Holding wet wood blanks

[Robert Feingold]

I'm drilling a hole past the bark and I'm using a 2 or 4 spur drive for roughing wet wood blanks but the drive strips out the hole when I hit a corner. I keep re-cranking the tailstock. I am removing the corners with a chain saw but there are still places for the gouge to grab. A face plate is too time consuming and doesn't allow re positioning. I'm turning 12-14" blanks about 700 rpm without vibration. Should i go faster? I'm using a Jet 1642. I'm using elm, cherry, oak, etc.

 

[Edward Weber]

Robert, I think the speed is fine, especially if there is no vibration. One method that many people use is to drill a 2" - 2 1/4" hole and use a standard 4-jaw chuck. In this method you won't have to crank on the tailstock, you should be able to get a tight enough grip that it won't slip.

 

[john lucas]

I'm like you I like repositioning the blanks so I mount everything between centers. You didn't say what size your drive center is. You probably need a larger one. The also make some excellent 2 spur drives that hold really well. These are good, www.bestwoodtools.com Oneway also makes a new one that fits in their chucks. It's a large 2 spur drive.
I made my own 4 point drive that is really too large but it works. I thought I had a photo of it but apparently don't. I'm rearranging the shop right now so may not be able to get to it to take a photo. I'll look. It's just a 1 1/4" nut with 4 pieces of drill rod glued into holes that I put in the nut. Then I sharpened the points. They really need to be a little shorter, I got carried away thinking I could punch them through the bark. They hold well without the need to punch through.
You could easily make one of these using a faceplate. Just drill and tap some holes. Screw some bolts through the holes with sharpened ends. If you put nuts on the back you could feasibly make them adjustable to extend however far you need.

 

[Bill Boehme]

Are you balancing the piece of wood before you begin?

Put a dead center in the headstock and remove the point from the tailstock live center so that it is using only the cup to hold. Next, adjust the wood until it balances in all positions. Reinstall the spur drive and the live center point so that the wood is mounted between the balance points. With the wood balanced, there is no shaking and less tendency for the spur drive to to lose its grip.

Other than that, don't poke the bowl gouge into the wood -- very slowly nibble the corners away until the piece is round. Since the wood is balanced, the speed can be cranked up a bit, but not too much, lest something besides bark and chips flies off the piece of wood while it is being rounded.

 

[MichaelMouse]

I'm drilling a hole past the bark and I'm using a 2 or 4 spur drive for roughing wet wood blanks but the drive strips out the hole when I hit a corner. I keep re-cranking the tailstock. I am removing the corners with a chain saw but there are still places for the gouge to grab. A face plate is too time consuming and doesn't allow re positioning. I'm turning 12-14" blanks about 700 rpm without vibration. Should i go faster? I'm using a Jet 1642. I'm using elm, cherry, oak, etc.

Swing the gouge from inside to out, shave from upgrain downward and you won't grab anything, even if you don't round and undercut your blanks on a bandsaw. Might at 150 rpm, but you can't stuff fast enough to get in trouble at 700. http://s108.beta.photobucket.com/user/MichaelMouse/media/PicturesfromGregs022.flv.html Smaller diameter gouge just takes smaller width shavings if you present as you see.

I use a pin chuck. You can see it here. http://s108.beta.photobucket.com/user/MichaelMouse/media/1012052.mp4.html Hole is all I have to do, and it not only holds the piece green, it starts it again when cured. Safer than spur drives too. Here's a cured piece remounted on the pin chuck to work the outside back to circular. http://s108.beta.photobucket.com/user/MichaelMouse/media/CherryPeelOut.mp4.html If you badly misread a piece of wood and still think you can get something out of the smaller piece, stuff a dowel in the hole with some CA, bore the new angle, and press on. You can do the same with a woodworm if you like, or with pin jaws. All are safer than the spur in wet wood. If you use the big mortise method, you will have to remove some around the original bore before you make the new angled one. You can also use one of the little 2" faceplates and screw into a flat made by a Forstner.

Many ways of doing all you want safely and with a sure hold. A little less convenient to reorient, but certainly not too onerous.

 

[hockenbery]

Robert,
Your problem may be more due to roughing technique than the holding power of the spur.

I do most of my roughing between centers. Corners should not be a problem or cause a catch.

I often rough small natural edge bowls from 9x6 half logs with square corners.
Just quicker than going to the bandsaw and more fun!

I have the flat face of the blank toward the tail stock.
I position the tool rest so it forms a 30-45 degree angle with the face of he blank and almost touching the closest corner.
I hold the gouge parallel to the floor with the top edges of the flute perpendicular to the floor.
I line the bevel on the nose of the gouge so that it points parallel to the tool rest then slide it down the tool res through the wood into air.
Take 1/4 cuts at first.
If there is any bumping on the gouge I pull the heel of the bevel off the wood a bit.

I readjust the tool rest a s needed so I don't get too far over the tool rest on the cut.
Once I get a nice circle cut across the end I begin to turn a curve with a bevel riding cut from the bottom to the rim.
I also begin rotating the gouge so that flute point up to 40 degrees or so.

I use a side ground bowl gouge but this technique will work with and gouge.

Have fun and be safe
Al

 

[john lucas]

I use what I call a levering action to get the really rough areas of an out of round piece turned down.
What I do is anchor the tool on the tool rest. Then I slowly move the tool cutting edge into the work by moving the handle. The tool pivots around my anchor hand so that I can engage the wood a little at a time in a very controlled fashion. What usually causes catches in this situation is taking too large of a bite when that errant piece sticking out hits the wood. This levering action lets me control the tool better so I take a reasonably small bite on each revolution. I can lever it in small increments or larger increments depending on how the wood is cutting. It's much more relaxing on your body as well because you aren't fighting the tool.

 

[Ron Rutter]

Robert. Work from the inside out, not outside in!!!http://www.aawforum.org/vbforum/images/smilies/wink.gif

 

[Jeff Gilfor]

Might want try a wood worm screw. You can get 'em cheaply enough (I know Penn Sate Industries has them). It's a pretty beefy screw, designed to screw into your blank (after drilling an appropriately sized pilot hole). The ones I use, can be held in the jaws of a 4 jaw scroll-chuck. That way, you can rough out without removing the chuck, placing the drive spur, then resetting to continue to finish the piece.

I've not yet had one lose a hold of my wood; even when roughing a firewood log into a tool handle (and my firewood can get pretty rough!).

 

[Bart Leetch]

I just saw this yesterday & thought it looks pretty simple & safe.

http://www.youtube.com/watch?v=LlHv4NnkE4Y&list=UU_txsr2OjQApEd0qvwbI8Yg&index=13

 

[Odie]

I just saw this yesterday & thought it looks pretty simple & safe.

http://www.youtube.com/watch?v=LlHv4NnkE4Y&list=UU_txsr2OjQApEd0qvwbI8Yg&index=13

Interesting.......I've seen some of Glen Lucas' videos in the past, and he is a very talented, and innovative turner.

This is similar to a screw center chuck, but by using the tailstock for holding power, the workpiece is instantly on and off.......I like that!

I also found it interesting that Glen Lucas made up a special jig for sizing tenons the same size on each bowl........It is turners like him that give inspiration, and motivates us to find our own way of developing a personal style.

He is definitely NOT a "herd" turner........😀

ooc

 

[Bart Leetch]

Interesting.......I've seen some of Glen Lucas' videos in the past, and he is a very talented, and innovative turner.

He is definitely NOT a "herd" turner........😀

ooc

No he's not but he can sure turn a herd of bowls in a herdy.

 

[Odie]

No he's not but he can sure turn a herd of bowls in a herdy.

Heh,heh,heh......ok, you made me LOL........😀

Yes, it appears as if GL is oriented towards production turning, and most of his jigs are intended to increase speed. You certainly have to admire his efforts. Some of his ideas have inspired me to elaborate on a basic principle and tune it to my own application.......his and my goals are not the same. Matter of fact, Glen Lucas once corresponded with me, as I was able to inspire him to make a special jig that I had written about......he probably changed it here and there, so that it fits his own needs.......and, that's ok........it's things like this that make me a regular participant on this forum. There are quite a few instances where input from other turners has given me inspiration and ideas that have altered my course......and, it's all good!

Thanks for posting the link.......I'm currently watching a few of his newer videos. I haven't seen any of his videos in a few years, and it's time I catch up on his creative and very ingenious mind.......:cool2:

Later, Bart......

ooc

 

[john lucas]

Pin chucks and screw chucks are great and they hold the wood very securely. However it's really tough to reposition if you start roughing the bowl and find that you would like to re-orient it in the lathe to either get rid of a defect or to change how a particular feature is highlighted.
That's why I prefer 2 and 4 pin drive centers. I can remove a little wood and then look at the blank more closely. Shift the centers if necessary to make the figure work better with my final bowl and then continue to rough it out.

 

[hockenbery]

As John said the screw mounts are quick fast way to securely mount a bowl.
But you are stuck with the grain you cut.

If you want to balance the grain or make the rims of a natural edge bowl the same height - between centers lets you do it.

When I teach beginning bowl classes I almost always start with a screw mounted bowl because the students can concentrate using the tools.
2nd Bowl is between centers, and the last bowl is a natural edge between centers.

Every decision you make in woodturning limits the choices of what you can do next.
Some have more limits.

Al

 

[MichaelMouse]

Pin chucks and screw chucks are great and they hold the wood very securely. However it's really tough to reposition if you start roughing the bowl and find that you would like to re-orient it in the lathe to either get rid of a defect or to change how a particular feature is highlighted.
That's why I prefer 2 and 4 pin drive centers. I can remove a little wood and then look at the blank more closely. Shift the centers if necessary to make the figure work better with my final bowl and then continue to rough it out.

Did you read how to compensate above? Covered all that.

Easy, and the enhanced safety makes it well worth the occasional - very occasional - change when you misread a piece.

 

[Dean Center]

Robert,
Based on a recent experience with one of our student club turners, I need to ask and don't mean to offend. Are you using a roughing gouge or a bowl gouge?

 

[john lucas]

MM I did read the above. I still contend that it is difficult to change the center of a piece when your using pin chuck or screws. How would you move it say 1/4" off center. If you need to move it 3/4" you could simply drill another hole however then you have a problem of putting the tailcenter where you want it. You would have to drill the hole lined up with your tailcenter. And then if you decided you needed to move the tailcenter a little you have the same problem again. Wouldn't it be much simple to just loosen the tailstock, move whichever center as little or as far as necessary to achieve the proper alignment. No hole drilling or fussing with the other drive centers.
Here is a photo of the drive center I made for very rough or bark side tunings. As I said above the pins are actually too long and I need to shorten them. I thought they would have to be that long to penetrate the bark and grap but they grap well no matter what. I would like to make them adjustable so that I could have all 3 prongs penetrating the wood firmly for those really odd shaped pieces where 2 or 4 or even 3 evenly extended points won't do.

 

[MichaelMouse]

I still contend that it is difficult to change the center of a piece when your using pin chuck or screws. How would you move it say 1/4" off center.

As above, plug the old, drill the new. At the very worst, I can always fall back on the spur center if time means more than my teeth.

 

[MichaelMouse]

Robert,
Based on a recent experience with one of our student club turners, I need to ask and don't mean to offend. Are you using a roughing gouge or a bowl gouge?

More important than what you call it is using it properly. You have to cut across and shave down grain, not hack up.

 

[robo hippy]

Robert,
A couple of questions.

Are you turning a natural edge piece, or a standard bowl?

What are you attempting to do when you 'reposition' the bowl? Grain orientation/centering? Or?????

I remember watching a demonstrator take a crotch piece and reposition it maybe 6 or 7 times so the pith, on all 3 points would line up at the same height on the bowl. An ounce of prevention is worth a pound of cure. For that type of piece, I would first cut the ends square to a flat surface (bandsaw table), then get 3 plywood legs and drill a hole at the same height on each piece so I could then screw through into the pith of each end, and suspend the crotch piece (3 points makes a plane, grade school geometry). I would then take it to the drill press, use a forstner bit to drill a centered flat spot, then mount a face plate, or a drill far enough in so that I could expand chuck jaws into it, and then it will have all the piths lined up.

For standard bowls, you can be 99% accurate to lining up the grain if you are careful when cutting out your blank. Most of the time I never bother. I just cut the blank so I can get the biggest bowl with no defects. This means that my grain is seldom centered in the bowl. This fascination for perfectly centered grain is beyond me, as in too artsy. It never has aided or hindered me selling my bowls.

Turning between centers is not a secure rock solid grip. You have to be gentle. Face plates do work, but I almost never use them. Drill a recess, and expand into that. You can pivot the piece a little if your recess is 3/8 inch or so deep, but again that is not a really secure grip for heavy cutting.

robo hippy

 

[hockenbery]

Robert,
A couple of questions.


I remember watching a demonstrator take a crotch piece and reposition it maybe 6 or 7 times so the pith, on all 3 points would line up at the same height on the bowl. An ounce of prevention is worth a pound of cure. For that type of piece, I would first cut the ends square to a flat surface (bandsaw table), then get 3 plywood legs and drill a hole at the same height on each piece so I could then screw through into the pith of each end, and suspend the crotch piece (3 points makes a plane, grade school geometry).

robo hippy

I line up three points in two steps.
I prepare the blank by drilling an 1 1/4 hole with a Forstner through the bark for the the spur drive to seat in.
Cut the blank round on the bandsaw.

First position I put two points up and position them so they are parallel to the floor and perpendicular to the ways and bring the tailstock up.
Check by rotating the two points past a finger on the tool rest.
Second step is to hold the two lined up points so they are parallel to the floor and rotate the bowl up/down until all 3 points are in the same vertical plane.
Takes about 20 seconds after you have done two.
Then check with a thumb on the tool rest.and tighten the tailstock.

As long as the drive and tailstock center are in solid wood and tailstock locks in place,
Between centers is one of the best holds on a blank. I think the between center hold is superior to a chuck with a tenon or a chuck with a recess.
There is no chance of breaking wood to release the bowl.
Screw center or faceplate are stronger holds.

Al

 

[john lucas]

I turn all kinds of things and shapes so the wood may be really out of round and you can't really see the grain or know what you want to do with it. Once I start turning I can see more detail and then readjust the centers.
When I'm turning bowls it's really easy to be off just a hair and not get the grain centered so I often have to move the bowl just a hair to get it right. The same is true with Natural edge. I can get the two high point pretty darn accurate before I turn the lathe on but sometimes I need to shift it to get the low points looking better.
I'm like Al. I can't remember the last time I lost a piece between centers. So it may not be as safe as pin chucks or screw centers but perfectly safe enough for me.

 

[Robert Feingold]

Thanks for all of the great suggestions.
I am using a swept back bowl gouge.
I'm turning natural edge bowls and sometimes reposition the blank so the wings are at equal height.
I should make a better attempt to nibble away but my tendency is to want to remove wood faster. I'm sure I'm in good company there. I start out using the Ellsworth roughing cut. Tool paralel to the floor, 45 degree tool angle, tool rest 45 degree angle to the bedways. I don't really understand the suggestions about positioning my cut. Is what I'm doing different than you are suggesting?
Looks like the larger spur drive may help. More $$$. What about orienting a two spur drive so the spurs are inline with the grain so they dig in better? Currently the spurs chew away the wet wood.
Glen Lucas is inspirational. I saw him at totally turning in Saratoga Springs last year. The size of is tool bevel and lathe speed is truly frightening. I doubt I will try that anytime soon.
Thanks again.
Rob

 

[Gretch Flo]

uneven hi and low points of nat edge

The same is true with Natural edge. I can get the two high point pretty darn accurate before I turn the lathe on but sometimes I need to shift it to get the low points looking better.

I frankly like the asymmetry, especially with cherry burl. Looks more artsy!!! Gretch

 

[hockenbery]

Thanks for all of the great suggestions.
I am using a swept back bowl gouge.
I'm turning natural edge bowls and sometimes reposition the blank so the wings are at equal height.
I should make a better attempt to nibble away but my tendency is to want to remove wood faster. I'm sure I'm in good company there. I start out using the Ellsworth roughing cut. Tool paralel to the floor, 45 degree tool angle, tool rest 45 degree angle to the bedways. I don't really understand the suggestions about positioning my cut. Is what I'm doing different than you are suggesting?
Looks like the larger spur drive may help. More $$$. What about orienting a two spur drive so the spurs are inline with the grain so they dig in better? Currently the spurs chew away the wet wood.
Glen Lucas is inspirational. I saw him at totally turning in Saratoga Springs last year. The size of is tool bevel and lathe speed is truly frightening. I doubt I will try that anytime soon.
Thanks again.
Rob

Rob,
Spur drives bore holes
When the tailstock is not tight, poor quality wood, when the spurs are too short, and when you get catches.
Assuming you cutting technique is ok it must be the tailstock or a spur that has bad teeth.

Swept back gouge and Ellsworth roughing cut are great.
If you are not getting catches, I will assume the gouge is sharpened properly and you technique is ok.

The direction of cut
Start on the outer edge of the blank. cut enters the flat face of the blank and exits through the bark.
The first cut should make a 60 to 45 degree angle with the flat face that will eventually be the bottom
Take small cuts on the first 3 bowls.

I drive a 4 prong center into the wood with a wooden mallet. I line up the spurs at 45 to the grain so they bite evenly.
The tail center must be tight to start and kept tight,
After a few cuts I tighten the tail center. this is important because the vibration from the cuts drives the two centers into the wood further.
If you do not tighten the tailstock as you rough the center can get a little loose and begin drilling.


I prefer a four prong center because I am usually moving the wood in two axis to balance the blank.
I use a inch diameter spur for bowls and hollow forms to 14" diameter. I have 2" spur but never use it.

A couple of other thoughts.
1. Your spurs need bite in a 1/4 inch or more. if your spurs are too short you may need a new spur drive.
I sharpen my spurs about once a year.
The spur drive that came free with a Woodfast I bought in 1995 had such short spurs I threw it away.
2. a spur drive will not hold in pinky wood or bark I usually drill a 1 1/4 Forstner hole throuh the bark.
3. Make sure your tailstock is not creeping. Hold your thumb behind the tailstock as you tighten the hand wheel. If you feel the tailstock moving clamp the tailstock down more. You may need to tighten the clamping plate. Most have bolt through a plate with nut you cab tighten. It has to both slide freely and tighten in place.
Sometimes these plate get worn an need to be replaced or machined so they hold.
4. A big problem people have with interrupted cuts is letting the tool advance over the tool rest when it is cutting air. This make too big of. Bite on the next bit of wood.
Hold the tool close to your body, the front hand needs to hold the tool down on the tool rest and to allow the tool to push over the tool rest.

Go visit a local turner and haven show you.

Have fun,
Al

 

[MichaelMouse]

I frankly like the asymmetry, especially with cherry burl. Looks more artsy!!! Gretch

Some even go out of their way to make it so, but if you want even, there's no problem if you bore your pin or screw hole on the drillpress. http://i35.photobucket.com/albums/d160/GoodOnesGone/Bark-up.jpg You measure wings and shim to what's there and what you want. Of course, even if it isn't what you had in mind, most will find a buyer, in my experience.


With some exceptions. http://i35.photobucket.com/albums/d160/GoodOnesGone/Mistaken-Conception.jpg