Non-wandering bit

[John Torchick]

I was reading a back issue of Wood while riding herd on two of my grandsons. School was cancelled due to the weather. Anyway, there was an article about drilling. The recommendation was a brad point bit or a Forstner bit as they have the point to start and grab the wood. Hope this helps.

 

[Clifton C]

Rereading your post # 18 I’m thinking you might have some alignment issues. A 1mm drop is fairly significant. First, I would check with a drive center and live center point to point and see if they are spot on. if there is a lateral misalignment, adjust legs, if it’s vertical, that’s a different color horse and more difficult to fix. As much as I like turning a tenon at the tail stock end, maybe turning it at the headstock end might help with the alignment. As I understand it, when flipping a piece of wood, any alignment error is X2, and the longer the piece, the more pronounced the error. All this does not help the wondering drill bit, but oft times, little problems lead up to the bigger ones…The bit has to start centered, if it’s off at the beginning, it will never center itself. I advocate, starting the initial drill hole way to fast, so the bit can find its own center, then slowing down to drill to depth. Sharp bits…Clear swarf often…never let go of the Jacobs chuck when retracting bit…etc…etc…

 

[Don Jarvie]

Unless I have misunderstood I think your problem is holding the piece with the tail stock then tightening the chuck. Unless the piece is sitting in the chuck perfect, as you tighten the chuck the piece is off a hair and it is translating to a crooked hole.

You could try after you make the tenon and put it on the chuck drill the hole then. If the shoulders of the tenon are square the your hole should be straight unless the drill bit or tail stock have issues.

Also if you have to drill multiple hole for ex a pepper ill, drill the small ones first so as the holes get larger the bit hits wood right from the start. Hope this helps
Don

 

[Jamie Straw]

Fortunately, the Comet is perfectly aligned, so that leaves other things to chase. Been really busy this week, but will get to all suggestions over the weekend, including the message you sent earlier. Thanks! Also, 1mm was a guess, it well could be half that.

 

[Leo Van Der Loo]

Fortunately, the Comet is perfectly aligned, so that leaves other things to chase. Been really busy this week, but will get to all suggestions over the weekend, including the message you sent earlier. Thanks! Also, 1mm was a guess, it well could be half that.

I doubt it very much that a wood lathe is “Perfectly aligned”, even metal lathes that ride on prisms are seldom “perfect”, as pieces of metal that are to be able to slide over/along each other, there has to be clearances, small but they are there.

I bet you can wiggle, o so slightly, your tailstock from left to right, I have glued brass shimming on a new Delta tailstock to get a better fit and alignment, after all these are pretty cheaply made machines and not precision machinery.

Some dust, wood chip under the tailstock anywhere, or non roundness of the piece of wood could very well cause that drop you are seeing, just a bit of dirt in the chuck can/will have the chuck push harder on one side or the other, even a difference in the wood’s harness will affect the position of the wood in the chuck.

I very often will move the toolrest right next to a spindle and hand turn the lathe while watching, and I will see vey often that very small gap open up and close, it is the result of very minute changes in the wood, differences in hardness chuck jaws o so slightly off, seeing what and where the difference is, like over the whole length or just at the end, I am able to get less of a runout/change of the piece, remember just 20 thousands of an inch out will give you a mm total runout.

 

[Bill Boehme]

I doubt it very much that a wood lathe is “Perfectly aligned" .....

Leo, you speak sage words.

...Here are the steps I'm going through for these items that need to be chucked and drilled:

1. Round a 6" long piece between centers, make a tenon on one end (usually the tailstock end) with a good shoulder and what seems long enough. Example: current piece on lathe is oak that's at least 100 years old, very tight grained and dry. Tenon is .6" long, well-shaped tenon ~.7" diameter.
2. Place tenon in Talon chuck with spigot jaws, not tightened yet. Bring up tailstock and insert nose of live center in the existing divot from original turning
3. Use tailstock to position stock snuggly against jaws, tighten chuck
4. Remove tailstock and get ready to drill

Problem is, the stock moves at Step #4 -- I back off the tailstock, and the end drops.....

Even though "eyeball precision" may look perfectly aligned when sitting still and no forces being applied, things move or deflect slightly when static and dynamic loads are applied. I think that it helps to understand why things move when you look at the outer loop of all the components holding the piece of wood: chuck jaws, scroll gear, chuck body spindle, bearings headstock, headstock clamping mechanism, lathe bed, tailstock clamping mechanism, tailstock body, tailstock quill, live center body, bearings, and live center point. The interface between each of these pieces has some compliance under load, meaning that there is some relative movement when a force is applied. When we check a lathe alignment by matching matching drive center and live center points, we can judge the radial misalignment for a no load condition, but the two things that doesn't tell us are angular misalignment (in other words boresight alignment) and compliance (flexing or moving) when loaded.

An analogy to turning between centers is the drive shaft in an automobile. In an automobile there is flexing and relative movement between the transmission and the rear axle. There is a slip spline connection at the transmission and then a universal joint at each end of the drive shaft. When turning between centers the interface between the drive and live center points and the dimples in the wood are universal joints. That enables the wood to spin about its own axis which isn't exactly the same as the spindle axis or the live center axis. This eliminates the inherent problems when the wood is held rigidly at one end and trying to force the other end to "fit".

 

[Raul McCai]

“Perfectly aligned”, .

Wasn't Bo Derek supposed to have been perfect? Perfect is pretty much subjective. Oh, that's right, she was a 10. Was there an Eleven?
To your point about compliance under load: I had a Machine Shop mentor who told an interesting story (inter alia) about a test that his team did at Texas Instruments dating from some time back in the 1960s where they were looking into deflection. They put a steel bar 1" square on the sides cantilevered off a granite inspection table by 1" . Then they put a super accurate indicator in the end of the bar and then applied various forces to the end of the bar. The result was the bar always deflected no matter how small the force.
So I'll submit that the idea of perfect alignment, along with Ms Derek's perfection, are both in the eye of the beholder.
Now +/-(X.XXX)TIR is a specification that I can understand.

 

[Jamie Straw]

UPDATE: I muddled my way through Christmas presents without really solving the problem. One thing I know now, though, is that something is wrong with either my chuck (Oneway Talon) or my lathe. I'm putting $$ on the chuck, because the "offness" between the headstock and tailstock with spindle turning is the same with both the lathes. The chances of that being the lathes are infinitesimal. Last year, I posted about a possible alignment problem when it was just the Jet 1236, got lots of answers, some indicating that it doesn't matter if the points aren't in a nice straight line for spindle turning. Uhhhhh, wrong. At least if you need to drill a hole after you've roughed the stock -- make a tenon, and then turn it around to mount in your chuck.

I played with the spigot jaws, closing, tightening, moving them around, and found that one jaw definitely stood proud, so I closed the jaws up and sanded things level as I could. But there's still something off (turned a couple of test spindles). I'm going to take the chuck to someone else's (much more expensive) lathe and see if it does the same thing; if not, obviously it's the lathe. Perhaps another possibility is that the jaws themselves aren't as rigid as need be (need spigot, not #2, due to size of stock). I've heard that the Talon isn't as solid as some of the other upper-end chucks. Somehow, this problem will be solved, and then I'll work on drilling technique/bits to get this all fixed.

 

[Jamie Straw]

Jamie, I think that the spigot jaws are the problem. And the length of your work piece.
Joe

So Joe, what kind of jaws should I use for a tenon that's too small for the #2 jaws of the Talon. I'm trying to be efficient with the wood that I select for these projects (handles for kitchen stuff). Suggestions from local turners have all been "Use spigot jaws." As to the length of the work piece, 5.5"-6" doesn't seem all that long (especially after turning a 16" French rolling pin ) I'm fanatical now about getting the perfect angle between the tenon and shoulder (OK, OK, this isn't a machine shop "woodworking-perfect")

 

[Joe Greiner]

For "handles for kitchen stuff," I'd drill the holes first and then turn the body, using the hole for centering. A revolving steb center in the tailstock can prevent splitting the wood. Use a bushing if necessary to mate with the point.

 

[Bill Boehme]

.... Uhhhhh, wrong. At least if you need to drill a hole after you've roughed the stock -- make a tenon, and then turn it around to mount in your chuck....

Uhhhhh ... not wrong. If one end is being held rigidly as in the case of a chuck holding the piece at the headstock end or you are drilling from either end then that is no longer "between centers".

 

[Jamie Straw]

Uhhhhh ... not wrong. If one end is being held rigidly as in the case of a chuck holding the piece at the headstock end or you are drilling from either end then that is no longer "between centers".

Different situation. I'm speaking of misaligned centers during the roughing-between-centers stage, and then mounting in a chuck. Seems to me that if the spindle is mounted between mis-matched centers, then rounded and faced off (to within a smidge of the points on the centers), then a tenon is made and THEN mounted in a chuck -- it could quite well not sit properly in the chuck if the chuck is perpendicular to the headstock but the spindle is ever-so-slightly cockeyed. Multiply that small degree of cockeyededness by several inches distance from the chuck, things won't be so good at the far end.

 

[Mike Johnson]

If you have a "wondering" bit just give it time and it will decide the direction it wants to go.
Drilling wood presents challenges that you don't have with other materials.
All it takes is one hard knot inside a billet to quickly change the course of your drill bits direction.
Every piece of wood is different from the last one used, you can have great success with multiple
pieces and then run into one that throws you a fit. For some of the tools that I make, it requires using
long drill bits to produce the items I need, I have worked on a couple of these pieces where a hard
knot was encountered on one end of the piece causing the drill bit to take a direction not intended and
the drill exited nowhere near the axis line on the other end of the tool. On the longer pieces I now usually
drill from both ends and meet in the middle to reduce the chance of the drill bit coming out in the wrong location
on a long piece. Some of the longer pieces I make are 24" to 36" in length, does not take much of a variance
for a long drill bit to flex over the length of the shaft and cause a problem.

 

[Bill Boehme]

Different situation. I'm speaking of misaligned centers during the roughing-between-centers stage, and then mounting in a chuck. Seems to me that if the spindle is mounted between mis-matched centers, then rounded and faced off (to within a smidge of the points on the centers), then a tenon is made and THEN mounted in a chuck -- it could quite well not sit properly in the chuck if the chuck is perpendicular to the headstock but the spindle is ever-so-slightly cockeyed. Multiply that small degree of cockeyededness by several inches distance from the chuck, things won't be so good at the far end.

No, you assumption isn't correct about a tenon created between centers when the headstock and tailstock don't line up perfectly. You could have a spindle turned between centers where there is a huge misalignment and everything on the spindle would be exactly as precise as a spindle turned between centers that were perfectly aligned.

The alignment situation that you are dealing with has two origins, both of which are always present to some degree. The first is that no woodturning scroll chuck has jaws that are perfectly concentric with the spindle axis. The second factor is that wood is a non-homogenous compressible material. Even at the perfect circle diameter of the jaws this can cause a noticeable shift in the rotation axis. If the tenon is larger than the perfect circle diameter then the corners of the jaws are the only points of contact and when they compress the wood it is a certainty that each of these "dimples" will be different.

Frequently we encounter wood with large internal stresses that are in a state of equilibrium... Until we start to remove some of that wood and upset the equilibrium. The wood responds by moving by bending or splitting to get the stresses back in equilibrium. This can even happen in very dry wood.

To elaborate on the first part, the error sources include:

• The scroll gear (that's the spiral on the back side of the ring gear) isn't perfectly concentric with the lathe spindle axis.
• There's slop (an engineering term for a loose fit) between the scroll gear and the gear teeth on the bottom of the base jaws. This slop is essential because the curvature of the spiral changes as the jaws are adjusted over their full range.
• There is some free play between the base jaws and the guides in the chuck body.
• There is slight misalignment between the base jaws and top jaws.

When you rough a really long piece of wood between centers and create a tenon and then mount it in a chuck all of these errors get multiplied considerably at the other end. The solution, once we know that these errors are an inescapable consequence of our methods of work would be to include plans for accommodating these errors. In this situation that might mean having extra material that can be turned away to to gets everything concentric with the chuck mount.

 

[Leo Van Der Loo]

For what we are making the misalignment that most wood lathes have are of no consequences when drilling shorter holes in relatively short pieces of wood, or when turning between centers, like a steb center and live center.
About the only time this is a problem is with the tailstock really close to the headstock, like in supporting a disk/plate/tray etc.
As with turning a longer piece of wood with a handheld tool, this has no influence on the piece.
Drilling longer holes in wood is not the same, IF we use the regular twist drills, these will follow the way of least resistance, to make these holes straight you will need other tools that are build/engineered for precision drilling, and these are made for metal, but some can be used for wood.

If interested take a look at the video

View: https://www.youtube.com/watch?v=W3H5o2DHloc

 

[hockenbery]

Trent Bosch uses a gun drill in many of his workshops. he has mounted his in a turned handle with a air valve control. It drills straight holes and clears the chips. For someone drilling lots of pilot holes for turning the gun drill works great.

 

[Mike Johnson]

On some handle tools that I make, I will drill the hole prior to mounting between centers.
This would be similar to making a shaving brush handle, drilling the hole first is easier for me.
If I start with a large enough diameter spindle I will rough the blank between centers and
cut a tenon on one or both ends and then mount in an adjustable chuck, I can then accurately
drill a hole in the center of the handle and bring my tail stock back up to the blank landing into
the centered hole to finish shaping the handle and then use a parting tool to remove the handle
from the blank.

 

[Tom Albrecht]

When I make tool handles I find it works best, and most accurately, if I drill my wood blank first and then make a sacrificial pin chuck of the same diameter to drive the wood while shaping to finished size.

 

[hockenbery]

When I make tool handles I find it works best, and most accurately, if I drill my wood blank first and then make a sacrificial pin chuck of the same diameter to drive the wood while shaping to finished size.

I use this method often but no so muchwith wooden pins.
I have a metal stepped pin chuck on a Morse taper - 1/8, 1/4, 3/8, 1/2....,
I also use metal pins in wood or a drill bit bored in with the lathe.
I use wooden pins on occasion too.

 

[Tom Albrecht]

t6

Trent Bosch uses a gun drill in many of his workshops. he has mounted his in a turned handle with a air valve control. It drills straight holes and clears the chips. For someone drilling lots of pilot holes for turning the gun drill works great.

What is TB making when he uses a gun drill?

 

[Bill Boehme]

What is TB making when he uses a gun drill?

Hollow forms. I have taken a couple classes from Trent and used a gun drill connected to an air hose to clear the chips. You can find gun drills on eBay for cheap prices. He puts an air tool quick connect fitting on the drill. He also uses a wooden handle at the back end of the drill so that you can hold it and keep it from twisting while drilling. The first time that I took the class he used a spindle gouge to do the drilling. The gun drill is much quicker ... so quick that I went right through the bottom of my HF before I realized it.

 

[Jamie Straw]

I know it seems odd, me the novice, engaging in such a vigorous discussion with all you experts. I'm just trying to wrap my head around what the heck's going on. Adding to the mush is the fact that now we've got two issues in one thread: (a) drilling a hole that goes acceptably straight and (2) having a roughed piece not line up when it's reversed (with a tenon) to put in a chuck. I'll just watch the discussion for awhile, and try to find something fun to turn in the meantime. Thanks.

 

[Charlie Knighton]

#2....my 2 cents worth....I do mostly hollow forms so it works better for hf than bowls....on bowls really depends if u can work round the headstock.... anyway....rough out hf between centers....make tendon on tailstock end.....take blank off , remount with chuck, finish turn the outside, hollow

 

[Jamie Straw]

#2....my 2 cents worth....I do mostly hollow forms so it works better for hf than bowls....on bowls really depends if u can work round the headstock.... anyway....rough out hf between centers....make tendon on tailstock end.....take blank off , remount with chuck, finish turn the outside, hollow

Bowls aren't the problem, it's the spindle-work (making handles for kitchen implements and such). I am looking forward to getting back to bowls soon though!

 

[Charlie Knighton]

Spindles and hf process the same, if u finish turn between centers, the wood moves on u

 

[Charlie Knighton]

I have never done any eating utensils, seems like you could turn it between centers if the eating part was at the headstock, and turn the tailstock end first and work back to headstock, I would expect to do some carving to finish......it just could not be as thin/fragile as a finale

 

[Mike Johnson]

I know it seems odd, me the novice, engaging in such a vigorous discussion with all you experts. I'm just trying to wrap my head around what the heck's going on. Adding to the mush is the fact that now we've got two issues in one thread: (a) drilling a hole that goes acceptably straight and (2) having a roughed piece not line up when it's reversed (with a tenon) to put in a chuck. I'll just watch the discussion for awhile, and try to find something fun to turn in the meantime. Thanks.

Jamie,
When drilling the hole in the wood blank first, it does not matter if the hole is centered in the blank or on either end of the blank. When you place the wood blank on the lathe between centers and use the holes as the center point the handle will be turned perfectly in circumference around the hole in the blank. You can always use a longer wood blank and do all of your work between centers and part the tool partially on both ends and finish sanding both ends on a power sander. I use a sanding disk mounted on my adjustable chuck on the lathe and use a V-shaped cradle to run the ends of the handles against the sand disk, this keeps the ends perfectly square to the handle.
If you don't drill a hole all of the way through the handle you can round the handle between centers and then
mount the round handle in an adjustable chuck and then use a jacobs chuck in your tail stock and drill the hole the distance you need in your handle. At this point I usually remount the wood handle between centers
which allows more room to use your lathe tools on both ends of the wood blank and make your final profile cuts, sanding and finishing while on the lathe. Partially part the handle off on both ends and finish sanding
these ends and touch up with your desired finish.
It really comes down to what tools you have on hand that you can use for the task. You can also use a metal
pin mounted in your chuck and place the handle over the metal pin and use your tail stock to put pressure on
the wood blank to finish turning, sanding and applying a finishing.
Once you do a few of them you will find a method that works best for you with the tools you have.

 

[hockenbery]

t6


What is TB making when he uses a gun drill?

straight holes quickly To make pilot holes in end grain hollow forms.
Hollowing is mostly done from the pilot hole to the side wall. When the bottom of the hole is reached the hollowing is complete at least for depth.

Mostly he is interested in the "quickly" a hole bored with a twist drill or spindle gouge requires removal to clear the chips every inch or so. A 7" deep hole will require removal of a twist drill 5 times or so to clear the chips.
The gun drill hooked up to a compressor blows the chips out as it drills from a hole that runs its length. The gun drill goes to depth in one pass quite quickly.

Also once in a great while a small hole made with spindle gouge or twist drill in and endgrain HF can run off center enough to make drilling the planned depth difficult or impossible.

 

[Bill Boehme]

Spindles and hf process the same, if u finish turn between centers, the wood moves on u

What Charlie said. Just think of a handle as being a slender hollow form.

Like several others have said, I usually drill the hole in a handle before I do the final shaping. That seems to give the best results. Several years ago I made what I considered a beautiful tool handle and then I drilled the hole for the tool. The result was a disaster. As hard as I tried I just couldn't convince myself that an offset handle was somehow more ergonomic than a handle that lined up straight with the tool.

 

[Jamie Straw]

I have never done any eating utensils, seems like you could turn it between centers if the eating part was at the headstock, and turn the tailstock end first and work back to headstock, I would expect to do some carving to finish......it just could not be as thin/fragile as a finale

You're missing the part about needing to drill a hole to insert the hardware (said hole is usually then threaded to receive the hardware, like a threaded tang).

 

[Charlie Knighton]

You're missing the part about needing to drill a hole to insert the hardware (said hole is usually then threaded to receive the hardware, like a threaded tang).

I would carve the working end of fork, spoon, or knife......they would not let u take on carry on for flight anyway....course I have never done any

 

[olaf Vogel]

Hi Jamie

I was making tool handles this aft...Lee Valley had a bunch of crappy looking old 3" rounds of ash, so I grabbed a few. I drilled the ends at 1" dis so that I can insert some steel pipe, and slide in my chisels.

The bit I use, really doesn't wander. Looks like this:

http://thumbs1.picclick.com/d/w1600...ELL-USED-NATIONAL-USA-3-11-32-x-MT5-TAPER.jpg

(Not that big though)

Still need to use a steady though.

Four flutes to clear chips well and an mt4 taper so it goes right into the tailstock.

Olaf