[OP]
Member
When turning wood the amount the headstock and tailstock are out isn't a problem but I free hand turn a lot of aluminum (some pretty large diameters 200mm) and then it's quite a problem. Drilling can wonder, the bearing in the headstock and live center are put under unnecessarily large loads... Anyone ever tried to true a 2436 up before. If so how'd you do it. Don't want to start pulling things apart and end up with an oh shoot moment if I can help it.
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Brian, have you called tech support at Oneway? Hard to find a better lathe than the 2436, and I'd think they'd be all over it to troubleshoot the issue.Originally Posted by Brian Ashton
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Did you make sure the bed of your lathe is level in both directions so that the bed doesn't twist/flex? This is not an uncommon problem for lathes. This is usually my first step if I find an issue with the points of a drive spur and live center lining up properly. That lathe is very stout but I think it can still twist. Check how level the lathe is and let us know.
Last edited by Dick Strauss; 06-26-2015 at 9:45 AM.
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Also, can you describe HOW is it mis-aligned? Vertical mis-alignment might require shimming. Side to side is more problematic since wood lathes lack adjustment in that direction, and a combination would probably denote twisting of the bed. Another issue is that they can be perfectly aligned when touching, but out of alignment when the tailstock is moved away if the bed is not true. In this case the mis-alignment would increase with distance between the head and tail stocks.
Level is not as important as 'true' (a smooth plane) but is easier for some to check, though the tolerance on levels is not that great. Carpenters are allowed 1/4" in 16' error. That will get you under 0.001" per foot if the bubble is measured EXACTLY. To check for twist use 'winding sticks' which are two very straight sticks laid perpendicular to the ways, as far apart as possible. It is not necessary to remove the banjo or tailstock. Move a distance away from one end and sight across them paying special attention to the ends. The longer they are the more they magnify any twist. It helps if one is dark and the other light in color. This is an old cabinet makers trick. I bought a couple of 1" x 3' long aluminium angles at Home Depot and painted one black.
Lyle Jameison talks about the weight on each foot needing to be the same and in his you-tube video on lathe setup shows his method for equalizing.
Retired - when every day is Saturday (unless it's Sunday).
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My 24/36 has a means to tweak the headstock/tailstock alignment in the sideways direction. The blocks under the headstock incorporate this feature. I am a fan of the 3520B, but did sell the 3520B and keep the 24/36 when one came my way at a price that needed buying.
Having been a user of machine tools since hector was a pup, an appreciation of the little features and overbuilt designs in the better machines resulted in the 3520B finding a new home. The PM is the best bang for the buck in the 20" and above lathes (IMHO). It is well built, has very user freindly features, but not neccessarily as well built as some of the more expensive machines in that class.
Since wood lathes neccesarily have flat ways to accomodate easy positioning of the banjo, there is always some clearance between the ways and the guide for the tailstock. On a sliding headstock lathe, there is also clearance in the headstock ways and guide. The accumulation of those clearances can result in misalignment in the horizontal plane, even when the machine is true and properly leveled.
When spinning metal, very slight offsets (misalignment) can cause difficulties in centering the blank and cause the blank to walk while spinning. What I have found that helps is to put a slight amount of pressure from the tailstock against the work, and the remove some of the tailstock lockdown pressure. Once the tailstock is barely loose enough to slide. run the lathe at a slow speed and increase handwheel pressure to slide the tailstock about 1/4". When the tailstock slides with the lathe running, the tailstock will attempt to center itself.
Sometimes it is neccessary to repeat this procedure to move/center the headstock.
In the OP's situation of drilling, if you are not using a center drill to start the drilling process, you need to. Also, lightly clamp the tailstock quill when starting the center drill to help hold it stable and prevent the bit orbiting.
As stiff as the bed is on a 24/36, I doubt there would be much bed twist if the lathe was setting on only three feet.
I don't think political tag lines are appropriate on a woodturning forum.
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Interesting. I didn't know any wood lathes had this feature. Of course OneWay is famous for attention to detail...
Retired - when every day is Saturday (unless it's Sunday).
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I don't see anything political about the tag line. it was quite direct as to what he has and the problem.
what has me wondering though as to what a "professional amateur" is?
ron
[OP]
Member
Responding to a few of the posts:
I've sent an email to oneway but no response yet.
The bed, from what I understand, is made from schedule 80 steel pipe. If I can cause it to flex then I'm doing something that is drastically bad and the least of my worries is the headstock and tailstock being slightly out of alignment. Oneway beds simply don't move or flex.
The headstock and tailstock are out horizontally about 0.5mm. When I think about it, as far back as I can remember, they've been out of alignment. It was especially noticeable when drilling with forstner bits, but since I was only turning wood at the time it didn't matter... But when turning aluminium between centres the headstock and tailstock have to be bang on.
I know about the blocks between the ways under the headstock but was hoping that someone else has been through it first and has a process I can work with. It's a fairly precise exercise that I suspect can unravel fairly quickly if not executed properly.
Last edited by Brian Ashton; 06-29-2015 at 7:21 AM.
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All materials move and flex under their own weight...it is just a matter of how much! Worst case is you have spent five muntes or less (including finding your level), you have a smoother running lathe, and have eliminated it from the list when Oneway responds.
Good luck!
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curious as to how and where you are coming up with that measure. the the way to get the measurement is to have a distance of having the points about 12" apart with a faceplate that is fairly true. Using a dial indicator with a magnetic base attached to the faceplate and the point of the dial indicator to go around the centre on the tailstock. makes it easier to read which way that you are off - sideways or up and down or off on a tangent. also believe this is the distance they also refer to when they take those kind of measurement
here is the tricky part; what are the allowable stds for runout on a wood lathe as per industry standards. I doubt that you will find any. if you are in the US then that is an imported piece of equipment, good luck. what do you expect the tolerances to be. remember that you bough a woodworking lathe and not a precision metalworking lathe which will also have working tolerances but tighter than a woodworking lathe. I am not defending anyone here; especially Oneway as I did have a problem with some oneway Items that I bought a few years back and talked to the son, he was quite arrogant and flippant about his answer. wonderful customer relations.
I did go through alignments problems with a General back in the early 80's and a drunk could come closer to touching the end of his nose than those points came together. finally ended up in court. The only standards that you may find for those tolerances are a set of US military standards from way back. I do have them somewhere and I came across them pre computer years.
still curious as to "professional amateur". either you are usually one or the other!!
ron
Member
Sorry for derailing part of the conversation but this conundrum raises an interesting question. I'd expect high tolerances for metal machining but what is the 'acceptable' range of plus/minus for woodworking or is it simply relative to what one will tolerate? Just curious...thanks.
[OP]
Member
Cant say whats acceptable tolerance except to say its proportional to how close the tailstock and headstock are to each other, the diameter of the piece being held and the way it's been held. a piece of aluminium 100mm dia x 150mm long held in a chuck and secured by a live centre in the tailstock will put a great deal of force on the bearings if they're not aligned well. Whereas a piece 12mm dia x 150mm long held in the same way will have much more flex and probably not put any undue stress on the bearings.
If you're turning between centres then there's no issues as the spur centre and live centre would act somewhat like universal joints and alignment would not be an issue. But for all practical sense you wouldn't be trying to turn metal this way.
Wood has similar factors but they're much less an issue as there is so much more give in it.
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[OP]
Member
Maybe I'm coming across as if I'm complaining but I'm not. I simply want to know if anyone has realigned their oneway lathe and what was the process they used. No point is asking if someone has aligned a general, delta, vicmark, stubby, robust or powermatic because the process will be much different than a oneway. I suspect it's probably different between oneway sizes also...
When i have a fairly substantial piece of aluminium anchored in a chuck and I know for certain I've cut, not drilled, an accurate hole (cause it doesn't wobble when the lathe is on) for the live centre to seat into but I can visibly see that the live centre is slightly off to one side (about 0.5mm), I know the two aren't aligned properly.
Professional amateur is just an oxymoron. It's not possible to be an amateur if you're getting paid. Though getting paid doesn't in anyway indicate if you're any good. Whereas being an amateur generally is construed that you're not as good as a professional.
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Hve you tried the 'after contact while spinning, slide the tailstock' thing and see if the center lines up better?
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it really doesn't matter what kind of lather that you have they do seem to share the basic principles; headstock tailstock and there is usually a ways wich sort of connects them. there are a few reasons why there may be a problem. both the headstock and the tailstock seem to be a fairly tall piece of cast iron. the ways(bed)(not the tube) may also be cast iron. somebody please correct if I am of base as I have never owned one and doubt that I will ever own one. cast iron can move( there is a term used with cast iron - green). it could have been made that way, but modern manufacturing process seen to eliminate them; but there is always but!!!
If you can measure it the way that I described at 12" with a dial indicator and jot done the discrepancies in measure of say the 12 measures of the clock. when you talk to Oneway give them those notes as it will tell them in what direction the discrepancy may be. it may help them in solving the problem. they may say that it is all in your head and what do you expect from a wood lathe.
is it a new lathe or a used on and acquired?
Professional is one who can do it proficiently all day and every day and make a living from from it
Amateur( or hobbiest for the use of another word). there are lots of them out there that can do good work, but they have all the time in the world in which to do it. they are not under the daily pressure of having to make na living from it. there are lots that do sell it also.
ron
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