# Why is this happening?



## Kevin (Aug 15, 2016)

Both end pieces are flat, and my skew is not moving when I take material off the handle. I don't see how the ovalish shape can cause these arced gaps. As you can see one tenon is centered and one is off center but both arcs are equally elliptical, not sure about the word being correct to describe but the longer portion of the handle is concave against the end pieces and it make no sense to me whatsoever how I keep getting this exact same result no matter what I do. My skew is scary sharp and it is not wavering when I use it, and as soft as this wood is you can obviously deduce I'm using the skew as a cutter and not as a scraper ....


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## deltatango (Aug 15, 2016)

How are you holding the wood being cut Kevin?
Jig/chuck/centers, etc.?
What lathe?


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## Tclem (Aug 15, 2016)

I'm more concerned about what it is you are trying to make

Reactions: Funny 1


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## duncsuss (Aug 15, 2016)

If you're doing what I think you're doing, this is purely a function of geometry.

I believe you're cutting a slightly concave shape when you make the shoulder of the tenon. If the larger section were a perfect cylinder, the outer rim would be circular (even though the surface is concave).

Try re-cutting the shoulders.

Reactions: Agree 1


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## Tclem (Aug 15, 2016)

Pie r square

Reactions: Funny 1


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## duncsuss (Aug 15, 2016)

Tclem said:


> Pie r square



Or as Long John Silver said, "Pie Arrrrrrr Squared"

Reactions: Like 1 | Funny 1


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## Schroedc (Aug 15, 2016)

I believe Duncan is right. Your shoulder isn't perfectly perpendicular to the tenon and that causes the arc. If you angled it the other way the narrow sides would touch instead of the wide sides. Need to hit exactly 90 and it should fit flush.

Reactions: Agree 2 | Sincere 1


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## Spinartist (Aug 15, 2016)

Does your skew have a flat bevel or concave? A flat bevel is easier to control on cut like that.


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## deltatango (Aug 15, 2016)

I think it's a tough cut to make because of the optical illusion of the ellipse as it's spinning.
A sure way to acheive 90 degree and flush would be to make a jig with a hole the size of the tennon, then put stick-it sand paper and exacto out the sandpaper from the tennon hole, then insert tennon into hole and rotate until the shoulder comes true. Since the shoulders are proud it shouldn't be too difficult if one is careful.
YMMV

Reactions: Like 2


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## duncsuss (Aug 15, 2016)

Although I generally support use of the skew, this might be one time when it's easier to get a perfectly square cut using something else -- a parting tool, a bedan, even a square-nose scraper. It's easier to tell if you've got them square or slightly off than with a skew (which you have to hold tilted slightly away from the shoulder to avoid getting a catch.)

Reactions: Agree 2


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## rocky1 (Aug 15, 2016)

As Duncan and Colin said, basic geometry, the angle of your concave on the long and short sides is the problem. Longer side has a longer angle. Cut it square, it'll fit flush.


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## ripjack13 (Aug 15, 2016)

Although I'm still a n00b turning, what I noticed is your cuts on the end...they are not square to the block...

Reactions: Funny 2


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## Kevin (Aug 15, 2016)

deltatango said:


> How are you holding the wood being cut Kevin?
> Jig/chuck/centers, etc.?
> What lathe?



Chuck at one end live center at the other. 



duncsuss said:


> If you're doing what I think you're doing, this is purely a function of geometry.
> 
> I believe you're cutting a slightly concave shape when you make the shoulder of the tenon. If the larger section were a perfect cylinder, the outer rim would be circular (even though the surface is concave).
> 
> Try re-cutting the shoulders.



I have and I am about to run out of length if I can't get it right soon, and will have to start all over with the handle. 



Schroedc said:


> I believe Duncan is right. Your shoulder isn't perfectly perpendicular to the tenon and that causes the arc. If you angled it the other way the narrow sides would touch instead of the wide sides. Need to hit exactly 90 and it should fit flush.



I know I have hit exactly 90 and have gone both ways at the joint both inward taper and outward and exact 90. I'll play around with it more later this week. 

Anyone notice my better pictures?


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## Kevin (Aug 15, 2016)

ripjack13 said:


> Although I'm still a n00b turning, what I noticed is your cuts on the end...they are not square to the block...



But they look the same when they are.


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## deltatango (Aug 15, 2016)

I think it's a tough cut to make because of the optical illusion of the ellipse as it's spinning.
A sure way to acheive 90 degree and flush would be to make a jig with a hole the size of the tennon, then put stick-it sand paper and exacto out the sandpaper from the tennon hole, then insert tennon into hole and rotate until the shoulder comes true. Since the shoulders are proud it shouldn't be too difficult if one is careful.

Reactions: Thank You! 1 | Agree 1


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## deltatango (Aug 15, 2016)

So in a perfect world you'd keep making that chip shot out of the trap until you made the green and the hole.
But I am seeing something else.
In keeping with your design concept of the Katana, the curved arc is a really cool form that could work beautifully with your tsuba if you matched the tsuba to the arc. I'm not saying "cheat" on a "right way" turning technique, but on the contrary, go with the happy accident that opens the door to subtle yet eventful design opportunities.


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## deltatango (Aug 15, 2016)

I don't know why that double posted my previous post - not anything I did...


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## vegas urban lumber (Aug 15, 2016)

i'm still trying to decide if the center piece is cut flush square on the end or if the two end pieces aren't flat


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## Tclem (Aug 15, 2016)

Kevin said:


> Chuck at one end live center at the other.
> 
> 
> 
> ...


That's how I turn my sticks. I do a laminated stick also and if I don't get a square cut on both pieces and a tight fit that will happen. And I use the skew on almost everything.

Reactions: Thank You! 1


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## vegas urban lumber (Aug 15, 2016)

sorry i see you detailed that.


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## duncsuss (Aug 15, 2016)

vegas urban lumber said:


> i'm still trying to decide if the center piece is cut flush square on the end or if the two end pieces aren't flat


Dead easy to test: simply rotate one of the end pieces 90 degrees.


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## Kevin (Aug 15, 2016)

deltatango said:


> In keeping with your design concept of the Katana, the curved arc is a really cool form that could work beautifully with your tsuba if you matched the tsuba to the arc.



You don't know how bad I want to do that. I just don't think I can devote the time to it from my day job right now (my boss is an ass). Believe me it has been tempting me. Maybe I will try it anyway next time I get a chance to work on it.


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## Kevin (Aug 15, 2016)

vegas urban lumber said:


> or if the two end pieces aren't flat



Believe me I eliminated that possibility long ago.


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## duncsuss (Aug 15, 2016)

Quickest way out is almost certainly the idea Mark (deltatango) proposed -- a sanding block with a hole (drilled square) to receive the tenon.

Reactions: Agree 1


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## Kevin (Aug 15, 2016)

Thanks to the brain trust + Mark I don't see any way that won't work. I'll update when I do it.

Reactions: Like 3


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## SENC (Aug 15, 2016)

Kevin said:


> Thanks to the brain trust + Mark I don't see any way that won't work. I'll update when I do it.


Given the operator, I'm tempted to take that bet. Are you laying any odds?

Reactions: Funny 8


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## deltatango (Aug 15, 2016)

So just a further explanation of how I would have made that cut starting from the beginning. Your tennon has its own axis. I would turn a longer dowel sticking out about 2" from the chuck (headstock side). Then drill and or bore a hole to accept the tennon friction fit, like a press fit in machining. Slowly bring the press fit handle up to a moderate speed, then use a block on the live center so the other end of the handle could float. Chances are that it is not perfectly in line with the tailstock center. Pulling it in line creates a new axis that makes any cut into the handle at the other end scarf (arc).
With the tail stock tight, using a piece of leather or whatever between the block and the handle, tighten slowly.
Go back to the headstock and with a parting tool, split the line between the handle and the round dowel. The dowel and the handle will be running true and it should be easier to get a right angle cut without tearout, etc.
Once satisfied the cut is correct, dismount the handle and dowel from the chuck and pull the handle out of the dowell. If it won't release, consider the dowel sacrificial and split the dowel in two places from the end and it will lift off the tennon. Thinking about that parting cut again, A thin square-nose tool might work best for this. The main thing is to drive the tennon side close to the headstock with a tight sacrificial piece next to it to split the cut line between the two.
That's probably how I would have done it, knowing I'd have likely run into the same result as you did.
But I've never been a "right way" kind of turner, knowing there are many ways to skin a cat, and that the end result matters to me most in a pinch. That cut does require a one side bevel skew as spinartist pointed out to make that cut unless you're really practiced and accomplished with that specific situation, particularly as the elipse of the handle obscures things. Without doing a lot of that, I'd probably chew through two handles until I got it perfect doing it the "right way." There are many factors that can cause that "arc" in your cut that aren't immediately apparent. Being off dead nuts on from end to end is one of them.

Reactions: Like 2 | Thank You! 1


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## Kevin (Aug 15, 2016)

deltatango said:


> There are many factors that can cause that "arc" in your cut that aren't immediately apparent. Being off dead nuts on from end to end is one of them.



I have a POS lathe which I've never even bothered to dial in so that's probably offensive to real turners like you (it should be!) so I think you might be on to something there also.

Reactions: Agree 1


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## ripjack13 (Aug 15, 2016)

And it could be your step stool is tilted......









Ooohhhh I'm in t-rubble now....

Reactions: Great Post 1 | Funny 8


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## Tim Carter (Aug 16, 2016)

You also should check and make sure your headstock and tailstock are aligned. If they aren't aligned, you'll get oval turnings. It's usually oval at both ends but it's a simple check. Put a 4-spur drive center in the headstock and a center with a point in the tailstock, bring the tailstock up so the points are about 1/16" apart. The points should be aligned so you could draw a line through the center of the 2 spindles that includes both points. If you have a lathe with a sliding headstock, this is a check you should do every time you move the headstock.


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## Mike Mills (Aug 16, 2016)

To hazard a guess..
I think it is because you are using a chuck AND the alignment may be off even after aligning the head and tail stock with spurs/points. By the time you move the tailstock out to fit the work it may not stay in alignment due to a twist in the bed or other reasons.
Can you turn it between centers instead? Imagine holding a two foot long pipe with one hand wrapped around one end (chuck) and the other end with a finger tip. You can't move either end and have it run straight. If both ends are held with finger tips you can move either hand all you want to and it will be straight. It may not be perfectly parallel with the ways but it will be straight between the two points.


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