Pen Turning

[Stuart]

I have a (very) cheap (cough) GMC Lathe, which has been doing a reasonable job, all things considered!

I am wanting to turn some pens on it, and have a pen mandrel for this. The GMC lathe does not have a taper fit on the driving end, and at best, I have a 4 jaw chuck which screw-fits to the drive.

To fit the mandrel, (given the 4 jaw doesn't close down to the 6.5mm diameter of the mandrel), I have vandalised an old, very cheap drill I had, and took the chuck off it, and mounted that in the 4 jaw. All this works fine, except....

In this instance, and others, how do you go about accurately centering something in a 4 jaw? I have gotten this close, but still have a +/- 0.5mm eccentricity, which is causing the pen blank to be turned off centre.

Suggestions much appreciated (and no, I cann't afford to upgrade the lathe, or the chuck!)

[DarrylF]

The only way I know of doing this even close is to use a dial gauge. You put something as close to perfectly round as you can find into the chuck setup, mount the dial gauge on an arm or whatever so that the tip rests on the top of the round bar, turn the chuck by hand until you find the high point, adjust the chuck centering and repeat until it's perfectly centered - or at least as close as you're going to get.

A complete pain in the ass and quite slow - if you want it accurate. Been there, done that many years ago with my old Emco lathe.

I'd be more worried about the chuck holding a chuck setup was safe though - doesn't sound it to me http://ubb.ubeaut.com.au/ubb/smile.gif

Save your pennies, keep an eye on the paper and buy yourself a second hand lathe setup with a decent self centering chuck and a vaguely decent lathe. There's one for sale locally here for $475 at the moment.

[jamesy]

I have never used a mandrel. Hold your blank in the chuck - turn to a rough cylinder and trim end- drill hole for brass centre- measure and mark (near accurate) the lengh of the brass centre- glue the pen blank in and part off- turn to your chosen wall depth between drive and REVOLVING centre. Use just enough pressure between centres to hold the unit.

Do the same with the other part and after connecting you can match them the same way, if you have left enough meat on each blank. This exercise should be some very gentle sanding.

Remember- You don't make a living from making pens this way but you get pleasure from making something that is functional and beautiful.

[Stuart]

Cheers guys,

Addressing some of the points raised: I have no intention of making a living from this: Xmas presents only!

Re not using a mandrel: When the wood becomes that thin, what stops it blowing apart under even light pressure? The lathe doesn't even have the ability to drill by fixing a stationary bit, so I have to drill the hole either before turning (and then fitting the mandrel), or after, and without a drill press, I have very little hope of getting the bit to pass even close to the centre of the turned piece! Yes, my workshop is still lacking some of the fundamentals- working on it, but the budget isn't unlimited!

Upgrading the lathe in the long term is definitely a go, but at the moment, see cash flow point above!

And finally, I do appreciate the concern of a chuck holding a chuck- in this instant, it is held REAL tight, and as I have not removed the first gear wheel from the drill shaft, I have a very good surface to get a purchase on, and it leaves the actual drill chuck clear of the lathe, so I can remove the work, without removing the drill chuck & having to recalibrate each time.

Guess until I can affor to upgrade, I will have to accept some very time consuming setup!

http://ubb.ubeaut.com.au/ubb/wink.gif

[Kev Y.]

stuart, Have you considered maybe turning the pen in your drill press?

I remember seeing an article on this technique in one of the "Australian Wodsmith" magazines, from memory it was june/july issue.

THAT way you can use the pen mandrel.

Kev

[Cliff Rogers]

Originally posted by Brudda:
stuart, Have you considered maybe turning the pen in your drill press?
.....
THAT way you can use the pen mandrel.

Kev

G'day.

Yeah, good idea, you can get a cheap chinese
drill press for about $99 at Mitre10.
Lay it on it's back & 'hey presto' one
mini lathe in a hurry.



------------------
Catchya,
Cliff

[Iain]

Or get a poolside recliner and keep the drill press upright http://ubb.ubeaut.com.au/ubb/biggrin.gif
I saw that article in woodsmith and it seemed OK with a metal rod beside the mandrel as a toolrest.

[Stuart]

Cheers for all the feedback- I tackled the lathe again & spent some time getting it set up, with an approximation of the dial gauge (eyecrometer, & tool rest), and have made my first pen. Very pleased with the results, (other than getting a couple too hot, causing the insert brass tube to expand too far & crack the thin wood of the pen http://ubb.ubeaut.com.au/ubb/frown.gif

However, it is all a learning curve!