In between center turning and lathe drilling idea

[jbeyer]

I just realized something that I'm not sure if it would work or not but wanted someone's opinion.
Since I turn in between centers there is no need for a mandrel, which means that the blank doesn't have to be drilled to turn. Now my idea is, since the blank doesn't have to be drilled all the way through, could it be possible to slightly drill, just enough for the bushing to be placed in it. Then turn. I've had problems with blanks chipping out, my though is because the blank doesn't fully glue to the blank (or for some other reason I have yet to determine).
So my thought was that if the blanks are just drilled about 1/4 of an inch, or what ever the length of bushing is, then turn in between the centers... and after it is fully turned, then drill all the way through...

Do you guys think that this would work?

Jonathan

 

[rej19]

Since there is just a very small fraction of an inch of material covering the tubes I think it would be very difficult if not impossible to drill with out blowouts. The CA holding the material to the tube prevents that.....at least most of the time.

 

[jocat54]

Jonathon if you have or can get a collet chuck you can turn the blank down to fit a collet and then drill part of the way thru and then turn the blank around and finish drilling it would eliminate any chip out at the end.

 

[Paul in OKC]

Drilling on the lathe is good, but I wouldn't want to drill ater turning to size. Leaves no room for any drill bit wander, and there will be some, even if minute.

 

[thetalbott4]

Drilling is best done when there is the most "meat" to support the drilling. You will definately kill more blanks drilling in thin material than by chip out. By chip out, do you mean you getting blow outs while turning or drilling? If when turning, then better glue coverage and roughing of tubes is in order. If during drilling, cut the blank longer and trim off the chipped area.

 

[wolftat]

I don't understand why you would want to try that, it leaves a lot of room for error.

 

[randyrls]

I've had problems with blanks chipping out, my though is because the blank doesn't fully glue to the blank (or for some other reason I have yet to determine).

Jonathan;
If your chip out is occurring during turning, make sure you are cutting from the center toward the end.

If your chip out is occurring during drilling, cut the blanks about 1/4" longer than the tube. Then cut the blanks to exact length after drilling.

 

[Robert A.]

Man that is a scary thought for me.I've always cut mine a little long.By turning then drilling I would think even IF the drill IS true,wouldn't the blank get too hot?

 

[nytefaii]

Jonathan;
If your chip out is occurring during drilling, cut the blanks about 1/4" longer than the tube. Then cut the blanks to exact length after drilling.

+1 my thoughts exactly

 

[Rangertrek]

Jonathan, If your problem is with the glue adhesion to the blank, try using Gorilla glue. This is the moisture cure variety. I have had much better results with it than with CA or epoxy. I have had only 1 chip out since I switched over a year ago.

 

[JerrySambrook]

Jonathan;
If your chip out is occurring during turning, make sure you are cutting from the center toward the end.

This is not always true, depending on grain orientation, grain structure, dryness of the wood, and bondability. Sometimes it is better to use a skew and come from the outside it, so that there is proper fiber support. On an acrylic blank however., blowout usually happens with dull tool, too much pressure, to big a bite, not enough speed.

The cutting technique of coming from the end to the middle does take a little practice, and once again, requires tools to be sharp at all times. This is the biggest factor of turning, is most of us do not sharpen enough, expecially when it comes to final cutting time

Just my .02

Jerry

 

[jbeyer]

I'll try the Gorilla glue. Is there a different procedure to follow with it? I think that I recall some at some point said that you need to clamp it on both ends together so the blank doesn't move out. How long does it take for the glue to set and be ready to turn...

Jonathan

 

[randyrls]

I'll try the Gorilla glue. Is there a different procedure to follow with it? I think that I recall some at some point said that you need to clamp it on both ends together so the blank doesn't move out. How long does it take for the glue to set and be ready to turn...

Jonathan; I use both Gorilla glue and CA. For both glues I use the same procedure.

1. Rough up the brass tube with sandpaper.
2. Plug one end with dental wax.
3. Put glue inside the blank then on the plugged end of the tube.
4. Insert the brass tube into the blank and insert it with a twisting motion. You should get glue coming out the other end of the blank. IF not, use more glue inside the blank on the next go-around.
5. Gorilla glue can cause the brass tube to slide in the blank. Check the blank about 15 minutes later and about 30 minutes after that to make sure the tube hasn't moved in the blank. if it has, push it back to the right position. You can wrap a rubber band around the ends of the blank to keep the tube in place.
6. Leave the blanks in warm room temperature for at least 8 hours. I usually wait over-night.

With Gorilla glue, you can pull the tube out of the blank and inspect the inside of the tube to check for coverage. Make sure you use enough glue.

 

[bitshird]

Jonathan, I also would recommend Gorilla glue, there is a quick setting formula out now that will allow you to turn in about 3 or 4 hours, Also if your chip outs are at the bushings try turning from the bushings towards the center, cross cut or angle cut blanks are the worst for chipping at the ends, even if you do have enough glue coverage.
Drilling after turning to size sounds like a recipe for disaster!! are you using an insert that has been chipped? or hit a chuck or bushing? try rotating your insert or changing it, even dropping your tool on the floor will ruin a carbide insert. and also if you use Gorilla Glue use a rubber band or masking tape to prevent the tube from crawling out, I've had it happen a few times.

 

[jbeyer]

I replaced the insert and so far so good. I'm going to start using Gorilla or Sumo glue, need to figure out which works better. The one concern that I had was that if you wanted to paint the inside of the blank or the outside of the tube, how would the glue affect the color...