wood chunking off at tip occasionally-any thoughts

[Nickfff]

Hello,
Occasionally, I am getting some wood chunking off at the tip on the lathe while spinning. I am trying to figure out why this occurs. It happens to the wood at the end farthest from the lathe motor. I was trying to deduce if it is a result of too little glue on tube(I use med ca), mandrel travel etc. I have the mandrel barely snug-not extremely tight...Any thoughts on why this occurs/how to avoid?

Thanks in advance for replies,
Nick

 

[palmermethod]

I had the same problem on one of my first pens. Not enough glue. Maybe the hole was too loose, don't recall. I took Gerry's advice and use two part epoxy. Not quite as fast to set but works better. Good Luck Nick

 

[Rifleman1776]

Without watching your technique only guesses are possible. It is probably with your technique. What tool are you using there? A gouge would not be my choice, try a skew if you aren't. What kind of materials? (burls are notorious for wanting to fly apart) The glue thing is a possibility, are you sanding your tubes before gluing? Can you send a picture of one of your failures?

 

[Blind_Squirrel]

Possible causes:

- Not enough glue in that area
- Using dull tool(s)
- Too aggressive/using too much pressure with the tool
- Tool catch
- Type of wood or direction wood has been cut (cross cut wood is MUCH harder to turn IMO)

 

[mdburn_em]

If you are using medium CA to glue your tubes in, that's not thick enough. You need thick and lots of it. Better yet use GG or the like.

Other then that, I second Blind_Squirrels thoughts, especially the dull tool part. Dull tool means applying too much pressure

 

[Nickfff]

Rifleman1776 here are the answers to your questions...

1) Gouge then skew
2) mainly burl wood
3) I sand tubes before gluing

I sharpen my tools before each pen and often midstream on a pen.

Nick

 

[Rifleman1776]

Originally posted by Nickfff

Rifleman1776 here are the answers to your questions...

1) Gouge then skew
2) mainly burl wood
3) I sand tubes before gluing

I sharpen my tools before each pen and often midstream on a pen.

Nick

Could just be the burls. I have a stack on my bench that are going off for stabilizing before turning. Burls are often just looking for an excuse to fly apart. I would rather see a fine burl on a pen than in pieces on the floor.

 

[ed4copies]

This will help:

After facing your blank, apply thin CA to the faced area, let seep in, apply more if it seeps quickly.

ALLOW TO DRY OVERNIGHT!!!

May NOT solve the problem, but it WILL help solve it.

 

[gerryr]

What Ed said will definitely help, just make sure you don't get CA inside the tubes. I would also highly recommend that you learn to use a skew, at least 3/4" or even bigger. Get a copy of Alan Lacer's video. He does some amazing work with a 1-1/4" skew. It isn't really that hard, it just takes some practice.

 

[RonInSpringTX]

everyone above has a great point. I've done some burls,(not as many as most of y'all, I'm sure,)but what I've noticed is the burls (done both stablized and non) had blowouts on both. Some of it was from not having a sharp enough skew and scraping, instead actually "peeling" it (am I saying that right?) you always scrape down to the bushing, or leave it "proud" and sand it, sand it, sand it. I've found leaving it proud & sanding it ALWAYS works, but still adding some CA near the tip. Putting a good amount of CA on tube & turning it into blank has been successful for me.

 

[RMB]

One thing I find works most of the time for me is to turn down the ends of my blanks first. Once I have a cylinder, I use a skew's heel, sometimes a gouge, and turn the ends down at about 45degrees until just above the bushings, then continue with the center. I think this works because most splits and chips for me occur at the very ends of a blank, usually when the grain runs at an angle, turning at a higher angle than the grain rather than straight across allows more support to the little end bits. I almost never get ends splitting out with this method, but I still have plenty of other ways to mess up a pen[}]. Don't know if that makes sense, but I could diagram it quickly for anybody interested.

 

[ChrisCurtis]

Another thing to check is to make sure your lathe speed is high enough. I learned the hard way recently after turning a bowl and using low speed to do some sanding and prep for storage/stabilization. I turned two pens next and forgot to bump up the speed - one PurpleHeart and one Zebra Wood and both got those little chip outs at one or two of the ends and my tools chattered throughout the entire turning process. It drove me nuts - I thought maybe there was a knot or something I was hitting or my mandrel was bent. Once I moved it up to about 1500 all was well again.

 

[GaryMadore]

I had this happen to me regularly until I discovered that I was cranking the nut on the mandrel down too tight: The end of the wood was splitting [B)]

Cheers!

Gary

 

[MichaelS]

Ryan has it. Mount and sand the tubs, glue them in the blanks with medium or thick, then always-always-always, on burls, turn the ends down first. With grain turns every 128th or less they are waiting to shatter. Also with burls follow Franks advice and sharpen. I turn almost only burls. Always use a light touch and high speed.
Mike

 

[MichaelS]

I also have to add, turn the ends down fully before you round the center of the blank. Less pressure on a unsupported end grain. Always turn the ends before you round the center. I covered my shop garden with expensive mulch before I got it!