Page 1 of 1

Lathe Use Advice

Posted: Thu Oct 04, 2012 12:06 am
by Cory
So, I got my 10x14 Jet and have only used it twice. The first time, I couldn't cut anything - sharpened tool with grinder and fine sharpening stone. Second time ended up bad because of chucking issues (I think) - the block flew off at the wall.

I have never had any problem with the metal lathes I have used (I am actually on the Baja team at my university and just got certified for their machine shop). I am very confident in using a metal lathe (we have two pretty nice lathes in the machine shop: one is a Jet 14x40 and the other I can't remember the brand but is about the same size), but I just can't seem to get the hang of the little 10x14 wood lathe.

I think my tools are sharp/ground properly. I am running at a decent speed. I get some wobble from the off center turning. I only have the 1/2" or so jaws that came with the Nova Midi chuck I have. Which makes me nervous wen compounded with the off center turning. I also keep getting lots of tear-out and chunks flying off (especially when trying to turn down from square to round).

I purchased a video called New Turning or something like that and I also purchased a book written by the guy who was in the video. I have watched the video many times and read the book through once. I am still nervous to use the lathe.

So here are some questions:

1. Solutions for tearout?
2. Suggestions for turning down from square?
3. Vibration/wobble (really bad when I chucked up a piece of plateau) solutions? Is there a way to turn plateau without shaking the foundation of the house?
4. Do I need different jaws? I only have four contact points (points of two jaws since they have a radius).
5. How sharp is sharp enough for tools?
6. Appropriate turning speed for my setup?

Re: Lathe Use Advice

Posted: Thu Oct 04, 2012 4:08 pm
by Sasquatch
Razor scary sharp. Like, if you drop it, it will cut through your shoe, your foot, the sole of your shoe, and the flooring. That sharp.

What tools are you trying to use for what purpose? Are you attacking from the side or in line with the rotation? Where is your tool rest located?

Get your lathe bolted to the bench to take care of the wobble, and/or slow it down. Huge big chunks I spin at 500. Prefer to work at 1200 or 1500 but that's not always possible on a small machine.

Re: Lathe Use Advice

Posted: Thu Oct 04, 2012 8:58 pm
by JHowell
Pics of your tools and setup? Scottie22 just went through something like this. Some tools, even properly sharpened, take more touch to use than others. I find round tools like gouges hard to use because if they catch they can roll on the rest and change the edge exposure and BAM!!!!

I like scrapers. They're flat so they don't rock, they don't tend to self-feed and grab, they're easy to sharpen.

Taking the block down from square can be tricky because those corners don't seem very substantial and you're tempted to take a bigger bite than you should. It doesn't feel like you're doing anything and you haven't developed the feel yet so the tool advances a bit further than it should and BAM!!!!! You might try knocking the corners down a bit on a bandsaw (though if you don't have a touch for cutting on an angle the blade will grab and create another memorable moment). Removing excess mass before turning helps with the vibration, too.

Speaking of vibration, Sas is right, you want to bolt that sucker to bedrock. I've seen wood turners bolt their lathes to heavy benches, then bolt the bench to the floor and pile the bench stringers with sandbags. Those little wood lathes aren't very heavy or rigid, so they need all the help they can get. And when you have less vibration you'll have an easier time controlling the tool even if you do nothing else.

Re: Lathe Use Advice

Posted: Fri Oct 05, 2012 10:38 am
by KurtHuhn
Another good tip is to bolt one of the other little jaws that you're not using to the chuck, opposite the shank side of the block, in order to balance things out.

Flying briar is usually solved by better/bigger jaws. From your description it sounds like you only have the small multi-purpose jaws. Deeper ones like the Nova Spigot or Long Nose will help immensely.

Tearout is all about control and experience. Go slow, don't rush, and you shouldn't have any problem.

Going to round is, again, all about control. Like Jack said, if you go too fast you're going to hurt the tool, the toolrest, or yourself.

Turning speed is a matter of preference. I prefer to turn briar at around 1200 RPM.

And running a wood lathe is very different from running a metal lathe. The learning curve can be fairly steep, since you're depending on your body to learn "the right way" to do any given thing instead of a rigidly mounted tool and some handwheels. When I got my wood lathe I decided to practice on some cheap wood before killing any more briar blocks.

Re: Lathe Use Advice

Posted: Sun Oct 07, 2012 6:57 pm
by wmolaw
KurtHuhn wrote:Another good tip is to bolt one of the other little jaws that you're not using to the chuck, opposite the shank side of the block, in order to balance things out.

Flying briar is usually solved by better/bigger jaws. From your description it sounds like you only have the small multi-purpose jaws. Deeper ones like the Nova Spigot or Long Nose will help immensely.

Tearout is all about control and experience. Go slow, don't rush, and you shouldn't have any problem.

Going to round is, again, all about control. Like Jack said, if you go too fast you're going to hurt the tool, the toolrest, or yourself.

Turning speed is a matter of preference. I prefer to turn briar at around 1200 RPM.

And running a wood lathe is very different from running a metal lathe. The learning curve can be fairly steep, since you're depending on your body to learn "the right way" to do any given thing instead of a rigidly mounted tool and some handwheels. When I got my wood lathe I decided to practice on some cheap wood before killing any more briar blocks.
"When I got my wood lathe I decided to practice on some cheap wood before killing any more briar blocks." :thumbsup:

Re: Lathe Use Advice

Posted: Tue Oct 09, 2012 7:59 pm
by wdteipen
I like to turn as fast as my lathe will go without excessive amounts of vibration. I get more grabs at slower speeds. I approach from the end like you would a bowl. The key is using the right tool at the right height and taking very small cuts. It's also important not to let your tool dip downward; go straight in. If you're going to err here it's better for your tool to go above horizontal than below.

Re: Lathe Use Advice

Posted: Mon Dec 17, 2012 12:37 am
by Cory
After taking a few months off from the lathe and spending more time reading books, watching videos, and reading posts, I finally whipped the lathe back out.

Everything is much better now - tearout is gone since I have learned to properly sharpen tools and control cut depth; roughing is easier with sharp tools and shallow cuts.

I am having one problem, with using my parting tool on smaller diameter pieces (like ebonite rod sections). I get lots of catches. I am almost positive it has to do with tool rest placement. I am putting it at the center of the piece and as close as possible to the work, but since it is such a small diameter piece, it creates a strange cutting angle.