What is aligned to you?

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Fish30114

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Oct 18, 2014
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How precise do your 'centers' have to be aligned to make good stuff. I checked my centers with a drive center in my headstock and a live center in my tailstock--the points were probably misaligned by about .01 of an inch--I think this is probably insignificant and that I probably won't be able to detect it in my work--just wondering what you folks think is acceptable for center alignment--or unacceptable.

Any advice/feedback welcomed.
 
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I could not live with that much misalignment. It means that the tailstock end of your workpiece will be 10 to 20 thou smaller than the headstock end of your workpiece (assuming you move the cutting edge of your lathe tool parallel to the lathe axis). When you assemble your pen there will be a 10 thou (approx) step between your turned blank end and the mating pen kit nib hardware. I can't tell you how to fix the misalignment but I am sure someone else can ... might depend on your lathe make and model ... but it needs to be fixed, IMO.
 
The points of my centers touch completely, point to point, but they are not perfect..which will eventually be another thing that I will drive myself nuts trying to solve. However, since ditching the mandrel, and sometimes, even the bushings...I have not had a problem that my fingers can detect.
 
Fish30114 said:
How precise do your 'centers' have to be aligned to make good stuff. I checked my centers with a drive center in my headstock and a live center in my tailstock--the points were probably misaligned by about .01 of an inch--I think this is probably insignificant and that I probably won't be able to detect it in my work--just wondering what you folks think is acceptable for center alignment--or unacceptable.

Any advice/feedback welcomed.
Click to expand...

When you say that it is out by .01, which way horizontal or vertical?
Did you check visually or place a razor blade between the points?
A common trick is to put a razor blade between the points, and check that the blade is square to the bed from above and vertical from the side.
You should be able to adjust the tailstock side ways as there is usually enough play side to side. Vertically is a lot harder depending which is highest, head stock or tailstock. If headstock is too high, you would need to shim the tailstock with shims in between the bed and the underside of the tailstock, unless its adjustable, if a metal lathe, in which case it could go in between. If the headstock is too low, you would need to machine or file very carefully, the tailstock to bring it down.
Kryn
 
magpens said:
I could not live with that much misalignment. It means that the tailstock end of your workpiece will be 10 to 20 thou smaller than the headstock end of your workpiece (assuming you move the cutting edge of your lathe tool parallel to the lathe axis). When you assemble your pen there will be a 10 thou (approx) step between your turned blank end and the mating pen kit nib hardware. I can't tell you how to fix the misalignment but I am sure someone else can ... might depend on your lathe make and model ... but it needs to be fixed, IMO.
Click to expand...

Ditto. IMHO anything more than .001 misalignment is excessive for most pen applications. Same with parallelism over the travel. Get that sorted out and you will eliminate many potential problems downstream like unexpected taper, imprecise threading, drill wandering, etc. The better you are with your setup, the better you will be in your product.

Rich
 
Argghh. I usually try to stay away form this stuff, but........If you are working on a wood lathe, that amount is nothing. Your diameters, parallelism, turnism, finishism (sorry, got carried away) is controlled by............You and the tool you are using. If turning with hand tools how far off the centers are is a moot point. Now, that said, if you are using anything that holds the mandrel 'rigid' at the head stock, like a mandrel saver, you may have some pull on the mandrel, but it will all be the same direction, which, if extreme, can cause issues with the mandrel or center bearings over time, but...... If you turn between centers, you may wear the centers of the bushings a bit. Wood lathes are designed to turn wood between a drive center and the tail center. What we do with pen turning is not beyond its capability, but to expect precision from a wood turning lathe is a bit much. I have never checked the alignment on either of the 2 jet lathes I have, EVER in over 15 years of pen turning, and I turn 90% of mine on a mandrel. As a machinist I am pretty darn annul about things, but this expectation is not one of them. Just my .02. Next on the soap box :)
 
Paul, I'm going to go with your theory. My misalignment is a TINY bit off horizontally and vertically, looking at it from above the tailstock point is VERY slightly below and to the right of the point in the headstock, it literally is so slight, that it would be difficult adjusting it out--if it were a fixture that was adjusted by a screw with say a 40 degree pitch, it would probably take a 1/4 turn to square it up, it may be a lot less than a 100th of an inch, but that was as small and amount as I could think of when making my original post.

Thanks for all the feedback.
 
Vertical alignment you may be able to use shims to eliminate. Horizontal alignment is another story. The tailstock has to slide so there will be a gap between the ways and the tailstock. For horizontal alignment you will find you can twist the tailstock enough so that it wll move to the right or left of the center. If you move the tailstock into position without locking it down then turn the lathe on. It will center itself and then lock it into position.
 
What lathe are you talking about? Most machines are not that rigid and can be tweaked by twisting them into alignment. Either with adjusting bolts on the floor, or shims between the lathe and the bench or legs.
 
These are wood lathes, first they are not designed or made to be as accurate as metal lathes. The lower the price you can expect a lower quality, the more problems you might have. Either you have to learn to live with it, or spend the money to buy the better quality lathes. There is a reason that metal lathes cost more, and the same goes for the quality, you get what you pay for.
 
My lathe is a Nova DVR XP, I actually like it pretty well, but see my other post 'Teknatool Home of thieves?' to see my true opinion of NOVA/Teknatool. I don't have any issues with the product my lathe (and I) are producing-in fact I have measured some of my pens with a micrometer to check their concentricity and it was excellent. I have not even tried to align these points--that was why I posted this issue, to garner feedback, and decide if I should delve into aligning my lathe further--at this point I don't think I'm gonna fool with it, I do appreciate all the feedback-and any more that you find folks care to share!
 
If you are happy with the results, then I would not worry about it. Sometimes when you try to analyze (and fix) a perceived "problem" it only makes matters worse ... remember the adage "If it ain't broke, don't fix it"

Fish30114 said:
My lathe is a Nova DVR XP, I actually like it pretty well, but see my other post 'Teknatool Home of thieves?' to see my true opinion of NOVA/Teknatool. I don't have any issues with the product my lathe (and I) are producing-in fact I have measured some of my pens with a micrometer to check their concentricity and it was excellent. I have not even tried to align these points--that was why I posted this issue, to garner feedback, and decide if I should delve into aligning my lathe further--at this point I don't think I'm gonna fool with it, I do appreciate all the feedback-and any more that you find folks care to share!
Click to expand...
 
I have a lathe with a movable bed, and use a Nova double MT2 to assure the tapers are aligned. Worth the $20

Nova made them to help assure alignment after rotating the head stock.
 
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