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tails stock alignment

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Forum topic by REO posted 12-10-2013 09:37 PM 1090 views 0 times favorited 37 replies Add to Favorites Watch
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REO

614 posts in 731 days


12-10-2013 09:37 PM

Topic tags/keywords: question

what is all the fuss about tail stock alignment? Often when a question is asked about whether a particular lathe is a good choice or not a poster will make a statement concerning center alignment. I can understand fairly precise alignment being important on several tools and the included problems if they are not.

Table saw blade misalignment with the fence or miter slot pretty common shortfall and predictable troubles.
Although I do not have or use a jointer I have set them up for others and understand what effect maladjustment can have on these machines.
Mills ,Drills and metal working lathes all cases I can understand.

Has anyone actually had trouble caused by misaligned centers or are troubles more imagined than real.


37 replies so far

View 2leggedtermite's profile

2leggedtermite

11 posts in 631 days


#1 posted 12-11-2013 12:12 AM

In a rush to start turning on a “new to me” lathe I didn’t check alignment.
Turned a spindle between centres, then turned a tenon on the tail stock end.
Reversed it, chucked the tenon & it was way out of true. Had to re-turn it.

After aligning it was all good with no more hassle.

HTH
Col

-- A bowl gouge is like a packet of chips.....you can't have just one.

View Jimbo4's profile

Jimbo4

1133 posts in 1420 days


#2 posted 12-11-2013 04:02 AM

i.e., What 2legged says. If the dead and live centers are not aligned point-to-point, and it’s required that the piece be turned around for some reason, it will wobble.

-- BELT SANDER: Used for making rectangular gouges in wood.

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Rick M.

3977 posts in 1037 days


#3 posted 12-11-2013 05:17 AM

Well it’s an easy thing to check and if they don’t line up I’d start looking for a reason why. Besides the reason above, it could cause the live center to wallow out it’s divot and introduce vibration. And if the tailstock is above or below the headstock then your piece won’t be spinning coplanar to the tool rest.

-- |Statistics show that 100% of people bitten by a snake were close to it.|

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REO

614 posts in 731 days


#4 posted 12-11-2013 08:25 AM

Guys you are turning between centers! two points where the straight line between those points is the axial center of the work piece. the distance from that line is the diameter of the work piece at that point. If you cant create a concentric piece its NOT the misalignment of the tail stock. being a little off on the tool rest is adapted to by the operator as cuts are made I have never seen anyone exactly adjust their wood lathe center that precisely it is adjusted to the point that the operator wishes to use it.

I am honestly looking for an answer to why alignment is a problem. it is used as a reason for not getting certain brands of lathes. why? I have been turning for a long time. I have built a few lathes as well. I have had people complain and bring parts of their machines to me to fix because they thought there was a problem with the machine. One fellow brought a hammer to me to grind the face flat and parallel with the axis of the handle. After trying to explain why the crown on the face of the hammer was by design he still insisted. I ground the face of the hammer for him. you can imagine the trouble he had trying to drive common nails! Even on some of the cheapest machines out there I have found most of the time it is an operator problem not the machine. On a typical lathe built for metal the problem you get with with centers being out of line is a taper on your turning whether they are out of line front to back or up and down. The reason. The ways are not parallel with the line between the centers of the lathe. The cutter is fixed to run in a line parallel to the ways. On a wood lathe the ways of the lathe do not control the distance of the cutting tool from the axial center of the work piece the operator does.

What trouble can be attributed to the centers being out of line.

View Nubsnstubs's profile

Nubsnstubs

173 posts in 387 days


#5 posted 12-11-2013 01:20 PM

Reo, alignment is not a problem. It’s misalignment is the problem.

Here is what I’ve experienced. If your tailstock is off a few thousand’s, it not an issue. But, if it’s off by 1/16”, when you turn a tenon, shape your form, and then turn it around to hog out the inside without truing up the outside, you are going to have an offset on the thickness. The wall thickness could be 1/4” on one side, and 180° away, it should be 3/8” thick. That is if my calculations are correct. It’s like doing off axis turnings all the time without wanting to do so.
I had that problem once and all my forms had thick and thin walls which I felt was a problem. When I solved that issue, my turnings got better, and the only times I get inconsistant wall thickness now is when the wood moves….
Correct me if I’m wrong as I don’t like giving out false information…........ Jerry (in Tucson)

-- Jerry (in Tucson)

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REO

614 posts in 731 days


#6 posted 12-11-2013 02:27 PM

This is exactly where I feel there is a flaw in thinking please refer to my previous post. We turn on centers. what you describe could not be from a misalignment of the two centers but a poor center itself! regardless of whether the centers at opposite ends are off or not the turning will be concentric with that center. when the turning is flipped it will still be concentric with the center mark. unless the center itself is not concentric with the spindle on the lathe or the bearing on the tail stock center. If you use a dead center there is no way that it being off center could create an eccentric turning.

View PaulDoug's profile

PaulDoug

558 posts in 361 days


#7 posted 12-11-2013 04:07 PM

I would think it is important in a smaller object such as turning a blank for a pen. You have a brass tube in the blank and are going to have a very thin amount of material over that tube when turned down to fit the hardware. You want everything to line up with the center of that tube.

-- “We all die. The goal isn't to live forever; the goal is to create something that will.” - Chuck Palahniuk

View Rick M.'s profile

Rick M.

3977 posts in 1037 days


#8 posted 12-11-2013 05:39 PM

A small misalignment is probably not an issue. But even though you are turning on centers, they are not gimbals and will want to spin the piece in the same plane. Sometimes I use my tailstock with a chuck and from experience if the live center is not coplanar with the chuck it will definitely cause problems. At a minimum the center will wallow out the tailstock end and introduce vibration or worse it will move off center and the workpiece won’t be round (I had this happen when I got in a hurry and my tailstock didn’t seat flat on the ways).

BTW, if anyone wants to test how well their lathe is setup, turn a spinning top.

-- |Statistics show that 100% of people bitten by a snake were close to it.|

View Wildwood's profile

Wildwood

1040 posts in 792 days


#9 posted 12-11-2013 05:51 PM

REO, guess you have not turned or worked on lathes with swiveling or sliding headstocks. Need to check after moving every time!

One cause given for out of round pen blanks (barrels) is bad head/tailstock alignment.

On my lathe Jet 1642, (sliding headstock) and others like it, beds do flex some before and during operation according to a Jet Technician. A technician told one owner to take his lathe off level to get alignment. It worked for him.

Now if want to discuss alignment with tailstock moved away from the headstock agree somewhat with REO. Not sure how accurately head/tailstock is aligned or how check. Guess could do it using a laser pointer.

Checking head/tailstock alignment on a wood lathe can tip us off to poor castings & poor fabrication, or worn components in those to items and perhaps problems along lathe ways. So whether buying new or used lathe worth few minutes of your time to check head/tailstock alignment among other things.

We are already working a material (wood) that contribute to unbalanced conditions due to density, porosity, moisture content and other factors, so if no other reason check alignment for peace of mind.

-- Bill

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REO

614 posts in 731 days


#10 posted 12-11-2013 07:03 PM

Wildwood your guess would be a Long ways from accurate! Ive been turning for oh…46 years(production turner, started when I was seven years old). I have turned, set up, or worked on most everything out there when it comes to woodworking equipment. I learned from my dad nicknamed Doc because he could figure out troubles that even factory techs couldn’t find. I am not claiming to be the end all and be all for lathes. there is a lot of hypothesis and conjecture about what the condition will cause. As Wildwood alluded to the problem if any would become more apparent with a short large diameter piece. on a metal lathe one of the ways a taper is turned on purpose is to offset the tail stock and chuck between centers. the part is still and always will be concentric just tapered. if you have the ability to check many will find that the tail stock quill is not on the same axis as the headstock. It will line up when in one position of extension but not at others most are pretty good but I have seen some real winners. I have heard the out of round because of misaligned centers excuse before. The mechanical physics of a lathe make this assumption impossible. Technique I believe would be found to be the culprit.

Rick I have been addressing turning between centers backing up a faceplate or chuck mounted piece with an off center tail stock is an entirely different matter but it can be handled.

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Rick M.

3977 posts in 1037 days


#11 posted 12-11-2013 07:46 PM

I understand the geometry, 2 points define a line. A point only has location, no width, height or orientation. A line is 2 points, a plane is the intersection of 2 lines. But lathe centers are not points they are 2 mechanical centers designed to operate in the same plane. In practical terms a small difference may make no difference but at some point the misalignment is going to affect how well the centers perform and how you interact with the material.

-- |Statistics show that 100% of people bitten by a snake were close to it.|

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Wildwood

1040 posts in 792 days


#12 posted 12-11-2013 08:31 PM

From the top & sides these bells appear round, looking at their bottoms guess not so much! Was it a naughty head or tailstock?

-- Bill

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Wildwood

1040 posts in 792 days


#13 posted 12-11-2013 10:03 PM

OOPS, another production turner and his lathe!

Looks like his alignment spot on!

http://www.wimp.com/footpowered/

-- Bill

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Jimbo4

1133 posts in 1420 days


#14 posted 12-12-2013 12:20 AM

REO, I check my centers all the time to make sure the points meet point-to-point. Not just up and over, or side to side, because that’s the way I want them to be! I know for a fact if the dead and live points do not meet, the object WILL wobble when turned 180, which is not acceptable to me, no matter how many years a person has been turning – in my case in the neighbor hood of 57 years, give or take.

-- BELT SANDER: Used for making rectangular gouges in wood.

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REO

614 posts in 731 days


#15 posted 12-12-2013 01:37 AM

ok so tell me why dont just tell me it does

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