How big is too big?

[Jay Drew]

I have been collecting some rather large chunks of wood to test the outboard capacity of my Powermatic 3520B but I was wondering how much weight can the bearings handle?
I have some maple and ash that could easily be over 500lbs after being cut into bowl blanks. Can I turn these without harming my lathe?

[curtis rosche]

when in doubt buy a bigger lathe

[Matt Hutchinson]

As great as these lathes are, their frames aren't designed for this kind of blank. I am fairly confident that it could spin a huge chunk, but I can't imagine it would be a good idea, especially not 500 lbs. Above all, don't try anything deep. If it's a huge blank, 8 inches is plenty deep. In fact, you would probably want to start at 6" or so. Machines like the VB 36 have the structure and bearings engineered to handle unbelievable chunks of wood, but most machines don't. I have a large lathe with huge castings, but large pieces will make it move a lot. It's amazing what a medium size chunk of wood can do to even massive machines. Of course, always start slow and you will be able to judge if it's safe or not. Also, the machine HAS TO BE bolted to the floor. If you can't do this, don't even attempt it.

I speak from nominal experience with huge chunks, but nothing as big as you are describing. A friend of mine has made 40" diameter bowls out of hard maple, but he can do this inboard, with tailstock support.

Hutch

P.S. Another thing, though any machine with a 3 HP motor can spin massive pieces in theory, their spindles are also another important factor to consider. Usually they are simply not large enough, even at 1.5".

[Bruce Pennell]

Jay check out Nick Cook's video on the woodworking channel (http://www.woodworkingchannel.com/dolphin/vidego_video_library.php) He is under Misc. about 5-6 video down. He uses 2 PM's to turn 1200# log, he had to help start it spinning, and had to clamp the two machines together. The ending he jumps into a 350# pile of chips. I know I would not have the nerve to try any thing like that. Can you imagine a 1200# anything coming off the lathe at you! To crazy for me.

[Nathan Hawkes]

Five hundred pounds, eh? That would be a big chunk of wood!! I've wrestled a couple 60 lb pieces, maybe a little more, but I can't imagine that! Anything that big would be a missle, with no exaggeration! I watch the show "mythbusters" on Discovery channel from time to time. They tested the compressed air tank myth about breaking the regulator, and whether it would go through a wall or not. Well, it did; through two layers of cinderblock. I can imagine that a large piece of wood spinning would try very hard to repeat this, or at elast in my imagination, to crack a wall, anyways. I hope your lathe spins sslllloooooowwwwwwww

[Reed Gray]

My theory on this, after having a 3520A for 8 years is that it could probably handle it once or twice, but it is made for bowls up to 20 inches, and a 20 inch bowl that is 8 inches deep is probably max. It is kind of like all the bandsaws that have riser blocks. They are made for 6 inch heights, and you can cut 12 inch high on them, but for production work at that height, you want a saw that is made for that.
robo hippy

[Chris Barnett]

http://www.taunton.com/finewoodworking/ToolGuide/ToolGuideArticle.aspx?id=28509

This video shows a rather large chunk being turned on a Powermatic. Conviced me that the 3520B was sufficiently large. Later info and comments makes me believe otherwise, thus the desire to change to the Oneway. One item that affects perception is the way this guy handles the burl. If it were green wood, seems it would be too heavy to handle so easily. Not really sure of the PM capacity, but one can easily see the relative bearing sizes between the two lathes. A big difference in price for larger bearings, though the longer PM extension puts it in close proximity to the Oneway. The PM still seems to be more versatile.

[Reed Gray]

Chris,
If I was turning that chunk, I would have whittled a lot of wood off before even mounting it on the lathe. If you want a bigger lathe, check out the Robust. Mine sits in a corner, and I wouldn't be able to turn on the outboard end, so I have to have the sliding headstock. It is the only lathe that I know of that has adjustable legs. I had my PM up on 2 2 x 4s. It will do big better than the PM, has more hp, and is made in the USA. In reality, I will seldom use the extra throw, I just wanted more power and weight than the PM had, and I have the extra throw if I need it.
robo hippy

[Gary Herrmann]

The Robust does look like a great lathe. If I had the funds, it would be my choice.

[John Gornall]

Have a look:

http://www.onegoodturn.ca/howidoit/v1.html

[Matt Hutchinson]

Don't forget that the original question mentioned outboard turning. Inboard turning with tailstock support is one thing, but as soon as you switch to outboard turning the size and weight of a piece of wood is much more of a concern. A Oneway, Robust, Powermatic, Woodtek, and probably others can handle massive logs between centers. But weight capacity inboard does not equate to weight capacity outboard.

However, I still love looking at all these videos. I hope that someday I will make a similar video. :) Turning a monolithic vase sounds fun! :D

Hutch

[John Gornall]

Yes, outboard has limits.

I have seen some very large and heavy pieces turned outboard on a big Oneway using the Oneway's outboard setup which allows use of a tailstock and center giving about 48" swing by 20" between centers.

[Matt Hutchinson]

Oh yeah, I totally forgot that the Oneways have that tailstock option. :rolleyes: Are there any pics of this anywhere?

Hutch

[John Gornall]

http://www.oneway.ca/lathes/2436_access.htm

[John Gornall]

These are interesting:

http://www.onegoodturn.ca/howidoit/p5.html

http://www.onegoodturn.ca/howidoit/p4.html

[Andy Hoyt]

Here ya go Matt. Took these shots at Dave Lancaster's house a year or so ago. That's a Oneway 2436 with the 44" Outboard setup and tailstock. Sure, he started with the tailstock but sure couldn't complete the piece with it in play. This stuff was soaking wet and weighed plenty. The history behind this particular lathe and the use Dave subjects it to is testament to Oneway's bearings.

89979 89980 89981

[Matt Hutchinson]

Well, I guess that gives me a better opinion of the Oneways. That's quite an extension from the headstock. I have had mixed feelings about the Oneways due to a situation that must have been cause by errant quality control. A 2436 owner couldn't get a large piece to spin without jiggin all over the place....inboard with the tailstock! Must have been a rare 'lemon'. Whatever the case may be, I have to say that the 48" outboard swing with tailstock is pretty sweet. Although, I am still waiting to see a 'normal' lathe turn a giant bowl outboard. I have seen flat/shallow pieces, and I am wondering if huge bowls are possible. I know it would be possible on this lathe. Oliver lathes rock my world.

http://www.owwm.com/photoindex/detail.aspx?id=2944

Hutch

[john taliaferro]

500 should not be a problem . i would want to see it first cut the roots off . mine is a 36 48 i made. you should think hard first. i parted some 36 inch platters last weekend . like life on big screen. just dont hurt the wood.