Newbie question about nova chucks

[John K Jordan]

Update: The bore of the insert was fine, so I assumed the threads weren't cut deep enough. Luckily I have a small South Bend lathe, and a 3/8" high speed tool bit I had ground for internal single point threading, just long enough to reach all the way through. After a few passes, then no fit, I took another few small cuts and it went on snugly using a wrench. I checked the chuck for runnout with an indicator. It was about .008 total on the O.D. and .003 on the face. That should work.

Yea, once again the value of a metal lathe is proven! It is odd, however, that the insert didn't fit the lathe - I've never run into that using the chucks on multiple lathes with a variety of spindle thread sizes, including some with 1" spindles. (I have a couple of Jet Mini lathes and one chuck with an insert for those.) Is the insert a Nova or another brand?

I don't remember if you said the type of lathe you have. Could it be the threads on the lathe spindle are a little out of "spec"? If so, I'd be concerned that other attachments might not fit, things like face plates and collet chucks. Or you might have to repeat the machining if you get another chuck. I'll try to measure the OD of my two smaller lathes for comparison but I don't have an easy way to measure thread depth.

Unlike metal work, a little runout on a woodturning chuck is not a problem since you always turn the wood round after mounting in a chuck. Unlike metal, the nature of wood usually prevents perfectly remounting a piece after it is removed from the jaws. (The wood fibers are crushed and deformed when tightened in chuck jaws and the wood itself moves with time and humidity changes.) If you know you will remount something it helps to mark the position of the jaws on the wood and remount in the same position, trying to get the jaws in the same depressions. (I usually make a mark between the #1 and #4 jaws.) Even then perfect truing is unlikely so it may be necessary to make another light truing cut if needed.

Sometimes you HAVE to remount the piece on the lathe, perhaps when reversing the piece to turn the bottom or some other special step on an oddly-shaped piece, for example, jamming between two pieces of wood or mounting on a vacuum chuck. Most people get close by using a finger or something to judge the runout. Remounting is where I use a dial indicator on the wood lathe - so much easier! Even then if I can get a 4" diameter piece to with .003 or .004 I'm happy.

This is held by friction, jammed between two pieces of wood turned to match the concave curves on each end.
Dial_indicator_IMG_20141122.jpg

BTW, I leave most of my precision measuring things at the mill and metal lathe. To a metal worker, woodturning might sound pretty crude but it is rare to actually have to measure something closely to an actual value! However, approximate relative sizes are sometimes important - I use dividers quite a bit as well as spring ID and OD calipers. The calipers I use most often at the lathe for spindle turning are cheap and crude stamped-metal verniers. I found them once on Amazon for $4 each and keep a bunch so I can set several and different diameters when sizing something such as when duplicating a spindle or turning a small tenon. So the jaws will slip nicely over the rotating wood, it is best to round them slightly as in the first one here:

calipers.jpg

JKJ

[Tony Pisano]

Spindle was .980 dia. I do have a 4 jaw and faceplate that screw right on. Thanks for the tip on calipers. The nova chuck came with insert, 2" jaws, ball hex tightener, and woodworm.

[John K Jordan]

Spindle was .980 dia. I do have a 4 jaw and faceplate that screw right on. Thanks for the tip on calipers. The nova chuck came with insert, 2" jaws, ball hex tightener, and woodworm.

I didn't make it to the shop to measure mine today - concrete, sawmilling, deck building, siding a farm building...

Some people found the ball end on the chuck key damaged the sockets in the chuck. The ball lets you insert and tighten the key at an extreme angle putting too much stress on points of the socket, deforming the metal. I understand Nova has replaced the damaged parts for anyone who asked.

I have some keys with the ball end but I use straight keys instead. Some people recommend simply cutting the ball of the end to eliminate the possibility.

JKJ

[Tony Pisano]

Thanks. I ordered a couple of the books today that you mentioned.

[Tony Pisano]

The fundamentals of woodturning by Mike Darlow arrived on Friday. It's really packed with information. I like the step by step lessons. I was working in the shop today and after I finished what I was doing, I mounted a square pc of scrap hardwood between centers and managed to turn it into a rough cylinder. I was a little nervous towards the ends, but worked them like the book instructed and everything went fine. It was very satisfying.

[John K Jordan]

The fundamentals of woodturning by Mike Darlow arrived on Friday. It's really packed with information. I like the step by step lessons. I was working in the shop today and after I finished what I was doing, I mounted a square pc of scrap hardwood between centers and managed to turn it into a rough cylinder. I was a little nervous towards the ends, but worked them like the book instructed and everything went fine. It was very satisfying.

Excellent!

That is probably my favorite book for learning woodturning. I still refer to it a lot after years of turning, often to show illustrations to students who come to my shop or to answer questions. I've heard people say the book was too hard to read but perhaps their technical literacy is different. I can't imagine anyone being afraid of the skew chisel after reading and following Darlow's exercises.

I think I have and have read every book Darlow and Raffan wrote. Another favorite Darlow book is Woodturning Design - an incredible and fascinating education on design from a historical, modern, and logical perspective. Reading this helped change my ideas about several things related to woodturning, specifically some of the "rules" of design parroted by lots of turners and instructors. https://www.amazon.com/Woodturning-D.../dp/1565231961
A word of warning - this is college-course level material!

For an understanding of the properties of wood itself, I highly recommend R. Bruce Hoadley's Understanding Wood. Hoadley writes from the perspectives of both a wood scientist and a craftsman. He explains things like drying and shrinkage of green wood, perhaps even more of interest to woodturners and carvers than flat woodworkers. Also, he includes an introduction to identifying wood by examining a transverse section with a magnifier.
https://www.amazon.com/Understanding.../dp/B004WYO862
His credentials: ... a degree in forestry from the University of Connecticut and a doctorate in wood technology from Yale. ...a former professor of wood science and technology at the University of Massachusetts at Amherst.... frequently consults for museums and acts as an expert witness at trials.

JKJ