Norm's Lathe101

[mjwallace]

Saw the new Lathe 101 NYW show yesterday (our local PBS station shows an "earlier" copy of it on Wednesday.

While I'm not a turner nor do I own a lathe, I would feel that I would need much more instruction then what he allows. He gives you a basic introduction to the elements of a lathe, how to set the tool rest and what tool you should use when, but really skips lightly over the choice of RPM, how to sharpen all the various tools (he only sharpend a gouge) how to do a bowl, etc. His "practice" project was a log of about 3 or 4 inches and his first "real" project was a baseball bat.

He did something, that I didn't expect tho - he was showing how to do the bat and in his left hand, he had calipers and in his right, a tool. While the bat was spinning, he took the calipers (from behind the bat) and measured how deep his cut was. He said it was ok to do that.

Is it? I would be curious from those who do turn as to how this is safe.

MJ Wallace

[fredfighter]

It is commonplace for turners to put the calipers to a spinning workpiece. I've never seen nor had a mishap though I suppose it is quite possible to catch the calipers on the piece and have them fly at you. I always wear a face shield when turning and keep if flipped all the way down to where it touches my chest so that my throat is protected.

Compared to the damage a skew chisel could do if it gets away from you, the caliper is not much concern. That said, you'd have to have a pretty weak grip on a lathe tool to have it torn from your hand. Typically if you catch the workpiece, the belt slips instead. Working on large pieces, especially large bowls at high RPM may be dangerous but for most of us the worse risk using a lathe is probably the danger of a tool rolling off the banch and landing on a foot.

Though he's better than I, Nahrm has never impressed me with his lathe work. He gets the job done, but an expert turner would use the skew chisel much more for faster, neater, work.

[Ron Kolakowski]

Measuring a diameter with the lathe turning is pretty standard. When turning a spindle to a specific diameter - i.e. a tenon to fit a drilled hole, about the only way to get it right on is to hold a calipers, or my favorite, an end wrench on the back side of the piece while taking a light cut with a parting tool. SOme folks sharpen one side of the end wrench and use it as a scraper, but I've never treid that.

Ron

[LRod]

Years ago when I first started turning I used to shut off the lathe all the time to take a measurement with the calipers, thinking the same thing you are. Then I started working out in my mind what possible mechanism there is for an accident. I took into account the material, its rotation, its size, the tool (caliper), the shape of the legs of the caliper, how it contacts the work, and everything else I could think of.

I concluded that there isn't anything that I could conceive of that would make this a dangerous operation. Years later after having done it a lot and seeing others (with more experience in a week than I have in ten years) do it, I feel perfectly comfortable with my analysis and decision.

If you have an idea of how an accident could occur, please let me know so I can revisit the process.

- - LRod

Master Woodbutcher and seasoned termite

Shamelessly whoring my website since 1999

[George]

What's left out? Turn fast enough to remove the wood from the piece, and any faster simply builds danger (square of velocity, remember?).

Keep the tool rest as close to the work as you can, because letting something spinning that fast have the leverage advantage is likely to remodel your face with the tool you _were_ holding.

You sharpen the tools the way you sharpen anything else, by removing steel to reproduce present contour a few microns back.

Bowls are covered in the 225 course.

[Andrew Barss]

: What's left out? Turn fast enough to remove the wood from the piece, and : any faster simply builds danger (square of velocity, remember?).

I disagree -- the minimal speed to remove wood can easily cause a really rough surface. Try turning a spindle or a pen at 200 rpm, then up the speed to 2000 rpm. The faster speed gives a much better surface.

-- Andy Barss

[Andrew Barss]

: It is commonplace for turners to put the calipers to a : spinning workpiece. I've never seen nor had a mishap though : I suppose it is quite possible to catch the calipers on : the piece and have them fly at you.

: Compared to the damage a skew chisel could do if it gets away : from you, the caliper is not much concern.

True point, although the skew chisel is going to be braced by the toolrest (and so a catch is really unlikely to fling it at you), while a calipers or wrench held from the back of the workpiece would, IF caught, be more likely to come flying.

I think it's unlikely that either a box wrench or a pair of calipers would get caught in the first place, since that would require them to be sharp enough to dig into the workpiece.

-- Andy Barss

[A.M. Wood]

Aren't larger diameter pieces are moving faster than thinner pieces at the same RPM.

[Duane Bozarth]

Yep, that's the key...it's the surface speed and wood specie and tool that are controlling. RPM is the way to get the proper surface speed.

[loutent]

Even though I don't own a lathe and never operated one, but having seen Norm do some turning over the years, I thought the show you mentioned was a good introduction to the lathe. I am thinking about getting one if I can convince SWMBO that I need it!

I think that Norm "confessed" that he was no expert and that he was self-taught. It is like if you went to a neighbor who was a pretty good woodworker and asked him for some "getting started" tips on the lathe. Sort of a summary of what he has learned in the past shows where he has used a lathe.

I respect Norm because he never has a problem with asking for help from an expert in a field he is not familiar with - steam bending wood, sharpening chisels, bowl turning pop immediately into my mind.

One would certainly not expect a complete and thorough lesson in

25 minutes or less (my PBS in Phila had this show last Saturday, the 12th.)

Don't mess with Norm!

Seriously, happy woodworking!

Lou

As a c> Saw the new Lathe 101 NYW show yesterday (our local

[Lyndell Thompson]

I haven't sharpened nary a wrench to use as a scraper but have used many a wrench (after being cleaned free of grease) as an accurate caliper that will not change sizes on you. Move it slowly back and forth and it will begin to burn the high spots. Sand or use the skew to remove high spots. When the wrench moves from end to end you have a fairly straight dowel to work with. When making pens I decide what max. diameter I want for the pen, and rough the blanks down this way. Lyndell

[Rob V]

Worse yet is having a bowl gouge catch on you while your roughing up a 50lb log that is spinning and have the bolts of the headstock shear off, dent the crap out of the toolrest, just about snap your gouge, have a 50lb object hearl right past you (best lesson I ever learned was stay of the firing line) - then have to clean out your pants!

[George]

OK, if you think you can substitute force for finesse, have at it.

Point is, you don't _have_ to. Speed doesn't remove the wood, the edge does. Folks who say you need speed for smooth are either working with poor edges or presentations. Does your plane produce a better surface if you move it faster? How about your carving gouges?

Sharpen and present properly, and it's merely carving with a moving piece of work.

[George]

And yet we don't change lathe speed when cutting from rim to bottom, or bottom to rim on a bowl. Might be a lesson about the need for speed in there somewhere.

[Duane Bozarth]

Well, sure...I'm talking of the gross speed setting matching the work, not minute changes...

Although I've watched some w/ variable speed use it almost the way you describe... :)

[CW]

I do but then, my lathe is CNC.

[Homer]

Don't worry about it, buddy.

There is NO chance that you will EVER have an accident that way. ZERO. ZILCH. NADA.

[Richard Clements]

personally I really liked it, Just got a lathe for Christmas, and have been trying to learn what I can, like the way to hold the chisel, I was holding it un an underhand manner until I saw him working, and the part on how to make the same peace multiple times was good to

but then aga> Saw the new Lathe 101 NYW show yesterday (our local

[Fly-by-Night CC]

The only mishaps I've had are when my elbow of the caliper-holding arm drops onto the spinning chuck. If the jaws are outside the diameter of the chuck it can smart pretty good but I've yet to draw blood this way.

I've not seen the Norm episode yet so the following is offered not knowing how he did it: To get the most accurate sizing with the caliper I make sure the legs are placed around the turning and with light pressure pulled out as I part down to size. If you try to push the calipers onto the turning you can mis-size the cut.

On a related note, I have certainly caught the straight legged pointed dividers when sizing mortises or diameters in end grain on numerous occassions.

[George]

That "underhand" business is something I would never have though of, but there are folks that do it. Seems counterintuitive to me.

A - Anchor the tool to the rest.

B - Bevel tangent to the rotating work.

C - Cut a curl by moving the handle for entry.

Worked for the kids. I used to tell them to "English" the "C" on bowls.