Mandrel fit question...

[Aaron Buys]

Well I'm almost ready to turn my very first pen and I'm not sure if my mandrel is fitting correctly. I have a General International Maxi-Lathe 25-100 and a PSI PKM-FLC #2 MT Mandrel. According to the lathe manual my lathe is also a MT #2. I knocked out the headstock center and slid the mandrel in to replace it however it doesn't seem to fit snug like my headstock center does. Side by side the mandrel is shorter than the center but they appear to be the same taper as stated earlier. My question is...how tight should the mandrel fit in the headstock? Does the live center apply the pressure to keep the mandrel snug in the headstock or should it be quite tight on its own? Help! My first turning is almost within my grasp!

[Bernie Weishapl]

Aaron mine fits fairly snug in mine. I can pull it out most times by hand and don't need to tap it out. The tailstock livecenter has to have a 60 deg. tip to fit the end of your mandrel. Just put enough pressure with your tailstock livecenter but not enough to bend the mandrel. Sounds to me like you are fine.

[Aaron Buys]

Hmm...I just went back and fooled a bit more with mine. It sure isn't a tight fit like you are describing Bernie...and really doesn't want to stay in there without me holding pressure or moving the tailstock up against it pretty firmly. As a matter of fact that whole mandrel sags down at an angle if I don't hold it upright by hand. I'm thinking there is something a miss here. My novice lathe knowledge tells me that the mandrel taper should be the same length as the headstock center in order for a tight fit to be acheived...is this right? Do I have the wrong taper here despite #2 MT being labeled on both items? I've included a picture in case it will help solve this mystery.

[Grant Wilkinson]

Aaron

Although it's a bit tough to tell by your pic, the mandrel taper does not look like a #2 to me. It is clearly not the same taper as your center is. Maybe it's a #3.
When I put my #2 taper pen mandrels in my head stock, they stay put. After I've turned the pen, neither of them will come out by hand. I need to use the knock out bar. Others will chime in, I'm sure, but I think that's the way they all should be.

[George Heatherly]

My experience is the same as Grant's. My mandrels fit snugly and require a knockout bar. I do have a Jacobs chuck on a #2 morse taper that will not stay in the headstock without pressure from the tailstock.

[Jonathon Spafford]

I would agree... that doesn't look the same taper! The difference in length between the two shouldn't matter if the taper is the same. I would get another one!

[Phillip H Smith]

Aaron...

I have the very same PSI mandrel and use it on a Rikon midi...the pen mandrel fits as tightly as the spur center. The pen mandrel, however, is a bit shorter...but as mentioned by others, it shouldn't matter.

Based on the photo you provided, the taper between your PSI mandrel and the your spur center does look different. Maybe you're dealing with a manufacturing or packaging error, or maybe somebody pulled the wrong item from a bin at the warehouse.

I'd give PSI CS a call...they're very helpful. Example: PSI sent me the wrong pens and replaced them immediately when I notified them.

It may not be a good idea to go ahead and use the mandrel you have, as it may cause some damage to the headstock taper....and that could get expensive.

[Joe Collazo]

It looks like you have the PKM-ELC rather than the PKM-FLC mandrel.

joe