am I turning to big

[alex carey]

I was reading up on lathes and how much they are capable of turning.

I use a GI maxi lathe 25-200
http://www.general.ca/pagemach/machines/25200a.html

With this lathe what are my capabilities? I have turned a few things in the 50 pound range. Can I go bigger than this or are the bearing already at their limit? The 3/4 motor has trouble but still seems to do alright.

Alex

[Reed Gray]

It is made for turning small things, and 50 lbs is maxing it out. You can turn a few things that size, but if you turn a lot of them, you will wear out your lathe. More power and more weight are needed for a lot of heavy turning.
robo hippy

[alex carey]

weight isn't really a problem. Here is a picture of my lathe. Recently I made an anchor to the ground on the outboard side. I am turning large out of balance stuff without a problem.

http://www.sawmillcreek.org/attachment.php?attachmentid=103306&d=1228977507


Without the anchor, starting this at 300 will make it dance quite a bit but with the anchor it doesn't budge. I actually roughed this around 450 if i recall correctly.

http://www.sawmillcreek.org/attachment.php?attachmentid=104280&d=1229942834

Which parts am I going to wear out and can they be easily replaced if they do?

Alex

[Don Eddard]

Which parts am I going to wear out...?

From the looks of the pics, your bearings, your tool rest, your banjo, and potentially your face when the next bowl decides to blow.



...and can they be easily replaced if they do?

Maybe, yes, yes, and no.

Just because a Honda Civic can tow a loaded horse trailer doesn't make it a wise practice. ;)

[Gary Max]

Remember you are going to be the first person to know that you have overloaded your lathe.
It's time to buy a bigger lathe.
Adding weight or bolting the lathe to the floor is not a safe answer.

[Steve Schlumpf]

Alex - the fact that you are asking the question tells me that you already know you are pushing this lathe. My lathe weighs 420 lbs all by itself and then I added 7 bags of concrete for additional ballast to help eliminate vibration when roughing out large blanks. The blank you show in the last photo - I would have used the tailstock the entire time roughing out the outside and for as long as practical when hollowing out the inside. Plus, the speed would have been down to 250 to 300 until the outside was smoothed out a little and the piece was a little more balanced.

I can appreciate wanting to turn larger pieces - but feel it is time for you to seriously start looking into larger lathes! Best of luck with that and PLEASE think safety when turning anything this large!

[Gordon Seto]

I think you are pushing the limit of this lathe to it is not designed for. It has a 1" spindle and the integrity of the lathe of this size. The tool post is the mini lathe class. Anchoring it is not a safe solution. It is going to break at its weakest link, when it breaks. You don't want to find it out when the 50# chuck rolling off the lathe at high speed. When something breaks, you will be thrown off balance as well. It will limit your chance of stepping aside.
Swivel head is good for something big but not thick, like platters. When big and heavy is what you do most, I think upgrading to a larger lathe is safer and more enjoyable.

[Dusty Fuller]

And I would hesitate to turn 50lbs. But then again, I don't have anything of that size. I make sure everything (no matter how small) is as balanced as I can get it before I even turn the lathe on, but that's just a habit that I learned on my old craftsman. The lathe will do some work though, its a trooper and I really like it. Its no giant mustard, but I don't have room or money for one of those. Yet. I'd try trimming those heavy blanks a little bit more, start out a little smaller. Less wear on the equipment.

[Jeff Nicol]

What was the wood that you turned that weighed 50lbs? The one on the lathe may weigh 12-15lbs. A 50lb piece of oak is quite large! If what you have on the lathe is as big as you have done then do what Steve said and make all the roughing and inside the bowl turning with the tailstock in place. With it between centers the load on the spindle is equalized and lessened. The weight is not what makes the lathe jump around it is the out of round blank.

A 10oz. chunk can give you 28 stitches, 50lbs is a killer!

Turn save,

Jeff

[Paul Engle]

Alex I would have to agree, 10% gross weight of the lathe for spindle limit is a safe bet( if the lathe weighs 400#'s , then 40#'s max weight of the blank). You will/may wear out the spindle brgs if the unbalanced weight exceds the makers ( bearing ) thrust and radial loading. Better off with bigger lathe, with bigger bearing, bigger spindle ( 1 1/2" - 7 )bigger foot print, and closer to 800 lbs total gross weight = 80 lbs of blank.

[Pete Jordan]

Alex,
I would also agree it is too big. I have that lathe and wouldn't think of trying anything like that. I can't believe it doesn't stall all of the time. You might want to stick with the thinner stuff.

[Barry Stratton]

An Alaskan saying applies here:

There's old pilots and bold pilots but there ain't no old, bold pilots.

[Bernie Weishapl]

Wow I can't believe you would put 50 lbs. on that lathe. At that rate the bearings won't last long. As my grandmother always told me when I was doing something I shouldn't was, "you are cruising for a bruising."

[Keith Christopher]

You know just looking at that turning and I don't even have to question that is it too much for the lathe. Kinda reminds me of the old Fred Flinstone cartoon, in the beginning where they put the HUGE rack of ribs on the side of his car and it tips over. And since you're roughing the outside this will mean you're in the line of fire if it comes loose.

Be safe!!!!!! 'learn when not to turn'. One of my fears is you successfully turn it before burning up your lathe, which will mean 'I've done it before with no problems...." that is the start of all things hurty.

[Jim Kountz]

Alex I would have to agree, 10% gross weight of the lathe for spindle limit is a safe bet( if the lathe weighs 400#'s , then 40#'s max weight of the blank). You will/may wear out the spindle brgs if the unbalanced weight exceds the makers ( bearing ) thrust and radial loading. Better off with bigger lathe, with bigger bearing, bigger spindle ( 1 1/2" - 7 )bigger foot print, and closer to 800 lbs total gross weight = 80 lbs of blank.

Paul, where did you come up with these? Im not at all doubting you, its just that I have always wondered about this too and never had any real info to go on. Your formula makes good sense though and if nothing else is a great guide to live by.

[alex carey]

well im convinced i need a bigger lathe. Hopefully one will be on the way soon.

Alex

[Jon Lanier]

I know I'm turning to big.... but I am trying to lose weight. :o

[Mike Lipke]

Anybody watch the Red Green Show??

This setup looks only one step better than a lathe Red would make out of a 1/4" drill, duct taped to a workbench.

Or maybe a faceplate attached to the drive wheel of an old K car, with his nephew running the throttle....."And look folks, its even got reverse for sanding!!"

Possum Lodge Pledge:
I'm a man,
I can change.
If I have to,
I guess

[Jon Lanier]

Anybody watch the Red Green Show??

This setup looks only one step better than a lathe Red would make out of a 1/4" drill, duct taped to a workbench.

Or maybe a faceplate attached to the drive wheel of an old K car, with his nephew running the throttle....."And look folks, its even got reverse for sanding!!"

Possum Lodge Pledge:
I'm a man,
I can change.
If I have to,
I guess

I love the Red Green Show... shame he decided to call it quits. They did have a good run. I also like Corner Gas... another Canadian import to the U.S.

[Curt Fuller]

Alex, you scare me!

I looked at the specs from the link in your original post and it says your lathe has a 12" swing. I turn on a lathe with a 14" swing and I can't imagine what kind of 12" blank is going to weigh 50 pounds to start with. A twelve inch bowl blank, green wood, even if it were 8-10" thick wouldn't weigh 50 lbs. Spindle work? I'm having the same difficulty picturing a 50 lb spindle project. I'm not trying to be a smart alec and I'm not trying to put you down, but considering this post and your previous post about the bowl explosion I seriously think you should do some serious research into the safety aspects of turning before you even turn your lathe on again.

[alex carey]

@Jeff Nicol and others the blank you see on the lathe is around 50 pounds. It's wet eucalyptus, only a week or two old. I've been getting a lot of people not believing how much it weighs. Just for assurance I'll go weigh the opposite side right now.

15 minutes later.

These two pictures are of the opposite side of the bowl blank in the earlier post. Before doing anything to it, it weighs 72.5 pounds. I used 2 different scales to check this and they both matched up. One an analog and one a digital. After I spend 10 minutes with a chainsaw and peel off all the bark I should be able to cut this one down to like 60 pounds. This piece is 14x16x8 roughly. I agree I am turning too large and want to upgrade very soon, after all my birthday is coming up. I probably won't turn anything near this big until I do upgrade.

But when I do is the Jet 1642 still too small? What about the Nova DVR? I assume the powermatic 3520 is big enough. How big can the 3520 handle? I'd like to be able to outboard 100 pound pieces if possible.

@Pete It stalls in the beginning, but once it's round it's not too bad. Nice sharp tools and I can take pretty heavy cuts.

Alex

P.S. Curt your not being a smart Alec your looking out for my safety, something I obviously need help with since my accident and something I am trying to take more seriously. That one of the reasons I started this thread.

[Gordon Seto]

Turning big sounds like work to me. I have the DVR; I think it is better than your current lathe, but turning big is not this lathe is known for. The swivel head is not designed for deep big bowls.
If large bowl is what you are interested in, look at the VB-36. I went to the owner's house, he has a rough turned bowl sitting in his garage waiting for it to dry enough to be re-turned. It still weighted over 140 pounds.
This lathe has a 2-1/2" spindle, and the tool rest post is over 1-1/2" diameter.
I hope these figures will convince you that you are pushing beyond the limits of your current lathe.

[alex carey]

as much as id love the vb36 that is years out of my price range. Keep in mind I am an 18 year old college student turning out of my parents garage. The powermatic is a slight possibility but the jet 1642 is more likely. If the Jet isn't capable of doing what I am thinking of then I will have to wait.

Alex

[Jeffrey Fusaro]

as much as id love the vb36 that is years out of my price range. Keep in mind I am an 18 year old college student turning out of my parents garage. The powermatic is a slight possibility but the jet 1642 is more likely. If the Jet isn't capable of doing what I am thinking of then I will have to wait.

Alex

ok... NOW i understand... the realization of one's own mortality hasn't quite registered, yet. :D

alex - what you are attempting is very dangerous. i admire your testicular fortitude and determination, but you should turn it down a notch or two before you get seriously injured (no pun intended).

if, by chance, you are an engineering student... some day, while you are sitting in a classroom, this little experiment of yours will set off a series of fire alarms in your head, and you will have all the answers that you need to understand why this is a bad idea.

that being said, this reminds me of my own exercise in madness on a lathe.

(disclaimer - do not try this at home!)

i wanted to make a large wheel for a project during my sophomore year in college. our lathe was a floor model, but it was not bolted down. my wheel needed to be 60" in diameter and 18" thick. it was made out of urethane foam. the lathe had an 8" faceplate. i made a 24" plywood disk to mount to the faceplate. then, i mountd my 50lb.(+) chuck of foam to the plywood disk with contact cement.

i know! i know! what was i thinking?!?!

that's my point - i wasn't! i was a 20 year old college student who hadn't yet realized my own mortality.

you should have seen the looks on the faces of my classmates when i turned the lathe on and that 1000lb. lathe started to walk across the room with that 60" diameter chunk of foam preparing for lift-off! :eek:

luckily, the glue joint between the foam and plywood faceplate failed before things got any more out of control. at that point, we only had to deal with chasing that 50lb. chunk of foam across the shop before it steamrolled anyone.

of course, i wasn't going to let this little setback discourage me.

i remounted the foam disk and tried again. this time, i got a buddy to operate the lathe on/off switch to regulate the speed. he cycled the lathe on and off to keep the rpms low while i turned the wheel. i was probable turning that piece at less than 50 rpm, but the surface speed at the tool contact point was still enough to make for a white knuckled ride.

ultimately, everything worked out fine. i got the project finished and most importantly - no one got hurt.

with the passing of time, and gaining in wisdom and experience, i can look back at this and see what a crazy/dangerous idea it was.

but, it makes for some good laughs, too.

i have a jet mini, so i understand the frustration of not being able to make larger pieces. the mini is good at what it does - small stuff. and for now, that's good enough.

be careful! make smaller stuff until you can get the proper equipment - like body armor and full-face motorcycle helmet. :D

[Philip Morris]

Alex,

The LAST thing you need is a larger lathe!

This thread, and your one from December 25, document an apparent lack of appreciation of the inherent dangers associated with woodturning. The lathe is not the only thing with limits. For example:

· The holding capability of chuck jaws and faceplate screws have limits.
· The size and design of turning tools have limits (i.e., spindle roughing gouge).
· The ability of wood to hold together has limits.
· The ability of safety equipment to withstand impact has limits.

A larger lathe will simply allow you to repeat the same errors in judgment with a larger piece of wood, driven by a more powerful motor, with potentially more disastrous consequences.

I believe that your long term interests would be better served by partnering with a mentor through a local woodturning club to learn how to safely operate the machinery of our craft within its limits.

[Steve Schlumpf]

Alex, I've turned quite a few large chunks of very green soft maple on my Jet 1642 that were right at the limits of what I thought the lathe could safely handle. These pieces were close to 16" diameter/10"-12" thick and were rough turned between centers! I did weigh one out of curiosity - it weighed 33 pounds! My lathe weighs 420 lb and it has a box with 7 bags of concrete in it for ballast - a little to much speed and it would vibrate big time! I roughed out those pieces with the rpm somewhere around 200 and kept it there until the piece started to balance out. I honestly don't think I ever turned it past 450 rpm even when finishing!

So, in answer to your question about whether the Jet 1642 could handle the load or not - my opinion is that it is simply not designed to turn such heavy loads. When you push equipment way beyond the operating parameters it was designed for - you open yourself up to what is called catastrophic failure. At that point in time - all bets are off when it comes to your safety!

I am sure you have noted that everyone here is concerned with your safety. Lots of very good advice and without exception everyone wants you to open your eyes to the very real dangers that you are exposing yourself to.

In my opinion, the very best advice has been for you to get with an experienced turner(s) and get some one-on-one time. There is a lot to learn about turning and safety should be your highest priority!

[Jeff Nicol]

Alex, O.K. I agree the blank being a very heavy dense wood can weigh 50# but still your lathe is no where big enough to turn that heavy and out of round. I have a 3520B and it will handle large pieces of wood, but to start out without the tailstock is plain crazy! I put a 19" by 6" piece of wet white pine on it and the weight was not evenly distributed even with the tailstock holding it in place turning at just 50rpm it made the big lathe jump and shake!

SO remember 50rpm at the spindle translates to: 1" spindle at 50 rpm outside diameter of 12" equals: 50 x 12 = 600rpm at outer surface of turning blank. Centrifugal force is an amazing thing, and scary too! Not to mention kinetic energy and other physical forces involved in the operation.

A large lathe set up to turn 8' columns that weigh a few hundred pounds turns slow, but because the blank is usually very evenly balanced and dry before it is turned there is not much wobble and is easily controled.

Balance is key and saftey first! Good luck and hope to see you turning on a larger scale in a very safe manner soon!

Have fun!

Jeff

[Keith Christopher]

thank you for all the advice. I am going to put the piece on my desk as a reminder just like you said Bruce. That will be my reminder of the dangers of turning.

Wilbur thanks for that equation, I had no idea it was moving that fast. Now that I see it that way I am shocked how fast the outside was moving.

Jason I think you are absolutely right. That makes complete sense. Every time I have broken other bowls it has been while the tool rest was there and I was cutting not sanding.

Thanks for all the kind words and I think in a week or so I will be back to turning. All this advice has been really useful, thanks for that.


Alex,

You still have that broken bowl on your desk ?

You have gotten some good advice from the people here, why not take that large blank cut it up a little and make some smaller bowls or lidded boxes from it. Or perhaps a set of smaller hollow forms.

I , like so many have said, advise you to unchuck that piece of material, turn your headstock back to on-board and work within those confines for a while. Build the skills and knowledge before you end up seriously injured.

Understand we are not putting you down or telling you that you lack the talent to turn objects this large, we are genuinely concerned for your safety.

Keith

[Alex Shanku]

For those big blanks:

http://www.owwm.com/photoindex/images/6926-A.JPG

92" swing

http://www.owwm.com/photoindex/detail.aspx?id=6926

[Dennis Peacock]

All said and done????? You'd better step up to a PM 3520B or bigger. Take it from someone who has sheared off a factory tool rest into 3 pieces before. :eek: :eek: :eek: :o

It's a LOT safer and more stable to turn stuff like that on a lathe that is designed to handle those loads.

What can you wear out on your lathe by turning big? The whole lathe. Just because a lathe can turn outboard, doesn't mean that we can turn whatever size we want to turn. The stresses are relieved or will eventually be relieved in structural failure of your lathe.

[TYLER WOOD]

I agree with the taking up a mentor. It will allow you to learn what is safe on a lathe, as well as help in understanding the limitations of the lathe. The motor may be able to turn it, but you are wearing the bearings out in the motor. Putting strain on the spindle like that may not break it today, but it will break eventually. It could be on a large piece or a small piece. Misdesigned buildings do not fail typically when the building is built, but later on after it has been straied for a while. Take the advice from the people here.

[alex carey]

Alex Shanku you have me salivating.

alex

[Paul Atkins]

Jeff, RPM is revolutions/min. I know you know this. Feet /min is what he needs to know. 12" diam. at 50 rpm=157fpm =about 33 mph. 500 rpm @ 12" = 1572 f/min = 335 mph.
Alex, If you want to turn this piece of wood, drill, carve, chisel, or chainsaw out the middle and get the weight down - dry it a little, too. ( Or save it in a plastic bag till you have more experience or more cast iron.)

[john l graham]

This lathe while not as big as some may be closer to your price range and give you some options for heavier pieces. Using Paul's estimate you could turn a 50# piece of wood. The spindle size might still be a little light. Just another option out there. John

http://www.vegawoodworking.com/2400%20Bowl.htm

[Harvey Schneider]

Looking at the photo of the rough blank, I am guessing that it is about 14" in diameter.
I am rather surprised that nobody has pointed out that 450 RPM is a speed more reasonable for finishing that piece rather than for roughing it. With that much mass and it's momentum at that high a speed, broken tools are very likely.
I have a Jet 1642 and I have worked close to it's limits on both diameter and mass (15.5" diameter, 60 lbs initial weight), but my roughing speed is more like 150 RPM.

[alex carey]

@Paul Yeah I got all that. I keep all of my stuff in a bag and wait for it to dry. This eucalyptus for some reasons disintegrates after a few months. Small holes start to appear everywhere and it looks terrible. It kind of crumbles. No other wood has done that to me.

@John I was just looking at that lathe. I am also thinking of doing some longer spindle work which that vega can't do. I am also seriously considering the powermatic 3520B. I talked to the guy over at toolnut. 2959$ and it comes with the 18" extension. Free shipping and all. After I sell my lathe I think I'll have enough to go with this lathe. I probably won't turn bigger than 18" for quite a while so this will do fine and I will be able to be inbetween centers which is much safer especially for a younger more reckless person like me.

@Paul I would rather be roughing at 150 but my lathe doesn't go that slow. The reason I went to 450 I was trying to up my torque. I don't actually have it turning at 450 consistently. I set the dial to that speed but as soon as I touch the tool to the wood it slows down. I am more turning at 200. I wait for it to speed up then make some cuts and it slows down. It's like flicking the switch on and off.

Alex

[Leo Van Der Loo]

Somebody needs to get his school money back I think ;) :D

A 30 CM bowl (about 12") is 3.14 X 30 = 94,2 CM circumference = .942 Meters
At 500 rpm 500 X .942 meters = 471 meters a minute
60 min in an hour, so 60 X 471 meters = 28260 meters = 28.26 KM = 17.56 miles per hour

You can use inches, 12"x3.14=37.68"
500 rpm x 37.68" = 18840" per minute
60 minutes x 18840 = 1130400' = 17.84 MPH

[Leo Van Der Loo]

Alex as you have heard from most here, you should get a larger lathe :D.
It might not be so much the weight on the spindle as the power required to spin that size of a piece of wood and to be able to cut on the outside of such a large piece of wood, as you will certainly shorten the life of that motor if not burn it out anytime you overwork it like that :(
I've turned on a lathe like that, and it is a sweet turning machine, but made for smaller pieces than you are attempting to do on it, more like the piece I'm turning on it :D.

[Paul Atkins]

Leo, Boy! My brain must have been really cold this morning! -Sounded pretty fast but I was just thrown by the 600 rpm thing. (measure twice - speak once)

[M Toupin]

remember 50rpm at the spindle translates to: 1" spindle at 50 rpm outside diameter of 12" equals: 50 x 12 = 600rpm at outer surface of turning blank.

How does the rim turn at more RPMs than the shaft without twisting it's self into a knot?

Mike

[Leo Van Der Loo]

Yup we all do that sometimes :D :D, just wanted to correct it :)

[Jeffrey Fusaro]

How does the rim turn at more RPMs than the shaft without twisting it's self into a knot?

Mike


isn't that how a black hole gets started? :D

[M Toupin]

isn't that how a black hole gets started? :D

Just might be... but I bet the grain is really cool!:D