help with bowl turning

Dana · March 13, 2009, 01:46:15 PM

As some of you know I just bought a lathe. I have turned a spindle and a vase with no problems. Now I decided to try to turn a bowl. I glued up three bowl blanks on 1' pine backer plates. I used one layer of newspaper to keep the bowl off the backer. The glue is TightBondII. Today I started to turn a piece of Elm and after a few minutes it seperated from the backer plate and fell on the floor. Then I tried a piece of Black Ash and that came off a few minutes later. The last piece I have is a larger block of Maple I don't want to see that come off. The lathe is turning at 300 rpm and I am using the large gouge trying to round the outside first. Any suggestions?

Radar67 · March 13, 2009, 01:59:58 PM

How are you fastening the blank to the lathe? Is it between the centers, did you get a chuck (3 or 4 jaw), are you using a faceplate?

I use a four jaw chuck and start out by drilling a 1 7/8 inch hole in the side of the blank that will be the bowl opening. I'll chuck it up, turn the outside to shape, cut a recess for the chuck on the bottom of the bowl, then turn the blank around. I cut the inside of the bowl out last.

Dana · March 13, 2009, 05:27:57 PM

Quote from: Radar67 on March 13, 2009, 01:59:58 PM
How are you fastening the blank to the lathe? Is it between the centers, did you get a chuck (3 or 4 jaw), are you using a faceplate?

Radar I used a faceplate. I didn't use the tailpiece to help stabilize the piece. Is that your recommendation. The piece wasn't "rounded off on the band saw either. Think of a piece of split firewood attached to the faceplate and you have it. I will post a picture of the maple in a while.

I didn't get a chuck yet. Tomorrow I'm going to Harbor Freight to look at a 3 Jaw chuck they have. Here is a link to it.http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=4486 Do you think it will work until I get the Grizzle chuck?

Dana · March 13, 2009, 06:13:33 PM

This is the maple blank and what I start with. The screws aren't installed in the faceplate. Other wise it is ready to turn?

Here's the photo of the Black Ash that delaminated from the backer board on the face plate.

pigman · March 13, 2009, 06:19:21 PM

You need to round that blank some before trying to turn it. Use a bandsaw, chainsaw, axe or something. Also, use the tail stock until you get the blank round.

Radar67 · March 13, 2009, 06:51:51 PM

Yes, you have to use the tailstock without a 3 or 4 jaw chuck. The one you linked to, I would use it for very small stuff, like 6 inches and under. Honestly, it doesn't look too sturdy.

I would eliminate the paper, glue the scrap straight to the block and use the tailstock. You can always turn a little off the block once you get it rounded up. I played with just the faceplates and centers at first, but now rely exclusively on my 4 jaw chuck for bowls.

Dana · March 13, 2009, 07:23:44 PM

Pigman I kind of thought I should round it off. But then I saw a photo of some square bowls someone turned and decided it wasn't neccessary. :

I had to learn the hard way.
Stew, Maybe I should save my money and not get the chuck I mentioned? I think it was ment more for their small metal lathes than for wood.
I also thought that the paper was required to keep the two glued woods seperated. Would you use a parting tool to do this then?

Radar67 · March 13, 2009, 08:25:09 PM

If the rest of the bowl is done, parting it off on the lathe is about the best way. There is another way to do it, but you have to have another set of chuck jaws to open up wide enough to hold the outside of the bowl.

Tom · March 13, 2009, 10:59:15 PM

I never messed with gluing a piece of wood to the blank. I put the blank onto the faceplate with screws and start turning, using the tailstock for support until it is balanced. I screw the faceplate onto the pith side of the blank. The side that will eventually be the top. I shape the outside of the bowl some, flatten the *bottom and hold a pencil to it as the blank spins. That marks the center. then I turn the blank around, screw it onto the faceplate from the bottom and turn the inside of the bowl.

When you reach this point, you can turn the inside and the outside (again) without rechucking it.

I turned mostly green bowls and refinished later. That means that your first turning is quite thick so that it will survive the drying.

tyb525 · March 13, 2009, 11:13:59 PM

I do as Tom does, except when I hollow it out I attach it using a chuck in a recess instead of a screwed on faceplate.

Dana · March 14, 2009, 04:44:34 AM

Tom to avoid screw holes you must use a larger than otherwise required block? My concern is leaving screw holes in a finished piece.

turningfool · March 14, 2009, 08:17:41 AM

i'd definitely round it up some by whatever means possible first,even at only 300 rpm it would be spooky..also you are turning side grain and must use a bowl gouge,thats nice and sharp with very light cuts..as far as the gluing goes your wood block is probably very dry vs the wood 1/2 log that you are turning,which ,even tho spalted is probably still pretty high in moisture content ,and so in turn your not getting a good seal

Lud · March 14, 2009, 09:01:37 AM

Forget the paper at this stage, Dana. I find the rounder the block the less roughing out beats you up. Adjust your toolrest as close as you can as it puts the leverage to your advantage instead of the wood block's. There's a lot of shock for you to absorb sticking your tool in a highspeed out of round. Protect yourself.

I got a tap that lets me thread a hole in a blank in a few minutes that is very strong yet I still support with the tail stock. I'll even run big flat drill bit in a Jacob's chuck thru the bark so the tail stock point seats in hard wood . Put the faceshield on at the start and always testspin before turning it on.

And , like Radar, I then turn the recess for the chuck and the outside of the bowl , even sanding the base out to 600 before I reverse and start to go inside. To some extent it is like turning two different bowls ; an the best outside bowl the block will let you have married up to the best inside bowl you can get, balanced as best you can and finished as fine as time and your patience allows.

You got to have a bowl gouge for bowls. Learn to get your tool sharp. There's a lot of satisfaction going back to the lathe with a newly sharpened tool and having it work better than minutes ago when it was workin' hard.

Idn't great? 8) 8) 8)

Tom · March 14, 2009, 11:24:24 PM

Dana,
we close the screw holes with plugs cut from the same wood. Sometimes we would cut plugs from contrasting woods. Sometimes we would just part the bowl from the faceplate by knowing how long the screws were and staying above them.

My little brother, Charlie, uses a jaw chuck to avoid the screws after he has turned the bowl around.

Using a faceplate and screws makes me feel a lot more comfortable when turning large diameters.

Dana · March 15, 2009, 08:24:00 PM

TurningFool, you are right the wood was wetter on the bowl than the backer. Lud and T.F. I will have to get a bowl gouge I guess that there are a few more things to spend money on. Tom plugs cut from a contrasting wood is an interesting idea to get rid of the screw holes.

I didn't get the chuck at Harbor Freight yesterday. They didn't have any no did they have a mt2 drill chuck for the lathe.

turningfool · March 16, 2009, 05:54:34 AM

when i first started turning,the screw hole dilemma bothered me too..but now i just turn them away..you almost have to envision your 1/2 log as a finished piece in your minds eyes before you start and tweak it from there

turningfool · March 16, 2009, 06:06:55 AM

heres a coupla small projects,i started on last fall,yesterday was nice so i wanted to play in the shop some

....charlevoix would be a good drive on a nice day for me iffin you'd like some pointers

Dana · March 16, 2009, 08:02:29 AM

T.F. I may need to take you up on that offer. I think if I cut the blanks round and use the tailstock for support I should be able to make some progress. It was my understanding that a bowl gouge was only needed for the inside of a bowl not the outside? Anyway to make my own?
Nice turnings by the way. Does the Box Elder in Michigan have that much redness in it?

turningfool · March 16, 2009, 09:13:40 AM

yes dana,it does on occasion..personally i prefer a bowl gouge to a roughing gouge almost everytime,be it inside or out..i do mostly faceplate work and cut a chuck recess most of the time..but not always as you can see by yesterdays projects..but for larger diameters i feel its held more securely with a recess..looks more finished too in my opinion

tyb525 · March 16, 2009, 07:08:29 PM

TF, I prefer the recess method also. I have heard it said that a tenon is stronger, but I really don't see how that could be.

Lud · March 16, 2009, 11:23:56 PM

TYB, the tenon is stronger theoretically as the wood will only compress so far. and can't escape the chuck's jaws. Plus it can be turned off for a smooth bottom. I like the recess too ....but I've had a few fracture, blowing out a piece of weak grain on the rim of the recess . Particularly if I'm trying to get away with a shallow recess. Using a dovetail cut, you can turn platters, plates, etc. with very little depth on a recess.

I've had some 40 pounders fly off the lathe and go 6-8 feet. You want to stay out of their line of flight, right, Charlie?

Dodgy Loner · March 17, 2009, 08:41:31 AM

In my experience, a turned recess is much stronger than a tenon for facework. I use both to some extent, but when I'm turning larger bowls, I always use a recess. The only time I've had one fail is when I left too little wood outside the recess. On the other hand, I've had tenons fail on many occasions even when I made them as wide and as deep as my chuck would allow. For centerwork, though, the tenon would definitely be stronger.

metalspinner · March 17, 2009, 08:51:15 AM

If the piece of wood being turned is rather small and thin and you want to maintain maximum thickness, glueing a sacrificial block to the bottom after it is turned is the way to go. The glued on block becomes the tenon that the chuck jaws hold to hollow out the interior. That does, however, leave the additional process of removing the glue block later. But for certain small blocks and designs, it's the only way to go.

Using a recess to hold the bowl for hollowing has the additional benefit of rechucking the bowl at a later date for refinishing.

Fla._Deadheader · March 17, 2009, 09:09:30 AM

When I was building Banjos, back in the last century, I would glue up rings, glue them together, and, when ready to turn, glue the bowl to a plywood piece screwed onto a faceplate.

I used brown paper bag between the bowl and plywood. Everything was dry, and it worked very well. When finished turning, you simply separate the paper with a sharp thin knife, and a small thin chisel.

Now, I use the screw to the faceplate, and tailstock to get the piece round as possible, before turning the actual shape.

HOW does one go about turning the oblong bowls ??? Just can't get my head wrapped around that one, EH ???

Burlkraft · March 17, 2009, 12:18:22 PM

http://www.volmer---ovaldrehen.de/_private/4Oval%20Chuck%20and%20Ovalturning.html

A friend of mine bought the VicMarc chuck at the AAW symposium last year.

2K !!!!!

I talked with him last week and he still has not figured it out.
There sits one DanG expensive chuck

He said I could 'prolly buy it cheap at his estate sale :

: