Shopsmith Forums

terrydowning wrote:OK, now we're getting more info.

Is the paper joint being supported by the tail stock? Was the tenon mounted piece being supported with a tailstock?

Green wood can be soft and it can break especially when turning cross grain.

For initial turning always support with the tailstock until you start hollowing, it's just a big spindle.

When you start hollowing, keep the tailstock in place and hollow between the live center and edge creating a pillar down the center. Once you have moved sufficient material you can take down the pillar. Most catches happen when working on the edge, not so much in the center.

I'm guessing that the tenon broke as the result of a catch. Sharp tools are still required even with green wood. What tool are you using for hollowing? I recommend a round nose scraper for just starting out. It's more forgiving than a bowl gouge. Bowl gouges are great but they are a lot like a skew and can catch easily if you aren't paying attention. They do require practice to use effectively. Do not use spindle gouges for hollowing, they just catch and they are not nearly strong enough. The shaft and edge geometries are all wrong at minimum you'll bend a spindle gouge if you try hollowing with one.

Keep up the effort Fred, you're first one was a beauty. It's all a learning experience.

Terry,

I started out with a drive center and tailstock supporting the work to round the stock and shape the bottom. I then cut a tenon and mounted the base on the Nova. I used a 1 1/2 forstner bit to drill out the center and begin cutting from the center to the outer walls. I have about 1/2 inch walls now and that's when the tenon broke off. I then glued up the faceplate and let it sit overnight. I was working with a round nose scraper working towards the lip of the bowl when the piece just fell off the mount. I did run into some very hard spots when it fell off. If it fails again tonight I will use white paper and give that a shot. I also sharpen my tools about every 15 minutes. I will take it easy tonight and not force the tools into the work as fast. Thanks for the advice.

Fred

From days of old, that being shop class in HS I have always used newspaper for the joint. I've never had one fail either but then I'm not sure I would have put a chunk of wood that large on a small face plate.

Just for grins I looked in my early 70's PTWFE and they suggest..... newspaper.....

Too lazy to look at other additions but for those with nothing better to do feel free.

Second thing I noted was the direction of stock removal, that should be the other way round, that is working from the rim towards the center once you have the hole drilled. I'm not a big tuner and the last bowl I did was like 20 years ago so I'll let the experts deal with this subject.

Ed

reible wrote:From days of old, that being shop class in HS I have always used newspaper for the joint. I've never had one fail either but then I'm not sure I would have put a chunk of wood that large on a small face plate.

Just for grins I looked in my early 70's PTWFE and they suggest..... newspaper.....

Too lazy to look at other additions but for those with nothing better to do feel free.

Second thing I noted was the direction of stock removal, that should be the other way round, that is working from the rim towards the center once you have the hole drilled. I'm not a big tuner and the last bowl I did was like 20 years ago so I'll let the experts deal with this subject.

Ed

Newspaper? What's that? Oh, that thing I read on my computer....

I typically use newspaper as well. Sometimes I skip the paper altogether and just use glue. It's end grain to end grain which is an inherently weak glue joint. I'll part off part of the glue block and clean up the foot using a jam chuck.

In the future, skip hollowing with the forstner, unless you buy some that are close to the amount you want to remove. I've seen video online of a guy hollowing a 5 in bowl with a 4 inch forstner. (too late for this particular project.)

Segment 6 of the video series posted by Bob above shows a great example of hollowing with the live center still in place.

Your wall thickness is almost there.

Keep in mind when turning green you have 2 options regarding wall thickness.

Option 1: Take the wall thickness to approximately 10% of the diameter of the bowl (1 inch thick wall for a 10 inch bowl, 1/2 inch for a 5 inch bowl) This is called rough turning. Place the rough turned bowl in a paper bag with some of the chips and ribbons from turning and set it aside for a few months to reach EMC. Then once it is stabilized, put it back on the lathe and finish turn to desired profile and wall thickness.

Option 2: (More Artistic) Take the walls and profile all the way to finished dimensions and let the bowl warp. (and it will warp). Once stabilized sand and finish off the lathe.

Variation to Option 2: Displace moisture by submerging in denatured alcohol (DNA), this will displace the water and flash off faster leaving much less distortion. I've never done this method as I'm cheap and buying enough DNA to submerge a bowl just isn't in my budget.

Keep up the good work Fred.

Ok, it's into the bag and stored away for a few months now. Not much to look at when green. It will be interestering to see how it turns out after drying. I still need to finish turning the lip of the bowl but wanted to wait until it drys in case it decides to crack. The thinner brown paper seems to hold the 3 inch face plate much better this time. I will implement some of the suggestions provided here on my next bowl. Like leaving the live center on the tailstock in place as I begin turning the interior of the bowl. And to turn from the outside towards the center as suggested.

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Add Me three!

Really nice job, Fred for your first and second.

What an informational thread!

Just remember to cut going down hill. On your next bowl practice the "hero cut" once you cut down the pillar.

Hero Cut - going from the outer edge to center in one pass of a push stroke or center to edge in a pull stroke (some people prefer the pull stroke which technically is an uphill cut but ultimately it's safety and the final result that counts and not how you got there.).

The hero cut produces a much nicer finish cut (Less sanding) but does take practice.

Looking good Fred! Waiting for the drying is the hardest part. I usually put a date on the outside of the bag and put the bag on a shelf some where out of my normal field of vision. If you don't have a moisture meter, weight the bowl now while it's still wet. In a couple of months weigh it again, then at regular intervals monthly, weekly. Once the weight stays the same on consecutive weighing sessions you have reached EMC.

skou wrote:I just looked at your "shorty" er, and an idea I've been thinking about might work.

Imagine, you had a full-length ER, and your short-base ER. Machine some (could be oak) plugs, 6 or 8 inches long, that would fit in the tail end of the long ER, and the top end of your shorty. Drop the shorty into Hz mode, and slide the 2 together. Instant 5 foot lathe ways.

Yes, you'd need to get a second tailstock, and a second carriage. You'd also want to drill and tap the new tailstock, to fit those carriage knobs. (So you can lock it in place on the upper end of the way tubes.)

Here's how it goes together, drop the headstock down as far as it will go. Slip on the second headstock, slip on the second carriage, and set it horizontally. Join the head end to the tail end of the long-bed ER. The height (bench tops) need to be close to exactly the same.

Now, you've got a real long bed lathe, with adjustable head and tail ends.

Yes, I've got all the parts to do this, just no room anymore.

steve

Ok Steve, I just made a deal for another 10ER today and will pick it up Saturday. I might play around with your idea after I restore this new unit just for fun.