How to keep wood from tearing off the lathe?


Recommended Posts

Hey, I am new to wood turning and of course running into lots of challenging problems. The biggest problem that I am having that I can't fix is keeping mostly softwood from not coming off the lathe. As I am turning, the tailstock starts to tear a large hole in the side or violently rips through the wood and then the piece of wood becomes wobbly. The piece of wood would come off the lathe if I just let it keep spinning. This has mostly happened with scrap pieces of pine that I have been practicing with and some other random pieces of wood that are very old and dry (these seems to wear away at the tail end). I gave up on using the four prong piece on the head stock because that was ripping through the wood as well and started using my lathe chuck. This method is still not fool proof but much more effective. I have turned a couple pieces of lacewood and mahogany with no problem though. I have determined that this has to do with the wood not being hard enough to take the pressure but I do not know how to fix this? If anyone has any suggestions I would greatly appreciate it.

Link to post
Share on other sites

Depends if you are using a mortise or a tenon to hold the work. I had a guy tell me once, end grain you clamp down on, long grain you squeeze out. Basically you cut a pocket into the long grain and open the jaws until tight, end grain you cut a tenon and squeeze tight on it. Hopefully someone can explain it a little better and maybe with a picture or two.

Link to post
Share on other sites

one thing is make sure you dont have checking on the pieces(cracking in the ends) that will certainly have the piece fall apart and coming off. when i mark my pieces to go on the lathe i take something that i can mark the center like an awl or anything with sharp point on the end. then take the drive spur off the lathe set it in the point in one side you made with the awl and drive the tip further in with a mallet. then put the drive spur back in the lathe and set your piece up to the headstock to align with those spur marks. then bring your tailstock up to the point on the other side and tighten as much as you can. make sure what tools you use are super sharp. now occasionally if you get a catch it will come off the lathe. catches will blow out any wood you use. now one thing is i hope you wear a full face shield when turning a piece coming off can hurt you and even kill you.

how thin are these scraps?

Link to post
Share on other sites

I had similar issues when I was starting to test turn too. I realized shortly after that when I was mounting the wood on the drive spur I was often splitting the wood just a bit, but it was enough to cause havoc when trying to rough out the stock.

After you pound your drive spur into the end of the wood, pull it off and inspect the wood before mounting it.

If you are still have trouble, be sure to carefully evaluate the entire blank that you are using. I found that pine, particularily old pine that had been laying around a while had a lot of small cracks, which I assume is just the weakness of the wood along with less than ideal storage on my part. If you have any scrap hardwood, I would reccomend that you give that a try. I found that hardwoods turned a lot easier for me than soft. That seems backwards to me too, but it is what worked for me.

The next major issue to watch for is grain direction. When you are first starting, I reccomend only cutting long grain. Cutting end grain takes a more steady hand and better tool control, and much much sharper tools.

As for tail stock, I think the basic rule is that you should always turn between centers unless you have to pull it off to work the end of a blank (think bowls). So always use your tailstock when you can, and make sure it is secured and aligned.

Link to post
Share on other sites

What kind of live center are you using in your tailstock?

It is just a standard something that came with the lathe 15 years ago. It has a very fine sharp point.

Chris H/ JWatson- I think you have a good point about my tools not being sharp enough. The wood is in great shape no crack, knots, or anything. This pine is actually scrap from drawers I was building. I agree about using the tailstock but I use the method described above to get the wood set up. After two minutes though the hole made by the tailstock will crack or become larger allowing for the wood to wobble around the point.

Link to post
Share on other sites

Try using a different live center. The one you are using is going to penetrate (especially end grain on a soft wood) just as far as you can tighten it. You are, essentially, helping to create a crack. Try using a little guy like this...http://www.woodcraft.com/product/2004436/8393/2-morse-taper-live-tail-center.aspx It has that lip that helps to control penetration. It also gives more surface to stabilize the piece.

I still have to say, I have never had the problem you are describing. I've had tearout on the headstock with a spur, but that's no big deal.

Are you periodically checking if you need to pull the tailstock forward? With those pointed live centers, they will naturally force fibers away from the center, essentially loosening the hold.

By the way... dull tools are the #1 cause of all problems when turning. Whenever I have an issue, the first thing I do is sharpen the tool and try again. 90% of the time, problem solved.

Link to post
Share on other sites

I am having a hard time getting my head around this issue. As they say, a picture is worth a thousand words. Any chance you can post up a pic of your piece as you have it mounted? Hopefully, that will help all of us, help you.

Roger

Link to post
Share on other sites

I would submit that the chuck you have is not really suited to holding a round object from the outside. It's great for holding a square from the outside, or a circular cup on the inside. If you need to hold your turning like this, I'd buy a new set of jaws, something like: www.oneway.ca/chucks/accessories/no5_jaws.htm You can also get versions that have teeth on the inside for better holding power..

Hope this is useful..

Da Bear.

Link to post
Share on other sites

what bear said and also you are turning in bowl orientation make sure you use a bowl gouge. spindle gouges can catch. also don't ever use a spindle roughing gouge with the wood in that orientation.

spindle grain parallel to bed.

bowl grain perpendicular to bed.

Link to post
Share on other sites

what bear said and also you are turning in bowl orientation make sure you use a bowl gouge. spindle gouges can catch. also don't ever use a spindle roughing gouge with the wood in that orientation.

spindle grain parallel to bed.

bowl grain perpendicular to bed.

Im not really following you here, can you please explain this further? What do you mean in bowl orientation and parallel to bed?

Link to post
Share on other sites

if you look at the grain orientation you notice from the side of the lathe the end grain can be seen that's perpendicular to the ways of the lathe bed. if the end of the grain is pointing to the tailstock and headstock thats parallel to the ways of the bed.

Link to post
Share on other sites

Ok, from looking at your pictures you have a set of pin jaws on your chuck. The piece you are attempting to turn has what im guessing is about a 2" or bigger tenon. First off, the pin jaws only have a bearing surface of about 1/4 wide to grip the tenon with. When I use pin jaws, it usually on a piece that is a small spindle, either square or round up to about an 1 1/2" or so.

In my opinion, you have the wrong set of jaws for the application you are trying to do. You need a set of jaws that are sometimes called #2 jaws, or 50mm jaws. I dont know what make of chuck you have so I cannot advise you properly on the proper jaws. The best holding strength of the jaws on a tenon is in the almost fully closed position. If the jaws close fully at say 2", then you would make your tenon at about 2 1/8" or a tad bigger. Be mindful of the angle of the dovetail as well. You want to match that as closely as possible. Also, the top of the jaws should bear directly on the bottom of the workpiece. And the tenon end should never bottom out on the base of the jaws. If your jaws are 1/2" deep, then your tenon should be no longer than 7/16"

This should go a long ways to helping you keep your workpiece mounted on the lathe.

Hope this helps.

Roger

Link to post
Share on other sites

i agree with roger get the right jaws that small set will not hold it as strong and i had a block about that big come off my lathe once and smack into my face shield. i was on super low as i was still roughing it out but it still could have been very bad. had the right jaws just didnt have a good enough angle on my tennon and it sliped. .................right tool for the job get a biger set of jaws to hold it

as for the tear out jwatson had it on the nose there is two types of grain basicly face grain great for spindles and then there is end grain. the way you have it glued up and mounted it looks like end grain it has more tear out on two sides rather then on the other two. well first off sharpen you tools get them realy sharp. then use a bowl gouge/ e-z cutters can prity handy as well great for hoging and shaping then a traditional tool more for the fine smoothing.

  • Like 1
Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

  • Who's Online   2 Members, 0 Anonymous, 171 Guests (See full list)

  • Forum Statistics

    29553
    Total Topics
    400508
    Total Posts
  • Member Statistics

    22276
    Total Members
    3644
    Most Online
    con
    Newest Member
    con
    Joined