Shoulder width on a bowl tenon

[Rip Littig]

It's my understanding Stu Batty and thus Ashley Harwood recommend a shoulder more narrow than the face of your chuck jaws. I believe the reasoning is when jaws are tightened they may bite into the tenon and be prevented from sliding up and making firm contact on too wide of an undercut shoulder. If there's a gap between the shoulder and jaw face, problems will follow. My question is how many of you create a shoulder more narrow than the face of your jaws? I may be missing something but don't see other turners advocating this practice. As someone with only two years experience I'm working on improving my tenons and shoulders which should lead to better turning. Thanks in advance for any feedback and apologies if the subject has already been discussed. I looked but couldn't find it specifically.

 

[William Rogers]

I do. Mostly because I can’t see the face seated better.

 

[Mark Jundanian]

I make my shoulder at least as wide as the top of the jaws.

 

[hockenbery]

Depends on the piece.
Mostly about the jaw width.
Sometimes larger

In some situation the is no shoulder and I just grip in a groove.

 

[Brian Gustin]

Mine will always vary - I just eyeball it any more, but almost never have a shoulder deep enough to bottom out in the jaws , and it is a matter of luck if I happen to get a "perfect circle" diameter (and bad luck if it happens to be a rough turned bowl needing twice turned because after drying and truing up, the tenon would then be too small)

 

[Emiliano Achaval]

I always make mine narrower than the face of the jaws. I also always test for fit, out of habit, with a spare jaw that I keep hanging from a nail. The goal is to have the run perfectly true when I turn it around. Nothing bothers me more than seeing a wobble, and it is next to impossible to true it up right without losing design. Maybe if you are a left-hander you could. When I spend some time designing a calabash, it has to run perfectly. I have seen several YouTube masters make horrible tenons, then have a noticeable wobble. One even said there is no getting away from the wobble! LOL

 

[Bill Blasic]

My guess is that mine is most always bigger than the face of the jaws but I do stress one thing, the very last cut before turning over is a finish cut on the tenon. Since the tenon is made early in the making of the bowl the stresses of the removed wood can make the tenon not as true to the bowl as it could be. Therefore one last finish cut on the tenon to get the truest running second side.

 

[Lou Jacobs]

Therefore one last finish cut on the tenon to get the truest running second side.

Thanks for this “rule” Bill. It is usually my practice to make the tenon last, but not always, and not with this logic in mind. I’ll pay closer attention from here on out.

 

[Tim Tucker]

I always make mine narrower than the face of the jaws. I also always test for fit, out of habit, with a spare jaw that I keep hanging from a nail. The goal is to have the run perfectly true when I turn it around. Nothing bothers me more than seeing a wobble, and it is next to impossible to true it up right without losing design. Maybe if you are a left-hander you could. When I spend some time designing a calabash, it has to run perfectly. I have seen several YouTube masters make horrible tenons, then have a noticeable wobble. One even said there is no getting away from the wobble! LOL

Emiliano - would you consider making a thread with some pictures about your method? I would find it extremely usual - and - I am willing to bet that everyone else reading this forum would also. You have touched on something that I believe is never emphasized enough: The importance of perfecting the tenon.....And it *IS* important for protection of the shape you are trying to achieve -true...BUT it is also a way that if done correctly - save a LOT of time for the turner. I think many/most of us will benefit from better education on this.
T

 

[Doug Freeman]

Aside from situations where a narrow, or no, tenon shoulder is needed due to design, the tenon shoulder should be equal or geater than jaw face OD.

The purpose of the shoulder seated against the top jaw face is 3 fold: 1) set tenon depth to prevent bottoming, 2) ensure the project runs true when reversed and reseat the tenon in the same spot if the project is removed, 3) resist the torque created while cutting the project and/or unbalanced work, keeping this torque force from concentrating at the sharp “top corner” of the tenon where it meets the bowl bottom.

Whether the shoulder is 1/2 or full jaw face width doesn't make a lot of difference, more with a smaller dia tenon and less with a larger dia tenon, in resisting the torque generated. Full width adds a bit to the lever arm length of the jaw face resisting the torque.

It is critical that the shoulder be flat or slightly concave so that the shoulder takes the load, and locates the shoulder against the jaw face in a concentric circle. Personally I prefer the shoulder to be full width and slightly concave. I can better see a good fit. It also covers the corners of the jaws so I'm less likely to get into them with a tool if I need to get into that area. Most of my "reversing wobble" over the years has been from not being seated against the shoulder properly.

 

[robo hippy]

Well, I don't use a tenon very often. When I do, I want the chuck jaws covered. This is in case I have to touch up the very bottom of the bowl. Wood cuts easier than metal...... The gouges in my chuck jaws come from learning how to use the McNaughton coring system.

Getting a bowl to seat and run true is an art. I do seem to have better luck if I shear scrape or use a NRS for the final touch up before reversing. The gouge always seems to bounce a little, the old end grain/side grain thing, or maybe with/against the grain cuts. With the shear scrape or NRS, you are nibbling off the high spots.

robo hippy

 

[Mark Jundanian]

I think Doug Freeman really covered it for me. I will add that if you're going for a "perfect" circle diameter, then you really should also have a full width shoulder.

Any comments on why Stuart & Ashley would favor a narrow shoulder?

On a separate note there has been some discussion of wobble after remounting. I pretty much always transfer mounting using the tail stock and a second chuck mounted to a live center. I'm curious what others do?

 

[Marc Banka]

I make the shoulder about the same size as the jaw width. I can come up with reasons why slightly larger or smaller could have benefit, but I think that’s just nitpicking.

larger diameter tenons are inherently more accurate than smaller, being a greater percentage of the total diameter.
The shoulder, on my tenons angle down a touch. No contact between bottom corner of tenon and inside of jaw.
I cut the basic tenon with my bowl gouge, then do the final angles with a spindle gouge. I’m very careful and exacting in how I make the last cuts.
Be careful about any vibration in the piece when making the tenon. If there’s vibration, even if it’s not visibly shaking, will cause run-out in the tenon. Slow down to a speed, even if it’s low for turning, to true it up.

If I’m doing rough turnings I mount the chuck to the tenon before reversing, to check for true running.
On final turning I don’t, in part because I don’t have duplicate chucks. So then, I’m careful, then look for run-out before reversing.
I also turn the outside to near completion before reversing. Shaping, any scraping, and first grit sanding is completed before reversing. That eliminates any need to have to re-tool any parts. As been noted above, that’s a sad place to be!

My last point is that, in my humble opinion, chucks are usually overtightened, which distorts the tenon, can damage and therefore weaken the wood, and causes the piece to run out of true. It’s the dovetail that is holding the wood, not clamping pressure. Snug it with one hand only, then just a bit more (still one hand only).

Proper tenons are such a huge part of successfully crafting a bowl. Inaccurate tenons cause lots of extra time and work. It’s well worth any amount of effort to learn it, to make perfect tenons each time. A real timesaver.

 

[hockenbery]

if you're going for a "perfect" circle diameter, then you really should also have a full width shoulder.

Not sure about this.
On some pieces I just use a groove with a full circle. Mostly smaller pieces.
If I’m Holding a ball with a perfect circle groove I don’t want a shoulder. The groove will be a detail.

Two benefits of the shoulder on top of the jaws is to reduce vibration and preventing the piece from rocking back and forth from aggressive or poor tool work.
A catch is less likely to break the tenon with a shoulder on the tops of the jaws

 

[Rip Littig]

I think Doug Freeman really covered it for me. I will add that if you're going for a "perfect" circle diameter, then you really should also have a full width shoulder.

Any comments on why Stuart & Ashley would favor a narrow shoulder?

On a separate note there has been some discussion of wobble after remounting. I pretty much always transfer mounting using the tail stock and a second chuck mounted to a live center. I'm curious what others do?

Ashley Harwood explains it in her bowl turning videos on https://thewoodwhispererguild.com/ Lesson 3: Wet Bowl Part I. I understand it as when jaws are tightened they may bite into the tenon preventing them from sliding up and making firm contact on too wide of an undercut shoulder. If there's a gap between the shoulder and jaw face some wobble may occur leading to problems. Stu Batty made similar comments during his demonstrations at Totally Turning in Saratoga back in late March.

 

[Lennart Delin]

Usually 2-3 mm. See further a memo I wrote of chucking.

 

[Doug Freeman]

On a separate note there has been some discussion of wobble after remounting. I pretty much always transfer mounting using the tail stock and a second chuck mounted to a live center. I'm curious what others do?

Turn ~ 50-90% of the bowl OD and all of the tenon. I don't have a hard "rule", other than knowing sometimes I get a bit of run out after reversing and I want to have room to re-true. I also know that as I start to removes the ID, the stress relief can effect the OD a little or a lot depending on the blank. Down to ~10% thickness I'm comfortable working on the OD.

I just turn the blank around, use the centerpoint the drive center made for the livecenter, lightly seat the tenon in the jaws, and spin it up at low speed with livecenter removed. If good, stop and tighten jaws. Recheck at low rpm, if good, keep going. If not, determine cause. Sometimes I mess up a tenon and need to switch the blank back around and fix the issue. Sometimes I can't ID the cause, and just retrue the OD - which is why I never finish the OD until I turn a blank around and chuck it up, whatever the form - bowl, HF, plate, etc. (most all start between centers). When I spend the time to get the OD just right and then find I messed up somewhere and can't get the OD to spin true, I have wasted time and effort.

 

[Mike Johnson]

If anyone has turned precision parts on a metal-lathe they will understand the proper technique in seating a work piece in the jaws of the chuck.
It might seem seated properly until you use a dial indicator against the material face to measure the runout. Most of the time you need to tap
the work piece with a solid piece of metal to get it to seat fully into the jaws. Most wood turners hold the work piece in one hand while using the
other hand to tighten the chuck jaws they then let go of the work piece to fully tighten the jaws, during this transition the work piece can drop a
small mount in the jaws. Using the tailstock to hold the work piece against the chuck jaws can reduce the amount of runout when remounting a
large wood billet which is usually top heavy and awkward to hold with one hand.

 

[robo hippy]

I think one common mistake when using a chuck to mount a bowl, and no difference between recess or tenon on this one, is that some will mount with 2 jaws on end grain, and 2 jaws on side grain. You will get different amounts of compression on the different jaw contact points, with the end grain compressing less than the side grain. I always rotate 45 degrees off of that, so rather than jaws at noon, 3, 6, and 9 o'clock, I go to 1:30, 4:30, 7:30, and 10:30, if that makes sense. The compression will be pretty much equal. On end grain mounts, this is not an issue, other than I would suggest NEVER use a recess for end grain turnings....

robo hippy

 

[stu senator]

I would suggest NEVER use a recess for end grain turnings....

And you know this how?

I agree with your complete post.
Stu

 

[Brian Gustin]

And you know this how?

probably the same way I do... chuck it up, touch gouge to wood, piece split in half and went flying.. and no I didn't have the chuck tightened too much (it was just snug, and expecting to do a very light cut with the gouge)

 

[John Dillon]

I would suggest NEVER use a recess for end grain turnings....

robo hippy

I've made a number of earring stands from 3x3" spindle stock. I learned from Kip Christensen how to make these using a recess in the bottom of the stand (endgrain). I've probably made 25 earring stands without any problem. Of course, these are relatively light-weight items, but the recess holds up well for me.

 

[robo hippy]

Can't remember if I ever used a recess on an end grain piece. Just didn't make sense. One secret of the recess, maybe more so than a tenon, is that you want it snug, but not tight. You can blow a recess apart, especially if you have a narrow shoulder. You can put enough stress on it, by over tightening, that even a tiny catch can cause failure.

robo hippy

 

[Randy Heinemann]

I think one common mistake when using a chuck to mount a bowl, and no difference between recess or tenon on this one, is that some will mount with 2 jaws on end grain, and 2 jaws on side grain. You will get different amounts of compression on the different jaw contact points, with the end grain compressing less than the side grain. I always rotate 45 degrees off of that, so rather than jaws at noon, 3, 6, and 9 o'clock, I go to 1:30, 4:30, 7:30, and 10:30, if that makes sense. The compression will be pretty much equal. On end grain mounts, this is not an issue, other than I would suggest NEVER use a recess for end grain turnings....

robo hippy

I think I might have learned this from one of your videos, Reed. It wasn't obvious to me until the video but it's really great advice.

I'm kind of confused by this thread, though. I have never seen, read, or been advised in a class, to create a tenon with shoulders smaller than the jaw faces. To me, with my 5+ years of turning experience, it doesn't seem to make sense. You want the most stability possible. Although, on a correctly sized tenon, the jaws will make contact around the entire circle and that is where I suppose most of the stability is, a tenon that makes the jaws extend beyond the outside of a bowl seems limiting. That means you'd need to make sure that the bottom of the bowl is completely formed before turning it around and mounting the tenon in the jaws. Correct? Or at least you'd need to wait to make any changes to the bottom until you're turning the tenon off at the end. I can see that, on smaller turnings, that you'd need to maximize the tenon size and it might be reasonable, but on most larger turnings, it just doesn't seem like a good idea.

Maybe I'm just not understanding the various information in the thread?

 

[Jason Matisheck]

I think I might have learned this from one of your videos, Reed. It wasn't obvious to me until the video but it's really great advice.

I'm kind of confused by this thread, though. I have never seen, read, or been advised in a class, to create a tenon with shoulders smaller than the jaw faces. To me, with my 5+ years of turning experience, it doesn't seem to make sense. You want the most stability possible. Although, on a correctly sized tenon, the jaws will make contact around the entire circle and that is where I suppose most of the stability is, a tenon that makes the jaws extend beyond the outside of a bowl seems limiting. That means you'd need to make sure that the bottom of the bowl is completely formed before turning it around and mounting the tenon in the jaws. Correct? Or at least you'd need to wait to make any changes to the bottom until you're turning the tenon off at the end. I can see that, on smaller turnings, that you'd need to maximize the tenon size and it might be reasonable, but on most larger turnings, it just doesn't seem like a good idea.

Maybe I'm just not understanding the various information in the thread?

[COLOR=rgb(0, 0, 0)]Lawrence Littig[/COLOR]'s post above explains it best. The advice is for a very specific set of circumstances. That is, turning wet wood with an undercut shoulder. In that case, the jaws can easily compress into the tenon, causing a small gap between the shoulder and the jaws. Pressing the piece against the jaws won't close the gap because the jaws are dug into the tenon. Also, if the shoulder is is overhanging the jaws, and undercut, you probably won't be able to see the gap.
The narrow shoulder lessens the potential amount of undercut and will let you see the gap between the shoulder and jaw should this occur.

 

[Tim Tucker]

[COLOR=rgb(0, 0, 0)]Lawrence Littig[/COLOR]'s post above explains it best. The advice is for a very specific set of circumstances. That is, turning wet wood with an undercut shoulder. In that case, the jaws can easily compress into the tenon, causing a small gap between the shoulder and the jaws. Pressing the piece against the jaws won't close the gap because the jaws are dug into the tenon. Also, if the shoulder is is overhanging the jaws, and undercut, you probably won't be able to see the gap.
The narrow shoulder lessens the potential amount of undercut and will let you see the gap between the shoulder and jaw should this occur.

I agree that being able to see any gap is important, but not sure I understand your reference to "undercut shoulder". So - assuming I am picturing what you are , reaching back to really old established principles of physics/engineering.....if the shoulder on the wood to be turned is narrower than the width of the jaw - top...that leaves a weak area which is easer compressed by side force being applied to the the wood by aggressive cutting - i.e. roughing cuts. That would be a leveraging force from the tool. Especially with wet or green wood. The compression would introduce a wobble in the wood, and possibly - in the case of someone not aware of why this was happening - could dis-lodge the piece from the chuck. Might result in stitches, or at least the utterance of purple words and a wall repair.....

BTW - is the avatar picture a Calumma parsonii? I used to raise Chameleo Jacksonii - years ago.....a lot of fun to feed them

 

[Tim Tucker]

It's my understanding Stu Batty and thus Ashley Harwood recommend a shoulder more narrow than the face of your chuck jaws. I believe the reasoning is when jaws are tightened they may bite into the tenon and be prevented from sliding up and making firm contact on too wide of an undercut shoulder. If there's a gap between the shoulder and jaw face, problems will follow. My question is how many of you create a shoulder more narrow than the face of your jaws? I may be missing something but don't see other turners advocating this practice. As someone with only two years experience I'm working on improving my tenons and shoulders which should lead to better turning. Thanks in advance for any feedback and apologies if the subject has already been discussed. I looked but couldn't find it specifically.

I will get Stuart's clarification in Oct. at a class with him. But currently - I think of the accuracy of the angle that the tenon is cut at - the dovetail - as being more Germain to the chuck jaws obtaining and maintaining a solid grip on the wood.

 

[Randy Heinemann]

Just a quick response to a previous response quoting me - I understand Reed's practice of rotating the jaws so that they are compressing the wood fibers equally all around and that is part of my setup. However, I still don't understand that the blank would be more stable with a shoulder that doesn't at least equal the outside diameter of the jaws. Part of the mounting strength results from the shoulders resting on the face of the jaws. With less to rest on, it would seem likely that the mounting wouldn't be as strong... Unless I'm just not understanding the thread.

 

[Doug Freeman]

Just a quick response to a previous response quoting me - I understand Reed's practice of rotating the jaws so that they are compressing the wood fibers equally all around and that is part of my setup. However, I still don't understand that the blank would be more stable with a shoulder that doesn't at least equal the outside diameter of the jaws. Part of the mounting strength results from the shoulders resting on the face of the jaws. With less to rest on, it would seem likely that the mounting wouldn't be as strong... Unless I'm just not understanding the thread.

The tenon dia, and thus the dia at which the jaws contact, gives the total lever arm length to resist the load generated.

Lets say we are debating the difference between an 1/8" and 1/4" shoulder width. Let's use 2 cases - 2" and 4" dia tenon. Load during roughing is higher, especially interrupted cuts. I'll just pick a # of 100 lb-ft that needs to be reacted to by the jaws/shoulder (generated by out of balance, interrupted cuts, continuous cutting). We will calculate the force, determined by the lever arm, that will be applied by the shoulder/jaws to maintain position. Torque = Force x Distance, therefore F = T/D

4" dia tenon, D = Radius + shoulder,
1/8" shoulder F = 100/2.125 = 47.01 lb
1/4" shoulder F = 100/2.250 = 44.44 lb
5.4% difference

2" Dia tenon
1/8" F = 100/1.125 = 88.89 lb
1/4" F = 100/1.250 = 80.00 lb
10% difference

A different load will obviously generate different #'s, but the % difference will remain the same. Most obvious is the effect of tenon dia. The effect of the shoulder width is relatively small and not the difference between success and failure typically. As tenons get smaller the % difference does increase. As stated in post #10, what is important is to seat the shoulder so that load applied at the sharp corner of the tenon and shoulder is greatly reduced.

Whether an 1/8" shoulder provides better visibility vs 1/4" or larger shoulder is debatable, and I say no. What I do is make the shoulder ~ width of jaws, and then cut the OD outside of that down a bit so I can see the fit.

 

[Randy Heinemann]

The shoulder is not the only aspect resisting the cutting force/torque. The clamp of the jaws on the tenon also resist that torque. Also, the tenon dia, and thus the dia at which the jaws contact, gives the total lever arm length.

Lets say we are debating the fifference between an

Sure, I understand that those other things matter but having nice flat surface that the entire jaw face rests on is a big deal I think. Angle of the outside of the tenon if you have dovetailed jaws, size matching a partially open jawset, and Reed's recommendation about orientation of the blank, all are important. However, for me, I like having shoulders which are at least the size of my jaws so I get that surface for a solid resting point. I'm smaller shoulders will work but I just don't like that concept.

 

[Doug Freeman]

I understand that those other things matter but having nice flat surface that the entire jaw face rests on is a big deal I think.

A surface that creates contact at the OD of the shoulder or jaws is critical. It is difficult to make an absolutely flat shoulder. It has to measured some way to make sure the ID is not a few thou more proud. I make all shoulders, whether wide or narrow, slightly concave to force contact at the outermost point (OD protrudes above ID).

 

[hockenbery]

However, for me, I like having shoulders which are at least the size of my jaws so I get that surface for a solid resting point. I'm smaller shoulders will work but I just don't like that concept.

As long as you cut the shoulder on a plane parallel to the jaw face.
@Doug Freeman points out that is hard for beginners and maybe impossible in a super accurate measure for anyone.

My thoughts are most experienced turners get close enough.

However if the face is cut less than the jaw width with the outside edge proud the outside edge will contact the jaw face every time.
I use face plates on my hollow forms always make the mounting surface slightly concave to ensure the outside rim of the faceplate contacts the wood. - same principle.
With faceplates the concave is quick and easy - cutting a 3 or 6 inch flat is really hard and time consuming.

Cutting a close enough 1/2” -3/4” parallel flat for chuck jaws is easy if you have turned a few hundred.
Easy to check with a ruler corner for square and parallel if you don’t trust eyeing it.

 

[hughie]

for me much depends on how I want the foot to look when the bowl is finished. If I am going carve feet then it will be longer, also the form dictates often on how high the foot will be. I really done have a hard and fast rule on width

 

[Jason Matisheck]

I agree that being able to see any gap is important, but not sure I understand your reference to "undercut shoulder". So - assuming I am picturing what you are , reaching back to really old established principles of physics/engineering.....if the shoulder on the wood to be turned is narrower than the width of the jaw - top...that leaves a weak area which is easer compressed by side force being applied to the the wood by aggressive cutting - i.e. roughing cuts. That would be a leveraging force from the tool. Especially with wet or green wood. The compression would introduce a wobble in the wood, and possibly - in the case of someone not aware of why this was happening - could dis-lodge the piece from the chuck. Might result in stitches, or at least the utterance of purple words and a wall repair.....

BTW - is the avatar picture a Calumma parsonii? I used to raise Chameleo Jacksonii - years ago.....a lot of fun to feed them

Since it's practically difficult to make a shoulder that is perfectly flat to register with the top of the jaws, most people cut the shoulder at a very slight angle, so that it contacts the outer diameter of the jaws and has a slight gap where the the jaws meet the tenon. That is what I mean by "undercut shoulder."

Picture is a panther chameleon, Furcifer pardalis.

 

[Tim Tucker]

Ah...- yes the undercut makes sense. it is what I do on mine as well. The Chamleon is a beauty.

 

[Randy Heinemann]

I have tried various ways to create tenons. I began turning using exclusively recesses, which I found easy to create with the help of the Nova dovetail chisel/scraper. Since my lathe was a Nova and my chucks/jaws all Nova, this was easy and essentially foolproof. However, I realized that, in many cases, a tenon was more stable and held the blank better.

I now almost always use my Easy Wood Square Rougher. Since the carbide insert is square cutting a flat shoulder is easy and rarely is it not flat. Since I always check it's flatness and squareness to bottom edge of the bowl, I can't think of any problem since I started using this tool. I had it left over from when I started turning and didn't want to learn about sharpening. Now it's almost exclusively used for creating a tenon (along with the diamond shaped Easy Wood tool to create a dovetailed tenon). It's fast, easy, and for me, foolproof. I've always realized the need to get the shoulders as flat as possible.

 

[Neil S]

I think one common mistake when using a chuck to mount a bowl, and no difference between recess or tenon on this one, is that some will mount with 2 jaws on end grain, and 2 jaws on side grain. You will get different amounts of compression on the different jaw contact points, with the end grain compressing less than the side grain. I always rotate 45 degrees off of that, so rather than jaws at noon, 3, 6, and 9 o'clock, I go to 1:30, 4:30, 7:30, and 10:30, if that makes sense. The compression will be pretty much equal. On end grain mounts, this is not an issue, other than I would suggest NEVER use a recess for end grain turnings....

robo hippy

Ditto

I just align any one gap in the jaws with the grain in the blank, which then positions the blank to receive equally distributed pressure to side and endgrain.

That's not important for me on the tenon at the green turning stage of a bowl as there is going to be a lot of movement in the blank between green turning and final seasoned turning, so a bit of run out is neither here nor there.

After green turning the tenon is only there as an insurance policy in case the inside tenon/recess is too off to grip at the seasoned re-turning stage, in which case the internal tenon/recess needs to be made round/true again.

As I only use a recess in the foot (no tenon) at the second stage of turning to get the outside of the bowl done to completion in one go, jaw positioning to get equally distributed pressure to both the side and endgrain inside the narrow foot becomes much more important.

If I'm starting with seasoned blanks I go straight to a recess in the foot and use no tenon at all.

 

[hughie]

"If I'm starting with seasoned blanks I go straight to a recess in the foot and use no tenon at all."

Interesting, there are some woody organisations I know who remain nameless that frown upon the recess greatly. I have Bruce Ledbetter recess chuck that is only for recess holding its works extremely well. Its not used often, as my standard method of operation is to make the tenon the foot then finish the outside before going internal

 

[Neil S]

"If I'm starting with seasoned blanks I go straight to a recess in the foot and use no tenon at all."

Interesting, there are some woody organisations I know who remain nameless that frown upon the recess greatly. I have Bruce Ledbetter recess chuck that is only for recess holding its works extremely well. Its not used often, as my standard method of operation is to make the tenon the foot then finish the outside before going internal

Yeah, well, I was turning before most if not all of those organisations came into being, so any attempts to educate me to their approved ways are probably doomed to failure...

I also have one of Bruce's recess chuck somewhere in a bottom drawer (and his recess maker). I'd like to think I can do them better and quicker by hand myself with making a nice recess, but Bruce's system was a good one at the time... many decades ago now.

Of course, tenons provide a more secure hold than a recesses, and for that reason I do still use a tenon when I'm coring large diameter blanks, but on final turnings a recess is more than adequate to hold the piece for the inside turning, that is if you are not prone to catches. I reckon I will have saved myself countless hours over the years by not having to go back and remove the tenon to complete the bottom of the bowl/form.

PS - I grew up in the same town as Bruce Leadbeatter and also learned bit about working with wood from Bruce's father.

 

[robo hippy]

I have a video up on You Tube about mounting things on the lathe. The debate continues about which holds better, a tenon or a recess. My response is that both hold equally well as long as they are made properly. Tenon has to be sized for the bowl you are turning. The shoulder on the recess also has to be sized to the bowl you are turning. In both situations, if they are too small for the bowl you are turning, you will get a failure.

As for the argument about 'the bottom is not finished because you can see how the piece was mounted on the lathe', that appears to be some thing that woodturners say, but not one single customer ever commented on. There is no real mystery in how things are mounted on the lathe, tenon, recess, glue block. I don't think any one uses the face plate and then cover the screw holes with felt any more.

robo hippy