center punch

[John K Jordan]

Ronnie,

I called John Lucas this morning about center marks on inside-out turnings. (Sorry, I had a couple of woodturning beginners here until just now.)

John said he he uses a technique very similar to what Dan described, knocking off the corners before the glueup. John said he uses a small carving knife. He said it is best to get all the corner bevels the same, of course, (I assume in both angle and size) but recommended also drilling a small hole since the point of the live center can still wander off. He said he's built jigs and things to drill the center holes but usually doesn't bother.

As for the center drills, Sir Lucas said in some circumstances he has still had them go off the exact center in wood with soft and harder sections - it's not the short, stiff drill bit that is flexing but the wood.

JKJ

[Kyle Iwamoto]

Have you tried an automatic center punch? That's what I use. Probably not a lot different than an awl. Yes I have tried an awl, and I like the auto punch. No explanation. It just seems to work better, in my mind.

[Keith Westfall]

You should not be fastening into end grain anyway.

How do you do spindle turning then?

[John K Jordan]

How do you do spindle turning then?

Most spindle turning is done between centers in the headstock and tailstock or with a chuck and a live center in the tailstock, or simply held on one end with a chuck. The method used depends on the wood, the size and length, and the types of cuts made. The chuck can be a scroll chuck, jam chuck, cup chuck, jacobs chuck, etc. In some cases a mandrel is used such for turning things like pens.

However, short spindles are often held by threads in end grain on a mandrel that fits into the morse taper of the headstock. This method is sometimes used for turning things like bottle stoppers and handles for kitchen gadgets. This works well, and in dense woods like cocobolo it is probably more secure than a screw in side grain of a wood like cherry. Typically when a mandrel with threads is used for something like that handle of an ice cream scoop the other end of the spindle is held by a live center in the tailstock until the piece is almost completed then the tailstock is removed and the end finished without support. Remember that turning spindles is usually done with more delicately controlled cuts than sometimes used in face turning so the forces are smaller.

Here is a typical mandrel with threads used in end grain spindle blanks: https://nilesbottlestoppers.com/inde...-2mt-a-mandrel Hardware for bottle stoppers and such can be bought with the same threads as the mandrel.

JKJ

[Jeff Farris]

<p>
I stumbled across this one a few weeks ago. It is now my favorite automatic. It is sharp and penetrates deep, and it is a little more compact that the General and the General knock-offs. Lisle is mostly known for automotive and trailer wiring supplies and tools. http://www.lislecorp.com/divisions/p...mp;category=29</p>

[Keith Westfall]

Most spindle turning is done between centers...

Thanks, a bit of sarcasm is hard for me to convey... the post I quoted said you shouldn't fasten into end grain, which is what spindle turning is, whatever method one chooses to hold the work. Whether between centers, screw chuck, regular chuck, it all involves end grain.

Thanks for the info though - good stuff!

[John K Jordan]

[COLOR=#333333]You should not be fastening into end grain anyway.

Thanks, a bit of sarcasm is hard for me to convey... the post I quoted said you shouldn't fasten into end grain, which is what spindle turning is, whatever method one chooses to hold the work. Whether between centers, screw chuck, regular chuck, it all involves end grain.
Thanks for the info though - good stuff!

Oh sorry, I didn't read sarcasm. The first quote didn't clarify his thinking (nor did yours) so I took the chance that both were equally serious. For example, I know some bowl turners who hold face-work blanks with screw chucks but have no spindle turning experience and to them, and to flat wood workers with no turning experience at all, marking end grain with a center punch might imply preparing to drive a screw into end grain as the sole means of holding the work with no tailstock support. This could be a problem for larger end grain pieces and longer spindle blanks!

A secret: I actually had an ulterior motive to list those methods! I was asked to do a club demo on "Work Holding on the Lathe" and it was a good opportunity to think about end grain holding.

But what did I forget? One old I read about but never used: drill a hole in wood held with a faceplate, then glue the rounded end of a spindle blank into the hole. And yikes, I plum forgot about collets and pin chucks! Anything else?

JKJ

[Jim Silva]

Yeah, that line you quoted was a bit puzzling to me also. On a small spindle using a screw or the like would not be terribly safe but do any large end-grain hollowing and you'll find that a faceplate is the way to go. I'm thinking the initial responder was speaking of small stock mounting. (Hope they were anyway...)
Jim