How Attach Tennon to Blank to Turn

Hi,

It's amature hour again. How do you attach the tennon to the Bowl blank for turning?

I spent an hour on the web trying to get a specific answer to this question. I found all sorts of casual comments like:

"Attach with cyanoacrylic." What kind? thin? thick? Which of the 3 or 4 basic types? What is a good source? How do you apply? Do you use globs and rub the 2 pieces together to smooth and thin the glue layer? Do you spread it with a spatula or piece of scrap wood?

"Attach with hot glue." What kind---(there are many!!!)? Low temp or high temp hot glue? What is a good source?
The hot glues that I have tried to use over the years have been unsatisfactory for me. They have started to thicken before I can get the two pieces together. This results in a joint that has "play." I do not need play on a woodlathe.

I learned that I am not to use soft wood or plywood for the tennon because of chucking problems. I learned that the tennon should be 1/4 to 1/3 of the blank diameter etc., but not how to attach.

I am turning with dry, store bought, hard woods.

Some time in the future, when I am more adept, I want to work with green woods. Unfortunately, the nearest woods is many miles away and if I picked up samples some man or woman in a car with a red light would probably show up to ruin the fun.
Ladies and gentlemen, please tell me what to do, with enough specifics that I can follow through.

Thanks in advance.

Enjoy,

Jim
 
Jim, there are a number of right answers to your question. If you're using CA glue, medium or thick would probably be the best bet. Good old yellow carpenter's glue, like Titebond or Elmer's Wood Glue would also work well if you can leave them overnight to cure. (I'd leave the CA overnight, too, but I know others who don't wait that long.) If you're using hot melt glue, I'd think the high temp stuff would give a stronger bond. Whichever method you use, you should clamp the two pieces together. Your lathe makes a handy horizontal clamp. You can use the tailstock to apply pressure, and use the spur center and live center to hold the wood pieces in position as you apply moderate pressure.

All of these suggestions assume you're mating smooth flat surfaces together. You'll need that for a good bond.

Does that help?
 
If I have enough wood thickness I do NOT glue a tenon on. I prefer to just turn one on the wood blank. It does not pop off- it is easy to create -it is easy to turn to smooth when finished. Don't have to wait over night. It does not waist much of the bowl blank.

BUT I do not buy wood blanks and I turn wood that is green - 95 percent of the time.

Listen to Stu and Vaughn they are a brain trust and use/do what they what they give advice on. not just desk jockeys....

Welcome -- share a few photos of your work.

Merry Christmas to you and yours
paul
 
I'll go along with what Vaughn and Stu said... except I don't know anything about the hot glue.. never used it myself.

I use CA on small pieces.. I prefer the thick myself and always let it sit overnight.

On larger pieces, I would use the wood glue.. it's just a matter trust... I have more for the wood glue than for the CA.

But like Paul, if I have the wood, I prefer to have the tenon cut from the blank itself...
 
I agree with what Stu and Vaughn said if you are turning a bowl and have no chuck. But like Chuck I very, very seldom use a glue block as I call them. If I am turning a bowl I will put a faceplate on one side, shape the outside of the bowl with a tenon or recess. Mount in the chuck and do the inside of the bowl, reverse and turn off the tenon.
 
This is just another 2 cents worth on top of the great advice you've already gotten. Make sure the surface of both the wood you want to turn and the tenon you want to attach are perfectly flat, both face grain, and preferably with the grain going the same direction. I wouldn't use hot glue for one reason. The joint will have a small amount of flex. It may hold just fine but as the wood turns and the tool cuts with and against the grain it creates vibration. With a joint that can flex that vibration will be greater and cause problems with a smooth cut. At least that's my experience. I like a Titebond II glue joint left overnight. Also, until you have the piece round and as much of the rough shaping done as possible, leave the tailstock in place to support the wood. Hope that helps.
 
Lots of right answers, Jim.

But I know you are in California where wood is expensive and dry. And you like me probably want to get as much out of your expensive block as possible. My mentor who has been turning for more years than I am old, and long before chucks where available taught me this.

He turns mostly big leaf maple burl, not inexpensive stuff. His bowl command rather handsome prices in galleries up and down the West Coast. He is famous for his very thin walled Southwestern hollow forms. His name is Wally Dickerman. Google him and you will see what I mean. I met him about 5 years ago and he got me started on turning. He still is my teacher. Nothing like starting with a real talented guy!

He used 5/4 or 6/4 alder. He bandsaws 3" disks. Now he has a supply of glue blocks, as Bernie calls them. Since chucks that open to 3 inches or more are very expensive, he rarely used them. He has a number of turnings in the works at one time and does not remove his chucking system until the bowl is finished. Can't do thin walled vessels if you remove the chucking system.

He uses small face plates with a lag bolt that extends from the center an inch or inch and a quarter. I find those face plates at Harbor Freight for around $15 apiece. Or find a machinist welder friend to make you some. Let me know if you want specific instruction on how to do this. If you use teh HF face plate, replace the screw that is in it. It is not long enough and it is too wobbly. Use a 1/4" lag bolt. It usually fits pretty snugly. There is a side set screw to keep the lag bolt for unscrewing.

Determine the top of bowl on your turning block. If it is not reasonable flat, band saw or plane a spot until it is. Drill an undersized hole for the lag bolt on the faceplate. Align the hole perpendicular as you can. Some turning blocks are pretty odd shaped! The depth of that hole is a little less than the length of the lag bolt protrusion on the face plate. Screw the face plate unto the turning block. Now face off a perfectly flat surface on what will be the bottom side of your turning. Use a straight edge to check frequently for perfect flatness. Remove fromt he lathe and remove the faceplate.

Back to your glue block. Drill an undersized hole for the lag bolt in the face plate. Screw the faceplate with the lag bolt unto the glue block. Mount on the lathe and face of the face side of the glue block to a perfectly flat surface. Use a straight edge to check and get it perfect. You can also round the band saw edges and slightly soften or chamfer the edges.

To glue the glue block to the turning block, simple apply medium thick CA glue to both flat surfaces. Smoosh the two together, smearing the glue around to cover the entire surface of both. Open it up and quickly spritz a light coat of accelerator on one surface and quickly mate them again. A slight twist will almost immediate grab and leave it alone. Let it sit for 10 minutes or so. Or go have lunch and fix a beverage. Whatever.

When you return, mount the face plate on the lathe. Bring up the tail stock. You are ready to round the blank.

Here's another tip I just remembered. "With tools so sharp, they seem to begin cutting before they're touch the wood."

The above isn't offered as a 'right way', simply a way that works.

Hope that helps, Jim.
 
Hi Jim,

A lot of good suggestions have been made.

Hot glue. For myself I would not trust it for large items (over 8”) but I have never used it myself. I have seen it used on youtube.

Wood glue, such as Titebond. Make sure the surfaces are flat and place a piece of craft paper (grocery bag paper works great) between the surfaces when you glue the up. It will be much easier to separate the pieces when the time comes and there will be much less sanding. Coat all surfaces completely with a small brush (you can wash it out).

CA glue. I follow Lyle Jamiesons directions in his discussions of transfer of power. I have also seen it used at our local woodturning club. That is to flatten the two surfaces, then on the glue block leave about ½ inch flat on the outside diameter. On the inside make it slightly concave. This insures a tight fit around the rim. Simply run thick bands of glue on the flat edge of the block and press together and let sit. It should be ready in about 15 minutes. The use of an accelerate will help. Some people spray one of the pieces, I just spray the seam after they are brought together. The rim on the glue block will be sufficient to hold it. You may glue the entire block but I have never seen it done (leave everything flat if you do).
I would use thick glue.
Wood glue or CA glues are available for many places such as Packard Woodworks or Highland Woodworking.

The use of a hard (density) wood is best. This may be either a hardwood (broadleaf) or softwood (conifer).

For myself, I would use a faceplate on the top. The screws do not need to be very long and the screw holes will be turned away when you turn the inside. For the bottom, a glue block or better yet, if you have sufficient room, a tendon or recess in the actual wood. Most turnings are slightly recessed or concave on the bottom to allow the item to sit on a ridge and not wobble (think of any bowl or plate you have). Which you use is largely dictated by the thickness of your stock.

Note, for any method, when working the inside do not use the bowl edge as a fulcrum while hollowing out. Your hand needs to be the fulcrum if necessary. Side pressure on the bowl is a sure way to dislodge your chucking method. Been there, done that.

Mike
 
I know of a few turners who use hot glue on 4 foot buurs without any problem. I have used it on really off centre unbalanced pieces as well again without problems. The trick is to make sure it is really hot. Dripping out of the nozzle before applying. It will hold. All the info given is good...including nit using CA glue on larger things as it cracks off DAMHIK. I use it (hot glue block) on some spalted woods which are too soft for a faceplate or as said if you are turning over a period of a few days with the chances of the wood warping. Glue the block onto your wood, then use a face plate or worm screw whatever you have to put on the lathe.

Pete
 
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