Loose blank?

[wortmanb]

I'm really new to turning and pens both. I turned a pen in a class at Woodcraft and followed it up with a seam ripper for my wife. Now I'm trying a second seam ripper using a blank of Coolibah burl, and the blank is rotating pretty freely around my mandrel. I don't think cranking down the knurled nut will help, and might make the thing spin eccentric, so what else can I try?

My tools are probably less-than-optimally sharp, so that maybe a factor too. I can, however, spun the blank when mounted freehand with no effort.

Thanks!

 

[bmlewis]

Is the blank still glued to the brass tube?

 

[Mike D]

You don't have to crank down on the nut but it should be snug. Brett is right. Is the wood still glued to the brass tube? If it's not then did you scuff the tube before gluing it? To attach the wood to the tube did you use thin or gap filling CA or epoxy? What type of wood did you use? If it's an oily wood it may have spoiled the bond. For oily woods, clean the bore out with denatured alcohol just before gluing in the tube. I stopped using CA and switched to 5 min epoxy and have had no problems but I always used gap filling CA when I used it for installing tubes, plus epoxy is cheaper than CA.

 

[wortmanb]

The tube is still glued in. I used gap-filling CA and scuffed the tube first.

I only squared one end with a pen mill. Perhaps the other end isn't quite square?

 

[wortmanb]

The wood is red Coolibah burl.

 

[StephenM]

Could you have run out of threads on your mandrel? Put a spacer in, then your first bushing, blank, bushing, nut.

 

[wortmanb]

It's a Woodcraft mandrel, so it adjusts down. I shortened it to be safe; no joy. Could my tube opening be a bit wide?

 

[StephenM]

Do the bushings fit snugly into the tubes? The tubes can be any size - it's the bushings that hold everything concentric.

 

[ed4copies]

Well, here are the choices I can think of:
1) It's a Penn State Mandrel and somebody else's kit (PSI mandrels run a little smaller than everybody else).
2) The kit does not use a 7mm tube and you need bushings with a shoulder to fill your brass tubes.
3) You say you are using an adjustable length mandrel. Is the mandrel slipping out of the "Morse taper gripper" (headstock end) as you tighten the nut on the other end?
4) OTHER (God only knows what could be messing you up). Call a friend to take a look at the set up and analyze the problem (or post pics here and we can all give NEW guesses!!)_

 

[wortmanb]

I'll take some pics and video tomorrow. I really appreciate the help. My closest Woodworking store is an hour away without traffic.

 

[wortmanb]

Do the bushings fit snugly into the tubes? The tubes can be any size - it's the bushings that hold everything concentric.

One does, the other might be a tad sloppy.

 

[NotURMailman]

I have had this problem before. Let me take a stab at it...

1 - you should square both ends of the blank before installing on shaft

2 - I (now) pull the shaft out of the collet and put the knurled nut on the 1/2 of the threads closest to the end of the shaft (tail stock end)

3 - slide the bushings and blank on from the collet end of the shaft

4 - insert the mandrel into the collet

5 - slide the tailstock (gently) up to the mandrel

6 - now tighten the nut on the mandrel collet

7 - now snug up the tailstock by turning the quill out (snug, not tight!) and lock the quill

8 - now snug the knurled nut up by hand

Since I started doing it this way I have not had any issues.

 

[wortmanb]

Thanks--I'll try that next.

 

[wortmanb]

The suggested approach to tightening the mandrel worked like a champ. And having just regroups my gouge on a new PC grinder, I finished the blank in good shape. And discovered just how badly burl wants to tear out!

 

[NotURMailman]

If you're talking about the method I posted, I am glad. I am still new at this and have gotten a lot of help from members here. I am glad I was finally actually able to return the favor!

 

[wortmanb]

If you're talking about the method I posted, I am glad. I am still new at this and have gotten a lot of help from members here. I am glad I was finally actually able to return the favor!

Yep, it was your help. Sorry, I was posting from my phone's tiny keyboard or I'd have made sure to be more specific.

 

[NotURMailman]

No worries, I wasn't looking for any credit or anything. Just glad to be able to "give back"!