Woodturner Pro Issue

[jswalters]

I designed a bowl using WTP with the first row being 4.5” and then each successive ring a 1/2” wider. It looks great on the software however the first row, which should be 4.5” is actually 4 3/8” in diameter. I checked the segment lengths and they were 91/6” as per the cut sheet but there is a definite difference in the first seg. Ring and the second. All other rings in the bowl are fine. Not sure if this is going to be an issue when I turn it but I am a little nervous. Any ideas what might be happening?
Jeff

 

[mfisher]

I designed a bowl using WTP with the first row being 4.5” and then each successive ring a 1/2” wider. It looks great on the software however the first row, which should be 4.5” is actually 4 3/8” in diameter. I checked the segment lengths and they were 91/6” as per the cut sheet but there is a definite difference in the first seg. Ring and the second. All other rings in the bowl are fine. Not sure if this is going to be an issue when I turn it but I am a little nervous. Any ideas what might be happening?
Jeff

would be helpful to post your WTP file here so we can pull it up and take a look at it.
It looks like you made 24 segment rings. as you stated the SEL would be 9/16"

If you have your options for WTP set to nearest 1/16th the SEL will be the same for a 4 3/8 or a 4 1/2 ring.) Remember: the option is presenting calculations to the nearest 1/16th. The software will do some rounding.

I generally use Imperial decimal inch. When that is selected a 4.5 inch ring has a SEL of 0.59" a ring of 4.375 (4 3/8) will have a SEL of 0.58.
for a 24 segment ring. That is a difference of 1 hundredth of an each or each segment.

Some thoughts:
- did you check the profile view to look at the Outside and Inside diameter to ensure there is enough glue surface.
- As far as the diameter being off by 1/8", It has to be in the segment edge length of your segments. One may be ok but what about the others?

Factors that can impact the SL when cutting segments.
- stock sides are not parallel
- sawdust buildup along the fence
- wood fibers on the end of the stock when pushing the stock up against the stop block will result in a shorter SEL.

 

[jswalters]

would be helpful to post your WTP file here so we can pull it up and take a look at it.
It looks like you made 24 segment rings. as you stated the SEL would be 9/16"

If you have your options for WTP set to nearest 1/16th the SEL will be the same for a 4 3/8 or a 4 1/2 ring.) Remember: the option is presenting calculations to the nearest 1/16th. The software will do some rounding.

I generally use Imperial decimal inch. When that is selected a 4.5 inch ring has a SEL of 0.59" a ring of 4.375 (4 3/8) will have a SEL of 0.58.
for a 24 segment ring. That is a difference of 1 hundredth of an each or each segment.

Some thoughts:
- did you check the profile view to look at the Outside and Inside diameter to ensure there is enough glue surface.
- As far as the diameter being off by 1/8", It has to be in the segment edge length of your segments. One may be ok but what about the others?

Factors that can impact the SL when cutting segments.
- stock sides are not parallel
- sawdust buildup along the fence
- wood fibers on the end of the stock when pushing the stock up against the stop block will result in a shorter SEL.

You are right. I should have posted my file. I will attache it here. The bowl came out OK and to accommodate the ring size I did kind of a Ogee shape. I'll also attach a picture. I did check the profile view and it looked just as I planned. I also blow all dust off the sled after each ring. I segments were sanded to get rid of fibers and all segments measured exactly as the file said they should be.So I am still a bit befuddled. In the end I really liked the look of the bowl and I have a customer already for it. So all's well that ends well but it is a bit of a mystery.
Jeff

 

[mfisher]

You are right. I should have posted my file. I will attache it here. The bowl came out OK and to accommodate the ring size I did kind of a Ogee shape. I'll also attach a picture. I did check the profile view and it looked just as I planned. I also blow all dust off the sled after each ring. I segments were sanded to get rid of fibers and all segments measured exactly as the file said they should be.So I am still a bit befuddled. In the end I really liked the look of the bowl and I have a customer already for it. So all's well that ends well but it is a bit of a mystery.
Jeff

Thanks Jeff.

Nice looking vessel and thanks for posting.

WTP has been around a long time. The math calculations have been proven to be accurate. It is all in the preference setup.

- I would go into WTP and check your preference settings. File/options/ numeric display. What you set can change the output figures.
For example your Row 2 with an outside diameter of 4.5" ring the SEL readout for 24 segments is
- imperial decimal inch is 0.59"
- nearest 1/64th sames as nearest 1/32nd
- nearest 1/32nd is 19/32
- nearest 1/16th is 9/16

The imperial inch or metric option will give you the most accurate. The other options rounds of to the nearest fraction.

In the rounding scheme for nearest 1/16th a 4.5 diameter and a 4 3/8 diameter ring has the same SEL
In imperial inch a 4.5 is 0.59 and the 4 3/8 is 0.58.

What you experience is one reason I use imperial or metric.

 

[jswalters]

Thank you for the nice comment. I will indeed check out the setting. I’ve used factions because it’s simply easier for me to get my tape measure in there. I have seen people adapt digital calipers to there stop block Caledonian but have not figured out how they di it. Nor do I want to tear my calipers apart to experiment.
Jeff

 

[mfisher]

Thank you for the nice comment. I will indeed check out the setting. I’ve used factions because it’s simply easier for me to get my tape measure in there. I have seen people adapt digital calipers to there stop block Caledonian but have not figured out how they di it. Nor do I want to tear my calipers apart to experiment.
Jeff

I do not have one of the fancy digital stop blocks. I do use digital calipers to set the stop block at the desired SEL.

- set the calipers at the desired SEL.
- mark a scrap piece of stock with the SEL dimension. (stock that has been mitered to the desired angle on one end)
- using the stock strip along the fence set at the proper angle I align the mark to cut side of the blade and the stock block.
- clamp the stop block and do a test cut.
- check the test segment and adjust the stop block as needed to fine tune to the SEL.

Hint: I tend to overbuild my rings by 1/8th of an inch. In WTP I will adjust the Outside diameter 0.125 more than the profile requires.
That is if I need a 6" ring I will build a 6.125 ring. It will be turned down to 6". I also check the inside diameter in the profile view to ensure there is enough glue surface between the stacked rings.

 

[jswalters]

Thank you again for the advise. This has been a fun and sometimes frustrating learning process but that’s what it’s all about. It has been a great experience. I have another bowl idea I am working on. Is it OK to post files when I design something for advise and opinions on design?
Jeff

 

[mfisher]

Thank you again for the advise. This has been a fun and sometimes frustrating learning process but that’s what it’s all about. It has been a great experience. I have another bowl idea I am working on. Is it OK to post files when I design something for advise and opinions on design?
Jeff

Of course it is ok. That is what the forum is about. Sharing knowledge, experience and asking for advice.

- Posting photos and the software project file greatly helps in providing advice.

Thanks for you post. Ask questions you may have. Enjoy your segement journey.

 

[jswalters]

Here is the next design I am working on and hope to start building it next week after I pick up some supplies. Any advise or recommendations are welcomed.
Jeff

 

[mfisher]

Hi Jeff
I took a look at your Calabash Bowl. Looks good.
The golden ratio is spot on, glue surface between rings is more than adequate.

I would make rings 5,6,7 all the same. Will same a little bit of set up time and the stock can all be the same width.
Ring 5 and 6 have an Outside Diameter of 10.4 inches. Ring 7 is at 10.38. (I would make it the same as ring 5 and 6)
Ring 5 has inside diameter of 8.9. Ring 6 and 7 have ID of 8.88 (make them 8.9)

Don't know if you are leaving the segments all the same species or do some pattern. Have fun.

 

[jswalters]

Hi Jeff
I took a look at your Calabash Bowl. Looks good.
The golden ratio is spot on, glue surface between rings is more than adequate.

I would make rings 5,6,7 all the same. Will same a little bit of set up time and the stock can all be the same width.
Ring 5 and 6 have an Outside Diameter of 10.4 inches. Ring 7 is at 10.38. (I would make it the same as ring 5 and 6)
Ring 5 has inside diameter of 8.9. Ring 6 and 7 have ID of 8.88 (make them 8.9)

Don't know if you are leaving the segments all the same species or do some pattern. Have fun.

I am working on a feature ring idea using Male and Walnut and it would replace the center 3 3/4” rings with 3 1/2” rings forming the pattern. I haven’t finalized it yet but will post the design once I finish it.
Jeff

 

[jswalters]

I am working on a feature ring idea using Male and Walnut and it would replace the center 3 3/4” rings with 3 1/2” rings forming the pattern. I haven’t finalized it yet but will post the design once I finish it.
Jeff

I took your advice and made the changes and also figured out how to get the feature ring in the image. I am attaching the file.

 

[mfisher]

Nice.
Here is a couple of artistic changes I would recommend. Very easy to do with your design.
Make the base and the top ring out of the same material as your featured ring (Walnut)
Make the main bowl out of maple or some light wood
and last, I added a 0.06 (1/16th) inch veneer ring on the top and bottom of your featured ring of a contrasting color (red)

The profile and the featured ring go well together. Take my changes for what they are worth. I like your bowl.

If you want some help on how to "paint" individual segments in WTP or adding a new species to the wood list let me know if you have questions.

 

[jswalters]

Thank you for the advise. I’ve got some Purple Heart that I can use for the thin strips or, I am going to the mill this weekend to get some Paduek and Bloodwood that I can also use. The main body itself will be Maple. I will also change the top and bottom rings to Walnut.
Jeff

 

[jswalters]

Hi There. I am attaching the modifications you suggested. My wife like the Padauk strips you suggested however she is not sure about going with the walnut top and bottom since the traditional Calabash bowl is made entirely of one wood. Of course a traditional bowl doesn't have a feature ring either. I can go either way on it. What's your thoughts after seeing the file?
Jeff

 

[mfisher]

Hi There. I am attaching the modifications you suggested. My wife like the Padauk strips you suggested however she is not sure about going with the walnut top and bottom since the traditional Calabash bowl is made entirely of one wood. Of course a traditional bowl doesn't have a feature ring either. I can go either way on it. What's your thoughts after seeing the file?
Jeff

Thanks for sharing. Did not know that about Calabash bowls. I would go with what your wife wants. It will be an awesome bowl.

 

[jswalters]

Thanks for sharing. Did not know that about Calabash bowls. I would go with what your wife wants. It will be an awesome bowl.

Thanks for sharing. Did not know that about Calabash bowls. I would go with what your wife wants. It will be an awesome bowl.

Thank you. After writing you, I thought more about it and decided to made 2 bowls. One with and one without. I’ll post them whe I am finished. May be a couple of weeks.
Jeff

 

[jswalters]

Hi There. I am thinking of doing a segmented bottom on this bowl. 24 segments. I'd like to put a 1/8" slice of walnut between the segments. Is there a way to show that on WTP?
Jeff

 

[Jim Grieco]

Hi There. I am thinking of doing a segmented bottom on this bowl. 24 segments. I'd like to put a 1/8" slice of walnut between the segments. Is there a way to show that on WTP?
Jeff

Not sure if there are other ways but I would use the vertical spacer option (found in the Row Details section on the top left side of the page. You can add the thickness you want to use.

 

[mfisher]

Jim is correct. The way is to use the vertical spacer option.
Keep in mind that the species selected for the vertical spacer is applied to every ring you want spacers in.