The Maple blues!

[chrisdaniels]

The easiest and most abundant wood in my neck of the woods is by far maple. specifically hard maple and that's usually what I get calls for asking if I want a tree, which I never say no. I'm running into this situation where every time I try to get a piece of hard maple going on the lathe it fights me from beginning until it hits the floor and I stomp off like a child. No matter what I do it seems like it refuses to get into balance so I can get smooth finishing cuts. my tools like to bounce around like it's made out of diamond.

Is this just because of the hardness of hard maple? I have a 20' section of 2' diameter piece with the most amazing spalting i've seen and every piece that i've tried has been mind blowingly difficult and i'm not really understanding why. I am assuming it's because of my lack of skill but does anyone have experience with hard maple to alleviate some of the issues or do I just need more practice?

Also these pieces are reading >35% mc but are coming off in dry dusty chips and in no way acting like wet wood but like chipping rock with a chisel. I know my meter is accurate so what's going on? are the pieces too far gone to try and turn or am I just not thinking of something?

The 2 pictures are a 15"x6" bowl and a 8" x 6" pot cut just today.

Chris

 

[Richard Coers]

I guess you'll have to tell us what tools you use. I don't have any trouble with hard maple. I use a Thompson V bowl gouge both to cut and shear scrape. Used with the Johannes grind. You need a very, very light touch shear scrape to finish cut and limit chip out in punky wood. Nothing beats time with a mentor when you are having trouble. Cuts the learning curve by 75%. That one picture shows powder post beetle lines in the wood, be careful that you get rid of the chips quickly. Not fun getting those things in the shop!

 

[chrisdaniels]

For my bowl gouges I have
5/8 V and 3/8 V thompson - fingernail grinds
1/2" U thompson - standard grind
1/2" henry taylor kryo - fingernail grind
I have not ever been able to get a sheer scrape to work properly for me, don't really know why. I have tried to get ahold of the closest turning club which is a few hours away but haven't recieved anything back, Population is pretty scarce here so you guys that take the time to listen to my rambling are really my only teachers, and the dvd's I buy lol.

 

[hockenbery]

For my bowl gouges I have 5/8 V and 3/8 V thompson - fingernail grinds 1/2" U thompson - standard grind 1/2" henry taylor kryo - fingernail grind I have not ever been able to get a sheer scrape to work properly for me, don't really know why. I have tried to get ahold of the closest turning club which is a few hours away but haven't recieved anything back, Population is pretty scarce here so you guys that take the time to listen to my rambling are really my only teachers, and the dvd's I buy lol.

Hi Chris
The grind is important. Ellsworth or similar grind on the Henry Taylor will work.
The wing edge must have a continuos convex curve. A flat is still convex.

The grip is one hand holding the Ferrell or top of the handle and the thumb and fingers holding the gouge a few inches from the tip.
The flute faces the wood. The lower wing contacts the wood the upper wing almost touches the wood but does not.
The handle of the tool is low so that the scraping edge is about 45 degrees to the rotation of the wood.
This gives a good sipirface and some leveling of minor bumps Lots of stuff to do at once. The move the scrap,back and forth.
I do most of the scrapie in the foot to rim direction.

Around minute 31 I begin refining the surface, minute 34.5 i do a shear scrap
The NE crotch demo
http://www.youtube.com/watch?v=8jVoI12Kfug

You can pretty much shear scrape with any curved edge tool
I often do a little touch up shear scrape with my spindle gouge when I an turning the bottom.

Al

 

[Richard Coers]

Also curious what size chip you are getting for the final forming. You can take a really fine curl to also control chip out. Sharpen the gouge, relax your hands, take a breath, then make the finest curl you can possibly make. Go really slow as well. With a shear scrape, I get curls about as fine as my whiskers. You can come close with a very sharp gouge and really thin cuts. You might look at getting a John Jordan shear scrape tool. Practice on some hard maple that you won't mind throwing away. It should almost shine off the tool when sheared cut properly. Half dried wood can also cause issues. Full wet or full dry should have better cutting characteristics. One last tip for the shear scrape with a gouge, the handle has to be about as close to vertical as you can get. Higher angle, better shear!

 

[robo hippy]

I would consider what I can see okay for a beginner to intermediate turner. Of course it can be better, and for me I am still working on getting better. My first guess is the tools are not properly sharpened. If they are not sharp, then it doesn't make any difference what you do with them, you will not get a good cut. I always use a swept back scraper for my shear scraping, but I am a scraper psycho and do things with them that most others don't. I did find with gouges when using them, if there is a heavy burr from sharpening, then it needs to be honed off, otherwise it interferes with the cut. The lines/form of the bowl looks fairly smooth and no noticeable waves or dips, which means you are moving properly with the tool. Other than that, we need transporters so we can beam over for a play date.

robo hippy

 

[Bill Boehme]

Chris, are you having problems with other species of green wood as well? If you are fine with other wood, it is likely that your tools aren't sharp. If you are having issues with other species of wood as well then it might be your turning technique plus dull tools. On rare occasions you might encounter wood that has a high mineral content that is dulling your tools. If that is the case, you might be able to see sparkling in the wood when looking at it in bright sunlight and using a magnifying glass.

 

[dbonertz]

What lathe are you turning on and what chuck do you use?
Do you start between centers or do you use a screw chuck?
If screw chuck do you use tail stock for support?
Explain your process a bit if you will.

 

[Gretch Flo]

Chris-are you sure it is HARD maple?? The annular rings look wide apart. The more spalted the wood, the the harder at times to get a good finish as there is intermittent punkiness. On the first bowl to the right side, looks like a branch. With a spot of different densities, even when rounded, there is a tendency for one side (heaviest) of the blank to end up at the bottom when hand turned. Crotch figure is denser as well.With the powder beetles chewing away wood asynchronously the blank may be noticeably unbalanced. Gretch

 

[Odie]

If you are fine with other wood, it is likely that your tools aren't sharp. If you are having issues with other species of wood as well then it might be your turning technique plus dull tools.

My first guess is the tools are not properly sharpened. If they are not sharp, then it doesn't make any difference what you do with them, you will not get a good cut.

Sharp tools is the first thing that came to mind for me, as well.

Dry dusty chips, and 35% MC doesn't make much sense.......unless your tools aren't sharp. It does make sense if the tool isn't as sharp as it could be, and a lot of heat is created in the cut. It does take some amount of pressure, but if you "muscle" the tool through the cut.....that should be a "heads up".

I've had some wet wood blocks that dull tools quicker than other pieces. The species isn't necessarily the root cause, but individual pieces of wood from the same species can turn entirely differently.

If you start with a sharp tool, it can be too dull for a clean cut after a few minutes, or even seconds of use. The only solution to this, is to sharpen often......more often than you ever thought you would need to.

ko

 

[hockenbery]

Taking another look at the blanks
Is the wood near the bark punky where the spalting is?

Punky wood is hard to shear scrap.
It will usually cut cleaner than scrap.
Sanding has to be delicate too.

Shear scraping is to improve the surface. When I am working softer hardwoods and punky wood etc. I will try an extra light shear scrape in a small area to check the results. If it is making a poorer surface I don't shear scrap.

 

[chrisdaniels]

It is a little punky on those pieces on a couple of spots so I think that could be an issue. Also good point with the beetles. I turn on a Nova DVR Xp with a Nova SN2 chuck with 100mm jaws. I turn between centers mostly but I like using a faceplate or a screw chuck much more. I've never been able to get a good answer but how big of a piece can you safely turn with a screw chuck? I'm always afraid my piece is too big and going to break something.

on my big blanks I start between centers and use my 5/8 gouge to shape the outside then turn a tenon and put it in the SN2. I am pretty sure i'm not doing a few things right, not sharpening enough, white knuckline through and I don't know that the bench my lathe on is properly weighed down or not. It's a bench that I built and put a bunch of blanks underneath for weight. it shakes like a beast around 400-500 rpm's with a good sized piece on there. I was thinking about getting about 4 bags of quick-crete and putting them down there instead. The picture shows my setup, I work on my front porch so my shop is only 14'x5' so I can't get much better a picture sry. any suggestions are more than welcome! also I got the bowl cored out, the smallest bowl was fine, the second one was too thin and ripped the bottom out when I twisted it off and the "money bowl" cored out ok I would guess, the pictures are the bowls and the lathe.

 

[Bill Boehme]

It is a little punky on those pieces on a couple of spots so I think that could be an issue. Also good point with the beetles. I turn on a Nova DVR Xp with a Nova SN2 chuck with 100mm jaws. I turn between centers mostly but I like using a faceplate or a screw chuck much more. I've never been able to get a good answer but how big of a piece can you safely turn with a screw chuck? I'm always afraid my piece is too big and going to break something.

on my big blanks I start between centers and use my 5/8 gouge to shape the outside then turn a tenon and put it in the SN2. I am pretty sure i'm not doing a few things right, not sharpening enough, white knuckline through and I don't know that the bench my lathe on is properly weighed down or not. It's a bench that I built and put a bunch of blanks underneath for weight. it shakes like a beast around 400-500 rpm's with a good sized piece on there. I was thinking about getting about 4 bags of quick-crete and putting them down there instead. The picture shows my setup, I work on my front porch so my shop is only 14'x5' so I can't get much better a picture sry. any suggestions are more than welcome! also I got the bowl cored out, the smallest bowl was fine, the second one was too thin and ripped the bottom out when I twisted it off and the "money bowl" cored out ok I would guess, the pictures are the bowls and the lathe.

Adding weight is secondary to getting the blank balanced. I don't feel a need to add weight to my lathe ... even when I was using my old Delta boat-anchor lathe. After balancing half logs as heavy as 80 pounds between centers, I can run my lathe with no shaking. Start off by marking the approximate geometric center of the blank then mount it between centers ... most likely one end of the blank will be much heavier than the other which will cause the lathe to shake. If you have a spur drive in the headstock, back tailstock pressure enough that only the center point is in the wood. Even better, if you have an extra live center, put it in the headstock. Now, shift the blank around until it is balanced at any position. It shouldn't take too long to fine tune the piece so that it balances nearly perfectly. While you are doing this, try to keep the flat face of the half log as close to perpendicular to the spin axis as you can. I have a Oneway live center with the center point removed specifically for this purpose. If your blank has been flattened on both sides, pick one side to keep perpendicular to the spin axis. If turning a bowl, I often completely rough turn the outside before mounting it on a chuck to rough turn the inside.

When I discovered the benefits of balancing a blank between centers, I almost completely abandoned using a woodworm screw or faceplate. The trouble with mounting the blank on a screw or on a faceplate is that you are stuck with the piece being initially out of balance. On the other hand, when starting between centers plus starting with the blank being in balance, it makes everything so much easier to do. Once you get a face flattened as a minimum, you can then mount it on a faceplate or on a screw chuck. To insure that the hole for the screw is on the spin axis, it is a good idea to put a drill chuck in the tailstock and have something under the blank to support its weight. Otherwise, the hole will drift off axis. My preference is to just turn a tenon for a scroll chuck. That is so much easier than the other options that the only time I consider using a faceplate is when I need to hold a very long and heavy blank for a tall vase.

 

[dbonertz]

As you were describing it initially my first thought was the bench and chuck or may I say your setup may be part of the problem. I don't think you bench is beefy enough to be trying to rough turn an out of balance 15" x 6" or 8" deep blank. Also if you are using the chuck in the picture the jaws are a bit small for a 15" bowl. The cores are not to bad but the stress applied with coring may be paling a role in your coring success. The plywood you have on the top of your bench - Is the lathe bolted to it alone. If so consider adding 2 x 4 or 4 x 4 cross members where you bolt the lathe. Make sure they are securely fastened to the rest of the bench and then use as heavy (thick) lag bolts that will grab at least 1/2 way through the cross member. Or better yet use longs bolts that go all the way through the cross member. I would also in the back of the bench add support from the top on one side to the bottom of the other side. I would also do this on both ends. This will help stop and sway or twist in the bench. Then add your weight and use more than the blanks. It would make a good storage area so use your concrete bags and add a shelf above the bags to hold blanks and such. that shelf could almost touch the bags to save room.

The process that Bill explained is good but more time consuming than using a screw chuck. Nothing wrong with that method as a matter of fact if nothing else works it may be your only option to alleviate your issue. A screw in a chuck will handle very large bowls. I rough turn and core lots of bowls. I use the screw in a chuck exclusively in bowls from 12" to 20" by any where from 5" to 9" deep. Just make sure you use the tail stock for support at all times. The only time I don't is when I want to reduce the nub to the flush level of the tenon. However the blank at that point has been roughed turned to shape and the tenon has been formed to size only. I'll turn the speed down, slide the tail center back enough to access the nub remove it and then re - engage the tail center. I will then form the tenon and take a final pass on the blank if it looks out of balance from removing the tail center for nub removal. I do this in that order so the tenon is true and the blank is true for the coring or removing the interior waste wood. Anytime you remove the tail stock and re - engage it when rough turning the piece most likely will drop a very small amount but enough to put your piece out of balance again.

I think over all your process is sound it just looks like you need some fine tuning to relieve your issue. I don't think it is any one thing but a combination of small things that are causing your problem. The tenon should be about 1/3 the bowl size whether you are coring or turning the inside. On a 15" bowl the tenon should be at least 5" and the jaws your showing I think are more like 3". I am not familiar with the SN2 but 100mm jaws say 4" to me but I don't know in the SN2 if that means in full open or perfect circle size. You can core and turn the inside with smaller jaws but it introduces it's own set of small issues.

Sorry for the short story book but it looks to me that you have a combination of small things that need addressed.