Lathe drilling

[warthog]

I am fairly new to this pen turning phenomena...and I purchased a used lathe from a gentleman in Colorado. Since I do not have a drill press available and to keep my cost down I decided to drill my blanks with the lathe. Maybe if I add everything up that I bought to do this with I may have been better off to get a drill press. Anyway...my problem is this...Every aspect of the lathe is great except for when I want to drill my blanks. The tailstock is not centering on the blank that is being held by a dedicated blank holder. And there seems to be a lot of wobbling. I have to physically hold the drill chuck while I advance the bit into the blank. The bit is hitting a little low and to the right of center. I sure would welcome any ideas on how to correct this.

 

[studioso]

first make sure the tail stock assembly is centered. do you have a live center? put that in the tail stock. put a dead center in the headstock. do the tips meet?
make sure the quill is extended enough so that the taper on the live center seats nicely. make sure both centers, as well as both female tapers are very clean: even a small burr can mess up the setup.
so run your finger into the trail stock and head stock to make sure they are clean.

make sure the tail stock is tied down. if the centers are still off, by more than a few thousands of an inch, you are in trouble

 

[glycerine]

Follow Alex's advice, but you will probably want to hold the drill chuck just as you are doing in ANY case. It can come loose, especially when retracting the tailstock. Also, what kind of bits are you using (brad point, etc.)?

 

[Russianwolf]

Actually, here's the best test.

put the live center in the tailstock and the blank you want to drill in the chuck. bring the tailstock up to the blank and let it scribe the end of the blank just barely. If you get a circle, then you have an alignment issue. If you get a dot, you are fine.

Remember, just because you have that blank in a dedicated chuck doesn't mean that it's spinning true. A mm out at the headstock end can be 5 mm at the end of a 6 inch blank. The blank could be less than perfectly straight, and the chuck could be holding it just a little off.

This is why I prefer round blanks and my collet chuck now.

 

[Texatdurango]

I am fairly new to this pen turning phenomena...and I purchased a used lathe from a gentleman in Colorado. Since I do not have a drill press available and to keep my cost down I decided to drill my blanks with the lathe. Maybe if I add everything up that I bought to do this with I may have been better off to get a drill press. Anyway...my problem is this...Every aspect of the lathe is great except for when I want to drill my blanks. The tailstock is not centering on the blank that is being held by a dedicated blank holder. And there seems to be a lot of wobbling. I have to physically hold the drill chuck while I advance the bit into the blank. The bit is hitting a little low and to the right of center. I sure would welcome any ideas on how to correct this.

Before we start thinking there is something wrong with the lathe, let's look at your comment above. Without looking at anything else I would suspect you are chucking your blanks into a chuck that is not holding the blanks true with the spindle. Just because you can chuck up a blank doesn't mean it will be straight.

Try this......... take a centering guide and mark the center of the blank with a punch or awl THEN loosely chuck the blank with just enoug force to hold the blank in place THEN bring your tailstock up and have the point of live center touch the dimple you just made THEN tighten the chuck with the live center still sticking in the dimple.

To get an idea of what I'm talking about, look at steps 2 and 3 in the following tutorial...........

http://content.penturners.org/library/techniques/turningbetweencenters.pdf

 

[sbwertz]

This may sound like a dumb question, but are you locking down the tailstock? If the tailstock is not locked down, it won't align with the headstock properly. DAMHIKT.

 

[dgerwin11]

Sharon,

It is good to know that I was not the first to not do this. I never get to be first. :frown:

 

[warthog]

Yes...I be locking down the tailstock.