Fun day in the play room

[smidsy]

Hei Guys,
Decided today to rough turn a chunk of jarrah that I've cut off one of a couple of slabs I have - this peice is 290mm square and about 250mm long.
Cut it square, hacked off the corners rough and then hit the switch - I knew the wood was out of balance but I didn't allow for the fact that jarrah is damn heavy, and that I had the head of the MC900 turned 45 degress outboard.

Just as I was reaching for the switch to kill the lathe (I'm using to resting my leg on the frame to stop it walking but this time it looked like a turn over was on the cards) the lathe head parted company with the bed.

Fortunately there looks to be no damage except for the edge of the switch broken, the split pin that holds the two parts of the swivel bolt gave way and the power lead had enough "travel slack" so that was fine.
I put it all back to together, ran it up to full speed unloaded and it seems fine.

This wood while pushing limits didn't look any worse than other big lumps I've turned, am I right in assuming that the fact that I was outboard turning was a contributing factor or was I just way outside the limits of this lathe.

Cheers
Paul

[gatiep]

How about telling us how fast it was spinning, as we would definately need that to even try and make an effort to reply.


Glad all is well.

:)

[smidsy]

Hei Joe,
Not sure what speed it was at - it was the slowest speed on the MC900.

I think the wood was just obscenely out of balance, I tried it on a Vicmarc 3000 tonight at Liddlelow and even that lathe walked with this chunk of wood on it.

Cheers
Paul

[gatiep]

That speed would have been 500 then. Must have been badly out of balance or maybe the headstock was not tightened down 100%. If it wasn't it won't take too big an out of balance blank to rattle it loose.


Liddlelow a Vicmarc 3000? Vicmarc does not make a 3000 but a 300. As far as I know they have a Vicmarc 175.......like Bill Q's and mine, which was supplied this week. The 300 longbed weighs about twice what a VL-175 weighs.

For your blank you should turn it a lot lower than the minimum that the MC-900 can do. It is possible to get the blank within reasonable balance with an arbotec blade in an angle grinder. I think you asked about that in another thread. If the boys at the club refered to a carver, it would be an Arbotec cutter in an angle grinder. I had mine there a few years ago and did a demo for them on carve/turning with it.


The MC-1100 would stand up better to unbalanced blanks being turned sideways. The headstock can be moved till halfway down the bed which will make for a better balanced set up. However too big/heavy/out of balance and too much speed will kill any lathe. The boys doing the big urns use down to a few rpm. Even then the speed on the circumference is massive.

Have fun......seems like you are anyway!
Maybe, take care, will be more appropriate

:)

[smidsy]

Hei Joe,
I assumed that the Vicmarc was a 3000 - it's a big blue brand new sucker with electronic variable speed.
I could have got away with it on the vicmarc if it had been bolted down but it was only delivered today or yesterday and hadn't been bolted down yet.

They have an old woodfast there (a short blue beast) that would do this wood perfect if it had a turning attachment on the outside end of the shaft.

I think I will endcheck this blank and wait till I can use the Vicmarc at Liddlelow - it's too nice to cut smaller.
Cheers
Paul

[westpest]

Hey Paul

I have a 175 and recently turned a piece of Jarrah that started out 420mm x 350mm and weighed about 22kgs and it was no trouble at all. Started at 100revs and finished bowl is 300mm. I have been discussing with Joe about turning a 65kg Salmon Gum Burl and trying to overcome the problem of even lifting it onto the 175...maybe I'll just let it dry out a bit...

Dan

[rsser]

Tasty Dan.

Be good if you could post some photos as you go.

Yeah, I have a 175 and have fought some great lumps into submission. Better than a session lifting weights at the gym ;-}

[westpest]

Hi Ern

Pics for perspective, you have a 175 so you can see what I am up against.
If I get it up and running I'll post progress..

Dan

[rsser]

Wow, I see what you mean.

With a bigger swing this is the kind of lump you'd bring up the tailstock to support.

Can only suggest a big faceplate and slow speed on the 175. (And then a big chuck for the hollowing phase! Have you thought of a free-form sculpture? ;-} )

[Babytoolman]

Does the 175 turn outboard??? I am assuming thats how you turned such a big burl... Is your lathe bolted to the floor? I am going to get VL300 short bed because of the depthover the bed and i was wondering what your preference would be? The 175 or the 300?

[rsser]

Yes, the 175 has a swivel head. (In my case, it is strongly mounted and bolted to the floor).

Paul is pushing the envelope with a piece this size esp when he comes to hollow and has to hold the piece with a chuck.

[westpest]

I haven't considered free-form sculpture and I cannot bolt my 175 to the floor as my workshop floor is 15mm conveyor belting laid over 60mm pavers. Gatiep has suggested I use an Arbortec wheel to gut the thing first. This makes sense because without the use of some sort of bowlsaver 80% of this piece will end up on the floor, so why not remove it first?..

Dan

?? If I wanted to take a "cone" out of the center what tool would I use and how??

[Kris.Parker1]

Just as an idea, and to save a few bumps and scratches, have you thought of making a frame that goes around the frame of the lathe? Securing the lathe to the frame and then to the shed wall would possibly alliviate any problems with the lathe walking.

Alternatively, have you tried rounding the wood more prior to placing on the lathe in order to perhaps stop the oblong shape that causes the walking?

Just an idea.

Cheers

Kris

[Termite]

Paul is pushing the envelope with a piece this size esp when he comes to hollow and has to hold the piece with a chuck.
How do you know what the limit is? Try pushing it and sooner or later you'll find out. :D :D

[Christopha]

Sorry Kris but, unless your shed is solid brick, attaching the lathe to the walls is going to turn your shed into a huge wobbly, rattly pile of tin! My suggestion is, if the lathe can't be fixed down, that you ballast it as much as possible with butts of sand. Not blocks of steel or concrete or such like. Sand will make a big difference not just in mass but in reduction of vibration.

[gatiep]

Good one Christopher

A metal shed will be a sound box!

:)

[rsser]

How do you know what the limit is? Try pushing it and sooner or later you'll find out. :D :D

True, though clearly there is a serious risk to be managed here and going past the limit will be a risk to life and (tree) limb ;-}

Good to see all the creative suggestions though on this challenge.

I agree with the Arbortech idea and have heard of others using it to make a turning job more manageable. It should enable the outside to be rounded, assuming you don't want to leave part or all natural. But the wrinkle that I see is holding the weight to hollow the piece without tailstock support. I look at my Vicmarc 100 chuck and it doesn't inspire confidence that it could hold a piece this size, though with big jaws maybe it could.

Anyone out there have experience on this?

[Baz]

Dan, I will presume you are not turning a natural edge bowl and are going to turn out board. On the face of the burl draw a circle ( I use a wood ruler with holes drilled down the middle every 10mm, a nail and a pencil), with a chainsaw ( I use an electric chainsaw) trim off the excess around the marked circle, if the burl is deep enough cut off the cap of the burl, you may be able to get a small bowl from that. Secure your faceplate to the burl and mount on the lathe, if it is still fairly heavy get someone to turn the spindle while you hold the burl up to get the thread started. Start turning at a slow speed. Turn the outside of the bowl and leave a good spigot for the chuck (I use a VM120 for large bowls), reverse and turn the inside, if you have a bowl saver use that. Hope that makes sense.
Cheers
Barry

[macca2]

Paul, I was always instructed to use the tail stock whenever possible. Especialy while the wood is out of balance. This also lets you true up the blank while inline with the lathe bed. I would never start to turn an out of balance blank with head turned at 45 degrees. I cant duck quick enough.

Macca

[Phil Spencer]

I overcame this problem on my Tough by fitting a variable speed drive, I can fine tune the rim speed and eliminate most vibration I havn't changed a belt speed since fitting the variable speed drive five years ago, all lathes should be fitted up this way as it is far safer.

Regards
Phil Spencer

[TimberNut]

I have a VL300 short bed, and turned a similarly large burl. It was way out of round. I used a chain block from the rafters in the shed to get it up on the outboard side.
I have a piece of steel plate about 40mm wide x 100mm long welded horizontally onto a tool post. I sit my grinder (with arbortech) on it, and use large hose clamps to secure it to the plate. Then turn grinder on and rotate wood by hand, continually moving tool post (with grinder attached) in as required, to remove bulk of wood. This way you don't even switch on lathe till most of the excess wood is gone - long before you go near it with a chisel!

Even though it was out of round originally it was bolted on the lathe as is. I used the tool post at the outside edge to rest a texta on it while rotating piece by hand, to scribe the cirle. Then locked index head, and used chainsaw to remove excess to get mostly round. Then arbortech as above.

I found this to be a lot safer.
Hope that helps.

[smidsy]

Hei Guys,
Thanks for all the input on this.
I usually do use the tail stock when rough turning, but the size of this wood necessitated outboard turning.

The Vicmarc down my club is a 175, I think I may save this timber until I can get on that lathe. I may also suggest to the club that people who need the capacity of the 175 get first priority on it, or that given the cost of the machine we charge more than the usual $4 a night to use it.

I think when I do turn this wood I will have to either use a face plate, leave the bottom of the bowl fairly thick so I don't hit the screws and then put felt on the base of the bowl to hide the screw holes on that side, or use a centre leaving an inch or so thick piece for the centre to hold and then remove and finish that bit off the lathe.

One idea I will take on board from this thread is sand in the bottom of the lathe - I'll put a base right at the bottom of the legs and then enclose it to about 200mm high and fill the area with sand.
It won't help for this piece but for other work it will help.

Cheers
Paul

[Gingermick]

Paul, get your club to put up booking sheets for time on the various lathes.
mick

[smidsy]

Hei Mick,
Not sure I would like that, at the moment people tend to get there early if they need a specific machine (we've got about 14 including the 175) but I think a booking system would encourage people to book machines and then turn up late of not at all.
Cheers
Paul

[rsser]

One idea I will take on board from this thread is sand in the bottom of the lathe - I'll put a base right at the bottom of the legs and then enclose it to about 200mm high and fill the area with sand.
It won't help for this piece but for other work it will help.

Cheers
Paul

Or a few big bags of concrete mix. Then if you need to move the lathe ....