Powermatic 3520C?

[Clifton C]

How about turning the inside of a bowl with your eyes closed? David E would have me start the cut then say "now, close your eyes, listen and feel". I would cut about a 1/4 inch before opening my eyes. Each time I tried this, I could cut a little farther. To be able to make a cut with out seeing, just listening and feeling, even for a short distance was an interesting exercise. Tool control, with a light touch is obviously a prerequisite. Dangerous ? I don't know, I can't see the cutter when I'm hollowing, or when I'm in a deep box. I still practice this every once in awhile, it slows me down and reminds me to use my other senses. Still, I would imagine it's not for everyone...

 

[Bill Boehme]

The Vicmarc 300 lathe is what you are talking about, robo? That is definitely a high end lathe. Doesn't the new 3520c have a sliding headstock......and wouldn't that make the long bed a moot point? I've never had anything but a long bed, and I consider it an advantage, even in bowl turning.....specifically because of the added weight.

-----odie-----

I think this is a case of the endless quest for perfection ... perhaps the grass is greener on the other side of the fence. I'm just one tool away from greatness.

 

[Gary Bonnot]

I'm always looking for the endless quest for perfection....either in tools or techniques to reduce the time to get a project finished. Some lathe designs have certain functions that appeal to different turners. I like the features of the 3520c since I am getting into more production turning. I have three PM 90 lathes and will end up with 8 or more when I get my shop layout done correctly. Most of the lathes will have duplicators installed. I am currently designing a boring bar duplicator to reduce the time to hollow out 11" diameter x 10" + deep pots for hanging flower baskets. Always striving to get things done faster.....

Gary

 

[robo hippy]

My first lathe was a long bed, Atlas 4 speed. I constantly got a sore back. When the 3520A came out, I got the first one out of the Wood Craft store here in town. The choice was obvious because of the sliding headstock, you get a bowl lathe and a spindle lathe. I really can't understand why some turners who have the sliding headstock don't slide it down to the tailstock end so they can stand up straight. I did a demo for our club a month or so ago, and one turner commented after, 'I never thought of doing that'. So, to get a 'bowl' lathe, there are 4 options.

One is buy a short bed lathe like the VB36 or that stubby PM that is out.

Two is a lathe with inboard and outboard available. If I had a Oneway, I would use the outboard end for all of my bowl turning.

Three is the sliding headstock, which the PM/Jet, Robust, Laguna and a host of others have. Great option.

Forth is the pivoting headstock. I spent some time talking to the actual engineer who started Vicmark ( Vic some thing I think, but can't remember). I believe they were the first ones to have a pivoting headstock. The other variations on the Nova, Jet, and a few others were sub par considering how the Vicmark is set up.

If you don't have a bowl lathe, and you want to turn bowls, you have two choices, extend your arms way out from your body like Stuart Batty does, or bend over the lathe, which is uncomfortable. Standing at the bowl end of a lathe also gives you much better and easier visibility on the inside of a bowl.

Now, the extended spindle housings and noses.... The only necessity for them is if you twice turn bowls because they give you easier access to the bottom of the bowl. Simple levers, the farther it sticks out off the mounting base (where the headstock is attached to the lathe), the more potential there is for vibration. Easiest way to explain is to think about the chatter you get on longer hollow forms. Lots of things can dampen it like light tool pressure, but for roughing and unbalanced blanks, you don't want that at all. How big the nose cone is does make a bit of difference, but the triangle up to spindle height, and out to mounting point is the critical measure. Now, if you want to twice turn a bowl, then rough turn on a spindle that comes off with no 'extensions', and then finish turn with extended jaws on your chuck...

Oh, I talked to Nick Cook about the speed ranges, and he said you could call PM and they would walk you through adjusting them. When I asked about the B, I was told the only way to do it was to remove the converter, send it in, and motor warranty was voided....

robo hippy

 

[Odie]

I think this is a case of the endless quest for perfection ... perhaps the grass is greener on the other side of the fence. I'm just one tool away from greatness.

Yep, it is, Bill........The only thing about that is.....among woodturners.....there is a thousand individual definitions of just exactly what "perfection" is.!

Regardless of that, I think this new 3520C is a winner, and will be very popular......

-----odie-----

 

[hockenbery]

One is buy a short bed lathe like the VB36 or that stubby PM that is out.

Two is a lathe with inboard and outboard available. If I had a Oneway, I would use the outboard end for all of my bowl turning.

A terrific option is a Oneway 2416 with the 17" outboard. If you rarely turn long items.
You can stand off the end for hollowing on either side. Hollowing bowls works nicely on the outboard side. You can turn between centers on the inboard side then hollow on the outboard side. Leave the chuck on the outboard side. Nice to have a 2nd banjo.

For The rare long work the outboard bed Is moved to make a long bed on the inboard side.
Easy job with a hydraulic table but it takes time to work the bolts.

I find hollowing bowls on a long bed is so natural, that I don't move the headstock when I demo on a powermatic unless there is some benefit to the video. with the side ground gouge there is no bending. When I hollow balls in a straka chuck I will often do it off the end so that the camera can see the hollowing.

 

[William Rogers]

I think Powermatic did a good job on the upgrades. To me it seems they are trying to compete with the higher price lathes instead of the lower price lathes, leaving that to Jet. As far as the cone, it is one of the reasons I bought the Laguna. I really don't see any vibration issue due to the cone. The spindle is still supported at the cone nose. I think it is an advantage having more access at the headstock.

Edit: I guess the easiest thing is to say I disagree with the vibration being an issue with the extended cone. The chatter/vibration you get in a long hollow form would be eliminated if you had support right near where the tool is cutting. I.e the spindle bearing. The cone itself is not going to vibrate due to the mass. My career was in turbo prop engines and every turbo prop had a cone gearbox.

 

[Odie]

I find hollowing bowls on a long bed is so natural, that I don't move the headstock

I'm also one who doesn't seem to have the problems that others have when working on the interior of bowls. There is an exception to this, though......doing bowls with inward slanting walls. I've been doing it forever on a standard long bed lathe, and there are times when doing inward slanting walls where some kind of relief would be a good thing to have. The sliding headstock would probably be fine, but there is a rotating headstock lathe made by Vicmarc that would probably serve very well, too. The link below is a detailed pdf informational on the Vicmarc VL240 lathe. It is very popular with turners outside of the USA, but for some reason has never gained any appreciable popularity here.

https://www.drechselstube.de/pdf/folder_en.pdf

The headstock on the VL240 has indexed settings of 30°,60°, and 90°. I've never had an opportunity to turn on a rotating headstock lathe, but suspect the 30° setting would be all that is necessary for the bowl turner to adequately handle any phase of turning the interiors of bowls.....especially those with inward slanting walls. When doing inward slanting walls, I often do have to reach all the way around where the handle of the gouge is almost touching the rim on the opposite side. This can get a bit uncomfortable at times, and probably just a little relief here would be all that's necessary.

There is a bit of advantage to doing interiors of bowls on a long bed lathe, in that the turner can brace his hips against the lathe itself. This will require great dexterity, or "feel" with the upper body and arms, but the support you get from bracing your hips is absolutely wonderful. Probably not all turners have identical physical abilities that I do......but, the rotating headstock could be used with great advantage for the few who do. This could employ the "hip brace" while giving the turner full movement while doing inward slanting walls......or, undercut rims, for that matter.

-----odie-----

 

[robo hippy]

I can remember bracing my hip against my first lathe, in part because I had to keep it from walking around the shop with a chain sawn blank... No risk if you are just 'feeling' it, but I found myself leaning into it some times which is a falling over risk if you lean too much. I prefer to stand up straight.... The Vicmark is a very well built lathe...

robo hippy

 

[Bill Boehme]

Using good posture while turning is important. A few years ago when I was still invincible I thought that I could get away with impunity when doing things that weren't good for my back. Even after having lower back surgery eleven years ago I eventually relapsed into bad habits like lifting heavy green logs into my truck, leaning way over my lathe while turning , standing stooped over while hollowing, and a multitude of of other things. Everything was fine (I thought) until it wasn't fine. So now I'm getting ready for another back surgery as soon as I sufficiently recover from shoulder surgery ... also a result of my once invincible behavior. What a bummer discovering that I'm mortal just like everyone else. I may as well turn in my cape now that I won't be leaping any tall buildings.

 

[Charlie Knighton]

You are luckily Bill...they can fix you

 

[RichColvin]

I think this is a case of the endless quest for perfection ... perhaps the grass is greener on the other side of the fence. I'm just one tool away from greatness.

Is woodturning just golf with sharp irons ?

Rich

 

[hockenbery]

Is woodturning just golf with sharp irons ?

Rich

Yes! but people pay you to get better by buying your work.

 

[john lucas]

Yea and I've never lost a bowl in the woods. I have had a few fly off and look like that beautiful slice that I worked so hard to develop when playing golf.

 

[Mike Johnson]

Usually when approaching the back nine I will have downed 3 or 4 drinks already,
that could be problem while using sharp irons.

 

[Tim Terman]

If Powermatic is serious about adding additional features before going into production I would love to see a the spindle lock disable the motor so it would be impossible to accidentally start the lathe with the lock engaged. Not essential, but nice to have.

 

[Gary Bonnot]

Powermatic does listen and take suggestions seriously. While checking out the 3520c at the Symposium, I overheard many conversations with the Powermatic reps and those who stepped up to ask questions. What I really noticed was the rep or engineer from the company that makes PM equipment would listen and observe from the sidelines. Often the PM Rep's would consult with the manufacturer rep on what it would cost to add or make changes to the 3520c.

Gary

 

[robo hippy]

I believe the PM does have a wired in 'stop' for when the spindle lock is on, that makes it impossible to start the lathe. I do have that on my Robust.

William, I missed your comment about the turbo prop engines. Yes, they do have a cone. A couple of notable differences to the ones on the lathe. Mostly the turbo props are designed for thrust, and that thrust is in line with the airplane body. There was a trend some years back where the engines were mounted up on the tail, I am guessing, to get them out of the slip streak for better thrust. They are now all back on the wings. When up on the tail, you again run into the cantilever problem where thrust is more efficient if it is in a direct line with the body rather than above it. Mass may help some, but the more height and longer levers add to the problem.

robo hippy

 

[john lucas]

The 3520A that I have will not run when anything blocks the spindle from turning. It's a program in the VFD. If you have the tool rest up too close and hit your bowl or leave an aftermarket index pin in an index wheel, or have a square blank on and move the tool rest too close. Not that I've ever done any of that you understand, it was "my friend". I think the 3520B does the same thing. It senses that there is an obstruction and simply shuts down.

 

[Bill Boehme]

.... William, I missed your comment about the turbo prop engines. Yes, they do have a cone. A couple of notable differences to the ones on the lathe. Mostly the turbo props are designed for thrust, and that thrust is in line with the airplane body. There was a trend some years back where the engines were mounted up on the tail, I am guessing, to get them out of the slip streak for better thrust. They are now all back on the wings. When up on the tail, you again run into the cantilever problem where thrust is more efficient if it is in a direct line with the body rather than above it. Mass may help some, but the more height and longer levers add to the problem.

robo hippy

I presume that you are talking about the McDonnell Douglas DC-10 and the follow on MD-11 variant. I wouldn't exactly say that the engine is mounted "up on the tail". The engine is mounted on top of the aft fuselage and then the vertical stabilizer is mounted on top of the engine nacelle. As far as the engine producing a pitching moment (due to off centerline thrust in the vertical plane), the engine is canted slightly tail down to counteract off axis thrust. Notice that the DC-10 and MD-11 both also have engines hung beneath both wings. The yawing moment created by having wing mounted engines is actually a much more serious issue because the loss of an engine on either side requires throttling back the good engine and cranking in lots of rudder trim to keep the plane flying straight ahead.

Everything in aircraft design involves a multitude of performance trade-offs. Every configuration has advantages and disadvantages. Designing a woodturning lathe also involves performance trade-offs although slightly less complex than aircraft design. (just keeping this focused on woodturning)

Here's a Boeing 727. It has three engines ... one on each side of the aft fuselage and the third is in the center of the fuselage. The air inlet for the center engine is mounted in front of the vertical stabilizer. All of this necessitated going with a T tail configuration.

Here is another view where you can see that the two side mounted engines have the exhaust canted slightly towards the centerline.

There's speculation about what the potential Boeing 797 will look like.

 

[William Rogers]

I believe the PM does have a wired in 'stop' for when the spindle lock is on, that makes it impossible to start the lathe. I do have that on my Robust.

William, I missed your comment about the turbo prop engines. Yes, they do have a cone. A couple of notable differences to the ones on the lathe. Mostly the turbo props are designed for thrust, and that thrust is in line with the airplane body. There was a trend some years back where the engines were mounted up on the tail, I am guessing, to get them out of the slip streak for better thrust. They are now all back on the wings. When up on the tail, you again run into the cantilever problem where thrust is more efficient if it is in a direct line with the body rather than above it. Mass may help some, but the more height and longer levers add to the problem.

robo hippy

Don't want to get into aircraft discussion, but I was talking about the smaller Cessna type turbos. These engines all have a cone gearbox mounted in the nose ( there are a handful known as pushers where the engine is mounted in the rear). (But nice pictures Bill) The point I was trying to make is that the shape doesn't lead to vibration alone. With an out of balance blank, the design of headstock and lathe must absorb the energy. Just because you have a cone that doesn't mean you will have more vibration. Mass does play a big part into the design. If you want to think of the cone as a cantilever you must also include gussets all the way around it for support. I am bias as I have the Laguna 18-36 that has a cone shaped headstock. I have not had a 16-18" blank mounted yet, but do not believe the cone design will be like a dog wagging its tail when roughing or finishing. Note: I do respect all opinions and it's good to have differences. Makes you think. As I don't agree a cone design automatically creates vibration I'm sure some will disagree.

 

[Rusty Fleeman]

Thank you for the insight! The 3520B is so good I wasn't expecting wholesale redesign at all but those changes sound much more evolutionary than revolutionary.

That movable control box is over due!

 

[robo hippy]

I presume that you are talking about the McDonnell Douglas DC-10 and the follow on MD-11 variant. I wouldn't exactly say that the engine is mounted "up on the tail". The engine is mounted on top of the aft fuselage and then the vertical stabilizer is mounted on top of the engine nacelle. As far as the engine producing a pitching moment (due to off centerline thrust in the vertical plane), the engine is canted slightly tail down to counteract off axis thrust. Notice that the DC-10 and MD-11 both also have engines hung beneath both wings. The yawing moment created by having wing mounted engines is actually a much more serious issue because the loss of an engine on either side requires throttling back the good engine and cranking in lots of rudder trim to keep the plane flying straight ahead.

Everything in aircraft design involves a multitude of performance trade-offs. Every configuration has advantages and disadvantages. Designing a woodturning lathe also involves performance trade-offs although slightly less complex than aircraft design. (just keeping this focused on woodturning)

Here's a Boeing 727. It has three engines ... one on each side of the aft fuselage and the third is in the center of the fuselage. The air inlet for the center engine is mounted in front of the vertical stabilizer. All of this necessitated going with a T tail configuration.

Here is another view where you can see that the two side mounted engines have the exhaust canted slightly towards the centerline.

There's speculation about what the potential Boeing 797 will look like.

 

[robo hippy]

I think some where in my book collection is the story of the development of the Northrop flying wing.... In my days as a hang glider pilot, I found them fascinating. Anything that flies. My dad was in the first graduating class at KU (Kansas) in their aeronautical engineering program, early 40's. He is the only one left from his class...

robo hippy

 

[Bill Boehme]

I think some where in my book collection is the story of the development of the Northrop flying wing.... In my days as a hang glider pilot, I found them fascinating. Anything that flies. My dad was in the first graduating class at KU (Kansas) in their aeronautical engineering program, early 40's. He is the only one left from his class...

robo hippy

Speaking of thr Northrop flying wing, the company that I worked for developed the first lifting body aircraft that had a blended wing and fuselage, the Vought V-173 "flying pancake". Unlike the flying wing, however, it had two vertical stabilizers.

 

[john lucas]

I thought the flying wing was what happened to an aircraft design after the Bean Counters got through with it.

 

[Bill Boehme]

The ultimate flying wing was the Northrop Grumman B-2 stealth bomber in which Vought was a major subcontractor.

View: https://m.youtube.com/watch?v=XiTpAHw-vJk

 

[Leo Van Der Loo]

Speaking of thr Northrop flying wing, the company that I worked for developed the first lifting body aircraft that had a blended wing and fuselage, the Vought V-173 "flying pancake". Unlike the flying wing, however, it had two vertical stabilizers.

I think the Germans in WWII developed and flew the first flying wing, after flying it succesfully for 55 hrs, that wing lost one of it’s 2 engines and crashed, killing the test pilot.
The Americans did find a full scale build one and took it back to the US.
I’m sure they did study and learn from something they had no idea it even existed.
The whole wing was made from wood with only one or two metal pieces, the use of the wood and shape was to be invisible for the radar.
I guess not many are aware of this and also the use of their jet engines which were used in this wing and the Messersmith jets.
Luckily too little and too late in the war as was the nuclear development/bomb they where nearly finished with.

 

[john lucas]

I've seen lots of methods used to lock the quill. In Powermatic's defense there are an awful lot of 3520 out there and you don't hear much about this problem. Mine is 15 years or so old and still running great.