pen turning problem
JCP
Jeffrey Silverman wrote:
>
> I am a novice turner who recently started making pens but am running
> into a problem which I am not sure of how to correct.
> When I try to put decorative grooves in the blank they seem to go deeper
> on one side than the other - it seems like the wood is spinning off axis
> but I am not sure how this can be. I am using the small Delta lathe
> (46-700), with a #2 morse taper mandrel. I aligned, and re-aligned the
> headstock over the bed (the point of my tailstock and spur drive align)
>
> any help would be appreciated
>
Jeff:
I can forsee several reasons in addition to a misaligned head/tailstock:
1. The ends of the wood/tubes may not be square. Try using a barrel
reamer. If you are tuning larger than a 7mm tube you will need to use a
bushing over your normal reamer shank.
2. You may be tightening the nut on your mandrel too much.
3. You may be tightening the tailstock too much.
4. You may be putting too much pressure on the stock whit your tool
when turning.
Jay Planalp
Robert C. Martin, Jr.
Jeffrey Silverman wrote:
>
> I am a novice turner who recently started making pens but am running
> into a problem which I am not sure of how to correct.
> When I try to put decorative grooves in the blank they seem to go deeper
> on one side than the other - it seems like the wood is spinning off axis
> but I am not sure how this can be. I am using the small Delta lathe
> (46-700), with a #2 morse taper mandrel. I aligned, and re-aligned the
> headstock over the bed (the point of my tailstock and spur drive align)
>
> any help would be appreciated
>
> Jeff
You don't indicate what type of mandrel you are using. I had a similar
problem with turnings which were not concentric with the tubes when I
first started turning pens using a morse taper mandrel which I purchased
from Woodcraft. The problem was that the mandrel was not centered in
the morse taper adapter. When I swithched to a Jacobs chuck with a
straight mandrel, I had no further problems. I had no problem in
returning the Morse taper mandrel to Woodcraft, and they would have been
happy to replace it, but I had already made the switch to the chuck.
If you have access to a dial indicator micrometer, it should be simple
to check whether the mandrel is centered relative to the taper - if you
don't have access to an indicator, you can try holding a metal rod
against the tool rest and the mandrel and observing whether a gap
appears as the headstock/mandrel are rotated.
Several companies (HUT 800-547-5461 and Craft Supplies 800-551-8876)
sell both Morse taper mandrels and jacobs chucks.
Good luck.
Jeffrey Silverman
Steve Worcester
On Mon, 13 Jan 1997 18:17:19 -0500, JCP <car...@erols.com> wrote:
The only thing that ever solved this problem , permanently, was to go
to the pen mandrel system by California Import/Export. (Fullerton, CA
(714) 992-5725). They have a system designed to do one barrel at a
time, using a stainless center on one side that a bushing slides over,
and a stainless bushing on the (live) tailstock side. If your ends are
true, you will turn a solid, even walled barrel every time. I made
about 200 pens last year using this system, and even with my heavy
skew, only went through one stainless center, because I banged it out
of whack with a mallet (another project). He has bushings for 7mm
Cross style, Parker Push, Parker fountain/Rollerball and Parker twist.
I have also used them for Monte Blanc styles as well! Reasonably
priced, the stainless mini spur center in a mt2 is about $25 and
bushings run $5 a set.
>Jeff:
>
>I can forsee several reasons in addition to a misaligned head/tailstock:
>
>1. The ends of the wood/tubes may not be square. Try using a barrel
>reamer. If you are tuning larger than a 7mm tube you will need to use a
>bushing over your normal reamer shank.
>
>2. You may be tightening the nut on your mandrel too much.
>
>3. You may be tightening the tailstock too much.
>
>4. You may be putting too much pressure on the stock whit your tool
>when turning.
>
>Jay Planalp
Steve Worcester
Madera Creations, Plano, TX
Pens are made by fools like me but only God can make a tree
Gregory R. Morse
Robert C. Martin, Jr. wrote:
>
> Jeffrey Silverman wrote:
> >
> > I am a novice turner who recently started making pens but am running
> > into a problem which I am not sure of how to correct.
> > When I try to put decorative grooves in the blank they seem to go deeper
> > on one side than the other - it seems like the wood is spinning off axis
> The problem was that the mandrel was not centered in
> the morse taper adapter.
>snip<
> If you have access to a dial indicator micrometer, it should be simple
> to check whether the mandrel is centered relative to the taper - if you
> don't have access to an indicator, you can try holding a metal rod
> against the tool rest and the mandrel and observing whether a gap
> appears as the headstock/mandrel are rotated.
The runout could also be caused by the tube being too sloppy a fit on the
mandrel.
Greg
Jack Grube
Yopu may be drilling a slightly oversize hole or perhaps the correct drill
bit with a drill press that is not running true. The adhesive is not
allowing the tube to be centered.
Douglas Turner
pressure can cause flexing to the mandrel resulting in the symptoms you
describe. Dull tools agravate the symptoms. Also if your tailstock is
tightened too much the mandrel shaft will flex and if the tailstock
centering hole on the mandrel is not deep enough for the live center to
fully seat you can get eccentric pen tubes.
Doug Turner <tur...@earthlink.net>