Mandrel sticks in Headstock

[John D. Ernst]

I am new to this hobby and have had a strange problem with the mandrel sticking in the headstock. I purchased a new Jet variable speed mini lathe (Model JML-1014VSI) and the appropriate mandrel from a local Woodcraft store. After turning the pen blank, I can only remove the mandrel by striking the knockout rod with many vigorous blows with a hammer. I returned the mandrel to the Woodcraft store and we inserted and removed it with no problem in a comparable Jet mini lathe in their workshop. Any suggestions? Thanks! John Ernst

 

[ed4copies]

A guess: you are overtightening your tailstock to the mandrel.

When you tried the one at WoodCraft, you probably did not turn anything on it. As you tighten the tailstock, the MT is forced into the headstock. This is normal. Make yourself a wood mallet to hit your knockout rod. Not unusual.

 

[Majorbdk]

I would question if you are turning pens that are out of round. I found that when I over-tighten the tailstock, that I would get out of round pens. The mandrel would bow. I replaced the mandrel rod and just tighten enough to lock the mandrel in place. Just a suggestion and thoughts that might help. Good luck.

 

[John D. Ernst]

Thanks for the response! It is comforting to know that this is not an unusual result and can probably be corrected by not tightening the tailstock so much.

 

[randyrls]

John; Indeed, Ed is correct, the tail stock is only there to keep the end of the mandrel from whipping around and "walking" out of the MT taper. Once seated, the taper will hold itself in. I only tighten the tail stock gently, and then tighten up the brass mandrel nut. Wiggle the mandrel to loosen the seat of the taper to remove. Be careful about the point of the tail stock. It hurts if you run your hand into it!

You may want to check the inside of the head stock taper for any burrs, grooves, or rough spots. Use a flashlight to spot any trouble spots.

 

[jleiwig]

I think that it also being a freshly machined taper will have a bit to do with it. After removing the taper a few hundred times it should slip out no problem.

 

[CSue]

Welcome John. You've come to the right place.

Below are links to two threads/articles that have lots of information on pen turning. The first one is a very basic overview of the many aspects of getting into turning pens.
http://www.penturners.org/forum/showthread.php?t=42446

The second link has postings by different pen turners and what they wish they had known earlier:
http://www.penturners.org/forum/showthread.php?t=46654


Here is another link - a PDF on the acronyms used here.
http://content.penturners.org/articl...9/Acronyms.pdf

 

[rherrell]

Welcome!

 

[Len Shreck]

I would suggest taking the mandrel back to the store again and this time when you put it in the floor model put the tail stock from that up to it and tighten it as you would at home and see. Try to reconstruct the same conditions to see if it is over tightening or what. That is if you try checking the head taper to make sure you dont have any problems with that. I am new but I learned from past experience with diff things to try and recreate what you are doing at home when you take something back to the store so the person that deals with the part/tool can see what you are doing. Just a thought. and Welcome to IAP home of some of the best and most knowledgeable people on the net in my opinion. Len

 

[Rifleman1776]

A male MT sticking inside the headstock receiver can be caused by any one of a number of things. I don't believe any of the previous responses really answered your problem. MTs are machined within a small range of spec. But, if the male is at one end of the specs and the receiver the other, you may have a strange mate. Do try other male MTs to see what happens. Do check for cleanliness in and out. Make sure the headstock interior is smooth and free of burrs. You may just have to end up getting another mandrel.
One answer would be to use an MT finishing reamer on the headstock. I sure wish these were not so expensive, I would like to have one.
You may just have to fiddle and switch until you find the answer.