Laguna 1524 with PWM Catch and STOP!

[Aaron Dodini]

Hi friends,
I'm new to turning and my laguna 1524 is my first lathe. I'm using carbide tools and I've been really surprised that while roughing out a square blank, usually around 500 rpm to 800 rpm, there are times when the tool will catch the corner of the blank and trap the tool at the tool rest. I'm at a 90 degree angle--meaning perfectly centered wth the tool to to blank. When that happens, the lathe stop turning entirely. Is this a safety feature of the PWM that the lathe has or am I breaking my lathe? I don't know if I'm doing something wrong or if the tool isn't sharp enough or the lathe isn't spinning fast enough, but it seems like the lathe shouldn't be stopping so easily. Any help is greatly appreciated!

 

[Odie]

Howdy Aaron......

This post will probably end up in the "getting started" forum......but, I have a few questions.....

What is the size of the wood you're turning? Is it end grain or cross grain?.....meaning is it a bowl blank, or a spindle turning?

What specific tool are you using to bring it to round?

When you say the lathe stops entirely, do you mean you have to hit the start button to get it going again?....or, is it still under power?

-----odie-----

 

[Aaron Dodini]

Hi Odie,
Thanks for your response
I’ve had this experience on bowl blanks ranging from about 8” to 12” in diameter. I’m using the square carbide simple wood turner and the round—not the negative rake cupped insert, just the regular round one. Both have caught and stopped the wood from turning—the lathe is still under power and I have been able to un-trap the tool when it’s pinned between the blank and the tool rest and the blank will immediately start spinning again. Most of the time I just turn it off very quickly so I can get the tool un pinned from the tool rest. The Laguna folks are telling me it's not hurting the motor--it's just bad turning technique. Perhaps I need to be less aggressive and start always from the bottom at the tailstock and move up slower. I also wonder if my carbide is not sharp enough. I feel like I sharpen the carbide after each bowl I turn, but perhaps I need to sharpen more frequently and go slower, less aggressive.
Thanks!

 

[Bill Boehme]

What are you using to sharpen your carbide inserts?

From your description, it sounds like you are applying excessive tool pressure to force a dull tool to cut. My experience has been that carbide can't be sharpened sufficiently unless you have a powered wet sharpening system such as a Tormek with a diamond wheel.

 

[Odie]

Sorry Aaron......I forgot about you!

Sounds like you're having these bad catches prior to bringing a square block to round......bringing down the corner and having "dead air" space in-between. Bill would be right, that you're probably trying to take too much of a bite, and advancing the tool into the dead air space too rapidly.

Until you bring that block to round, you need to take very light cuts, gradually bringing it to round. I'm not familiar with the edge profile of the square carbide insert, so don't have much of a concept of what tool you're using. To bring a square block to round, I cut the corners with a band saw and usually use a standard round point scraper, held level at the 9 o'clock position. Maybe someone else has a better concept of what you're using for this purpose......

-----odie-----

 

[Aaron Harris]

Hi, Aaron-I'm Aaron too. I'm no expert, but I've learned from hard experience that trying to round square blanks that big is asking a lot of that carbide tool. I've gotten those same kind of terrifying full-stop catches on my Laguna 12/15 when maybe pushing an iffy carbide edge a little too hard, especially while you're still cutting into dead air-it's easy to do. I don't guess you have (or know someone who has, who might like a nice wooden bowl) a bandsaw big enough to round those blanks? I have found that it is worth the time to do for bowls.

Whereas for spindles, I get a kick out of quickly rounding a square blank with a roughing gouge or large skew-very satisfying.

 

[Aaron Dodini]

Man I love this community! Great support and help, gentlemen! I've just been using the diamond credit card style sharpeners with lapping fluid to sharpen my carbide cutters. I sharpen them or turn them to a new edge before starting each bowl, but Bill may be right--perhaps they just don't hold the edge well and I just need to replace them more often. From the Youtube videos I've watched, it seems like folks believe they can be sharpened and reused almost indefiniately, just by doing the credit card style diamond sharpening. Anyone else have experience with sharpening these things? Maybe it's time to invest in a sharpening station and get HSS steel gouges....
Thanks all!

 

[John King]

Hi friends,
I'm new to turning and my laguna 1524 is my first lathe. I'm using carbide tools and I've been really surprised that while roughing out a square blank, usually around 500 rpm to 800 rpm, there are times when the tool will catch the corner of the blank and trap the tool at the tool rest. I'm at a 90 degree angle--meaning perfectly centered wth the tool to to blank. When that happens, the lathe stop turning entirely. Is this a safety feature of the PWM that the lathe has or am I breaking my lathe? I don't know if I'm doing something wrong or if the tool isn't sharp enough or the lathe isn't spinning fast enough, but it seems like the lathe shouldn't be stopping so easily. Any help is greatly appreciated!

Not clear to me what you are doing. But if you are starting with a square bowl blank, turning it round is not going to be a lot of fun. Take the square bowl blank to the bandsaw (or similar) and cut a circle blank out of the square blank. You will enjoy turning much more when starting with a round bowl blank.

Also, if the tool is getting wedged between the bowl blank and the tool rest, the tool rest is probably too far away from the bowl blank. - John

 

[robo hippy]

Hmm, thought I responded, but don't see it.... Anyway, like a martial arts instructor of mine used to say, 'Appetizer first, main course second.' I still get some stalls, and mostly they happen on rough blanks. Once it is rounded out, then almost never, though I do like to see the shavings fly. I generally start in the center of the blank, and work my way out to the rim. Some times I will true up the top side/rim of the bowl after going down the side, before finish turning the outside, some times not, mostly it depends on how bad of a job the chainsaw did... No blank ever mounts perfectly true, and by starting in the center, there is less run out and the feet/minute speed is less. I work my way out to the rim, then plunge down the side to the rim. On the outside, I would suggest the square tool to start, and for the insides of the bowls, I would use the round one. Until the surfaces are running true, I take it easy and nibble. Once things are more true, then I turn up the speed and take bigger cuts. Part of the learning curve is knowing how much you can take off at a time. That depends, equally on how big your lathe is, and how skilled you are. I do have a bunch of mostly bowl turning videos up on You Tube.

robo hippy

 

[Aaron Dodini]

Hmm, thought I responded, but don't see it.... Anyway, like a martial arts instructor of mine used to say, 'Appetizer first, main course second.' I still get some stalls, and mostly they happen on rough blanks. Once it is rounded out, then almost never, though I do like to see the shavings fly. I generally start in the center of the blank, and work my way out to the rim. Some times I will true up the top side/rim of the bowl after going down the side, before finish turning the outside, some times not, mostly it depends on how bad of a job the chainsaw did... No blank ever mounts perfectly true, and by starting in the center, there is less run out and the feet/minute speed is less. I work my way out to the rim, then plunge down the side to the rim. On the outside, I would suggest the square tool to start, and for the insides of the bowls, I would use the round one. Until the surfaces are running true, I take it easy and nibble. Once things are more true, then I turn up the speed and take bigger cuts. Part of the learning curve is knowing how much you can take off at a time. That depends, equally on how big your lathe is, and how skilled you are. I do have a bunch of mostly bowl turning videos up on You Tube.

robo hippy

Thank you! I have watched some of your videos over the past year. They are great! I think I may have posted on two different threads--total newbie mistake, so I think you posted on that one and now on this one. Twice the thanks!
A--

 

[Rusty Nesmith]

Sounds like you are trying to take to big of a cut. I have the same problem trying to round out a piece with carbide tools. I would recommend a good bowl gouge when you can get one if you don’t have one.

 

[Steve Perrone]

I’m also new to turning (less than a year of experience) and was having a very similar issue while roughing bowl blanks on my rikon 70-220 vsr. I also don’t have a bandsaw and just use a small electric chainsaw to cut my blanks out of green wood that I find locally. I was also using carbide tools at first mostly the square cutter or the almost square shape with slight curve. Every bowl I would get aggressive catches like you’re describing while roughing. I was also really worried I was breaking my lathe and it wasn’t a fun experience, although I don’t seem to actually have damaged it at all so don’t worry. Anyway, I eventually bought a couple traditional hss bowl gouges and started roughing with one of those and now I very rarely get a catch like that. I start in the middle and work my way out and slowly nibble off the rough edges left by the chainsaw. I don’t know why but I get much better and consistent results with the bowl gouge vs carbide cutters. Even just yesterday I tried to use the carbide tool thinking that maybe my technique had just improved and it would work better but sure enough I still had the problem ! I would definitely recommend trying traditional tools if at all possible!

 

[hockenbery]

started roughing with one of those and now I very rarely get a catch like that. I start in the middle and work my way out and slowly nibble off the rough edges left by the chainsaw. I don’t know why but I get much better and consistent results with the bowl gouge vs carbide cutters

when I have to use a chainsaw. I draw two circles on the face of the half log.
one the size of the bowl. The other 2” larger. I cut off all the larger circle and leave all of the smaller circle.
I have a bunch of hardboard disks to draw the circles with a wood crayon.

a long time ago Christian Burchard taught me an “A Frame” cut” for initial roughing.
it is unbelievably smooth once you learn it. Both arms are straight one hand holds the tool on the tool rest and
the other holds the end of the handle on the top of my thigh. Angle the flute up about 40-45 degrees 10:00-10:30 on the clock face. Turning your hips swings the cutting tip through an arc with the hand on the toolrest holding the tool on the pivot point. That rides the bevel through the air. Terrific on the interrupted cutting on air and wood.
start cutting only air and move the tool a 1/4” closer to the wood with each pass. Eventually you cut off a small bit of wood from the highest corners left by the chain saw. Each 1/4” advancement takes or more corner edges. By the 3rd, 4th,or 5th cut. ...eventually you will have cut a ring. You can make a few more passes

This 4 minute video could make roughing a smooth process for you.
Bowls Cove Ruffing cut -

View: https://www.youtube.com/watch?v=EIHADKjfL2c

 

[Brian Gustin]

a long time ago Christian Burchard taught me an “A Frame” cut” for initial roughing.
it is unbelievably smooth once you learn it. Both arms are straight one hand holds the tool on the tool rest and
the other holds the end of the handle on the top of my thigh. Angle the flute up about 40-45 degrees 10:00-10:30 on the clock face. Turning your hips swings the cutting tip through an arc with the hand on the toolrest holding the tool on the pivot point. That rides the bevel through the air. Terrific on the interrupted cutting on air and wood.
start cutting only air and move the tool a 1/4” closer to the wood with each pass. Eventually you cut off a small bit of wood from the highest corners left by the chain saw. Each 1/4” advancement takes or more corner edges. By the 3rd, 4th,or 5th cut. ...eventually you will have cut a ring. You can make a few more passes

So.. it has a name.. cool.. I do something similar to that, just seemed to be the way to go.. teaching myself and trying out different ways of achieving what I want, and found that doing the pivot on tool rest thing helps a ton.. I started using that sort of technique when roughing bowls to get my outside shape roughed in , and found it made getting my blanks to round so much easier.. except I dont have both arms straight - none of my tools are anywhere near long enough to work them straight-armed , but I hold my gouges to the rest in pretty much an identical fashion and swing the hips without moving arms at all to just take curved nibbles at the bowl blank until I get somewhere close to round..

 

[Timothy White]

All good advice also check your belt tension.

 

[Gary Norton]

Hi friends,
I'm new to turning and my laguna 1524 is my first lathe. I'm using carbide tools and I've been really surprised that while roughing out a square blank, usually around 500 rpm to 800 rpm, there are times when the tool will catch the corner of the blank and trap the tool at the tool rest. I'm at a 90 degree angle--meaning perfectly centered wth the tool to to blank. When that happens, the lathe stop turning entirely. Is this a safety feature of the PWM that the lathe has or am I breaking my lathe? I don't know if I'm doing something wrong or if the tool isn't sharp enough or the lathe isn't spinning fast enough, but it seems like the lathe shouldn't be stopping so easily. Any help is greatly appreciated!

You would probably need to be an electrical engineer to understand PWM or Pulse Width Modulation, I have stopped my smaller Laguna a few times. seems to be a non-issue.
The Wiki on PWM fo those interested https://en.wikipedia.org/wiki/Pulse-width_modulation
But I agree with most try to saw in close to round 1st.

 

[Mike Johnson]

Cutting the 4 corners off of the square blanks will leave you with 8 points to round off which is a lot easier than a square blank. A sharp roughing
gouge will quickly bring the blank to round depending on the wood type and dryness. You should try a brand new carbide insert and compare that to
your old carbide inserts you are sharpening. On extremely hard dry woods you are better off starting you cut from the face of the blank working your
way towards the base of the blank while bring it to round, this method reduces the amount of splintering the corners off of a dry piece of wood. Starting off with a saw cut round blank saves a lot of time on the lathe depending on the wood type and dryness. Even on spindle blanks I will knock
the 4-corners off to end up with an octagon shape to save time on the lathe and reduce the number of times going to the grinder to sharpen the tools.