Skew questions

[John K Jordan]

I have been thinking about turning some long stem flowers. ... in "tension" mode rather than "compression" from the tailstock.
...how to center and then attach the tailstock end to the live center eludes me. Anyone out there with any good ideas on how to do that?

This has been tried and discussed elsewhere. In theory, using tension a great method to reduce vibration and chatter. If the spindle is thin, however, a potential problem is in starting and stopping the lathe. Inertia from mass of the support on the tailstock end during acceleration/deceleration can create torque which might snap a thin spindle. Another issue is you can't pull tension by simply cranking the tailstock quill back without pulling your holding means out of the tailstock MT taper. You could devise a low-mass spring-loaded means to provide tension.

Rudy Lopez does a demo where he turns a long goblet with a very thin stem. He starts with a green branch. He uses a gentle jam method to support the goblet bowl, turning the stem from the tailstock to the headstock. http://www.virginiawoodturners.com/s...tuff/Lopez.pdf He sometimes uses a clothespin as a steady rest. Catch one of his demos if you can - a wonderful turner!

Rudy wrote these instructions: azwoodturners.org/pages/tips/ThinStemmedGobletFromALimb.pdf

For lots more search google for rudolph lopez goblet

JKJ

[Thomas Wilson80]

NOT a silly question!

A drawbar is simply a threaded rod with some kind of nut on one end. One came with my milling machine to hold Jacobs chucks and end mill collets.

I made drawbars for my wood lathes from lengths of all-thread rod, available at hardware stores and Home Depot in various threads. A common size for tools you buy in the US 3/8"; I made one from 3/8" all-thread for tools and another from 1/4" all-thread to hold wooden spindles.

The drawbar rod is long enough to go through the hole in the center of the headstock spindle. It threads loosely into something with a taper you want to hold tightly into the morse taper in the spindle. For example, if you use a Jacobs chuck in the headstock to hold a drill bit, without a draw bar it will very likely come loose during use. A nut on the end pulls the tool firmly into the headstock.

These are the two I made for woodturning. For the smaller one I simply turned a piece of hard wood and drilled and tapped 1/4-20 hole in the middle. For the larger one I epoxied a washer on a threaded fastener I found somewhere. A nut and washer would have worked for either of these but then I'd have to keep wrenches handy.

Attachment 384036

I use the 3/8" drawbar for my Jacob's chucks and I'll use it on the new MT2 collets I just bought.

Attachment 384037

I use the 1/4" drawbar on thin wood spindles where I've turned a MT2 taper on one end to jam into the headstock and when the spindle is unsupported (or not well supported) on the tailstock end. I filed a flat in the middle of the drawbar thread so I can hold it with an adjustable wrench to force threads into a hole in the wood. As mentioned elsewhere, I file a few grooves through the threads on the end to make a tap that will easily cut threads into wood.

The 28" walnut spindle tapers from 1/2" down to 1/16", turned with a skew without using a steady rest. It's the reason I made the 1/4" draw bar since I couldn't finish turning it since it kept popping out of the headstock!

Attachment 384038

Unfortunately, a drawbar can't easily be used in the tailstock and still let you adjust the quill with the crank. I did see a post from someone who devised a spring-loaded mechanism to allow this but I don't remember the details - it might have been on another forum.

BTW, if you want to use a drawbar on a Jacobs chuck make sure you buy one that is threaded for a drawbar! Many are not. I had to pay a little extra for a MT/JT mandrel threaded for a drawbar.

JKJ

Great explanation and information. Thanks!

[JohnC Lucas]

I don't use tension or compression on long thin spindles. I have an adaptor that I built for my live center that just has a hole just a little bigger than the spindle I want to turn. I move the quill out until it captures the turning without putting any pressure on it. Then I just take really light cuts with the skew. I do have the other end in a chuck.

[Peter Fabricius]

Holding Spindles in the Beall Collet Chuck is the absolute best and most accurate. The Chuck 1 1/4" x 8tpi Spindle thread with five ER32 collets (1/4" to 3/4") are great but when you add 18 x Metric Collets this Chuck becomes fantastic. The Chuck screws on the Spindle and there is no length restrictions as long as the wood fits in through the hollow Lathe Spindle. I should advertise for JR but this is a seriously functional Chuck especially in the production Drop Spindle turning Mode.

[John K Jordan]

Holding Spindles in the Beall Collet Chuck is the absolute best and most accurate. ...

Most accurate: Peter, have you measured the accuracy of various holding options and other collet chucks? A dial test indicator could measure the runout on a precision drill rod. I use cheap R8 collets in my milling machine and they are spot on.

A collet chuck does look useful except for one special application for me - turning wands from 13-1/2 to 14" stock on my Jet mini lathe. All ER-32 collet chucks I've seen appear to extend several inches past the end of the headstock spindle, no problem for a longer lathe but impossible to use on the mini I carry places to demonstrate turning. The bed length limitation on the mini is what led me to hold wands by a short morse taper rather than use any kind of a chuck.

In the mean time I bought this in 1/2" size for $11 which is well big enough for 1" stock: https://littlemachineshop.com/produc...ProductID=4314

1608.480.jpg

I probably will get an ER-32 collet chuck at some point for my larger lathes. Does anyone have experience with both the Apprentice set ($89.90)and the Beall ($163.00)?

https://www.woodturnerscatalog.com/p...ck-7-Piece-Set
app_col_chu.jpg

http://www.bealltool.com/products/tu...olletchuck.php

colletchk.jpg

The less expensive Apprentice is also appealing if the knurling will let you hand tighten. It sounds like the Beall comes with and needs spanner wrenches.

I know Beall is generally has good quality stuff but and probably worth the extra $73 if the cheaper Apprentice is poorly made and not concentric. Maybe I'll ask if I can return the Apprentice if it is not concentric or poorly made.

Peter or anyone - any experience with both brands?

JKJ

[Peter Fabricius]

John J. I only have experience with the Beall. It does come with two spanners but these are rarely needed in turning mode. Just hand tighten and go. I have seen the Apprentice and the fit and finish is not close to the Beall. The accuracy, I cannot comment on since I have not tried it. There is no question in my mind that the Beall works perfectly. I have not put my indicator on it but there is no runout by sight or feel. I do have a 3/8" R8 Collet and drawbar to hold the cutter for tread making, works great but it is depth limited. If you are selling anything turned in the Collet Chuck then buy the best.

John L. the little adaptor on the live centre is called a soft nose. I have made a whole bunch of these for different applications. As you noted I too made them with a hole to accept the Spindle, I even made some with 1/4" ID Bearings set into them. This allows almost friction/torque free holding because both the Live Centre and the Bearing will turn. Great for my Drop Spindles. I knock out the point in the live centre so the Spindle can go as far as needed into the quill through the live centre.

[Jeffrey J Smith]

anyone - any experience with both brands?

JKJ

I don’t have experience using the Beall - but I have handled one, and it is nicely machined. I bought the Apprentice a few years ago and it too is well machined, although perhaps not as shiney as the Beall. While I haven’t broken out the dial indicator, in use there is no indication of runout that would cause me to check. It is a good working, solid piece of equipment that I seldom take out of its blow-molded case...when I do I always appreciate having it on hand.