Offcenter holes

[John Torchick]

I'll post here as I still consider myself new to the craft. I have a HF lathe, #34706. The headstock and tailstock line up OK. I turn cork for custom fishing rods. I use a piece of 1/4 in .X 12 brass tube for a mandrel. I turned a foregrip today and noticed that the hole was a bit off center when I reamed it to fit the rod taper. Maybe shorten the tubing to eliminate any flexing? Any and all help is appreciated.
I would say get a new lathe but SWMBO would get involved in this discussion.

 

[ray hampton]

how far can you shorten the tube ?

 

[john lucas]

So your inserting the brass rod into a hole in the cork, using this as a mandrel between centers and then turning the cork. Does that sound right? If the rod flexed that would only affect the center portion I would think. The very end would still be running on center. Either end. How big are you reaming. That could easily pull off center or was it off center before you started reaming. When I was doing a Windsor chair we learned that you could change the alignment of the leg when you ream the hole by applying more force on one side vs the other as you ream.

 

[Dean Center]

How are you holding the mandrel at the headstock end, John? A drill chuck can sometimes be a little off. Or you can get a little debris inside the morse taper. Or the mandrel could be bent. Or you may have had your one bad reaming for the year. If you use that mandrel again, check the symmetry before you ream.

 

[Ed_McDonnell]

You might consider switching to a solid steel rod for a mandrel instead of brass tubing.

Check the ends of your brass tubing and make sure they are still round. It's pretty easy to deform brass tubing and if they are out of round you will have problems. If you are mounting the brass tube mandrel between centers, consider making some bushings that will help keep things centered and stop the live / dead center from deforming the brass tube at the end. If you are using a chuck of some sort to hold the mandrel and you don't want to switch to a solid mandrel, consider changing to a collet chuck. It's much less likely to deform the tube.

Got any pictures?

Ed

 

[John Torchick]

Thanks to all! I'm using a Jacobs chuck in the headstock. I could cut the tubing down as my grips are only 7 inches long at most. I have a solid mandrel and will go back to it to see if that cures the problem. I use tapered reamers that are used by rodbuilders to enlarge and taper to fit the taper of the rod blank. I used a drill to save a bit of time but I'll experiment with some cheap cork to see if hand reaming will help.
Ed, I have pictures but they are all of the grandchildren. Ready for a 30 minute presentation?

 

[Ed_McDonnell]

Ed, I have pictures but they are all of the grandchildren. Ready for a 30 minute presentation?

Only if the pictures are of them turning stuff on the lathe .


Ed

 

[John Torchick]

Only if the pictures are of them turning stuff on the lathe .

Ed, I'm going to have to get up early to top that one. They are too short to reach the lathe. One of these days, I'll get them turning timber. I was turning a grip a while back and the two oldest ones didn't like the noise, even with ear muffs.