uneven turning pen

[Snazzypens]

Hi When I am turning a pen, I am noticing the pens have all these divets out of it. I was blaming the tools but now when I look down the barrel near the tube it also turning one side down a lot more than the other. The pens are like overhanging the fittings on one side. the really dinged up blank is the one nearest to the tailstock...What is the cause of this and how do i fix it?

Thank you for your reply
bye
Toni

 

[redfishsc]

You're getting a common problem (well, at least common to me).

There are several threads here about out-of-round pens--- oval pens--- and there are several things that can cause it.

First thing, however, is check out Russ Fairfield's page on the "Lathe Tune Up". Great info. This, in and of itself, may solve your problem.

Several questions to ask, though, regarding this issue that have shown to be problems for me.

1) Is the live center at the tailstock getting mauled up by the mandrel?

2) Is the mandrel end-- where the live center fits in--- clogged with crud or even worse, CA?

3) Is your mandrel bent? Remove everything off of it and roll it around on something DEAD FLAT like the flat space on your lathe. If it has any sort of hop to it, replace the mandrel.

4) You are a good pen turner so I wouldn't suspect you to be pushing too hard on the pen blank, but if you DO push the pen blank with your cutting tool too much, you will push the mandrel out-of-round with the force.



There are many other things that can cause this.

I am soon ordering the Beall collet chuck to ensure the headstock is dead-center. I wish there was an equally accurate way of holding the tailstock that bit down on the mandrel like a collet.

 

[gerryr]

If you're using the live center that came with your lathe, it doesn't fit the mandrel correctly. You need a 60 degree live center.

 

[Skye]

Not only that, it may be time to get some new bushings.

 

[ctEaglesc]

After you check out Russes site, there are other things to look for.
Take a look at the end of the blank after you have milled it.
Sometimes the mill will "peen over" the brass.Rarely does it do this evenly,chamfering the tube will take care of this.
Sometimes CA will "creep" into the space between the bushings and the blank,Since it is clear you may not realize it,clean off the mating surface of the bushings.

One other thng I just notoced.You say it happens on the tailstock end.
HAve you been turning the same type of wood lately?
HAve you switched the blanks end for end on the mandrel?
In other words can you duplicate the problem every time or is it the orientation of the grain in that particular blank?
What type of tool are you using and what type of cut?
Are you SURE your tools are sharp?
YOu use the phrase
"the really dinged up blank is the one nearest to the tailstock"
Dinged up suggests a "catch" Are you presenting the tool from a different direction and possibly that area of the tool is not as sharp as it is when you go from the other direction?(From right to left as opposed from left to right).
Lastly I have turned a LOT of pens with a stock center.The steel on those points is cheap and it normally conforms to the indent in the mandrel.
A 60* center is often recommended to solve all problems but I don't believe it is a panacea.

 

[Rifleman1776]

The bent mandrel is my first long-distance guess. As suggested take off morse taper and roll on flat surface. In the lathe, the end should meet the tailstock perfectly. Any deviance is unacceptable. Also be sure to check everything on the lathe for concentricity. Make sure the head/tailstock meet perfectly point to point. Fiddling with a faulty mandrel won't help, only replacement will help. Some will say to find a "sweet spot". They are full of [explitive deleted], this is no such thing. A lathe and/or mandrel is true or it is junk.

 

[redfishsc]

Originally posted by Rifleman1776
<br /> Fiddling with a faulty mandrel won't help, only replacement will help. Some will say to find a "sweet spot". They are full of [explitive deleted], this is no such thing. A lathe and/or mandrel is true or it is junk.

There are many absolutes in this world, and by golly that's one of them.

I fought, and fought, and fought trying to make pens on a shopsmith. Problem is we used it in the shop for various other things, so we often had to change the assembly of the thing....just when I got the thing "dailed right in"--- meaning I had the removeable, adjustable, penturning-UNFRIENDLY tailstock set just right.



Life got a lot easier when I got the Delta. Yes, I still make the occasional oval pen, but I know what the likely source is, and I'll be taking care of that problem real soon.

 

[Justin_F]

Hi Toni, I had a problem like yours this week. It was that I was using a variable length mandrel (Carbatec). When I turn using either of my other two standard size mandrels I don't have a problem een if using the same live centre. Just a thought.[B)]

 

[TellicoTurning]

Toni,
I don't have the expertise these guys have, but I did have similar problem while back... turned out I had tightend the ferule nut too tight and set the tailstock too tight and caused the mandrel to bow ... learned not to do that and don't have quite so many problems with the oval pens.. others still yessss.

 

[mikes pens]

While my lathe is turning, I run a pencil against the mandrel to make sure that the mandrel is in good shape. If it is, the pencil line should go all the way around the mandrel and show no difference in thickness (or skips).

 

[Snazzypens]

Hi I bought a new mandrel, I am still having problems on one side the pen is flush the other side and the pen it jutting out a whole millimetre.
Toni

 

[Justin_F]

Ok this is frustrating! Have you cleaned out the inside of your morse taper? Also would recommend you check the live centre in the tailstock. I havent bowed a mandrel yet by overtightening and dont assume you have done this.
Jus

 

[Snazzypens]

how do you clean out the morse?
Toni[:I]

 

[Sir_Stinkalot]

Turn the lathe of and stick a little finger in to made sure there isn't any built up grime that may make the insertion of the mandrel off centre.

 

[DCBluesman]

Toni - For my nickel, Russ Fairfield has the definitive answer on the problem. If you read this page, http://www.woodturnerruss.com/Pen12b.html , you should be able to solve your problem once and for all. (I have a vested interest in this site...Russ has taught me more about pen making than any other person. [8D])

 

[Dario]

This thread may help you (or not)
http://www.penturners.org/forum/topic.asp?TOPIC_ID=12099

and this...

http://www.penturners.org/forum/topic.asp?TOPIC_ID=16594 pic of the set up is on page 2 by the originator (kiddo)

 

[Snazzypens]

[]I spent all last night cleaning her morse they are clean. Well I can't feel or see nothing in it. I tried swapping the blank..Well now I have blank both chipped out on each end. Like the last 3rd of the pen nearest to the head stock have chipped out on my last 6 pens. I bought a new mandrel because my last one I gave a bad time it even had hunks ground out of it.[:I] but still problems. The only other turner I know is my father in law and his lathe knowledge is exact same as mine we started nearly together.[] I thought it could be my drive because it was pretty dinged up. so I tryed another one. I am definitely gluing them up enough because you can see on the blow off pieces that I am regluing back on where the glue been. see the photo I have added one side is on the bottom is flush the top one is out.
Any other suggestions??
Toni

 

[Firefyter-emt]

Is your tail stock lined up to the headstock? You will need a spur (or dead center) in the headstock to check this. Remove the mandrel and put the center in the head stock and with the tailstock turned in all the way, try to line up the points and see where you are. They should be dead perfect. Also spin the headstock and see if it looks like the headstock end wobbles. (aka a bent headstock.) Not sure what lathe you have but it should have a side to side adjustment for the tailstock to be adjusted.

 

[Snazzypens]

NO it not lined up but I finally got hubby to have a look....We think he found the problem..The tail stock gone wobbly so he thinks he may of found it. The tail stock has a lot of movement in it the part that holds the drive parts
thanks.
Well I hope this is it this time
bye
Toni

 

[Snazzypens]

After 2 weeks fiddling tonight hubby thinks he found it the problem. The part that goes into the tail stock. that spinning drive bit bearings are gone...Can you tell me what it proper name is so I know what ot ask for when I order new bearings in the morning[:I][]
hopefully tommorrow I get to finish a pen with no blow out. I am os looking forward to that. Nothing more disheartening
TOni

 

[Firefyter-emt]

Do you mean the 60 degree live center? The cone shaped ball bearing tip?

 

[Snazzypens]

yeah that him. Thanks.
Toni