the image with the right stack - pixel accurate - and thru software the overlap is feathered so you cant see the blend region . it gets better .... about half of the time the projectors are flown from trusses about twenty five feet in the air access is by sissor lift.... be safe and keep the videos coming ! I do enjoy them and Im learning alot thanks ! chip
Hey Chip, You just sent a shiver down my spine. Sounds like a fourth order tensor calculus word problem. All I can say is I'm glad you are doing it not me. Cheers, Tom
Darn it Tom I was hoping you had a hot ticket method for leveling. You were going to save me hours of crawling around on the floor and test cut after test cut. I figured you'd have some Mr. Wizzard way that would make say "Man why didn't I think of that". I guess sometimes the easiest way is the hard way.
Thanks Mr. Tom. This is invaluable information. I fought that a taper was created only by the tailstock. I am confident that I will now be able to set up my lathe properly. Warm regards.
Outstanding! I've set up many machines before but never a lathe. I was always curious about it and you did a fantastic job of explaining how it's done. Thank You for taking the time to explain it so well!
Hi Tom, I wish that when I align my lathe it will be as easy as when you did yours, fall asleep in the first 15 seconds and then when I wake up 42 minutes later and it's done...! Yes... Well done video, everything to complete successfully the task is there. All I have is a garage Cat called ''Gros-Tata'' (It's French) He rushes out when I show up and scratch at the door when I leave, he doesn't like the noise of the machines, he FREAK'S out. Cheers, Pierre
Thanks Tom for the "long boring video". It was very informative. When I set up my small 11" Logan it still took me 4-5 hrs. Our Queensland is named Cinder and she is a sweetheart. Great dogs. Thanks again for the video's, maybe one day I will be able to join the You Tube group.
Great video Tom! Sometimes the most important things in this trade may come off as boring, but they are very important. I ran into a situation where I was re-leveling the lathes at work and could not for the life of me after lots of adjustment figure out why it still tapered. Then it dawned on me....check the removable bed gap. At first feel the transition felt "fine". After further inspection and some indicator work, found that the gap bed had been removed, but then replaced hap hazardly. After even more work of cleaning out the mating surfaces and re installing the gap and some inspection, some one at one time crashed the machine. They tried to "fix" it by hand grinding down the high spot on the mating surface, which was not so precise. In the end I had to shim it all into place and got it straight. So now the handy feature of a removable gap bed is no longer removable. What did I learn? For some, things are "good enough". Ps.....good enough can always be made better!
Hi Flineman, The tailstock is aligned last once you have bed twist and spindle alignment taken care of. You can cut a test bar with the tailstock in play and measure taper that way or sweep the tailstock spindle with an indicator mounted in the spindle. cheers, Tom
Maybe someone else has pointed this out (301 comments, I'm not reading them all), but I cannot get past it... 2 1/2" is not 65mm [63.5], and 200mm is not 8" [7 7/8"] (That tape and our eyes wouldn't see the 25micron difference. :-)) Ok, now I can watch the rest of it.
hey tom , am doing my under graduation in mechanical engineering and i kind of like machine shop very much because you can show your way of creativity and art, the engineer's way....And I kind of learn a lot from your videos ,those little tricks help me a lot in my college shop ..... so am much obliged for that..... (thank you) x (n) - for the upcoming videos and the past videos and I saw in one of your videos , you have a marking up the viewer in the world map kind of stuff ....so I would like to see If any one is from INDIA if not I would like to be the first one ....
Hi Msshyam, Thanks for the nice comment. We do have another viewer in India I think in Bombay. He has a shop there I believe. Best of luck with your engineering career and be sure to learn as much about how things actually get built in the shop. It will pay you back a thousand times. I put you on the list for a pin when I get back to that. Cheers, Tom
Hi Tom. Another great vid! Was wondering.....Have you assumed your bedways are not worn in the vacinity of the chuck. I was thinking potentially the nearest way could be worn say .001 , in a saddle shape, which would set you off chasing your tail from the beginning as it would show maybe .0015 or more on the test diameter.
Hi Nick, This test gets you as close as you can be with the machine you have. It does not cover the entire length of the machine. When we look at the overall length the tailstock comes into play and that is a can of worms all by itself. Thanks for the comment. Cheers, Tom
Yea your not twisting it much if any! Years ago I battled with a fairly large hollow spindle lathe, 9 1/4 bore, that cut a taper and we were constantly messing with the tailstock to try and compensate Finally figured out the headstock was off and it turned out all the bolts were loose and the adjustment screws that moved the thing on the gear end that are supposed to lock against each other and then had jam nuts weren't even tight against the block........ Yea it takes a while but once I got it sorted it was a whole different machine and a joy to use!!!
Hi Gent, Even as long as this lathe is I only got a couple tenths. I can feel you on the big lathe. Compensating for a jacked machine is a royal pain in the neck that you rarely have the time to fix. Cheers, Tom
I have just moved my lathe, so I have to go through what you have shown. Always helps to refresh the procedure in your mind, great video. By the way, can I have your 6 jaw chuck, ha ha..... Maybe not, my little 9" South Bend clone might sweat a bit trying to haul that monster around. Look forward to the next one. Thanks
Hi Robert, Thanks for the offer of taking the six jaw boat anchor off my hands. Sorry but I tossed it in the scrap bin. You missed out. Thanks for the comment. Cheers, Tom
Silly question as I didn't see anyone ask or mention it in the first 30 or so comments, could some of the taper you were chasing be caused by worn bed ways? We have several old(er) machines where I work that will cut taper up by the chuck where most of the work has been done, and cut straight further down the ways... This with exception of the lathe that has pretty much only turned shafting, which has fairly consistent wear for the length of the bed.
Hi Ice, This lathe has hardened bedways which appear to be in good shape. You would have to do a much longer sample to expose and diagnose that kind of a problem. This was pretty clear case that the headstock was out of alignment. Cheers, Tom
Hello Tom Great video. These problems can be a real pain to rectify. The spindle bearings can have a lot of influence on tapers as well. They can lift to different heights depending on RPM. Even belt tension and cleanliness on units without headstock gearboxes (CNC mostly) will affect taper in my experience. A question, my main concern was when moving the headstock so much did it affect the flatness when facing? It doesnt take much to make a big change there. Cheers
Darren Wright Hi Darren, Yes it did. It improved it as you might expect. Facing flatness is actually difficult to check on the machine. Thanks for the comment. Cheers, Tom
Hi Tom, it's a bit late for my comment , i started watching all your videos from beginning. When I was in school 20 years ago they says that the overhang in the chuck can not exceed 3 times the diameter of the part, or you have to use the tail stock to support it, that's to prevent a small flex and vibrations in the part. Can it be that 0.001" difference comes from this vibration? Is this a true statement? Thanks. Bobby uk
Hi Bobby, For regular turning you are correct. This is a special case where we want the most separation between the turned bosses as possible. If you watched the video I just barely took a cut on them. The bosses make it so you do not have to cut much material at all. The large diameter is stiff enough so the push of the tool is not a factor. Thanks for the comment. Cheers, Tom
Tom, this was an interesting video. I guess very few machinists bother with this type of alignment - I know I haven't. I've been pretty lucky that I haven't had any bad tapers worth the trouble in the many lathes I have run. Wish you could have shown the actual adjustments on the headstock jack screws - I'm just curious
Hi Ujeb, Its always nice to run a machine that has already been setup or just cuts well no matter what. I have a LeBlond at work that I cant make cut a taper no matter what I try to make it do. The headstock screws are pretty boring. A couple of greasy set screws and socket head cap screws in a casting. snooooorrrrrrr. Thanks for the comment. cheers, Tom
Hey, used this procedure after an 'oxtools headstock alignment' search was recommended at practicalmachinist. This worked out better than I expected, any other problems notwithstanding, but getting down to about a .0002 difference between ends is a good start. Thanks.
Why use a micrometer that only reads to 0.001 versus a caliper that reads to the same amount? I have been wondering why they make micrometers that only read to 0.001" when you conceivably get the same resolution from a caliper?
Hi Walter, Micrometers are much more consistent and accurate than calipers across the board. You can easily interpolate fractional parts between divisions with a micrometer that only reads in .001 inch increments. The micrometer I was using in the video reads to .0001. Cheers, Tom
So, if you have a smaller lathe using the "suggested" set-up of 3 point contact, 2 under the headstock, 1 under the tailstock, how do you adjust the tailstock end? If you adjust a single screw, are you not just moving that end up and down?
Hi Russ, The three point contact is only for the initial plain leveling of the machine.After the machine is level then you bring all feet into bearing with the floor. Only after this can you start the test cutting and fine alignment work. The single point is placed on the visual center of gravity of the tailstock end which is typically between the two levelers. Cheers, Tom
I particularly like that you don't cut much out of your vids. I don't like the vids that skip massive portions of the process. It's too much like "then a miracle happens and we wind up with what you see here." I realize there is a balance to keep boredom down, but this was the same length as an hour tv show minus the commercials. Perfect for me!
Tom, I just gave you a thumbs up as the 666th positive viewer. Ernest is one good looking animal and obviously smart. You should have had him assist you. On a more serious note. . . the lathe I am restoring is an old Nebel sliding gap bed jobber. With everything that you did, how would one know if the taper was not being generated by wear in the ways and carriage? Love your videos!
Hi Gordon, Well if I could get some of the taper out by good leveling work and not by biasing the levelers in some weird way I would say that was from twist. Wear is harder to diagnose. When we look at taper with this test we kind of ignore the center section of the test bar and just measure the ends. So we are really measuring a short area of the carriage travel near the headstock. Hope this helps. Thanks for the comment. Cheers, Tom
This is, by far, the most useful bit of instruction I've seen about setting up a lathe. On behalf of my old Logan, thank you! Forgive the silly noob question, but why cut a chamfer in the test bar? Does it help keep the feed-in more accurate on the first cut, or is it just 'good practice?'
+Hessian Deiter Hi Hessian, No particular reason for the chamfer other than attention to detail. It does provide some lead in for the tool but its negligible. Thanks for the comment. Cheers, Tom
I bought a 18x60 jet 15 years ago it had been setting unlevel for a couple of years it took about 3 months to get to a point where it quit moving and stayed level, I checked it the other day after watching your video and it needs a little adjusting but I'm about to move it so it can wait until then, good video tom.
Hey Tom! Well, i´m sure this was a distress for you, but i´m also sure you helped a whole bunch of people in particular me. We have an old Colchester Triumph lathe at the shop with the same kind of a problem. Everyone told me the same argue that it´s just a mangled up machine, dedicated for the scrapyard. finally i´ve got the confirmation of none-ability. I bet everyone want´s you to be his coworker haha Thanks for the Video! Sincerely regards from germany, Simon
Hi Tom, very nice presentation. You aligned your the lathe on the vertical plane, how about the horizontal plane? I had to do just the same you did years back and I thought I am nuts to take the head stuck off the bed. Also I found under the head stock brass shims. I assume they are there for the feature scraping, to lower the head stock or just correct the angle against the bed. Thank you shearing all your insides. Radu
Hi Radu, I don't even want to thing about the horizontal plane. That is going back a ways to access any adjustments. Thanks for the comment. Cheers, Tom
I served my apprenticeship on flat bed lathes. Aligning the headstock was a regular operation. What was worse was the gap. It never went back into the proper place. Then there were the gibs for the bed. Too tight and feeding was a chore. Too loose and chatter and inaccurate sizes. It was a constant fight - Man [or rather boy] and machine.
Tom that was very good information thanks for sharing it. Suppose you did not check and correct the lathe how you did. You instead use the same method to check the alignment of the tailstock and adjust the tailstock to minimize the taper. Are you good then as long as you use the tailstock to support the work?
Hey Bill, I'd have to think that one through. If it measures the same diameter at any point its the definition of a cylinder. So my tentative answer is yes. You can correct a lot with the tailstock. The problem is lots of work doesn't use it. Cheers, Tom
Hey Tom, What a grueling process! Thanks for the informative video. It's amazing what can throw things out of kilter like that. Your lathe and its operator should be now be happy campers! Regarding the lathe, "I YAM what I YAM", to quote a famous sailor cartoon character! Regards, Oxen Dave
OH boy, as soon as I read the title I had a deja-vu moment. Unlike old lathes where the headstock was laid on extended v-ways most new units with gap beds seem to have the adjustable headstock. I had this exact same gremlin with the new lathe. Carefully levelled but yet still cutting a pretty severe (.002" in 2"piece) taper. Finally figured to do the head alignment and all was well. It' is worth anyones time to do the checks for head alignment as it may save you some headaches chasing tapers. And to make it all better I'm going to have to go through the procedure again when I move the machine soon.....:-( Great video Tom...brought back a horror story for me...LOL Colin
oxtoolco I wish I had your video BEFORE diving into that last year. I just went on guts! I may video the next session once the machine is set up in the new location.
+Jerry Halcomb Hi Jerry, Not all lathes have adjustable headstocks. Be sure you understand your geometry problems before you suspect headstock misalignment. Be sure the machine is level and straight first. Thanks for the comment, Cheers, Tom
Hey Tom, i remember dealing with this problem on a big Tos cylindrical grinder, the bed was in bad shape so had to use a dialindicator to adjust the machine it was a lot of times very frustrating job to make a long perfect cylinder with no taper, on modern machines lathe, mills, grinders it can be set up perfectly with time and patients, cheers from romania.
Hi Andras, Thanks for the comment. The work is easy on good machines. The trick is finding one that is really good and well set up as you mention. Cheers, Tom
This was very educational, it makes you wonder how much work goes into making machine tools and making them accurate and consistent. I don't fully understand how you knew that you got all of the twist out of the bed and needed to adjust the headstock? How long did the whole process take?
Hi Tyler, The whole thing took maybe six hours. It was over the course of a week. The measurements show basically no change going from level to not level and loaded at different points. What I mean is the leveling feet had no real effect on the cutting conditions. Cheers, Tom
this may help if you level the machine right you will know if you have a twist in the bed. most good or well built lathes have head adjustments the other thing is that a .002 or .003 cut does not load the saddle so you have the unpredictability you are seeing good luck we all have to learn you are ok keep working. go back and relevel the bed before it twists from load over time
Hey Sparrow, Most of your fine finish cuts are in this.002-.003 range. It is understood that the machine behaves differently under maximum load. What we care about is when working to fine finishes and fine tolerances. The level will get you close then you need to make test cuts to see how the machine behaves. Lathes should be checked and calibrated once year or more depending on the work and how much use it sees. Cheers, Tom
Could a re jacking the tail stock and and letting it set back down possibly in a new position also maybe corrected the twist. It seams the the twist was induced by the moving out of the lathe to begin with and that the headstock was obviously parrellel before... Just a thought.
I never noticed any serious taper issues in the past. Perhaps the jack bolts were not bearing properly and some heavy cutting took it out of alignment. . The tailstock has nothing to do with any taper in an unsupported part. It was probably vibration from the less than ridged feet I had the machine on before. It used to want to dance a bit at higher RPM's. cheers, Tom
Hey Tom, thanks for the videos! just curious...i have a bench size lathe and i don't have any jacking screws, could i chuck a nice chrome piece of round up, indicate it in, and then do a sweeping indicator reading off the compound rest to measure taper? Hopefully you know what i mean.. Thanks!
Hello there TOM Watching this the second time round 'cos we need get our Lathe cutting right and it's driving us crazy as well. Like U said, it has to be done, albeit painstakingly, and we sure have a much better idea now, with a good dose of confidence boost. Now to get 'er done, like the Man says !!! Thanks again for taking time out to show and share. ATB aRM
I am new to the wold of machine work. Some of the mathematics are over my head but not boring. I compare the machines to the pool playing I used to do. Geometry and physics are more detailed than most would expect. By studying your videos I am learning little by little and I appreciate all the help. Keep teaching and I will keep studying. but I am never bored, Thank You very much. J.D.
Hi Tom. Very helpful about checking level calibration. Do you think lathe headstock was over set too much to start with in order to ensure lathe turned faces concave rather than convex?
Robert Hawtin Hi Robert, I think the lathe had not been used for anything long for some time. It had probably been moved several times since the last time it was adjusted. I do not believe it was an intentional offset. Thanks for the comment. Cheers, Tom
You didn't bore me to tears. I'm not a machinist but last Friday they asked me to machine an alignment rod that would be 3.234" diameter and 36" long on the lathe which I figured I could do. Well it didn't go so well and turned into a royal pain. I managed to get what they needed by adjusting the tailstock but tomorrow I'm going to use your method of leveling and then proceed to realign the tailstock. The lathe I'll be working on is a newer Jet 16x50 that looks very much like your lathe. I'll let you know how I did.
Tom you ended up moving the head stock itself to correct the taper in this video. If the headstock wasn't level with the ways would it have resulted in the same issue? Is there a similar adjustment on a lathes' headstock for that alignment or is that in the ways themselves?
Hi Hank, There is no adjustment for up down just side to side. I guess its easy to make the spindle bore parallel to the base of the headstock casting. Cheers, Tom
