live center

[wizical]

Im having a proble with my live center and pen mandrel. Everytime I make a Pen. It seems that the Live center is wearing down faster than anything else. I have talked to a lot of people about this and nothing seems to work. Any help would be greatly appreciated.

Keven

www.custom-woodturning.com

 

[ahoiberg]

keven,

could you supply a bit more information? how exactly is the live center wearing down?

 

[wizical]

the live center is wearing down at the tip when it is inserted into the mandrel. I cant figure out why

 

[wdcav1952]

Keven,

It sounds like you do not have a 60 degree live center. If the tip of the center does not fite correctly into the end of the mandrel it will wear down like you describe.

 

[wizical]

William,

I should have said this earlier, it is a 60 degree center, and it seems to wear down faster that usual.

 

[ed4copies]

Originally posted by wizical
<br />William,

I should have said this earlier, it is a 60 degree center, and it seems to wear down faster that usual.

A 60 degree center, if turning without friction, should not wear noticeably, at all.

Is it hot? Friction? Are you tightening with a "death grip"? (tailstock to the mandrel?)

 

[Rifleman1776]

Originally posted by ed4copies
<br />

Originally posted by wizical
<br />William,

I should have said this earlier, it is a 60 degree center, and it seems to wear down faster that usual.

A 60 degree center, if turning without friction, should not wear noticeably, at all.

Is it hot? Friction? Are you tightening with a "death grip"? (tailstock to the mandrel?)

Or, it could be too loose and spinning on the tip rather than turning the unit. The bearings could be dry. Try a good gun oil.

 

[Malainse]

Where did you get your 60 Deg. live center ? My first one was ebay and was 15 bucks shipped. Had issues with it in a week, over heated and was Dead a short time later....

I have had the Little Machine Shop one now for about a year and hundreds of pens and going strong....

Have you looked at the other end ??? Could the issue be that the pen mandrel is not drilled correctly, off center, not deep enough ????

 

[wizical]

I bought it from CSUSA, and it is brand new, it spins perfectly fine. I have to experiment and see what happens. Thanks for all of the advice.

 

[ed4copies]

Check for heat somewhere. If it is wearing, it will produce heat.[][]

 

[wizical]

i did notice that the live center does get warm, so what would cause that?

 

[LandfillLumber]

Might just be a bad batch of steel it does happen even with high end tools. People make mistakes even if its programming the batch mix wrong and then letting machines finish off the mistake. Steel is wierd and wood is normal,LOL. Good Luck, LabdfillLumber

 

[1080Wayne]

Keven Check the alignment of the live center with the end of the mandrel - leave a small gap between them and turn the lathe by hand . If the end of the mandrel moves relative to the live center , the mandrel is bent or , more likely , the Morse taper is damaged or dirty . If the tip of the live center does not precisely center on the end of the mandrel , you have a headstock/tailstock alignment problem . Either of the above conditions will rapidly destroy a live center tip . Wayne

 

[GaryMGg]

I've had a similar problem to you Keven. My mandrel was drilled deeper than the 60-degree live center could bottom out in and the edge of the mandrel cut a groove around
the live center. I had to grind a few threads off the mandrel.

Gary

 

[Rifleman1776]

Originally posted by wizical
<br />I bought it from CSUSA, and it is brand new, it spins perfectly fine. I have to experiment and see what happens. Thanks for all of the advice.

I have several, all from Grizzly. I have learned that those in the $10.00-$20.00 price range are prone to wear. I took a couple to a machinist friend to have modified for a duplicating machine I have. He took one look at them and said, "There aren't hardened steel." He is right, of course. Soft steel. I plan to pop for more bucks and get a top end 60 degree lc to avoid problems. Mine aren't bad and do last for about a year but they really shouldn't give out for many decades.

 

[bob393]

My old PSI adjustable mandrel didn't seem to have a deep enough 60 deg hole in the end.
It gave me fits until I realized what was wrong.
Now I use an old delta 60 deg live center with the tip slightly ground off
and it solved my problem. If I use my good (new) live center just the tip touches
and not the sides of the taper. It will wobble like crazy!

 

[JimM]

Originally posted by wizical
<br />the live center is wearing down at the tip when it is inserted into the mandrel. I cant figure out why

Keven,
This set of countersinks will give you what you need to redrill the end of the mandrel:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42280

If you look at the large countersink, you will see how there is additional depth to the tip of the bit to allow the live center's tip to seat on the 60 degree side and not bottom out.

Before 'live centers' in metal work, the center was non-revolving. The lathe operator would apply a lead paste in the hole and bring up the center. Pressure was 'lightly' applied so as to retain some lead and squeeze out the excess. One developed a touch for the amount of friction/pressure while constantly checking the tailstock to prevent damage.

Remember, heat will also build up on the center and mandrel as it revolves and also heat from your cutting tool. This causes the mandrel to expand and give you the famous 'out-of-round' condition. Additionally, I suspect that many turners that complain of tail stock alignment are really bottoming the center's tip in the mandrel and causing a wobble or out of round condition especially as things heat up.

I also find that HF has a fairly inexpensive live center:

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=38573

I personally drill the end of my mandrels with a countersink (who knows what was used in China) and use a metal lathe MT2 live center in my tailstock. Still I check it while turning to see if too loose or too tight.

YMMV...Jim

 

[LandfillLumber]

Hello, I'm no steel guy but have been laid up with a busted foot and never have a ton of money to play with so I have been looking into making some simple lathe tools for myself mainly the Oland tool (wish me luck) and have been looking at different steels. Seems that a live center made of M2 steel like the one from HF is not the right type steel just a good hardened steel should be all that is needed. Some one will correct me as I'm a wood man not steel if I'm wrong. I think woodcraft has a live center that is like $15-20 with 2 different tips for it. Good luck, LandfillLumber

 

[PenPal]

A perrenial discussion brings every ones solutions over again so this is my solution. Choosing not to use the point of a live centre in the end of a mandrel.The pic shows the live centre mod with a brass sleeve with a snug fit 3/8 inch deep to receive the mandrel.

The brass sleeve before it was pressed into the live centre showing the removed section. No more problems.

Take care Peter

<br />

 

[jrc]

Your live center is for wood. I wore out 3 before I got the right one. Harbor Freight has one for $20 and will not wear out.
It is the best live center for the money you will find.
The point is to long, you will have to take a little off the very point to fit the mandrell.

http://www.harborfreight.com/cpi/ctaf/Displayitem.taf?itemnumber=38573