RE: cross slide issues

RE: cross slide issues

I don't want to step on any toes or be out of line.
I do think a closed post about cross slide issues on, lets say a worn out old lightweight American classic such as a LeBlond Regal series or an old South Bend, for instance, were never really addressed.

Someone asked how you could survey the cross slide ways.

One quick way for someone with minimal equipment other than a DTI to do a peremptory "survey" would be with a dowel pin. First level the lathe, do the collar test and turning, align the headstock.

Mount a 10ths DTI to a faceplate or chuck such that the probe extends radially out just far enough to miss the lathe ways, wings of the carriage, and anything in between when the spindle is rotated by hand. Remove the topslide. Lock the carriage to the ways*. Use a clean new dowel of sufficient diameter to lay in the dovetail and contact the bottom flat way and about 1/2 to 3/4 up on the dovetail. Put the dowel at the leadscrew side of the ways and swing the DTI to find the highest reading. Move the dowel to the far side and swing the DTI again observing the highest reading. Compare. Obviously do repeat readings and observe all best practice.

Stepping up a notch with equipment, scrape the bottom of the cross-slide flat to a surface plate. Then use that and a dovetail straight edge to scrape the flat part of the cross-slide ways, flat all over*. (Keep them equidistant from the carriage-to-bed ways of the carriage so the cross slide travels neither up- or down- hill). Next use the dovetail SE to scrape the non-gib side of the carriage top (cross slide) ways dovetails straight, and to the offset desired for the lathe to turn concave when infed normally. IOW, continue to use the Dowel and the DTI on the spindle to monitor progress and inform which end of the dovetail to scrape more heavily. End up certain the way is straight, not curved.

Now, mic'ing over dowels to keep the ways parallel, scrape the back/gib side of the ways parallel. Then scrape the cross slide ways to match, keeping them essentially parallel. Then fit and scrape the gib.

It is pretty obvious why people think this would be a worthless enterprise on a low cost poorly designed import, but it might be better to just lay out the work entailed and let them make their own decision. Sometimes if we ignore where the machine came from, many of us can learn something new about the process applied to "any" machine. To some people who may eventually become "professionals" following such a process on a "junk" machine may be a good learning experience and better than taking on something bigger and "better" anyway. People learn best from their own mistakes despite all well meaning advice.

I scraped a whole bunch of wood-whacking equipment when starting out, including a tenoner, and a run of shaper sleds/fixtures I used to sell (due to not having a surface grinder at the time) Later/20 years ago, I rescraped a Taiwan mill drill bought new and worn out by me even longer ago. Not supposed to talk about it, but it is still a good machine and gets regular use. (Got plenty of good old American iron, too, of course including a regular SB turret mill)

*Obviously it should also have been determined that the carriage was a good, non rocking, full contact, scrape fit with the ways, before locking the carriage "gently" to begin surveying and scraping the cross-slide ways. Since it is owner's lathe, make your own choice about whether to spot and scrape in the clamped or relaxed condition. On small lathes facing is done with carriage locked. If the carriage fits well made ways, either choice works fine, and I have done both on my own lathes.

A reminder: Once you scrape in the cross slide ways, you are locked in to that exact geometry for lathe bed level and spindle alignment "forever", so be sure they are correct before proceeding.

That said, i don't doubt that even "close" could improve the accuracy of a lot of small lathes, imports or worn out Euro/American.

But it is not a trivial process, so as mentioned in previous posts, select your re-build candidate wisely.

smt

Thank you for your incite Stephen, your posts are always good to read and thank you for participating. The thread was closed because of several requests from different members. I didnt really have the time when it was closed to offer an explanation. But it was really just to stop things from getting out of hand as the tone was beginning to be confrontational rather than educational.

I will take a few moments here to explain some things, I am sure no one will mind if I add something off topic to your thread. I have not been very active for a few months, not only have I been very busy with business but there are family issues. My father has suffered from Alzheimers for some years but it was mild and we were dealing with it. But suddenly last summer he when down hill fast and now I am spending a lot of time at my parents house. Now just two weeks ago my mother needed surgery for her shoulder and is incapacitated for several weeks. So things just got busier.

I still check in and as long as no one is getting out of line I have not bothered much. I apologize for my absence but frankly I kind of think I needed a short break anyway. I hope you all enjoy a nice weekend.

Stephen if you want me to I can move my post. But thanks again for starting your post, lets see if we can all try to remember that being right isnt as important as learning from each other.

Charles

Charles -

Very sorry to hear about your parents. Went through similar myself last summer, but have quite a few siblings who took up much of the slack, so not as time intensive, wearing, all - encompassing as your situation. I do understand, though and hope everything goes as well as can be expected.

Did not mean to add to your time burdens or concerns. You clearly spent some time with my post and your summary is perfect! Thank you!

smt

With all due respect Stephen I cannot find myself agreeing with your post. If somebody was to follow the instructions provided they would effectively finish up trashing a lathe. Sorry.

There is a specific order that machines, and in particular lathes, are aligned, and although the equipment required is relatively basic it is still required. By all means for a quick check and commissioning of a lathe shortcuts can be used with minimal equipment, but once a person starts seriously rebuilding it things change considerably.

It was suggested to "First level the lathe, do the collar test and turning, align the headstock." I'm afraid that is just bad advice right there, and the number of times I've either seen or heard of people screwing up a perfectly good lathes but messing with the headstock based on a flawed technique is innumerable. The ONLY time that technique is valid is with a brand new lathe with no wear and otherwise correctly aligned. So in other words if you're commissioning a new lathe the "collar test" is perfectly valid and should indeed be the final check that a new lathe is cutting accurately. However if a lathe is worn in the way they normally wear, it will not cut without a taper with the headstock correctly aligned and visa versa. If the headstock is not correctly aligned it will present problems with other operations. Nobody should expect to go from that point and start hacking away with a scraper!

For many years I worked in servicing and a rule of thumb I earned my living from, and can offer others, is to assume the machine you're working on once worked correctly. Clearly there are times that assumption is sometimes flawed and it left the factory faulty, but that situation is certainly much less common than some people seem to assume. If it once worked correctly, the task is to find out why it is not working correctly now, and (if you're good at your job) what caused that situation to occur.

Pete-

Very valid comments.
My intent was to convey how much effort there is to straightening out a cross slide; and that it can be surveyed practically with simple equipment. Precepts included (mentioned) considering that the lathe bed was in good shape or had previously been made so (fit of carriage to ways). The many things to consider before the effort to "merely" straighten out the cross slide.

My point was that starting with a lathe in which everything except the cross slide was "ok"; (I used what I intended to be shorthand to "check and verify all other alignments") it would still take this much further work. The cross slide is about the last part besides the compound, to complete on a complete overhaul.

There are also a lot of practical repairs that will improve work on machines without a full overhaul.

smt

stephen thomas said:

There are also a lot of practical repairs that will improve work on machines without a full overhaul.

smt

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Definitely. However there are even more otherwise perfectly good machines that have been completely ruined by people making "repairs" without properly understanding what is causing the issue to begin with.

Here are my thoughts:
I also don't want to step on toes either. Stephen and Pete are successful with their methods more power to them, But I do not believe in some of what I have read. I am successful with my methods too. More then a few times.

Many Asian lathes have a pivot pin under the headstock and if someone crashes the compound into the chuck the head moves. If you have an Asian lathe and the head-stock is sitting on 2 flat ways then it could be a simple 2 collar test cut to align the headstock to the bed to repair the machine. A few years back a fellow bought a brand new Asian 14 x 40 lathe and he was begging for advice on another forum.

The dealer installed the machine by leveling it and he said the tech did not take test cuts as he forgot the tool bits. Anyway I told him to align the bed by setting a level on the flat cross-slide and moving the saddle L to R and adjust the leveling screws. He did that and locked the jam nut, the screws were on the factory leveling plates.

Then he had a 2" aluminum bar he did the 2 collar test at 6" and it was off .006. so .001" per inch. He had a difficult time finding the 4 bolts that held down the head, finally found the back side left one inside the electrical panel, loosened it and there were adjustment bolts that were in a block under left end of lathe under the feed change gears. It was a long process but it finally cut straight just aligning the head.

I have also aligned American made machines where the headstock sits on a V and Flat and can't be aligned by first aligning the bed using a level. The bed is worn. Then using the 2 collar test and depending on the size of the machine: Big say 30" and bigger machines adjust the headstock to twist the bed under the head. If it is a small Southbend, LeBlond, etc lathe 14" or so I twist the bed out of alignment to get the 2 collar test right on. Many times the lathe owner turns with out the tail stock and seldom bores (you ask them) and the bed beig twisted compensates for the worn spot under the chuck.

Also I NEVER say it again NEVER sweep dowel pins from the head-stock to the cross-slide . I will write more later. Rich

Richard King said:

Then he had a 2" aluminum bar he did the 2 collar test at 6" and it was off .006. so .001" per inch. He had a difficult time finding the 4 bolts that held down the head, finally found the back side left one inside the electrical panel, loosened it and there were adjustment bolts that were in a block under left end of lathe under the feed change gears. It was a long process but it finally cut straight just aligning the head.

Rich

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Sure. That will work well. But how did it face?

If a lathe is not set up correctly or is badly worn it can be made to still turn accurately. Indeed I have an old lathe (admittedly one I now never use) that I deliberately twisted the bed to make up for bed wear. It turns relatively accurately up near the headstock, where most work goes on. Even though I don't use it I'm keeping it for now and will do a full rebuild on either Youtube or forums to document the process. There are all manner of bodges available to get by on a lathe that is worn. In my opinion virtually any idiot can do high quality work on a lathe that is accurate, but it takes a lot of skill and creative thinking to both use and setup a machine that is worn yet still turn out high quality work.

If a lathe is NOT worn however and just not setup correctly, and the headstock is moved out of alignment to get it to turn accurately (and compensate for improper installation) it will not face accurately, and may have issues in other areas too. There are no ifs or buts about that fact, that is just pure geometry. There are no free lunches unfortunately.

Rich I actually initially posted about a crash and knocking a headstock out of alignment, but deleted it as I didn't want to get into particular faults. However that reiterates what I said about there being a reason for the fault, and the lathe certainly didn't ship that way from the manufacturer. It normally takes a mighty big crash to shift a properly secured headstock and it's not like the person wouldn't realise they'd done it! If the lathe was otherwise new, properly levelled, but had known to have a headstock out of alignment, I don't see any reason that a two collar test wouldn't bring the whole machine back to alignment. But that's not normally what happens. Instead people often don't properly level the bed, it is twisted and they start screwing with the headstock to get the machine to turn without a taper. All great until they need to face accurately and then complain the machine won't face accurately, therefore, in their wisdom, the cross slide must be in error. That's crap, and the only problem was it wasn't installed correctly before Bozo went to town on it.

I drove again yesterday and I'm tired plus I have to run my business and make $. Will update things later. I cover all these simple tests in my class. I wish one of the students would step up and TEACH what I taught them. Lathe alignment is one of the first things we teach apprentices as lathes and mills rebuilding represents 90% of what a rebuilder does. Simple as heck once you figure it out.

Pete F said:

Even though I don't use it I'm keeping it for now and will do a full rebuild on either Youtube.........

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THIS is something I am sure many folks would love to see. I don't think there are any videos of a professional going through a lathe rebuild and it would be great to see one IMO.

I hate to ask but when, "leveling a lathe" one is actually aligning the lathe to itself yes? I know this term has been beat to he'll but we have a few professionals talk no about leveling so is it fair to say that alignment is more the objective in the "leveling" process??? This is what I have read many times-that lathes on ships blah blah blah but now, after reading this thread and all the references to leveling, I'm asking again to be clear.
Thanks

Galaxy S4, Slimkat
If I wasn't married I'd quit fishing

Richard King said:

...Also I NEVER say it again NEVER sweep dowel pins from the head-stock to the cross-slide . I will write more later. Rich

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Richard,
Honestly, I'm a bit confused and I suspect there is a misunderstanding. I think (almost) everybody agrees not to sweep dowel pins in the cross-slide dovetails in order to align the headstock. But, what Stephen Thomas was describing in his post was to use that test while scraping back to alignment the cross-slide after the headstock had been aligned and assuming both that the bed is in decent shape and that there is good fit between the saddle and the bed.
Possibly, it should have been made clearer that the results of sweeping the dowel pins should be combined with the survey with a angle straightedge (e.g. bowed ways could theoretically give a 0-0 reading on the swipe test, but would leave a few thousands gap when tested with the straightedge).

Pete: I somehow agree with you that, if you were to read Stephen Thomas's initial post as step-by-step instructions on how to rebuild a lathe, not all duckling were in a row. However, at least to me, it was rather clear that it wasn't his intent.

Paolo

I understood what he was saying. I do not know any professional rebuild er that sweeps dowel pins for any purpose!

The cross slide has to be square to the bedways using a square that can rest on dowel pins against the cross-slide. Paolo if you still have the class work booklet look in the back section that shows the KingWay and you see the test.

Sweeping from the head can give you false readings. The headstock bearings could be loose, indicators change when turned. Do that flip test. With mag base and do it side to side.. the. Indicator moves when. Only touching the plate. Hardinge had you mount a parallel on the spindle nose held in by a threaded rod thought the spindle and you swept it parallel you the spindle bearings. Then slid the cross slide. With mag. Base with indicator to test square Ness. More later. Rich

Yes - some people seem resistant to the idea: my post did not tell you when to scrape your cross slide or even if you ever should. That is up to you, and in most cases except perhaps poorly built import lathes, would not occur until most of a complete rebuild had occurred. My original post assumed and stated the rest of the bed and carriage must be aligned and in good condition.

My post did tell how I have successfully scraped the cross slide for my SB 10K lathe, after rescraping everything else. I have also scraped many other slides and slideways & compounds, with various geometric requirements. The post stated a method that will work if applied thoughtfully.

Richard - you are the gold standard and I am saying that with admiration. Please explain why sweeping a dowel is not a good idea to understand cross slide windage once everything else is in "perfect" shape. I can see camming bearings as a factor. That could be mitigated by swinging the DTI on a bar directly in the bearing housings.

Another method could include 2 dowels, a scraped square, and slide the cross slide up and down the ways against a DTI. But it introduces several more stack tolerances (1 more dowel, the square itself).

Several people in various posts have said that they don't believe, or have never noticed that their lathes face hollow. What do you recommend as far as flat or hollow? How much in 6" or 12" ? I think Schlesinger is about .0008 in 12" ?

Taking this a little further - probably "most" people rescraping machines these days are not professional rebuilders. They are people who bought old American iron and find that it is not really in tolerance. Or they are people who bought import machines that were maybe abused for a while and put out wet and maybe never were in alignment. They need basic info as this forum provides, and simple methods that work, so long as the person is rigorous in approach.

smt

3:12 - Richard & I were posting at exactly the same time. (some overlap)

stephen thomas said:

Taking this a little further - probably "most" people rescraping machines these days are not professional rebuilders. They are people who bought old American iron and find that it is not really in tolerance.

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I think this is an important truth. Also consider that whilst the rebuilder might declare scraping in JUST a cross-slide not a worthwhile enterprise it might be just what the owner wants and nothing else - whether from ignorance, time/cost restraints or perhaps they have some other particular reason but if it's their lathe and they are happy to work around the machine's other wear issues but would like to improve the fit of the cross-slide then I see that as a perfectly valid reason to do the work or pay to have it done.

I try to teach all, hobbyists and pro's the proper and easiest way to do it. You may have good results, but that is not the way most experienced scrapers do it. I want people who read this forum now and a hundred years from now to know the way the majority of pro's do it. Stephen your in Elmira, drive over to Hardinge and ask to see the test bar they used to send me when I did service calls for them. It is a slick set up that fastens to the spindle nose and you sweep it in to the spindle bearings and indicate off the saddle cross-slide ways. If your way works for you go for it.

It's like building a house, plumb and squareness of foundation and up. Not top down.

I added a pic out of the book I mentioned in Paolo's answer. I have a copy of the Connelly book and the Schlesinger book with me and will look this up and add some pic's. Rich (have chores today fixing my cabin, got to go)

L to R, Fig 6 and 7, 2nd page fig 9.

It's like building a house, plumb and squareness of foundation and up. Not top down.

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Not part of my post.
No argument. I've built a lot of houses

Once one gets to the part of the "house building sequence" where it is time to scrape the cross slide, how does sweeping one qualified dowel in a couple locations differ materially from sweeping a parallel aligned in the spindle and proved by swinging it both ways? Or am I missing part of the procedure? (Can't really see the pics clearly, need to get that book)

Would love to be able to resource Hardinge stuff. They don't talk to peasants, though. Tried to get a tour of their scraping dept for my articles in HSM almost 20 years ago. Probably gone, now, since the auction.

smt

Can we be realistic here and say that the majority of people who might be reading this in the future will not have access to a full suite of tools and gauges. They will be forced to do their best and make do with what they have - and that doesn't mean that they should be put off trying. Results from all non-professionals will be highly variable, you could give some people every tool in the box and they might still mess it up yet another person might be highly adaptable and innovative and possibly come up with the results via a highly unorthodox method and with minimal gear.

What I'm saying is that there's more than one way to cook a cat, some efforts might not make the machine perfect but still offer a significant improvement and that can only be a good thing. I think there should be less arguing and more encouraging or it's all going to get very stifling in here.

I have said that many times on here "Many ways to skin a cat" But sweeping off the spindle in my opinion is not a good way.

The cross-slide needs to be aligned square to the bed as one builds or rebuilds, you grind, plane, or scrape the bed, then you match fit the saddle bottom to the bed, measuring the top of the saddle so the top is parallel to the bed and one can use the bottom where the carriage bolts on to the saddle as a guide too, so the feed screws and shafts run parallel to the bed, on a rebuild one must add wear-strips so the rack and pinion match to. Much to think about when scraping the saddle to the bed.

The cross-slide can be scraped at the same time, but you have a game plan before hand. The saddle cross slide ways can be scraped square by scraping the saddle bed ways to if they are scraped during the process. The squareness test to the bed does not need the headstock to be on the bed when you either set a square against dowel pins on the cross slide and indicator on the blade square so the cross slide is scraped so the bed so when you do face it will face concave. I have also mounted a granite or blade square on the top of the bed and indicate the square bottom parallel to the travel of the saddle on the bed and then use a gage resting on the dovetail of the cross-slide and indicating the blade of the square. Similar to plate 22 on page 272 of the Connelly book or the test they are making on page 275..figure 26-20..but the square is mounted directly on the bed and not on a surface plate. The test device that Hardinge used is similar to the one on page 305 fig 26.63 and page 306 fig 26.64. If anyone wants a copy of the Connelly book I sell them. PM me for more info. Rich
PS: That section of the book was written by South Bend I believe.

Then the proper way to rebuild / build the lathe is to scrape the Tailstock and then the headstock if you do not want to shim up the tailstock. Many times I never scraped the head down and put a phenolic shim glued between the bottom and top of the Tail-stock, but if you don't you scrape the headstock down last using test bars in the spindle or the parallel square mounted on the spindle nose. The Schlesinger book can now be downloaded on
Testing Machine Tools (Dr.Schlesinger).

You can sweep your pins and teach folks to do it that way, but My Dad hated people doing that way, I hate seeing it done that way because of indicator error, plus you have to do it with the headstock on the machine, have new bearings, etc. Sweeping with an indicator flipping it side to side you get false readings, indicator bar gravity drop, so much to get a false reading (bad way).

Even if I didn't remove the head I would never do it your way I would scrape the cross-slide square to the bed as you could move the saddle anywhere on the bed and get the same reading. If the bed is worn near the chuck and you swept it up there and scraped it, you could move the saddle back down the bed and it would face convex possibly. Rich

Peter. said:

Can we be realistic here and say that the majority of people who might be reading this in the future will not have access to a full suite of tools and gauges. They will be forced to do their best and make do with what they have - and that doesn't mean that they should be put off trying. Results from all non-professionals will be highly variable, you could give some people every tool in the box and they might still mess it up yet another person might be highly adaptable and innovative and possibly come up with the results via a highly unorthodox method and with minimal gear.

What I'm saying is that there's more than one way to cook a cat, some efforts might not make the machine perfect but still offer a significant improvement and that can only be a good thing. I think there should be less arguing and more encouraging or it's all going to get very stifling in here.

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There is a lot of crap on the internet, and we don't need yet more*. There is nothing wrong with what you've said, and good luck to you. Suitable forums abound where there's no end of people who can satisfy your urge to "have a go" despite it being incorrect. I'd suggest HSM would be a good forum and I'm sure Evan there will tell you how it is.

THIS forum on the other hand is for people who are interested in learning to scrape and align machine tools to a professional standard. Scraping and aligning most machine tools takes only a remarkably small number of tools. It makes me laugh when I read people say they want a cheap, quick and easy way to do this type of thing, presumably because they must think that those who do it for a living will take the lengthy, difficult, and expensive way, just because they have nothing better to do with their time!

* For example I've often read of people advocating moving the headstock "for correct spindle alignment" without properly levelling the bed. The bed is twisted but they gloat how they were able to use some idiot's Dad's method to get it "perfectly aligned". What they fail to appreciate, apart from the fact that the lathe doesn't face accurately, is that it is ONLY at the point of those two collars on the lathe that it will turn accurately. Closer to the headstock and it will be either over/undersize depending on which way the bed is twisted/headstock moved, and conversely further from the headstock it will be the opposite. That is the sort of crap this forum can do without and if it means being a bit "stifling" then so be it.

Richard King said:

Sweeping with an indicator flipping it side to side you get false readings, indicator bar gravity drop, so much to get a false reading (bad way).
Rich

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Rich posted at the same time I did. I wanted to emphasise what he said here. Sweeping with a horizontal spindle is always a crap idea. This is the sort of information this forum should be about in my opinion, because a LOT of people don't realise that and do things like try to vertically align the tailstock based on sweeping it, and don't know why that doesn't work.