I bought a 40 year old Shop Smith two weeks ago and have been experimenting with the lathe - something I've always wanted. I figure that I must be doing something wrong and I would appreciate a little advice.
My wood "bounces" as I shave it. Of course it's worse in the middle of the piece and especially on the longer pieces.
I also can't seem to get it centered on the lathe. I have been finding the center by drawing a line across the corners of the piece. X marks the spot so to speak. Even though the point for each lathe end is in the middle of the X, there is still a small but noticeable wobble in my piece.
"10sc" wrote: My wood "bounces" as I shave it.(clip) Even though the point for each lathe end is in the middle of the X, there is still a small but noticeable wobble in my piece. ^^^^^^^^^^^^^ If the piece is long and slender, you are going to have trouble on the middle unsupported part. This can be made worse if the piece is not straight. The solution would be to use a "steady rest," but, since you are just starting out, I suggest, instead, that you work on shorter pieces. (i.e., instead of table legs, make candle holders.)
As far as centering the ends is concerned, the procedure you describe is correct. If you center the spur drive and tail stock center, the wood should run true. If you are not getting it perfectly centered, of course, there will be a little wobble at first. But it should true up as you remove wood. If this is not happening, check to see whether something on the lathe is bent.
Leo's advice is good (as usual). Something I do differently, though...
If you do flat work, you probably have a marking gage. If so, and if you are starting out with square blanks (or near square) set the marking gage to slightly over half the width of the blanks. Then make 4 marks, one from each side, on an end. That will give you a small square in the middle and from there it is easy to eyeball a mark (with an awl) in the center of the small square. I find that finding the real corners of the blank (the 'x' method) can be difficult and just a little error causes problems. My way is far more accurate -- in my hands at least.
It sounds like you are turning spindles, like spokes, handles, etc. A rule of thumb is 10 to 1 ratio. A spindle that is 10 inches long needs to be 1 inch in diameter, or it will start to vibrate, or wobble, because that is how much mass it needs to be steady. There are some tricks to turning thinner than that ratio, such as a steady rest. Play around for a while, get some books, find a local club, have fun. robo hippy
Bill Rubenste> Leo's advice is good (as usual). Something I do differently,
first is for a guy called Darrell Feltmate and has a heap of info,the second one is an aussie forum but well worth joining and evensearchable.
The best advice I can give you though is that you should join a club in your area - apart what you will learn it's great to see what others are up to. Cheers Paul
Unless otherwise stated all references to location refer to Western Australia
I do a variation of Bill's method using a 90/45 deg. Stanley square -- quickly cycling through the corners and drawing a line.. A little square usually develops as he noted.
The last few spindles I did were 1" and 3/4 " max. diameter and 15" in length to 16" in length -- so probably a little "thin". They definitely developed some middle area wobble.
You might also try taking care to remove wood in a symmetric fashion on these small spindles. I did not take the time to make accurate estimates of wobble after deciding to do this (no wood to waste) but I believe that it helps despite the lack of measurements to back up my guesswork.
So even during the roughing phase now, my first step is to get a symmetric, round blank as quickly as possible -- then I actually feel for vibration along the blank. If I have any -- it is not as symmetric as I would like...
As the piece becomes "smoother" I increase the speed of rotation as well.
The while roughing out the form -- again I try to move from side to side and keep it symmetric.
The in the finishing phase -- the same exercise. It _seems_ to help.
Use a "smoothing stick". This is just a rectangular piece of wood of wood - the same length approx. as the decorative portion of the spindle. You apply crayon - apply it against the entire decorative portion and check for high spots by applying it to the "round" blank.
Note that I keep the mating surfaces (or "waste areas" on candle sticks) at the end a little lower always than the decorative portion. They are going to be smaller anyway, and then my smoothing stick does not whack on the ends and get flung at me.
Before turning every piece I plane the bottom edge of the stick to restore the smooth surface, then add the crayon.
This method is mentioned in some of the turning books -- but most don't go into enough detail on how to get the most utility from the tool. IMO
As for the remaining 63 crayons in the box? My SWOB says I can use them to compose my philosophical postings and to draft business letters and business proposals. So nothing is wasted. Now I just need a crayon sharpener so they make a good impression...
There are other issues on spindles. This is _Very Important_ . (... and any old timer who giggles will be hunted down and whacked with a wet, slimy noodle.)
If the spindle is going to be mated to anything (stuck into another spindle, table leg etc...) _Check your available drill sizes._ I assumed
-- only once -- that I could adjust to whatever size I spun on the lathe. Oooopss! A micrometer is your friend when you do the "end pieces" where you will mate it with something. Use a micrometer, take your time and get _exactly_ the desired result. Say 1/2 or 3/4 inches -- with the tiniest of tapers so it mates in your drill hole.
Pay _real close attention_ to determining the total length of the center area versus the length of the mating areas at the end. Have you allowed for some variance in _all_ the pieces? The safest thing is that the centre decorative portion be a "little" shorter than actually required, and that the mating cylinders at the end be a little longer. Then you can adjust things at the dry-fit stage.
Note that in Item 2 if you make a 1/8 error on each spindle _end_ - that is a 1/4 inch error per spindle, and a 1 inch error on a 4 spindle design that "circles" the bottom of the chair.
These last points may of course be far less important on lamps and candle stick holders -- unless you have mating pieces.
The above points are more about design, but even when following a plan you can give yourself some wiggle room by a bit of advance planning.
Hope that helps as well.
You can see my setup on my web site -- see sig at end.
Most spindles are slightly off center and will wobble at first. Turning the spindle will correct that quicker and easier than perfectly centering to begin. Unless, of course, there is absolutely no wood to waste.
If the problem is vibration and wobble in the middle of a thin spindle, holding the blank in a chuck very firmly instead of by a spur center helps a lot. I don't know why. Our engineers will have to explain. Also be sure not to bow the spindle's middle with excessive tail center pressure.
Welcome to rcw. Hope we helped to keep you and your Shop Smith in harmony.
Thanks to you and Derek who mentioned the tailstock pressure - it's easy to forget. Not that I need to correct mine. :-)
As Derek mentioned(implied?) I think it is the "bow" getting amplified I am sure...
I will test if turning faster or slower increases the wobble.
My guess - before testing is that faster speeds give smoother cuts -- and increase any sympathetic vibrations (amplify the bow - and the bow is essentially an imbalance I guess). Resonance I guess...
Maybe this is a use for the High Speed Flash on the camera.. Hmmm :-)
Has anyone done a technical analysis which can be read -- to save time?
One other item I didn't see mentioned. Once the stick is round, start cutting away the wood from the tailstock end. That leaves more wood, and stronger piece, between your chisel and the driving force of the headstock.
You can also try taking smaller bites with the chisel. Sometimes helps.
"Arch" wrote: (clip) holding the blank in a chuck very firmly instead of by a spur center helps a lot. I don't know why. Our engineers will have to explain.(clip) ^^^^^^^^^^^^ Thanks for the invitation, Arch. You are correct--a chuck stiffens the piece of wood by holding one end on axis. A spur drive acts like a universal joint. However, from the OP's remarks, I doubt that he has a chuck at this beginning point in his career.
And very does not have a steady rest either. After the piece has been made round and smooth, it is possible to damp vibrations by draping the fingers of one hand over the work. CAREFULLY, making sure that the direction of rotation UNWINDS the fingers, and not the other way. And don't wear a glove--that's dangerous.
I agree with those who commented that there may be too much axial pressure on the workpiece. Also, there is an adjustment on the SS tailstock intended for off-center turning, and it may be that your headstock and tailstock centers aren't aligned. Remove the workpiece, slide the power unit all the way to the right, and extend the quill so that the two centers are almost touching. Loosen the set screw on the tailstock adjustment dial and rotate the dial until the points are perfectly aligned.
If you don't have a SS user's manual, get one, as well as a book they sell called Power Tool Woodworking for Everyone, they're both invaluable references.
I got this one. I did read the book (which amazed my wife) before I started using it. Actually, since the SS is so old, I went through the book for maintenance procedures and what had to be done before using any particular tool. So I did see how to align the lathe.
To be honest though. . . If the SS didn't look like it needed a little maint, I likely would not have opened the book so early in my woodturning career. After all - I know what I'm doing :o
"10sc" wrote: (clip) SWMBO has "requested" I make a gate (clip) ^^^^^^^^^^^^^^ Sounds like a worthy project. One of the challenges you have is making all the spindles the same. First, you should know that they don't heally HAVE to be perfectly alike, as long as they look the same after they are mounted. After all, YOU are the only one who will be able to hold them against each other for comparison.
Another idea occurs to me: If you have two patterns, and alternate them in the finished gate, it will be REALLY hard for anyone to notice small variations.
SNIP .......... ========================= Arch, I think the chuck drive is better than the spur drive due to the tendency of the spur to continually try to push itself out of the workpiece while the chuck holds it in a more rigid location. No scientific evidence, but it seems logical to me ...... which often doesn't mean to much! {:-))
"Ken Moon" wrote: (clip) the tendency of the spur to continually try to push itself out of the workpiece while the chuck holds it in a more rigid location.(clip) ^^^^^^^^^^^^^ Ken, since the drive faces of a spur drive are not angled, I don't think they develop any thrust of their own. But, your idea suggests another factor I had not previously thought of: for a drive center to work it has to have considerable force against the wood to remain seated. This force, coming from the tailstock, tends to bow the piece--this is why several people have suggested minimizing the tailstock pressure. Holding the work in a chuck, the tailstock can be touched into the dimple with virtually NO pressure.
Thanks Leo and Ken, Good explanation. I I wonder if the chuck compresses the wood fibers into a sort of monolithic spindle? Something like the cables that support bridges? Could this play any role in preventing a thin spindle from swaying in a vertical plane? Smiles are ok, but no loud laughing please.
I have been turning things on my ShopSmith for nearly 20 years (mostly bowls). The reason I am posting here is that I was so gratified to see all you people pitch in with ideas to help solve the problem without one person suggest that he quit trying and get a "real" lathe instead. Obviously I have been pretty satisfied with my unit and upgraded to the Universal Tool Rest that Shopsmith came out with a few years back. It has a nice design, weighs about 35 pounds which the SS can use. I also have upgraded to all High Speed Steel gouges and scrapers, bought a OneWay Stronghold chuck and a set of Jumbo Jaws. The new tool rest also allows me to use some of the heavier bowl tool rests from Grizzley and other suppliers. Everything really works nice for me.
I don't mean to scorn but I do believe that a shopsmith in lathe mode is at best a compromise. I once used a shopsmith and before that an AMT Heavy Duty (all AMTs were advertised as 'heavy duty', 'G') and before that a Sears Dunlap. I don't use them anymore, but I still enjoy keeping them in good condition. Senility?
Then again much work that's light years better than mine, has been turned on that compromise. Same with Sear's tube beds. The work of Melvin Lindquist (SS), Darrell Feltmate and Ruth Niles (Sears tube beds) comes to mind. It's the turner that counts the most. Enjoy your Shopsmiths with no apology. You are in some very good company.
I actually have 2 1/2 done. The half is my pattern - I just flip it over for the other end (no distinguishable top or bottom that way). I made the first two from this pattern and they have to be fairly close together to see the differences. However, two patterns is a great idea! It'll also be a great way to break up the monotony of the same pattern over and over.
From all the comments, it looks like a chuck is the way to go. But yowza! I looked up the OneWay Stronghold you mentioned here. I realize that you get what you pay for. However, if I pay for that I'll get it (if you catch my drift). Any suggestions for a less expensive chuck or should I stay with the spur drive for the time being?
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