Returning bowl blanks

[Wally Wenzel]

I normaly use a tenon when roughing out a bowl and do not have a problem truing a tenon up to return it,but the last couple I decided to try a mortis and in remounting with the tail stock holding it in place it is nearly impossible to true the mortise again. What do the rest of you do to accomplish this?Wally

[Dennis Ford]

I also normally use a tenon (or faceplate) for rough-outs. A custom ground scraper will work to true a recess; just have to grind it so that the handle does not interfere with the tail-stock.

[Bernie Weishapl]

I use a tenon on all. Had trouble with recesses when I started and never used them again.

[Michael Mills]

I use a mortise/recess most of the time. Don’t clear out the full mortise when you rough out. Unless you have a super deep mortise the center can’t bottom out. I cut mine about 3/8” deep, the diameter of the fully closed jaws, and a little wider than the width of the jaw tops. This leaves a center area with the divot from the tailstock to align it with again in a friction chuck when remounting. How much you leave in the center doesn’t matter, may be a 1” diameter or may be a ½” diameter.

I use a recess mainly for security. For 50mm jaws the area of wood holding is 3.14" for a tenon/spigot. Using a recess with one inch of wood surrounding it gives 12.5+ inches of wood; minus the 3.14" on the interior which is holding nothing you still have three time the area of wood holding it.

[Dan Forman]

I nearly always use a tenon for that reason, but Technatool makes a dovetail shaped scraper that can true up the section where the jaws will seat in the recess. One advantage of this approach is that if you start with a minimum diameter recess, you not have to worry about the recess getting too big for the jaws, whereas if you start with a small tenon, it is possible to turn away enough of the tenon when truing it that the jaws will be too big to grasp it. Even with the special dovetail scraper, it can be awkward to to get it in position to cut, especially if the recess is of small diameter.

The only time I use a recess with for green wood is if I have a crotch piece that I want to preserve as much of the feather as possible, where using a recess means that I can turn away less of the wood that will comprise the bottom of the bowl or platter.

Dan

[Bill Bolen]

I have several oland style tools. When I run into a recess that has gone way out of round I remove the 3/8" oland bit and put in a dovetail router bit. Straight in then a bit to the side and there is a new recess edge with the right angle for the dovetail jaws. Quick and easy. Does get a bit tight working with the tailstock in the way but just enough room to get it done.

[Thomas Canfield]

I prefer a tenon on green wood requiring returning, but have used a recess with my #4 jaws on Stronghold since the recess is then over 4" D and can be accessed to true up . The recess on the larger diameter was used to reduce wasted wood since the recess and surrounding wood would be later included in the base ring of the bowl. With standard jaws, I always use a tenon.

[robert baccus]

I love a recessed dovetail but only on dry wood for the above reasons. On green wood and dry sometimes, I use a glueblock wasting no wood. Use a good strong hardwood and you can use a single screw to hold it on. Thick CA is great on green wood.

[Dan Forman]

I love a recessed dovetail but only on dry wood for the above reasons. On green wood and dry sometimes, I use a glueblock wasting no wood. Use a good strong hardwood and you can use a single screw to hold it on. Thick CA is great on green wood.

Robert --- What's the screw for? Wouldn't any screw cause a hole that would be visible on the finished piece?

Dan

[robert baccus]

I was referring to a single screw hold on the glue block. I often turn a 2" thick GB of very hard wood and dovetail the back to allow the chuck to have a good grab on the 2&1/2" dia. GB. Also I drill and tap for a single screw grab on the glueblock. As in double purpose.

[Philip Duffy]

Use a tendon all the time. When the bowl is dry, I stick in on the face of the chuck, bring up the tailstock and re-turn the tendon so it is Round! End of problems. Philip

[Pat Scott]

Just like Phillip, I always use a tenon and I true it up the same way. Just make the roughed out tenon at least 1/2" bigger than the minimum diameter of your jaws to allow for truing up. It also helps to have different size jaws just in case something happens when truing up and you need to switch to a smaller set.

[john taliaferro]

I was referring to a single screw hold on the glue block. I often turn a 2" thick GB of very hard wood and dovetail the back to allow the chuck to have a good grab on the 2&1/2" dia. GB. Also I drill and tap for a single screw grab on the glueblock. As in double purpose.

some of my GB even have a threaded hole for the spindal seams to hold tighter tolerance for me if the piece is not to large .

[Prashun Patel]

I use a tenon also. I made a few with recesses, but they felt awkward. Also, a tenon gives some more options if you want to make a foot.

I've not turned as many bowls to call myself a pro. But I have turned probably 200-250 green blanks. I've only had one or two snap off at the tenon, and they weren't even that big (5-6" with a 2" tenon). That was at the very beginning when I was getting a lot of catches. Once my technique improved in that regard, I've never snapped one, and I do a fair amount of 11-12" bowls with a measly 2"x1/4" tenon. I'm sure a recess is theoretically safer, but anecdotally, it just hasn't been a practical concern for me.

[Reed Gray]

I use a recess all the time, and turn green to final thickness, so there is no returning. Not sure how I would do it if I was going to twice turn a bowl. It would be difficult to true up a recess for the second time. If you are going to turn the bottom flat and remove your mount, I would think a tenon would be your best bet. The way some of my bowls warp, I would want at least 3/16 high/thick, maybe even 1/4 inch. Either way, you would want to leave a center mark for remounting. There are dove tail scrapers from a couple of the toy stores, and they seem to be ground to the same angle as the chuck jaws, which is about 7 degrees.

robo hippy