PDA

View Full Version : outboard mounting question



steve mcconnell
12-03-2012, 12:02 PM
I have a Nova 1624 and the outboard attachment, which has a 29inch capacity.

I had a tree taken out of the back yard over the weekend, and kept some of the wood. My question is concerning how to best mount wood to the lathe. I used a faceplate ring for about an 18inch piece. I turned the blank at 200rpm and I never felt unsafe, but had to re-tighten the screws a couple times due to the wet wood. I think the big 28 inch pieces would be too big for the rings, and I probably need to use a faceplate instead, but I am still somewhat concerned about the holding power of the screws in the wet wood.

Should I have been using a faceplate instead for this smaller one? Is there a better way to do this? The wood was only 2-3 inches thick, and since I was trying to turn a platter (until it exploded) I was somewhat concerned about screw holes. If I were to turn thinner dry (lighter) laminated stock, how would one attach then so as to avoid screw holes? Just very short screws?


Thanks for this great resource.

steve

Michelle Rich
12-03-2012, 12:28 PM
Turning a wet platter will be problematic, as it will move like crazy . If i were you i would dry a portion of your base, and then glue on a waste block & put screws into the waste block..I have basically the same lathe, and I would be very very careful turning something that large & heavy on it. Even at 265 that's a heck of a chunk to turn

Dennis Ford
12-03-2012, 1:06 PM
The holding power of a faceplate with screws is dependent on:
* Strength of the wood
* Diameter of the faceplate
* Screws used

I am comfortable putting a very heavy piece of hard wood on a 6" diameter faceplate with 1/4" x 1-1/2" long lag bolts (1" length into the wood) if it is cross grain orientation.
If the wood was wet Willow then the max size blank would be less.
Just because the faceplate can hold the wood does not mean that your lathe can turn it safely.

Reed Gray
12-03-2012, 1:13 PM
When turning pieces that size, I do prefer to have tailstock support. Not possible in your case. I would use a 6 inch face plate minimum, and as many screws as you can get into it. I would want 2 inch screws for a 1/2 inch thick face plate, and if there is room, toe nail/angle the screws in different directions. For a wet platter, and warpage, you would want the center of the tree on the bottom. The sides/wings will warp upwards in this orientation. Otherwise, it will warp down, and anything round will roll off the edges. If you are planning on twice turning it, probably the same orientation because you will be able to get a deeper platter.

robo hippy

Sparky Paessler
12-03-2012, 2:15 PM
I just turned a 19" platter/4" deep bowl on my Nova DVR with the outrigger setup. What I did was use a faceplate screwed the open side o fthe bowl and turned the bottom of the bowl first. in the bottom I turned a foot with a large recess that I used the chuck in expansion mode to reverse the bowl and turn the inside. Once it dryes I will be able to rechuck it in in the recess and turn a flat spot in the inside bottom of the bowl and glue on a block that I can turn a tenon on that I can grab with the chuck. I will then true up the bottom of the bowl (cleaning up the recess). I will them flip it around and chuck it in the recess and turn off the glue block and finish turn the inside of the bowl. Might not be for everyone but seems to work for me. I will keep the speed very low while I am chucked in the untrued recess.

Allan Ferguson
12-03-2012, 6:57 PM
I have the same system that you are using. Life is a lot easier with a dry blank. I have both wet and dry. Wet warps as it drys causing problems with remounting. Be careful and have safe fun.

robert baccus
12-03-2012, 11:54 PM
You are fighting a common problem with wet woods. On wet woods andespecially endgrain/wet woods I always use a 4" heavy glueblock and thick CA which holds great. I have used this on several blanks over 100# vase shaped with the tailstock. For hollowing they still weighed 50#+ with no TS support. Haven't lost one yet. When I started this I sometimes used long heavy screws as well but found them to be overkill.

Olaf Vogel
12-04-2012, 12:04 AM
I have a Nova 1624 and the outboard attachment, which has a 29inch capacity.

I think the big 28 inch pieces would be too big for the rings, and I probably need to use a faceplate instead, but I am still somewhat concerned about the holding power of the screws in the wet wood.

Should I have been using a faceplate instead for this smaller one? Is there a better way to do this? The wood was only 2-3 inches thick, and since I was trying to turn a platter (until it exploded) I was somewhat concerned about screw holes. If I were to turn thinner dry (lighter) laminated stock, how would one attach then so as to avoid screw holes? Just very short screws?

steve

28" diameter is a lot, but 2-3 thickness is not. so you won't have a great deal of mass. Try using short, fat screws, lots of them, in a portion of your platter that will later be turned away.

If you pre cut it as circular as possible on a bandsaw, then your vibration issues should be minimal.

I've personally not tried glue blocks onto wet wood, mostly because I hesitate to glue anything to wet wood.

Is this a cross sectional slice of the tree?
If so, I wouldn't trust any screws and you'd have to glue on a block.
Also, I'd be sceptical that it would dry without cracking.

If you are using a large faceplate and have a hard time getting a really flat section on your blank, then I use a circular cut-out, screw it on the blank and level the center section with a router. Then the faceplate has a nice flush fit.

Olaf

Roger Chandler
12-04-2012, 7:04 AM
What about Gorilla glue on wet wood to mount a glue block? A polyurethane glue cures in the presence of moisture, and you won't get a stronger hold than Gorilla glue!

John Keeton
12-04-2012, 7:32 AM
Roger, good thought on the Gorilla glue given the wet wood, though I would probably disagree with the proposition that there isn't a stronger bond than Gorilla glue. It should be strong enough for this task, but as I recall, the testing puts Titebond, and similar glues, far ahead of Gorilla and the urethane glues.

Roger Chandler
12-04-2012, 7:45 AM
Roger, good thought on the Gorilla glue given the wet wood, though I would probably disagree with the proposition that there isn't a stronger bond than Gorilla glue. It should be strong enough for this task, but as I recall, the testing puts Titebond, and similar glues, far ahead of Gorilla and the urethane glues.

I guess that is what I get for believing the advertising :o I use titebond 2 and 3 and have never had an issue with either of them. I used the titebond 3 for a blanket chest I made for a lady, and it has held very tight for years now.

I do remember Norm Abrams saying that polyurethane glue was very strong.........I guess that is why I remember that one like I do....:D

John Keeton
12-04-2012, 8:52 AM
Roger, this is just proof positive that advertising works!! Particularly, when the folks use a well known spokesperson. I do think the urethanes have their place, but IMO it is limited. This might be a good situation for them.

steve mcconnell
12-04-2012, 10:00 AM
Thanks, all. Great information.

Olaf, the first one was cross sectional, which is why I was very careful and very slow until I got the tenon. (and moved everything breakable out of the potential paths) I was also pretty much expecting it to split. In this case that is not that big a problem, as the wife wants the tree cross section for an outdoor wall hanging. I think I will go with the router method for the really big slice to get it to a manageable/hangable thickness.

With the wood being as wet as it was, it was a live tree when taken down, I was concerned that the water would inhibit the glue curing, and even CA wouldn't hold well because of all the water. Perhaps I should buy a bigger bottle of CA? Endgrain as well as soaking wet, I just assumed nothing would hold well enough, which is why I went with screws. However it was still endgrain.

Thanks again. This is a great forum, I really learn a lot lurking here.

Reed Gray
12-04-2012, 2:03 PM
Urethane glues have their uses. They do not take shock loads, and do not fill gaps with anything other than bubbles. Two stories:

One turning friend made expresso tampers with lignum or other exotic bases. He used urethane glue because they would hold the exotics pretty well. He sent some to Japan, by air. Flying at altitude for the trip, the air bubbles expanded, and all the bases came loose.

I called Franklin glues to ask some questions (they make Titebond), and got the 'old timer' tech. When asked about the urethane glue, he said they experimented with making laminated baseball bats. The urethane glued ones delaminated every single time, and the titebond ones held up. I didn't ask about CA glue, but probably should have.

robo hippy

robert baccus
12-04-2012, 7:52 PM
Roger Keeton on the glues. Gorilla was rated last in a Fine Woodworking test. All the various "wood" glues (white and yellow and hide) showed great strength on dry wood. CA is the only glue I have read or found to be full strength on wet wood. It also hardens in minutes and requires no clamping pressure to
develope strength. An advantage when trying to glue a block onto a long heavy vase blank. Epoxy has these same qualities but will not hold on wet wood at all. Just be sure you have a strong wood block turned true and a level true base on your block. CA is relatively brittle which allows a finished blank to be removed with a chisel and hammer if not too large.

Leo Van Der Loo
12-04-2012, 8:44 PM
Even if you are able to mound that piece of wet endgrain onto the lathe,
then of course there's the other problem, lathe size and reach, I'd hesitate to put a 4 or 5 inch slab of endgrain wood on a lightweight lathe like that.
Never mind what claims there are made to the lathe's swing outboard cap., this picture should explain some of it I hope

Be safe, too many new turners (and older doesn't mean wiser) are getting hurt trying to turn extra large pieces without the experience and equipment to handle things like that :eek: :eek: :(.

247122

mark ravensdale
12-10-2012, 2:24 PM
I have a nova dvrxp and have turned 20+ inch pieces upto 6+ inches deep so your lathe will handle those sizes happily, biggest piece I have turned (if I remember correctly) was around 26 by 7 or 8 inch thick, now at those sizes we a talking a considerable amount of weight and the last thing you want happening is for wood and lathe to part company, I used an 8inch faceplate and used all the holes available, the bolts I use for big wood are actually designed to tap there way into concrete!!! But they work VERY well at holding wood to lathe, I did have to drill and enlarge the holes in the faceplate first though, also try and centre the faceplate as well as possible and try and ensure the wood is as round as possible before hitting the go button (I have a little battery powered chainsaw for just this job)
One last thing, sandbags and/or concrete work well as ballast and try and bolt your lathe down to concrete (though mine is not!)
i too agree with the other guys that wet wood of those dimensions is going to move quite a bit, if your not in too big a rush I would let it air dry for a while before bolting it to your lathe

Have fun!!!