Shopsmith Forums

a1gutterman wrote:And also the implication that it flexes back. Once bent, why wood it flex back?

The spinning wood. If the bit touches a 32nd below center, it just cuts a larger than planned hole. But once it grabs the wood, one of two things happen.

A. It follows the wood around the circle, weakening and eventually breaking the bit.

B. It migrates to the center where it stops flexing and finishes the cut true.

Fortunately B happens far more often than A.

Hi,

I was thinking the stop rings should help so are they in place and adjusted?

Ed

Just WHAT is moving???
Tail stock in frame holes?
Tail stock eccentric?
Chuck adapter?
Chuck?
Bit?

Is everything aligned properly" i.e.:

Put tailstock center in tailstock.

Put lathe spur on quill shaft.

Slide headstock all the way to the right.

Extend quill until point of spur almost touches tailstock center.

The points MUST be aligned! Make them so.

Retract quill, remove taiilstock center, mount chuck adapter,chuck and bit.

Extend quill until it almost touches bit point. They should align.

If not find out why and "fix".

Any misalignment will cause the problem you are describing even with NO tailstock "slop".

If properly aligned, the "slop" will tend to "self center".

1/32" play seems excessive if everything is "tight".

Don't forget the "step drill" suggestion.

P.S. What is aligning the "blank" or whatever is being bored at the "right" end???

grauenwolf wrote:The spinning wood. If the bit touches a 32nd below center, it just cuts a larger than planned hole. But once it grabs the wood, one of two things happen.

A. It follows the wood around the circle, weakening and eventually breaking the bit.

B. It migrates to the center where it stops flexing and finishes the cut true.

Fortunately B happens far more often than A.

With "A", it sounds like the bit isn't tight in the chuck or the chuck arbor is spinning in the tailstock.

JPG's post got me to thinking again (ouch). Assuming you have aligned the tailstock center with the quill center - before you drill - make sure the drill bit center is exactly at the center of the workpiece as you tighten the chuck.

If the work piece gets chucked a mite off center, and the bit enters away from center, such mis-alignment could possibly cause a funnel shaped hole or a bent hole.

grauenwolf wrote:Essentially the problem is all the weight from the chuck and drill bit cause it to sag

Johnathan,

I see that PennState is having a sale on drill chucks on Morse tapers.
here is a link to a 3/8" chuck on a Morse 2 taper
http://www.pennstateind.com/store/TM22.html

IIRC, that's the right taper for the SS tailstock, but I would not trust my memory on that. there is also a Morse 1 taper version.

it seems like this ought to be quite a bit lighter than the SS 1/2" drill chuck with its 5/8" spindle hanging off the SS tailstock arbor adapter. it looks like the PennState unit might be shorter than the stack of SS units. if so, it would also reduce the cantilever moment even more.

question: after you drill a blank and get the funnel effect, if you turn off the SS and then extend the quill, does the drill bit always touch the bottom of the funnel? I seem to recall from other threads that the quill can sag a bit if the feedstop adjustment is way loose. in that case, the drill might touch the top of the funnel when you check it after drilling.

Ivan

iclark wrote:Johnathan,
it seems like this ought to be quite a bit lighter than the SS 1/2" drill chuck with its 5/8" spindle hanging off the SS tailstock arbor adapter. it looks like the PennState unit might be shorter than the stack of SS units. if so, it would also reduce the cantilever moment even more.
Ivan

That sounds really promising. (Though I still would like a stiffer tailstock.)

iclark wrote:question: after you drill a blank and get the funnel effect, if you turn off the SS and then extend the quill, does the drill bit always touch the bottom of the funnel?
Ivan

I'll have to cut a new blank to test that. Lately I've just been doing things in drill-press mode. The setup is longer, but at least its accurate.

beeg wrote:With "A", it sounds like the bit isn't tight in the chuck or the chuck arbor is spinning in the tailstock.

I was talking in generalities, I haven't had that particular problem with this machine.

jpg40504 wrote:Just WHAT is moving???
Tail stock in frame holes?
Tail stock eccentric?
Chuck adapter?
Chuck?
Bit?

You people don't listen to well.

The alignment is fine. The problem is the combined weight of the chuck and drill bit is causing the tailstock to flex and the tip of the drill bit to dip. If I swap it out for a live center, which is considerably lighter, everything is fine.

This is why I want a stiffer tailstock (or a much lighter chuck).

If it were not so darn cold in my shop I would put my tail stock in and tighten the handle. I would mount a dead center or live center then using my digital angle gauge and zero it on that. Then take the drill chuck and mount it and chuck up a length of drill rod. Put the gauge back on and see if the angle has changed due to the weight of the chuck. If it has then you might want to check to see if you can find the spot that caused the change, like is the chuck tilted etc.

Another good test might be to set up in drill press mode so the gravity is out of the picture and see if the holes have the same look... that should only take a few seconds to do and the results would be interesting to here about.

Or hand holding the chuck and pulling up when starting the drilling might prove useful or at least be an easy way to see how much movement is really happening... I give that a go if I could.

From what I do know I would be surprised to see the weight of the chuck causing much if any change as long as all the equipment is in good working order... something loose, bent, out of round, tolerances out of speck might well be the issue. But hey I could be wrong.

Ed