High School Engineering group needs your help.

[Andrew Creemer]

Hello all! I am a student attending my senior year of high school and am in the Purdue University PLTW EDD engineering class. We are required to design and create a prototype for a solution to a problem. Our problem is the wood-turning of non-radially symmetric or irregular shaped woods.
-How many of you have an issue with turning non-radially symmetric or irregularly shaped woods?
-How many of you own/feel you could benefit from owning a two jaw chuck?
-How often would you personally need/use one?
-What are some alternatives instead of a two jaw chuck for turning non radially symmetric pieces?
-If you use an alternative way, are there any safety issues?

Thanks again everyone. Any responses would be very helpful to us, either posted in response to this post, or in a PM.

 

[Clifton C]

non-radially symmetric

Andrew,
Most wood, bone, stone or other inanimate object I put on the lathe starts out as "non-radially symmetrical".
In answer to the first question, I don’t know how many turners have issues, I don’t.
Second question, I just remove two opposing jaws and I have a two jaw chuck.
I’m sure I’m not the only one who does this.
Third, not often, a few times a year maybe.
Forth, Double stick tape for small stuff, nylon strap or chain to a wood faceplate for large stuff.
As for safety issues, all I can say is YES…YES,YES,YES…Think Darwinism.
So the question I have is, is the wood-turning of non-radially symmetric or irregular shaped woods a problem?
Or, what is the problem of turning non-radially symmetric or irregular shaped wood?

cc

 

[hockenbery]

Hello all! I am a student attending my senior year of high school and am in the Purdue University PLTW EDD engineering class. We are required to design and create a prototype for a solution to a problem. Our problem is the wood-turning of non-radially symmetric or irregular shaped woods. -How many of you have an issue with turning non-radially symmetric or irregularly shaped woods? -How many of you own/feel you could benefit from owning a two jaw chuck? -How often would you personally need/use one? -What are some alternatives instead of a two jaw chuck for turning non radially symmetric pieces? -If you use an alternative way, are there any safety issues? Thanks again everyone. Any responses would be very helpful to us, either posted in response to this post, or in a PM.

I would answer much like Clifton did.

Most wood is asymmetrical when mounted on the the lathe. I also remove 2 jaws from my 4 jaw chuck to make a 2 jaw chuck.


Most often I work asymmetric pieces between centers. Do some shaping and make a faceplate or chuck tenon on one end and then hold it on the lathe for further refinements.

I also do some multi axis and multi center turnings which takes a symmetric piece in one axis or center and makes it unsymmetrical on another center or axis.

An example is a spindle object turned with a ball somewhere on its length.
The ball can be held with a vacuum chuck, or a jamb chuck. The new axis of the spindle can be roughly 30 to 90 degrees from the first turned axis in a jamb chuck
70-90 degrees in a vacuum chuck.

Al

 

[Bill Boehme]

Radially symmetry is not the issue. Hardly any turning starts out radially symmetric and sometimes the final product is deliberately not radially symmetric. Generally, my initial objective is to mass balance a piece of wood with a secondary objective of minimizing cross products of inertia. When you begin with an irregular shape, mass balancing is almost always possible, but by definition it never will be radially symmetric. Regarding chucks, the mass balanced piece is turned between centers and not installed in a chuck until until it has been approximately shaped to size.

 

[Charlie Knighton]

I can not imagine taking 2 jaws off a 4 jaw chuck and then using it. not sure how long it took me to start things between centers, probably over a year, but when someone enlighten me, I have not regressed. I had used faceplates and waste blocks and such. bill has the techo speak and is what works safely.

 

[Odie]

It was mentioned that a standard wood lathe chuck could be configured by simply removing a couple jaws. Maybe someone else has a different perspective, but I do have need to mount seasoned bowls w/tenon for preparing a flat surface prior to mounting a waste block. Sometimes the warp during seasoning means the tenon is warped to an irregular shape. I still use my Stronghold chuck to mount that irregular shaped tenon, and sometimes two jaws are all the comes into contact with the tenon. There is no need to remove jaws, but essentially it's a two-jaw chuck.

ko

 

[Charlie Knighton]

I just turn to finish thickness, but if I needed to I could jam chuck form and return the tendon so all 4 jaws are usable. a lot of things can be done safely for one turner that another turner does not feel comfortable doing, speed also would be a major factor

 

[Odie]

I just turn to finish thickness, but if I needed to I could jam chuck form and return the tendon so all 4 jaws are usable. a lot of things can be done safely for one turner that another turner does not feel comfortable doing, speed also would be a major factor

I think I see what you're getting at here, Charlie......and I think you're right that safety issues could come into play, if one were to turn an entire bowl using only two contact points for the chuck to grip on.

Maybe I should clarify.

When I use my (two point contact) chuck gripping a warped tenon, all I need is a flat bearing surface along the rim to set while using that surface as a reference for preparing a flat on the tenon for gluing a waste block. This is a very light cut and not much material is removed......only takes a minute to do it.....on/light cut/off quickly.

Thanks for bringing this up, because I wouldn't want others to do what you were thinking I was doing!

ko

 

[hockenbery]

I just turn to finish thickness, but if I needed to I could jam chuck form and return the tendon so all 4 jaws are usable. a lot of things can be done safely for one turner that another turner does not feel comfortable doing, speed also would be a major factor

This is what I do.

On small bowls you can sometimes get away with not truing the tenon where side grain of the tenon doesn't make much contact.
Definitely not safe on larger bowls. It is so easy to turn the tenon on a jamb chuck. I usually just jamb it in the open jaws of the 4 jaw chuck as any marks will be turned away in the finish turning.

 

[Odie]

This is what I do.

On small bowls you can sometimes get away with not truing the tenon where side grain of the tenon doesn't make much contact.
Definitely not safe on larger bowls. It is so easy to turn the tenon on a jamb chuck. I usually just jamb it in the open jaws of the 4 jaw chuck as any marks will be turned away in the finish turning.

Big bowls, small bowls......doesn't matter.

Al, I believe you and Charlie are both thinking I'm discussing doing some finish turning while gripping the roughed bowl in a "two jaw" chuck......which I'm not. All I'm doing is getting some reference points for mounting the waste block. I suppose I could teach you my technique for doing this, but that would require some alternative thinking......

ko

 

[Charlie Knighton]

ok, I believe you have alternate plan.....I like the results you achieve

 

[Mark Mandell]

The Original Question

Hi Andrew,

I hope you have gotten the impression from the above responses that your "design problem" may be a solution looking for a problem to solve. It appears that your teacher/professor may have a rather limited understanding woodturning because, as you may have gathered from the discussion, "asymmetrical" wood is probably the type of wood most often used in the craft outside, perhaps, of the more limited field of turning wood in spindle orientation with the wood grain running parallel with the rotation axis of the lathe. You should also have gotten the impression that use of a 2-jaw chuck on anything other than a spindle-oriented piece of wood would be inherently dangerous due to the nature of the material rather than the design of the chuck.

If you can do so without appearing to be a smart-alec "kid", perhaps you could invite your teacher to drop in on this forum where highly knowledgeable and experienced wood turners might be able to assist him or her in formulating design problems for your group.

 

[Odie]

ok, I believe you have alternate plan.....I like the results you achieve

Thanks Charlie.......Actually, I'm one who is clinging to the notion that old fashioned faceplates w/wasteblocks are a better option. There is nothing new about this, since the faceplate/wasteblock method far predates woodturning chucks.....(or metal working chucks, for that matter!) Most turners, these days, rely on the chuck for most of the effort, but I've found that chucks have their best advantages for roughing. Face plates have a particular advantage that is more applicable to the finished turning of seasoned roughed bowls. It requires a single mounting that doesn't interfere with tools or sanding, and the faceplate can remain attached during the entire process (with exception of the foot). In the transition between roughing/seasoning and remounting for a finish turn, that transition needs to incorporate an accurate method of converting the tenon to a waste block mount. This can't be done with wet wood, since glue doesn't adhere..... so the seasoning process needs to be a part of the transitional equation. Nothing I do is new and/or unique to me, but I am taking what I feel is the best of both attachment methods to their own particular advantage. I'm combining new and the old school thinking.....instead of discarding the old, in favor of the new.

ko

 

[Charlie Knighton]

i like starting between centers.......the points can be used to center from either end, and while roughing balancing its easy to change orientation if a new desired orientation is revealed, and you can center from the new points and turn the old points away, either end can be the top or the bottom depending on what is revealed.....just saying

 

[Odie]

i like starting between centers.......the points can be used to center from either end, and while roughing balancing its easy to change orientation if a new desired orientation is revealed, and you can center from the new points and turn the old points away, either end can be the top or the bottom depending on what is revealed.....just saying

Hey, that's ok Charlie......

Because I have my own ideas and beliefs, doesn't mean anyone else should adopt them.....

Yes, I understand the benefits of turning between centers.......and I feel equally committed to starting a bowl block on a faceplate attached to the interior of a bowl (screwed to the waste)......rough turning the exterior and tenon, and then reverse turning, using a chuck......all this in preparation for the seasoning process, afterwards which I proceed to attaching a wasteblock to the seasoned roughed bowl.

I do what works for me, just as you do.....and our individual conceptions about desirable results may be entirely different. I get this feeling, over and over again, that when I try to explain how/what/why I do things, that there are always those who feel I am trying to change the opinions and views of others. My purpose is to reinforce my own beliefs, and I do that by trying to put my thoughts into words anyone can understand. My standard, as to how well my philosophy/techniques pans out, is the results I get......and, MY results are the only thing that matters to me.

ko

 

[hockenbery]

. This can't be done with wet wood, since glue doesn't adhere..... so the seasoning process needs to be a part of the transitional equation. Nothing I do is new and/or unique to me, but I am taking what I feel is the best of both attachment methods to their own particular advantage. I'm combining new and the old school thinking.....instead of discarding the old, in favor of the new. ko

I have turned hundreds of NE bowls from wet wood with glue blocks. Thick CA glue. Hold the bowl for hollowing.
The a chisel breaks the CA glue. The glue block has to come off before the wet wood moves. Never a problem in the 10-30 minutes the NE bowl is in the glue block.
CA bonds nicely to the wet wood.

I prefer a chuck for most bowls. I Prefer face plates for most face grain hollow forms.
Al

 

[Clifton C]

Well, I was not thinking of bowl turning with a two jawed chuck but more for small stuff.
The jaws here are dovetail so the carrier is "pulled" into the chuck, the kerf is compressible
and takes up variances in the project, the off set is about 1/4 inch. If you look to the left
of the corners of the jaw, you can see the bite mark for the off set.
It is a "propeller" so if you drift to the wrong side of the tool rest, it will remind you...
cc

 

[Edward Weber]

Hi Andrew,

I hope you have gotten the impression from the above responses that your "design problem" may be a solution looking for a problem to solve.

Andrew, I hope by now you can understand the general consensus mentioned in the above quote by Mark.
This is virtually the same wording as on another forum where the same question was asked.
You seem to have already decided that you prototype is going to be some sort of 2 jawed chuck and now you're looking for someone who has a need for it.

 

[Bill Boehme]

It would be beneficial to both us and you, the students, to provide some feedback to gain a better understanding from both perspectives in defining your project and understanding the nature of the project. Hopefully, it hasn't been cast in concrete at this early definition stage. BTW, there are several engineers on this forum who might be able to provide some ideas and general guidance. I think that many of us are also curious about the selection of woodturning as your project since it isn't as well known as other things like "world peace", for example. Woodturning is a great pastime for many and a rewarding profession for a few, but it probably isn't the next "big thing on the horizon" if that matters at all. However, a creative design for a chuck is always a great mechanical engineering design challenge.

I visited the PLTW website to check out the different programs. I saw an EDD program for the University of South Carolina, but I didn't see that Purdue had an EDD program, but they did have an Industrial Technology program. Maybe their web site needs updating. Anyway, it would be worth engaging in a discussion to help get things rolling.

 

[Odie]

Hello all! I am a student attending my senior year of high school and am in the Purdue University PLTW EDD engineering class. We are required to design and create a prototype for a solution to a problem. Our problem is the wood-turning of non-radially symmetric or irregular shaped woods.
-How many of you have an issue with turning non-radially symmetric or irregularly shaped woods?
-How many of you own/feel you could benefit from owning a two jaw chuck?
-How often would you personally need/use one?
-What are some alternatives instead of a two jaw chuck for turning non radially symmetric pieces?
-If you use an alternative way, are there any safety issues?

Thanks again everyone. Any responses would be very helpful to us, either posted in response to this post, or in a PM.

You know.....it just occurred to me that Andrew might be speaking of a 2-jaw chuck that has independently adjustable jaws. Maybe, maybe not.....but, I'll bet all of the forum members were thinking of a 2-jaw scroll chuck.......

ko

I have turned hundreds of NE bowls from wet wood with glue blocks. Thick CA glue. Hold the bowl for hollowing.
The a chisel breaks the CA glue. The glue block has to come off before the wet wood moves. Never a problem in the 10-30 minutes the NE bowl is in the glue block.
CA bonds nicely to the wet wood.

I prefer a chuck for most bowls. I Prefer face plates for most face grain hollow forms.
Al

Al.....I prefer a chuck for bowls, as well......up to the point where it's seasoned, or moisture stabilized. At that point, I prefer a wasteblock attached with Titebond II, or III glue. I suppose I should have made my preference for glue known, when I made the comment about glue not adhering to wet wood. I wouldn't mind seeing some of those hundreds of NE bowls you've done. Can you show us some of your recently completed NE bowls?

ko

 

[Shawn Pachlhofer]

I'm sure he wouldn't want to post any photos that might influence your journey, Odie.

 

[Odie]

I'm sure he wouldn't want to post any photos that might influence your journey, Odie.

Heh,heh,heh,........you suppose?

Then again.....maybe there is another reason.....!

ko

 

[Odie]

Kelly,

Here is a video from a demo before a live studio audience. It is a natural edge bowl from a crotch and shows how to balance the three wings in two steps.
Also features some advanced cuts.

https://www.youtube.com/watch?v=8jVoI12Kfug

I've seen the video, Al.......

Setting up a gallery is easy to do.......why not show us your recent works, and keep it up to date?

ko

 

[hockenbery]

I've seen the video, Al....... Setting up a gallery is easy to do.......why not show us your recent works, and keep it up to date? ko

Then you know what meager skills I have.

What did you Learn???

Al