# Adjustment Needed?



## mecompco (Jun 13, 2015)

Did my first turning of steel today on the 12x36. My project was to turn round stock to a diameter--should be pretty simple. Used the 4 jaw chuck and live center. Everything seems to work OK, but I noticed that the closer to the chuck the I got, the smaller the diameter got. Over 5 thousandths over 5 inches. 

Why would this happen, and what can I do about it? Thanks!

Regards,
Michael


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## Franko (Jun 13, 2015)

The problem is with your tailstock alignment.
This is from the PM 1127 manual.


If the stock is thinner at the chuck end, the tailstock needs to be adjusted toward you the amount of taper.




If the stock is thinner at the tailstock end, the tailstock needs to be adjusted away from you to the amount of taper.


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## mecompco (Jun 13, 2015)

Franko said:


> The problem is with your tailstock alignment.
> This is from the PM 1127 manual.
> 
> 
> ...



Hmmm--I think I've got my tail stock alignment pretty g00d (at least as good as I can get it by eye-balling the two centers. I didn't mention it in the original post, but I also tried it again w/o the center. It is half-inch stock, so I didn't think there'd be much flex trying it that way. Got the same results. Perhaps more experimentation is in order. 

I never noticed this turning wood as I've been doing, but then I don't suppose a few thousandths makes much difference when turning wood.

Thanks for the suggestion.

Regards,
Michael


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## RJSakowski (Jun 13, 2015)

Tool pressure causes the part to flex.  More flexing as you go out so the diameter grows.  This is common and more pronounced on smaller diameters.  There is much written about this problem


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## mikey (Jun 13, 2015)

How long a piece are you turning? Did you turn it supported by the tailstock? How far is it sticking out? Are you using HSS or carbide? How is your lathe mounted and how is it leveled - shims or leveling bolts?

My first impression is that your lathe is out of level and is cutting a taper but we cannot tell unless we know what your setup was. I would suggest chucking a piece of 1" or better round stock (mild stuff - mild steel, aluminum, brass) in the chuck with a stickout of at least 6-8". Use a sharp cutter and take a light roughing cuts of about 0.010" from the unsupported tail end of the piece and cut close to the chuck.  Use power feed if you have it and continue these cuts until you can cut all the way from end to end. Then take a very light finishing cut, maybe 0.001-0.002" depth of cut. If you get a taper with this then your lathe is out of level.

If the piece is larger at the tailstock end then the front mounting at the tailstock or the rear mounting of the headstock should be higher. If the piece is smaller at the tailstock end then the rear of the tailstock or the front of the headstock needs to be raised.


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## mecompco (Jun 13, 2015)

Mikey, this was .5" stock, about 5" long (~1" in the chuck). I tried it first using the tailstock, then again unsupported. The lathe is on a rolling cart--I have no idea how level it is (I got it set up this way). Up until this point, I've only used it for wood an it's been fine. 

I do have power-feed, and was using it. Not sure how to adjust the height of the tailstock--there does not seem to be any adjustment that I can see.

Thank you for your advice--I will try it on some larger stock and see what the results are.

Regards,
Michael


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## T Bredehoft (Jun 13, 2015)

The illustrations are looking DOWN on the lathe, there is no vertical adjustment needed or possible.


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## mikey (Jun 13, 2015)

Mike, having your lathe on a rolling cart means it is very likely out of level and you cannot expect the lathe to turn accurately that way. Sorry but some things are just that way. Actually, turning a small taper like you have is good for the setup you're using.

If you want the lathe to turn accurately you must mount it on a solid bench or cabinet. You must then have some way to adjust the ends of the lathe to bring the ends of the lathe into alignment. I'm sure you've heard of leveling a lathe; this is what they're talking about. If the bed of the lathe is twisted then it will turn a taper, as you now know well. Typically, a lathe is leveled at four points, although three points is ideal. There are usually two height adjustment bolts at the headstock end and two at the tailstock end. These bolts are then adjusted to bring the two ends of the lathe into alignment so they are in the same relative plane. Some lathes don't have adjustment bolts so shims must be used but the end result is the same; both ends must be aligned so all taper-producing twist is removed. 

My comments above were referencing these height adjustment bolts and given your cart set up, they are totally not applicable. Sorry about that. I knew a guy who owned a Craftsman 12 X 36 and he did some amazing work with that lathe. He has passed now but he showed me that the lathe is capable of fine work if you set it up to do so. 

My best advice is to build a cabinet. You can ask for advice on this forum and get all the help you need to design it and even make it mobile if that is a priority. If you build it, provide some means to accurately level the lathe and your taper adventures will go away.


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## mecompco (Jun 14, 2015)

Mikey, thanks for the detailed reply! Below is a pic of my setup. Yes, I've read about lathe leveling, but that's about it--for what I've been doing, it hasn't been a problem (wood turning). The cart is pretty stable--1.5" ply for a top with lag bolts down through the 2x6s into the cart. I do see the three bolts that secure the lathe to the top--I assume these would be used for leveling?

Do the floor/cart/lathe all have to be level, or just the lathe? Any quick suggestions on an easy fix (I will read up more on how to level). I'd really like to keep the setup as it is, if possible. Thanks again.

Regards,
Michael


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## John Hasler (Jun 14, 2015)

[QUOTE="mecompco said:


> Mikey, this was .5" stock, about 5" long (~1" in the chuck). I tried it first using the tailstock, then again unsupported. The lathe is on a rolling cart--I have no idea how level it is (I got it set up this way). Up until this point, I've only used it for wood an it's been fine.
> 
> I do have power-feed, and was using it. Not sure how to adjust the height of the tailstock--there does not seem to be any adjustment that I can see.
> 
> Thank you for your advice--I will try it on some large





mecompco said:


> Mikey, thanks for the detailed reply! Below is a pic of my setup. Yes, I've read about lathe leveling, but that's about it--for what I've been doing, it hasn't been a problem (wood turning). The cart is pretty stable--1.5" ply for a top with lag bolts down through the 2x6s into the cart. I do see the three bolts that secure the lathe to the top--I assume these would be used for leveling?
> 
> Do the floor/cart/lathe all have to be level, or just the lathe? Any quick suggestions on an easy fix (I will read up more on how to level). I'd really like to keep the setup as it is, if possible. Thanks again.
> 
> ...


None of it needs to be level.  The lathe bed needs to be flat.  Leveling is a means to that end.


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## mikey (Jun 14, 2015)

Your cart looks pretty sturdy and if you're looking for a quick fix then make or buy some leveling feet, not so much to level the cart but to get the whole thing solid on the floor. You can attach the feet (you know, the screws with pads on the ends) to the sides of the cart and hopefully that will be solid enough and still enable you to move it at need. What you need is a solid base upon which the lathe can be leveled. Again, by that I mean both ends of the lathe being in alignment so there is no twist in the bed and if you have that then you're good. The cart itself does not have to be level, although you will find that if you move the lathe around the cart itself will twist and so will the wooden base and this can introduce twist in the lathe bed. That's why a cabinet that doesn't move around is better and a metal base is even better as it doesn't move with changes in humidity.

The bolts you mentioned are intended to lock the lathe down to the surface it is sitting on. In order to level the lathe you will need to use shims near these bolts. Many guys use horseshoe shaped shims and the bolt passes through the center. I hate the tedium of working with shims so I would personally get some 1/2" plate; drill and tap for 2 heavy bolts in each plate and inset the plates into the top, one under each end 0f the lathe, so the bolts can be used to dial out the twist in the bed. You can then use the lockdown holes to bolt the thing down.

If you're going to do mainly wood turning then this may not be necessary but if you want an accurate metal turning lathe then you are going to have to level it. 

As an aside, I know a 98 year old plantation machinist. He turns huge bowls on two big engine lathes. He lag bolts the bowl blanks onto his faceplate and winches the thing into position. He makes the most beautiful bowls, larger than most turners can make. This guy throws a fish net for dinner 3-4 times per week and plays the Sax every night. Still sharp as a tack but getting a bit deaf! They don't make 'em like they used to.


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## mecompco (Jun 14, 2015)

Mikey, thanks again--that gives me some ideas to work on. I just watched a vid of a guy leveling his lathe by adjusting the leveling foot on his bench (he showed testing the level with a plumb-bob, it was amazing how little twist amounted to 5 thousadths difference from one end of the bed to the other).

I hear you about giving up the rolling aspect of the cart--I assume every time it is moved, it would have to be re-leveled (and it does tend to get moved).

I mostly turn wood (a wood lathe is on my wish list), but as in this case, I do see a need to accurately turn metal from time to time. Here is what I was working on--my goal was to make two sets of parts out of five inch pieces of .5" stock. Of course, I was measuring at the tail stock end and only too late discovered my taper problem. Ended up re-doing a couple of them. The bigger ones are .420 stepping down to .245 and the smaller ones are .333 down to .245 (well, that's what they "should" be, but these are within a couple thousandths and close enough for their intended purpose which is as bushings to turn pen barrels between centers).


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## mikey (Jun 14, 2015)

You're welcome!

Your bushings look good and if they fit then that's what matters. I think it is very cool that you are able to do it in the first place - most wood workers cannot.

I saw that pendulum video - pretty cool. If you try it, let us know how it goes.

Hang in there, Mike. You'll work this out. Maybe when you get your wood lathe you can find a spot for your 12" lathe to sit and really get it sorted. In the meantime, please ask questions. There are some great guys here and we all enjoy sharing.


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## mecompco (Jun 15, 2015)

mikey said:


> You're welcome!
> 
> Your bushings look good and if they fit then that's what matters. I think it is very cool that you are able to do it in the first place - most wood workers cannot.
> 
> ...



Mikey, thank you. Though I wouldn't call myself a wood turner yet as all my pens and other wooden odds and ends have been turned on said 12x36 using the same cutter I did the bushings with--honestly I've never held a skew or gouge.

The metal lathe makes turning more-or-less straight walled wood projects easy, and I use the power feed. It does, though, make tapers like the ends of pens or "creative" shapes rather difficult. I end up using files and sandpaper to get the tapers I need.

I think having both the metal lathe and a wood lathe will be the ultimate answer and I will at some point get both solidly mounted. Thanks again for your help. Here's a pic of one of my pens (Bocote with a CA/BLO finish):





PS: I use the lathe to drill the blanks, true up the ends (with a disc sander I made for the head stock) and to assemble them using wooden (more-or-less) Morse tapered inserts I made for the head and tail stock for a press.


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## mikey (Jun 15, 2015)

That's a really nice pen, Mike! You might think that something like that is simple to make but most people cannot do it. I would be proud of that if I were you!

You may not be aware that you can turn metal just like you can turn wood. The tools are called Gravers and allow you to turn and carve metal just like wood, including hardened materials. It does require a hardened tool rest but the gravers themselves are simple to make and use. Sherline has a pdf about gravers as made by WR Smith if you are interested. Mr. Smith also produces some videos on the subject, too. If you do make some gravers you will find yourself using them on almost all your lathe metal projects; they can add a subtle touch to your work that shows your craftsmanship. Check it out.


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## brino (Jun 15, 2015)

First, great work on the pen! That's very nice.   

Second; this statement caught my eye.....


mecompco said:


> I think I've got my tail stock alignment pretty g00d (at least as good as I can get it by eye-balling the two centers.



Besides leveling the lathe (or really avoiding the bed twist) above, tailstock alignment is also important. Cutting tapers is exactly why the tailstock is adjustable. The eyeball technique was likely good enough for wood turning. However if you are now measuring to thousandths of an inch it may no longer apply.

Turning a part, measuring the taper, correcting the tailstock, and repeat is one (slow) method of adjusting the tailstock. Tubal Cain does it here:





You might consider acquiring some more precise measuring tools. Like everything else there are options, you can trade off cost, precision and easy of measurement. Faster tailstock alignment could be done with:

1) a dial indicator
Commonly just called an indicator or a "clock" these have a round face and a stem. The stem has a central plunger that moves in/out. A spring pushes it out, and any inward movement is shown by the hands on the round face or on a digital display. Different indicators are marked in thou. or half-thou. and the total movement of the plunger might be only 1/2 or 1 inch. Often there are two hands, the long one measures thou. and the short one measures the number of full turns of the big hand. There are many different mounting arms, magnetic bases, etc. available. They can be mounted either by a little boss on the back, or clamped around the little stem. 

These are among the most used measuring tools on a metal working machine. You can measure lathe spindle run-out, mount one to a carriage stop as a travel indicator(http://www.hobby-machinist.com/threads/double-duty-micrometer-stop-project.34769/). For centering your tailstock to your headstock you would mount the indicator to something in your headstock(preferably in an accurate collet), measure against the shoulder on the tailstock center and manually rotate the spindle at least 180 degrees from front centre to back center. Note the face of the indicator will be moving too, so some rubber-necking or a mirror can help. Adjust the tailstock location (front/back) until you get the same indicator reading on the front and back.

My local used tool place has some new-old-stock (made in china) enco dial indicators at less than $20 apiece.
Here are some examples:
http://www.leevalley.com/en/wood/page.aspx?p=32525&cat=1,43513,51657,32525
http://www.leevalley.com/en/wood/page.aspx?p=51598&cat=1,43513,51657,51598
http://www.leevalley.com/en/wood/page.aspx?p=71664&cat=1,43513,51657

2) a dial test indicator
Resembling a dial indicator with a small lever at the end so that rather than measuring linear movement along the stem it measure deflection  
These often have a little dovetail on the back and are held with a matching dovetail holder with a round pin for a mounting arm. These have very limited deflection, but can measure in either direction. These are often used to mount a vise to a mill table by putting the indicator in the vertical spindle and running the indicator along the fixed jaw by moving the table back and forth. The vice gets bolted down when the reading it the same from one end of the jaw to the other.

http://www.littlemachineshop.com/products/product_view.php?ProductID=1249

3) co-axial indicator
Some see this as the best option for aligning two cylindrical parts......but they can be expensive, and therefore many people just use the above instead. These are very handy for aligning a vertical mill spindle with an existing hole or boss on the work piece. One advantage of them is that they have a little arm that stops the gauge face from spinning. No more rubber-necking or mirrors.





Whatever you hold the indicator with could add to error, if it is attached to a bar held in a 4-jaw chuck where the jaws are not centred to the lathe spindle, you could end-up either setting the tailstock wrong, or never being able to zero it!

-brino


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## John Hasler (Jun 15, 2015)

mecompco said:


> Hmmm--I think I've got my tail stock alignment pretty g00d (at least as good as I can get it by eye-balling the two centers.
> 
> Regards,
> Michael



Pinch your 6" steel machinist's scale horizontally between the centers and adjust the tailstock until it is perpendicular to the ways.


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## MikeMc (Jun 15, 2015)

"Lathe centering buttons are very easy to make on the lathe."
Not my idea, rather a quote someone else posted.
I hadn't intended to repost this so didn't save an attribution, sorry.
I googled it not knowing what it was and plan to make myself a set as it's simple to use and appears it would be very accurate.

Mike


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## mikey (Jun 15, 2015)

It appears that the taper is present, with and without using the tailstock.


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