Revolving center

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TXTurner

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Hi all,

I'm completely new at this, so please pardon what may be some stupid questions.

I've made a couple slimline pens on my Jet 1236 using the existing tailstock center, which I believe is a live cone center. I could be wrong, as I've got lots to learn.

Some of the pen kits I'll want to tackle as I move along call for a revolving 60 degree center. I see where I can buy this from a number of different sources.

My question is whether or why it's necessary. Can I not turn these pens with the existing live center?

Any help is appreciated.

Thanks,

Mark
 
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Rifleman1776

Rifleman1776

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The cup centers are less than desirable for a couple reasons. One is the point may not be 60 degrees. That is the standardized angle for the female (tailstock) end of the mandrel. You could, and probably will get wiggle, vibration and resulting less than perfectly round results. The other big reason is the woodworking cup tip is (usually, e.g. 99% of the time) not hardened steel and will wear out in short order. Meaning, either way, you will have to buy a new center or two.
Do get a machinist type live center and make sure it is hardened steel. The difference in price is about $20.00 compared to $10.00 for soft.
 
Gentleben

Gentleben

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The 60 degree cent is very usefull if you use you tailstock at all. It allows you to work on the tail end father in without catching your tool. Most turners I know use them all of the time. It is almost a almost a requirement if you are going to bring your tailstock up to hold a brass tube.
 
Russianwolf

Russianwolf

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not sure what your center looks like, but the one that came with both my PSI and Grizzly lathes has a point in the middle and a circle a little further out. The point is not 60 degrees.

If you are turning an a mandrel and the end of the shaft has a 60 degree recess, it will eventually chew the point on your center up. The mandrel shaft is a hardersteel than the center. To prevent the wear on the center the point and the recess in the shaft have to match exactly (and this is SUPPOSED to be 60 degrees).

I've eliminated the mandrel and switched to turning between centers as many here have done recently. A member, johnnycnc, makes very good bushings for between centers turning but he has taken a vacation for the time being. To turn between centers you will still likely want to replace your center with a 60 degree cone center as it doesn't get in the way as much.

I do use my stock center for other spindle work as the circle that surrounds the point is good for preventint the spindle from splitting.
 
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hehndc

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When I switched to a 60 degree live center. I found the end of the mandrel fit much better, giving resulting in less "wobble" (so to speak).

Money well spent IMHO.

Steve
 
rjwolfe3

rjwolfe3

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Okay on this thread I have seen Dead Center, Live Center, and Cone Center. What's the difference and which do I need to turn pens without a mandrel?

Thanks,
 
johnnycnc

johnnycnc

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To turn pens with no mandrel,you'll need:
A.)dead center for your headstock.No internal moving parts.
transmits power/rotation directly.This "drives" your blank.
B.)live center for your tailstock.Has internal bearings.
allows for support,while spinning, to a rotational object,
such as your pen bushing/blank,
while being mounted in a non rotational socket(your tailstock).

(cone,or cup center is used,for the most part,directly into wood,
such as spindles or other items where no bushings are used).

Originally posted by rjwolfe3

Okay on this thread I have seen Dead Center, Live Center, and Cone Center. What's the difference and which do I need to turn pens without a mandrel?

Thanks,
Click to expand...
 
Rifleman1776

Rifleman1776

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Originally posted by johnnycnc

To turn pens with no mandrel,you'll need:
A.)dead center for your headstock.No internal moving parts.
transmits power/rotation directly.This "drives" your blank.
B.)live center for your tailstock.Has internal bearings.
allows for support,while spinning, to a rotational object,
such as your pen bushing/blank,
while being mounted in a non rotational socket(your tailstock).

(cone,or cup center is used,for the most part,directly into wood,
such as spindles or other items where no bushings are used).

Originally posted by rjwolfe3

Okay on this thread I have seen Dead Center, Live Center, and Cone Center. What's the difference and which do I need to turn pens without a mandrel?

Thanks,
Click to expand...
Click to expand...

Cone center is a type of live center for the tailstock. You shouldn't use this type for 'no mandrel' turning. Use a regular cone live center. For the drive, or headstock, end use a dead center. Normally, this is a basic center for the tailstock. But, those of us who make pens have justifiably been called a d'frnt type of critter and we do stuff equally d'frnt.
 
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