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Thread: Skew questions

  1. #1
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    Skew questions

    I am a new turner and just purchased two skew chisels and started practicing on some pine 2x4s. I cut the wood into 1 1/2 x 1 1/2 x 13 inch strips to practice. I've tried it between centers using a spur drive or in a chuck (squared). I can get a really nice surface at first, but once the spindle gets down to 1/2 inches or less, I get tons of vibration and a lot of tear out (even trying the finger steady method mentioned on this forum).

    Is there something I'm doing wrong? Is it the wood? I made a few wands for my kids but they required a lot of sanding.
    Any advice/comments/critiques welcome.

    tom
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  2. #2
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    The pine will be more difficult IMHO.
    If you have applied a lot of tailstock pressure it could flex/bend the wood as you get to a smaller diameter. You may try backing off the pressure a little.
    I think most folks hone their skews (razor sharp) mainly for planing cuts. As it gets thinner you want to apply as much pressure as possible towards the head/tail stock rather than into the wood perpendicular due to the flex of the wood. A really sharp tool takes less pressure to cut.
    "I became insane, with long intervals of horrible sanity." - Edgar Allan Poe

  3. #3
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    Pine is a difficult wood, so try some cherry or walnut. It'll be stiffer and won't flex so early. And also keep tailstock pressure to a minimum. Those do have a nice shape, and you're going to be fine. I made about 18 magic wands and conquered my fears of the skew. You're off to a great start.
    Maker of Fine Kindling, and small metal chips on the floor.
    Embellishments to the Stars - or wannabees.

  4. #4
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    What the other folks have said. There is not any wood that will not vibrate when you get down to 1/2" and 13" long.

  5. #5
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    It has to do with the diameter of the wood, the length of the turning, the type of wood, the pressure applied by the tailstock and the pressure you apply to the wood with the skew as you are cutting it that causes the wood to deflect to cause the vibration. Really proficient, production turners are able to support the turning with fingers on one hand while they manage the skew with the other hand. Other wise, one has to use a support mechanism.
    Last edited by Ken Fitzgerald; 03-21-2018 at 10:48 PM.
    Ken

    So much to learn, so little time.....

  6. #6
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    As was said use some nice straight grained hardwood, clamp one side into a chuck, and drill a dimple in the other side, that way you do not need any pressure to keep the piece rotating, just enough to have the live center touch the wood.

    And yes sharp skew and the only pressure in the direction of the head or tailstock, the other thing you can do is to build a steady rest, that way you can steady the wood and make your piece like half the length.

    Here are two steady rest you can build, first one uses a magnetic base and two scare wheels, the other one uses 2 pieces of UHMW plastic with half a hole in each one, two clamps hold the plastic in place.

    Magnetic base steady rest.jpg UHMW steady.jpg
    Have fun and take care

  7. #7
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    wands and thin spindles and wands

    Quote Originally Posted by Thomas Wilson80 View Post
    I am a new turner and just purchased two skew chisels and started practicing on some pine 2x4s. I cut the wood into 1 1/2 x 1 1/2 x 13 inch strips to practice. I've tried it between centers using a spur drive or in a chuck (squared). I can get a really nice surface at first, but once the spindle gets down to 1/2 inches or less, I get tons of vibration and a lot of tear out (even trying the finger steady method mentioned on this forum).

    Is there something I'm doing wrong? Is it the wood? I made a few wands for my kids but they required a lot of sanding.
    Any advice/comments/critiques welcome.

    tom
    Tom,

    One of my favorite topics! I've turned hundreds of wands now and other even thinner spindles - I included a picture below of a much longer spindle turned down to 1/16" on the small end. I don't have any problem with pine or any other wood I used as long as it has reasonably straight grain and no big defects in the thin section.

    There are some good ways to control the chatter, the best is using the left hand as a steady. I use several hand positions I used depending on the situation and the direction of the cut, sometimes crossing my left hand over to the right of the skew. I hold the skew in one hand close to the tool rest and jam the end of the handle against the underside of my forearm for support. (I don't use long tool handles for most turning.)

    Another very important thing is to hold the blank firmly at the headstock end, not between centers. This stiffens up at least the first third of the blank. I've used a chuck but I find it better to first mount it between centers and turn a short morse taper on the end and cram that into the headstock spindle - it holds the piece fine, gives more clearance, no spinning chuck to watch out for, and a partially completed wand can be taken out of the lathe and put back later with exact registration - something not easy or perhaps not even possible with a chuck!

    Sometimes there is a sweet spot in the tailstock pressure and increasing or releasing some pressure can change the amount of chatter. BTW, I like to use a 1/2" steb center in the tailstock.

    Another thing might be your skew grind. I assume it's razor sharp, honed/stropped. I generally use a 1/2" or 3/4" skew with about 35-40-deg included angle on the bevels. A small angle can slice wood easier but can sometimes tear out more with certain woods. Play with the angle of the edge to the work; 45-deg is usually recommended but sometimes varying it a bit can help. Make sure the tool is pressed firmly down onto the tool rest, but that's usually not as much as a problem for thin spindles.

    Make sure your tool rest is not too high. I've seen people put the skew nearly horizontal with the bevel nearly on the top of the spindle. This is a horrible position.

    High speed helps. Light cuts help. Slow traverse helps.

    1-1/2" blanks seem like too much work to me! I start with blanks about 1" or 1-1/8" or so square by 13-1/2 to 14" long, some shorter, some much longer. I have made wands from wood as small as 3/4" square. I trim away a bit of the wood on the bandsaw before turning to save a bit of time. I turn at full speed on my lathe, over 3000 rpm. The skew is the best tool for the shaft and I use spindle gouges for coves and detail. I have had chipout on some specific osage orange blanks with the skew and had to use a different tool for a clean cut. Sanding can often start with 400 grit, perhaps coarser if I leave too many tool marks.

    Some trimmed blanks.

    wand_blanks_P2273870es.jpg

    I've turned spindles nearly 30" long with the same technique. These taper from about 1/2" down to about 1/16" - one from walnut and one from pine - a piece of shelving pine from Home Depot. (I don't have a steady rest and I've never tried using one.)

    pointers_IMG_20140311_11390.jpg

    I wrote a document for a handout when I do thin spindle demos at clubs. The document uses a wand as the example. It needs some updating but it should cover most of what I found works. If you want a PDF send me a PM with your email address. I've gotten success stories from people who previously had big problems and even a string of failures.

    For inspiration, these two students turned wands in their early lessons, one as her first real project after an introductory day two years previous and the other for her second project. Neither had access to a lathe outside my shop so they had no practice time between sessions. I start out all new students with the skew as the first tool in their hands.

    Naomi_wand.jpg Kristina_wand_comp_IMG_7396.jpg

    Some of my own recent wands, eastern red cedar and ebony:

    cedar_and_ebony2_IMG_7528.jpg

    These were a huge hit when the Harry Potter books were released - I set up on the sidewalk in front of a bookstore and turned wands on a mini lathe I bought just for that. Wands and variations are the only thing I make to sell - I made an obscene amount of money during the book sales.

    wandmaking_comp1.jpg wands_bowl_P7203947cs.jpg

    Conductor's batons are also good for thin spindle practice:

    batons2a_IMG_4996.jpg

    BTW, my hat's off to you for tackling these. A number of versatile woodturning experts say that turning spindles will teach you the fine tool control that will let you turn anything, even bowls and platters!

    JKJ

  8. #8
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    Also, too bad you live so far away. If you find yourself in this area stop in and we'll have a wand-making day!

  9. #9
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    Tanks for all the replies. My skews are sharp (honed) and my included angle is about 40 degrees. I tried backing off the tailstock pressure but will try drilling a small hole and setting the headstock end to a Morse taper, as suggested. Overall these were much easier than bowls but definitely different.
    thanks, tom

  10. #10
    There is about a 10 to 1 ratio for spindle turning, so 10 inches long and 1 inch diameter will be pretty solid. 20 to 1 will want to whip. It takes surprising little push to get the spindle to flex when it gets thinner. Some of it is feed rate and some of it is bevel rub. "The bevel should rub the wood, but the wood shouldn't know it."

    robo hippy

  11. #11
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    Using a chuck to hold square stock will eliminate the need for higher tailstock pressure on live center and reduce the whipping as mentioned earlier. Pine also has the different growth rings with fine and coarser grain which has a greater impact on the "shaft" stability as diameter decreases. Above suggestions and some good wood should really improve the start you show with the pine work.

  12. #12
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    Reducing chatter on spindle turnings just requires lots of practice. do your best to reduce the pressure on the bevel of the skew. Can't push this enough. Very very light pressure. You should be able to reduce the chatter using your fingers on the back side. If it' burns your fingers then you have too much pressure on the bevel. Your fingers counter the pressure. too much on the skew requires too much on your fingers and they burn. You can also reduce the pressure from the tailstock, hold one end in a chuck or use a morse taper like John Jordan does. If you get chatter when you make your next pass use even lighter pressure and change the angle of the skew so it cuts the tops off the chatter from the previous pass. If you keep the same angle you just accentuate the chatter. Oh and if in Doubt sharpen it again. I picked up my skew the other day, thought it was sharp. When turning the rounded foot on a stool spindle leg It kept acting like it wanted to dig in so I had tiny facets and it was hard to control I had just done a planing cut and though it was sharp. I went to the grinder and used the leather strop. Next pass over the foot was perfect and easy to control. It was sharp, but not sharp enough.
    Last edited by JohnC Lucas; 03-23-2018 at 10:24 AM.

  13. #13
    "Another very important thing is to hold the blank firmly at the headstock end, not between centers. I've used a chuck but I find it better to first mount it between centers and turn a short morse taper on the end and cram that into the headstock spindle - it holds the piece fine, gives more clearance, no spinning chuck to watch out for, and a partially completed wand can be taken out of the lathe and put back later with exact registration - something not easy or perhaps not even possible with a chuck!"


    That's an elegant solution.
    Thank you. Is it critical to get the taper perfect, is their leeway? John, have you used a drill chuck in the headstock to hold a small tenon?
    Last edited by Prashun Patel; 03-23-2018 at 3:17 PM.

  14. #14
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    In addition to my and other prior comments. You state you are a "new turner" and "I get tons of vibration and a lot of tear out". The vibration is one thing but the tear out may be another. Are you cutting downhill with the grain. If cutting against the grain you will get tear out whether vibration (flexing) occurs or not.
    The changes from harder to softer growth rings in pine may exasperate the problem if cutting uphill on a spindle.
    Just another possibility.
    "I became insane, with long intervals of horrible sanity." - Edgar Allan Poe

  15. #15
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    holding spindles with a short taper.

    Quote Originally Posted by Prashun Patel View Post
    "Another very important thing is to hold the blank firmly at the headstock end, not between centers. I've used a chuck but I find it better to first mount it between centers and turn a short morse taper on the end and cram that into the headstock spindle - it holds the piece fine, gives more clearance, no spinning chuck to watch out for, and a partially completed wand can be taken out of the lathe and put back later with exact registration - something not easy or perhaps not even possible with a chuck!"

    That's an elegant solution. Thank you. Is it critical to get the taper perfect, or is their leeway? John, have you used a drill chuck in the headstock to hold a small tenon?
    Thanks! I started using the short taper very early when making wands (and other thin spindles) when I found out how much easier they were to turn when in a chuck. But when I wanted to turn them at the book store on the mini lathe the bed was just tool short with the chuck but it fit with the taper. I'd heard about people carving the corners from a piece of square stock and hammering it into the headstock taper but I didn't like a lot about that. The MT proved to be so effective I use it all the time now.

    I make the tapers with the help of a little brass gauge but at first I made them with two cheap vernier calipers. Put a drive center or something in the headstock and mark where it exits. Pull it out and mark some distance down from the first mark, say 1/2" or 3/4". Set the calipers to the diameters at the two marks and use a parting tool to cut two sizing grooves the right distance apart, 1/2" or 3/4" in this case. Make sure the distance between the two grooves is measured from same side of both grooves. I use the parting tool to cut the taper between the two sizing grooves by eye, cutting a little extra for clearance on the larger end to be sure it will seat completely. Notice I also cut a shallow relief in the middle to make it seat easier and since it really only needs to be supported at two points. If it doesn't fit when testing I pop it back between the centers and shave a bit more, extending it a bit on the wider end if needed.

    morse_taper_IMG_5054 - Copy.jpg morse_taper.jpg A01_wands_IMG_5046.jpg

    The mini lathe bed is too short for me to even turn the taper between centers so I do that ahead of time on the larger lathe. Note that some lathes are made to seat an MT2 a little deeper or shallower than others. If making blanks for a second lathe I always test on that lathe, or if not possible, make the taper a little longer on the large end just in case. For a short lathe I also take my shortest live center.

    I think a collet chuck would provide some of the same advantages except for the length problem. Cutting a tenon to hold in a collet would be quicker than making a taper. I don't have one but I'm saving up for one. https://www.woodturnerscatalog.com/p...ck-7-Piece-Set

    I have used a Jacobs drill chuck in the headstock for tiny tenons. It will tend to come loose in use so I use a draw bar. (Not all come threaded for a draw bar.)

    Speaking of draw bars, for the very thin long spindles I drill a hole in the MT on the wood and held it tightly in the headstock MT with a 1/4"x10 drawbar. (I drill the hole by hand and don't worry if it's exactly in the center and I don't tap threads in the hole - I filed grooves in the threads on the end of the drawbar to make it work like a tap.) This eliminates the need for any pressure from the tailstock when a spindle gets very thin on the far end. In fact, when the thin end of the 30" spindle approached 1/16" I removed the tailstock completely and did the final cut supporting the wood entirely with my left hand.

    BTW, there is another excellent (and ancient) way to hold tiny tenons, taught by Mark StLeger and others, a clever method sometimes also called a "collet chuck". I think it's better than the Jacob's chuck which only holds the wood in three places. Make one as needed: clamp a small disk/short cylinder in a scroll chuck and drill a hole the size of the tenon. I mark the wood first so I can put the disk back in the same place. Take the disk out of the chuck and and make a saw cut from the outside all the way into the center hole. Remount the disk and tighten very slightly. (You can redrill the hole at this point for more precision). Then insert the tenon in the hole, and tighten enough to hold to squeeze the tenon tight. A variation of this is used in machining metal too: https://www.youtube.com/watch?v=gCUkJydSmdA

    A real collet would be even better but you would have to turn the tenon to fit an existing collet. The ER-32 collets will only contract 1/32 or so.

    JKJ
    Last edited by Prashun Patel; 03-23-2018 at 3:17 PM.

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