I'm going through pen mandrels...

[RobW]

I just bought my 3rd pen mandrel (first was the el-cheapo from Woodcraft, then the adjustable length Penn State, now just a new shaft for the adjustable). Using it on a little Wilton mini-lathe. The first 2 I think I bent out of shape by cranking on the tail stock too tight. This new mandrel, I just twist the live center into the mandrel until it just barely snugs up. Only turned about 10 pens on this new one, and already it looks out of whack. I can feel that the bushings by the headstock, when running are very smooth, the ones by the tailstock seem like they almost wobble when the lathe is running. Maybe that's not a good way to explain it, but it just feels like the mandrel is not perfectly straight.

My live center is that low-end one from Woodcraft with 2 interchangable tips, and the pointy tip is kid of chewed up from tightening too much with the other mandrels. When I bring the tail stock up to the head stock, the points seem perfectly in line, so what would make the tail-end of the mandrel seem to have run-out? Do I need a better 60 degree live-center? I need to make about 35 pens in the next 12 days, so I don't have time to mess with this.

Help....

Rob

 

[TomServo]

If you're using WC centers, they're probably not 60 deg. I hear littlemachineshop has the right ones - you'd have to ask someone else, i'm using a "dead" center that's part of my tailstock on my metal lathe. If your live center is a wood-type live center, then it is not 60 degrees. That would cause your tailstock end to be off-center, especially if the point of your center is marred.

I've found the berea mandrels to be pretty high quality.

 

[jimbo 31751]

Rob, I had the same type of problem with my jet mini.
I got the 60 deg live center from Little mach shop and that took care of my problem.

 

[loglugger]

Same here, littlemachineshop

 

[alamocdc]

I got my 60 degree from Woodturningz. It works great and it wasn't very expensive.

 

[arjudy]

www.littlemachineshop.com

 

[dubdrvrkev]

I use the wood craft madrels all the time except for the B mandrels. I have better luck with those than the CSUSA ones. I'd agree it could be the center or you could be pushing a little to hard against it. One other thing that it could be is the compression fitting that WC includes with the mandrels. If you tighten that too much it will also put a nice bend in the mandrel. I use them as spacers but just barely snug with my fingers.
Mandrels are easy enough to straighten though. If you put the mandrel in and bring the tailstock up to about 1/16" away and rotate the mandrel by hand you will find out how bent it is and where is tracks. Rotate it a few times and find its highest point and give the end a little push down then repeat until it runs true.
Good Luck

 

[rduncan]

So which live center are you folks using from Littlemachineshop?

I see: http://www.littlemachineshop.com/products/product_view.php?ProductID=1592
and http://www.littlemachineshop.com/products/product_view.php?ProductID=1189
I checked for MT2 tapers but they have others.

Thanks,

 

[gerryr]

Grizzly also has a 60 degree live center that's about a buck cheaper than Little Machine Shop.

The other possible cause of your problem could be that the morse taper in the headstock has some kind of gunk in it. I clean mine at least once a week with lacquer thinner.

 

[jwoodwright]

I had the same problem. I put the live center in the headstock of my Jet Mini. Turned it on and touched a file to the bruised tip. Turned it off and checked the mandrel. Without the sharp bruised tip it worked great!

Then I ordered the 6o degree live center from Grizzly.

While waiting 6 weeks for the Grizzly, I turned about 25 pens... So, the file will help...

 

[vick]

if you are bending that many mandrels I would guess either your tools are dull and you are applynig to much preasure, or you are titening you tail stock to much. The 60 degree live center is much better to work with and you will get less wobble on your mandrel. I got mine from the little machine shop, the light duty one work great and is only 10 or 12 bucks.

 

[knottyharry]

Rick, IMHO I would go with the #1189 from The Little Machine Shop. You are not supporting a lot of weight here, so I see no need for the heavy duty live center.

Rob,
You are getting some good advice here.
If you are using the live centers that came with the lathe, they are made for wood.
Not for metal.
You should invest in a 60 degree live center. Check out the #1189 from The Little Machine Shop.
A couple of other things to watch while turning.
The nut should only be tight enough to keep the blanks from spinning on the mandrel.
Just finger tight. The first video I watched, showed them tightening the nut with a pair of pliers..... I learned the hard way.
Sometimes it will tighten on it's own... check it from time to time.
Another thing to watch is that the majority of the bushing is on the smooth part of the mandrel, not on the threads.
Don't ya just love doing this.
Harry

 

[Randy_]

You are getting a bunch of good advice!!! "<b>DO NOT</b>" order the 1592 heavy duty live center. It is designed for turning big heavy metal projects. It has been know to function poorly with little wooden pens. The standard duty 1189 will work just fine. I bought one at the recommendsation of others here at IAP and it works like a champ. $12.95 + $8 for shipping.