Turning In Reverse?

[Randy Heinemann]

I own a dovetail chisel (really a scraper with a dovetail shape on the end I guess) made by Nova which will cut the the required angle for Nova jaws on the edge of the recess. I realize that there are a number of ways to cut required angle on the jaws but, over the past 3 years while learning to turn, I have found that this tool makes that task extremely easy and foolproof and I always use that tool when creating a recess on a bowl bottom.

However, I have begun to use tenons more often rather than recesses and this tool won't perform the same task to create the required angle on the tenon (since the edge of the tool is angled just as a scraper would be angled downward). So, finally my question . . .

Could I use. the tool on the tenon by turning in reverse? Or is that a dangerous thing to do?

I realize that I could, through trial and error, cut the needed angel into a square scraper and again, I realize that there are a number of ways to create the angle on the tenon but using the Nova dovetail chisel would be the simplest and would help me to get an accurate angle until I can master doing it with a skew, detail gouge, or other tools.

 

[Tom Gall]

DON'T turn in reverse!
"I realize that I could, through trial and error, cut the needed angel into a square scraper and again, I realize that there are a number of ways to create the angle on the tenon but using the Nova dovetail chisel would be the simplest and would help me to get an accurate angle until I can master doing it with a skew, detail gouge, or other tools."
You just answered your own question.

 

[Randy Heinemann]

DON'T turn in reverse!
"I realize that I could, through trial and error, cut the needed angel into a square scraper and again, I realize that there are a number of ways to create the angle on the tenon but using the Nova dovetail chisel would be the simplest and would help me to get an accurate angle until I can master doing it with a skew, detail gouge, or other tools."
You just answered your own question.

Actually, if I really knew the answer I wouldn't have bothered asking the question. OK, so understand you think I shouldn't turn in reverse, but why is turning in reverse, especially just to cut the angle on the tenon a bad idea?

 

[Chris Lawrence]

As far as I am aware Nova jaws do not have a true dovetail on the inside of the jaws. I have always made a straight tenon and compressed it.

 

[Randy Heinemann]

As far as I am aware Nova jaws do not have a true dovetail on the inside of the jaws. I have always made a straight tenon and compressed it.

The 50 mm jaws I got with my G3 a few years ago don't seem to be dovetailed and have a ridge around the edge that would be against the base of the bowl. The 50mm jaws I got with the Nova Pro-Tek SuperNova have both a dovetail and serrations on part of the jaw. The 100mm jaws I bought with the SuperNova just have a dovetail. Seems like they are in transition...?

 

[Al Chavez]

Some of the SuperNova bundles have the dovetailed 50mm jaws. The Nova 23108 Premier Pro-Tek Supernova 2 Chuck Bundle with Pro-Tek 2" Jaw Set is the set I bought that has them. Here is a pic of the 50mm jaws with the dovetail on both inside and outside of the jaws.


My preference as a new turner is to not have to stop the operation I am working in to reset the tool rest to the other side and move and then reset the tailstock if I can avoid it. I like recesses more than tenons but when making a tenon I get as close as I can to the right diameter on my tenons and then use a skew, detailing carbide tool or this homemade Angled Dovetailing scraper to get the right angle on the tenon.
Its easier and quicker and you'll only get better quicker the sooner you start.

Here is the angled dovetail scraper I ground down from a cheap skew chisel. It is GREAT for cutting the dovetail recess with tailstock support from a pin. You don't have to remove the tailstock center until the end to remove the nub because you can cut from an angle next to the tailstock center.

Sorry Randy, I see you are already aware of reshaping a tool. Maybe just modify your dovetail chisel on the other side.

 

[Chris Lawrence]

Even if there true dove tail on the inside your compressing the wood when you tighten them down. In my opinion there is no need to fuss with making a perfect dovetail on a tenon. Just compress the tenon to make the perfect fit.

 

[Tom Gall]

Actually, if I really knew the answer I wouldn't have bothered asking the question. OK, so understand you think I shouldn't turn in reverse, but why is turning in reverse, especially just to cut the angle on the tenon a bad idea?

Randy, maybe it's a terminology or technique problem? As I see it, if you turn in reverse your tool will come off the tool rest...and you don't want that to happen!!! It's just as easy to use a skew as a scraper - just like your dovetail tool, but with a different angle of approach. I assume you are using a live center for safety which wouldn't allow turning in reverse anyway.

 

[Randy Heinemann]

Sorry Randy, I see you are already aware of reshaping a tool. Maybe just modify your dovetail chisel on the other side.

 

[Randy Heinemann]

All interesting replies . . . What I guess I'm really asking is would it be dangerous to cut that very small amount of wood off to make the angle with the scraper by turning in reverse? If not dangerous, I would just try it and see if it works.

Tom, I'm not sure why the tool would come off the tool rest. I would be running the lathe in reverse and cutting the dovetail on the tenon from the right (or back) side of the lathe. Since the lathe would be turning toward the back it would be the same as turning forward and on the other side. All my chucks have setscrews so I doubt there would be a problem with the chuck coming off for the minimal amount of stress to merely cut the dovetail shape on the edge of the tenon. I do use the tailstock. However, to cut a recess or a tenon I have removed it to cut the dovetail shape. It can be tough to get in there with the tailstock in place on smaller bowls.

Al, I could grind the dovetail on a square scraper. I just didn't want to take the time right now to get that angle just right and I don't really have any old tools I don't care about to experiment on. I have used a diamond shaped carbide tool I have from when I started but it's easy to cut an angle that doesn't match and that gave me a problem the other day. I needed to turn the tenon off and start over. No big deal, but just an interruption in the bowl process I didn't want to deal with. I hate skews, but I guess I could just practice it until I got it, and may just do that anyway.

Chris, If there is a dovetail on the inside, I've found that the best holding power comes from matching that angle. I did have a problem the other day because the angle wasn't right. It hasn't happened often but when the angle is off it sometimes just doesn't hold well enough when hollowing out hollow vessels. That's especially true if you get the angle just a tiny bit too acute. Not as much of a problem when you don't get the angle acute enough but still not as good.

 

[JeffSmith]

I turn in reverse fairly often (as needed), with no problems. Learned to hollow in reverse using Dave's D-Way hollowing tool. I find it much easier to turn a domed shape on the bottom of a bowl turning in reverse. Just make sure your chuck is secure, use grub screws if you've got em. There's no problem with the toolrest and the tool lifting as long you're doing everything in reverse - that means the tool is cutting from center to the right. The tool is forced down on the rest, just as in normal turning.
There are some advantages - when hollowing its much easier to see where the cut is happening in reverse.
Full disclosure - I'm left handed so I do many things that may look a little cockeyed to some, but are completely safe...

 

[Glenn Lefley]

If your chuck can be secured to not come off the threads when running in reverse then it would be safe for small cuts, if your cutting on the opposite side of the lathe. I sand in reverse all the time, but my chuck has a set screw to secure it to the lathe, in forward and reverse.

 

[Bill Boehme]

What Glenn said. The chuck is likely to come unscrewed from the spindle unless it is secured by setscrews.

You might also want to verify that the dovetail angle on the inside of the jaws is the same as the dovetail angle on the outside. I had planned to make a tool for getting precise dovetail angles until I discovered that the inside and outside dovetail angles were different on my Vicmarc standard jaws for my VM120 chuck. My next thought was that I'll make separate tools for the inside and outside angles. But, then I checked the dovetail angles on the 6" jaws and discovered that the angles were different from the standard jaws. Since I have a full set of Vicmarc jaws I gave up on the idea of a dedicated scraper and went back to using a bowl gouge and skew. When using my Vicmarc chuck I always size the tenon to the perfect circle diameter of the jaws being used. If I didn't do that, there wouldn't be much reason for making a precise tenon (or recess) dovetail angle.

 

[Bill Blasic]

The 2" Nova Jaws that have that little hook at the top, that little hook is a dove tail. I always make my tenon no more than an 1/8" deep (it doesn't haver to be any longer than that). I have never lost a piece out of that tenon. I see no reason not to turn from the other side of the lathe other than the fact that you have to walk around the lathe to do it (if you have a chuck that is locked to the spindle). What is easier is to make a tool, a 1/4" square of HSS ground at the angle of your dovetail is easy to make and put in a small handle. You then can go straight in from the normal side of the lathe to make the tenon. I made one from an old bedan.

 

[Brian Gustin]

wow.. so much discussion over something that I had always (but then only been turning tenons for 7-8 months) assumed were simple no-brainer techniques... when I do a roughed out bowl blank (for twice turning) since I know the tenon is going to warp as well, I turn it about a quarter inch radius bigger than "perfect circle" diameter of my jaws (and I have a no-name china set of jaws that are tightened with what I've learned are called tommy bars) - That way when I go to finish turning and true-up the tenon I DO get a perfect circle tenon to work with for the finish turning.... but as far as achieving perfect holding dovetail (which I fairly quickly learned you do need to get pretty close on some species of wood, after having a couple that separated from the bowl blank!) I use my 3/8 detail gouge (with shallow, I would guess 35 degree bevel fingernail grind) and just eyeball the angle any more (though I did make a tenon gauge early on that I posted in another thread somewhere) and have had no problems. A Recess on the other hand, which I rarely ever use (mainly since I have a harder time cutting one) I just ground an old oil seal remover tool to get roughly the correct angle when the flat of the tool is resting on bottom of recess the dovetail angle is a perfect match to my jaws.. It works, but, because of the shape of the original tool, it is difficult to really get it in there when the blank is between centers since my tailstock really gets in the way of things..

 

[hockenbery]

Like @Brian Gustin - I use a 3/8 spindle gouge to refine the tenon I roughed out with the bowl gouge.

the spindle gouge can cut square tenons for my oneway jaws, 7 degree dove tail for the one way Chuck, and 14 degree dovetail for the vicmarc Chuck.

there is a learning curve. I put the bevel on the corner of the roughed out tenon. Lift the handle and roll the tool to engage the cutting edge. The gouge then doe it’s thing cutting the tenon profile. Then I cut the flat for the tops of the jaws. Usually go over each cut a second time being sure to leave a crisp clean corner.

a skew laid flat scrapes a nice dovetail for those still gaining comfort with a spindle gouge.

 

[robo hippy]

I can't remember who made them, but there used to be 2 sided dove tail tools so you could turn either a tenon or recess. You can use a skew chisel to turn that dove tail, you can also use detail gouges. I have one NRS that I use for the recess in my bowls, and it works as well or maybe better than the dove tail tool, leaving a cleaner surface. Also, you can grind one fairly simply if you have the square edge CBN wheels. Like Bill said, 1/8 inch is plenty. 3/16 or so is safe, but you go deeper than that and you are wasting wood. The height or depth of a tenon or recess is not the most important part of mounting things on the lathe. Appropriate size is.

robo hippy

 

[Randy Heinemann]

What Glenn said. The chuck is likely to come unscrewed from the spindle unless it is secured by setscrews.

You might also want to verify that the dovetail angle on the inside of the jaws is the same as the dovetail angle on the outside. I had planned to make a tool for getting precise dovetail angles until I discovered that the inside and outside dovetail angles were different on my Vicmarc standard jaws for my VM120 chuck. My next thought was that I'll make separate tools for the inside and outside angles. But, then I checked the dovetail angles on the 6" jaws and discovered that the angles were different from the standard jaws. Since I have a full set of Vicmarc jaws I gave up on the idea of a dedicated scraper and went back to using a bowl gouge and skew. When using my Vicmarc chuck I always size the tenon to the perfect circle diameter of the jaws being used. If I didn't do that, there wouldn't be much reason for making a precise tenon (or recess) dovetail angle.

Good suggestion. I just assumed all of NOva's dovetail angles were the same. Maybe not.

 

[Randy Heinemann]

Like @Brian Gustin - I use a 3/8 spindle gouge to refine the tenon I roughed out with the bowl gouge.

the spindle gouge can cut square tenons for my oneway jaws, 7 degree dove tail for the one way Chuck, and 14 degree dovetail for the vicmarc Chuck.

there is a learning curve. I put the bevel on the corner of the roughed out tenon. Lift the handle and roll the tool to engage the cutting edge. The gouge then doe it’s thing cutting the tenon profile. Then I cut the flat for the tops of the jaws. Usually go over each cut a second time being sure to leave a crisp clean corner.
a skew laid flat scrapes a nice dovetail for those still gaining comfort with a spindle gouge.

I started using my 3/8" spindle gouge but my technique leaves a lot to be desired and I get catches when doing the tenons. I realize it's practice, but sometimes I just want to turn something without perfecting, which for me, is a "new" technique. For the time-being I was trying to do some turning using tools and techniques I'm comfortable with. I have a class with Trent Bosch this fall and will bring my spindle gouge along to perfect my technique since that is how he turns his tenon angles.

 

[Randy Heinemann]

I can't remember who made them, but there used to be 2 sided dove tail tools so you could turn either a tenon or recess. You can use a skew chisel to turn that dove tail, you can also use detail gouges. I have one NRS that I use for the recess in my bowls, and it works as well or maybe better than the dove tail tool, leaving a cleaner surface. Also, you can grind one fairly simply if you have the square edge CBN wheels. Like Bill said, 1/8 inch is plenty. 3/16 or so is safe, but you go deeper than that and you are wasting wood. The height or depth of a tenon or recess is not the most important part of mounting things on the lathe. Appropriate size is.

robo hippy

I have seen at least one source for 2-edged dovetail scrapers, but then wasn't sure that the angle was really the same. Without buying it and using it, I couldn't tell. Given it's relatively inexpensive compared to most turning tools, I might try it but don't want to buy something I really have no use for. I will perfect another technique, most likely with the spindle gouge, since that seems, when watching videos, to be one of the simplest. Right now, I just wanted something within my skill set before I learn new ones. It may seem simple to most of you, but the spindle gouge does require not doing some things.

 

[hockenbery]

have a class with Trent Bosch this fall and will bring my spindle gouge along to perfect my technique since that is how he turns his tenon angles.

You will learn a lot from Trent. He is a terrific teacher. Also a good freind.

spindle gouge( all gouges) ABC
A- Anchor- Tool on the tool rest not touching the wood
B- Bevel- bevel on the wood not cutting
C- Cut - engage the cut with some combination of raising the handle and rolling the tool.

spindle gouges are more prone to catches when the cutting edge touches to wood before the bevel
bowl gouges often Just tear the grain when the bevel is not in contact before the cut.

don’t practice on tenons or your bowl will get too small.
one day when you Don’t have the time or inclination to do something big - turn a 1/2 dozen spin tops using the 3/8 gouge.
once you master cutting the edge of the top cleanly you won’t have any catches on tenons.

 

[jimbarbour]

I took a beading tool I do not use much (3/8” square stock) and ground the end to the proper angle. I simply use it as I would a parting tool only at the angle that puts the “skewed” end flat. It cuts recesses nicely and to cut a tenon I just turn the tool over.

 

[robo hippy]

That version is for coming in from the side, and it works. Since I am turning on a sliding headstock lathe, with the headstock at the end, I prefer the dovetail one and I line the shaft up with the lathe bed. Both work. You could also use that one for a skew....

robo hippy

 

[Dave Hulett]

5 years ago I bought a $35 Hurricane straight edge scraper and re-ground it into a V matching the 15 degree (or was it 13 ?) to match the angle on my Nova chucks. It works awesome for a tenor or recess.

 

[Randy Heinemann]

5 years ago I bought a $35 Hurricane straight edge scraper and re-ground it into a V matching the 15 degree (or was it 13 ?) to match the angle on my Nova chucks. It works awesome for a tenor or recess.

Before I got my Powermatic 3520, I had a small Nova midi lathe. Both allow me to access the bowl bottom from the tailstock end and that works best for me. Hence, the desire to have a tool that, after getting the tenon the right diameter, just cut the dovetail correctly. I'm aware that there are a number of ways to do this. I just like the dovetail chisel for it. I could grind a scraper, but only have a Tormek (which has so far handled all my turning and non-turning sharpening except for regular chisels and planes which I hand sharpen). I'll work through it one way or the other but thought I might be able to easily cut the dovetail with the same tool I used for recesses in the meantime.

 

[Randy Heinemann]

Thanks for all the suggestions. I'm sure, with time, I will find one that works (except the skew). I just wanted a temporary solution till then and, since I have the Nova dovetail scraper already, I thought I'd try to use it for now.

 

[Allen Mattsen]

I, so far, have preferred a skew or 3/8 spindle gouge for forming a tenon but I usually end up removing the tailstock. I get why that would be hard to do if only turning between centers, heh. Maybe I'll play around with an old bench chisel and the grinder and try to match it up. My only concern is putting old, questionable metal to my CBN wheels. Maybe a belt sander would be better or is it safe to grind what the heck ever metal on CBN?

 

[Al Chavez]

In this picture I am showing a skew that I reground to cut dovetail recesses. I know I've posted it a few days ago but maybe it isn't very clear on how it is used. It is used WITH the tailstock in place. The angle of attack is close to 45 degrees so that the angled flat is cutting 90 degrees to the axis of the lathe. I think I saw this demonstrated by Al Stirt in a video meeting but I am not sure. It works incredibly well. I may grind another one out of a HSS blank but this works so well there is no need to at the moment. Its quick, easy and accurate and just leaves a small nub where the tailstock is centered. That is easily removed by a number of methods.

 

[Al Chavez]

Deleted- Duplicate post.

 

[Allen Mattsen]

In this picture I am showing a skew that I reground to cut dovetail recesses. I know I've posted it a few days ago but maybe it isn't very clear on how it is used. It is used WITH the tailstock in place. The angle of attack is close to 45 degrees so that the angled flat is cutting 90 degrees to the axis of the lathe. I think I saw this demonstrated by Al Stirt in a video meeting but I am not sure. It works incredibly well. I may grind another one out of a HSS blank but this works so well there is no need to at the moment. Its quick, easy and accurate and just leaves a small nub where the tailstock is centered. That is easily removed by a number of methods.

View attachment 39125View attachment 39126

Thanks for the detailed pics. I've seen this done before in a video or two I've watched but these pictures make it much easier to see how to grind the tool.

 

[Rusty Nesmith]

You can buy left handed bowl coring systems the require turning in reverse. I wouldn’t think they would make them if it was dangerous. I have never turned in reverse myself but wouldn’t have a problem if I needed to.

 

[Tom Gall]

Al, thanks for your photos. However, the OP (Randy) was asking about a tool to make a dovetail TENON - not a RECESS. He already has a recess scraper.

 

[Rusty Nesmith]

Al, thanks for your photos. However, the OP (Randy) was asking about a tool to make a dovetail TENON - not a RECESS. He already has a recess scraper.

I use the same tool for recess or tenon.

 

[Tim Tucker]

THIS>>>>> https://www.thewoodturningstore.com...il-tenons-3-4-wide-high-speed-steel-w-handle/

Works GREAT for creating dovetail tenons.

 

[Bill Blasic]

THIS>>>>> https://www.thewoodturningstore.com...il-tenons-3-4-wide-high-speed-steel-w-handle/

Works GREAT for creating dovetail tenons.

I have made several of these out of old carbon steel tools and they work very well. And like I stated above I've made them out of old bedans. I use which ever is closest to hand when needed.

 

[Tim Tucker]

I have made several of these out of old carbon steel tools and they work very well. And like I stated above I've made them out of old bedans. I use which ever is closest to hand when needed.

They look to be the simplest of any tool to make. Really, one could take a diamond point scraper - and grind one side to the angle needed...and there you have it. I dont always use it - but it is one that could become habit forming.