Run away core...

[Fred Belknap]

I was coring a NE ash bowl this afternoon and the core came out unexpectedly and hit me right on the breastbone. Almost knocked me down. It was about 10” core. I am still kind of new at using the McNaughton tool and coring NE pieces aren’t the easiest. No real harm just a little sore, just enough to remind me to slow the lathe down when I get near the center. It could of done some real damage.:eek:

[Bob Bergstrom]

After taking half a hard maple blank in the sternum ( 3 weeks with a bruised sternum) I know use a foam stadium cushion under my coveralls. I also have a soccer shin guard on my left forearm.

[Josh Bowman]

Fred, I also have the McNaughton, where were you standing??? I to am kind of new with it and will insure I don't stand there!!!;)

[Fred Belknap]

Fred, I also have the McNaughton, where were you standing??? I to am kind of new with it and will insure I don't stand there!!!;)

Josh I was standing about the only place you can and still hold the handle. I had just moved the toolrest closer to the blank as I had run out of blade. It might not have been aligned perfectly when I turned it back on and it was in deeper than I thought it was. It broke out about 1" of center. I have had the centers to get loose but this was the first one that attacked me.

[Josh Bowman]

Ouch! I'm glad your ok. I was just curious, I try to stand at the end of the lathe and avoid getting too much to the side of the piece. But when it's spinning like that, no telling where it might go!


Josh I was standing about the only place you can and still hold the handle. I had just moved the toolrest closer to the blank as I had run out of blade. It might not have been aligned perfectly when I turned it back on and it was in deeper than I thought it was. It broke out about 1" of center. I have had the centers to get loose but this was the first one that attacked me.

[Reed Gray]

When I know I am getting close, I turn the speed down. Just habit. You can feel it cutting differently as you are going more into end grain rather than down through it. Most of the time if it comes out all by itself, it will just spin inside the bowl. I don't think I ever go above 1000 rpm on smaller pieces, more like around 600 to 800, but I don't have a read out. Glad you survived without too much damage. When getting close, I will stop and push on the core to see if it is wiggling. At about 1 inch, it does wiggle a bit, and I generally break it out.

robo hippy

[Harry Robinette]

I've had one come out,it hit the tool then landed between my left arm and my chest. I try to stay around 600 rpm but NEVER over 700rpm.

[Dale Bonertz]

When you say not aligned properly I am assuming in height. That is why I suggest using a stop collar on the tool post. It will keep the alignment where you need it. Glad you're OK and as others have said slow it down towards the end. On the pulley that I use when coring it goes to 823 rpms but I usually only core around 750.

Dale Bonertz

[Faust M. Ruggiero]

I've never used a McNaughton coring tool because my system is a Oneway. When I core bowls with the Oneway. I stick a 6" Morse taper extension in the tail stock so the core can't escape unexpectedly. Will that technique work with the McNaughton?
faust

[Fred Belknap]

When you say not aligned properly I am assuming in height.

Dale the curved part of the blade was all the way through the tool rest so I had to move the tool rest closer to the blank. I was turning about 550rpm. Here is a picture of the type of blank I was coring
270808

[Dale Bonertz]

Nice looking bowl. If your alignment (misalignment) was do to moving the turret in the best way to ensure it stays in alignment is to insert the tool all the way into the kerf (while still in the turret). Then move the turret in and this will ensure it stays aligned. The speed maybe was a bit fast once down that far but not to bad IMHO. I start around 750 and go down from there. Often times I am finishing around 200 rpms. It is tough to save the bark sometimes when coring natural edge like you are. Do you use the straight blade to get in a bit prior to going to the curved blade? I find it interesting you were hit in the chest. I have had many bowls pop out and everyone of them fell off to the right side of the lathe and down into the pile of chips on that side. I am glad you are OK those incidents can be a bit frightening.

[Bob Hamilton]

I have always tried to stop before the core comes free and break out the last little bit, but sometimes it comes out unexpectedly. So far any that have come out have gone behind the lathe, not forward. I was actually just doing a core this morning and it finally clicked in that when I had the knife deep in the cut there was nothing in the way of bringing the tailstock up to support the core. I tried it and it worked great. When the core came free it just stopped turning and the tailstock kept it from coming out.

Take care
Bob

[Fred Belknap]

Thanks for all the great reply's. I think using the tailstock to control the final cutting is the way I will go and slowing down the lathe a bit when doing the last couple inches. I may spring for the larger set of cutting tools. I took a good hit and was pretty sore last night but this morning am feeling much better. I had a face shield on but if that large a piece had hit me in the face I doubt if it would of helped much.

[Dale Miner]

Coring a natural edge with a McNaughton is a rather dangerous proposition. Pulling the knife from the kerf to clear shavings, and then reinserting into the interupted cut has a high danger factor. A small inaccuracy in one's aim can cause a huge catch. The tool rest/turret should never be moved with the lathe running using the McNaughton, wheter natural edge or conventional blank. Stop the lathe, insert the knive well into the kerf, readjust the tool rest/turret, make sure the knife does not bind by inserting removing a couple of times and spinning the lathe by hand, insert the knife partway, and then restart the lathe. Moving the tool rest/turret with the lathe running can easily cause a bind and disaster.

The only times I cut a core completely to center with a coring system is on end grain blanks, burl blanks, and cross grain blanks with heavy figure. Typical blanks are cored to about a 1" to 1.5" diameter spot, and then a bump with a fist or mallet will crack the core loose. The speed of the lathe is slowed down when the knife gets near the end of the cut just in case of an error on my part (and is does happen once in a while). If the core does break out with the lathe spinning at a slow speed, it just falls off the bed onto the backside of the lathe.

[Reed Gray]

It is just about impossible to use the tailstock when coring with the McNaughton, unless you are using the flat curve blades. Having the laser set up on it really helps when learning, so you do know exactly where you are. The blade curves are not always a true arc of a circle, which can make the blade bind a bit. This can actually break the core off as you get really near the end of the core, and pop it out a bit. One of those things I learned, but don't think about because I am used to it. Having a stop collar is really big as the vibration during coring can lower your tool rest. I cut a hole down some end grain wood, and wrapped it in nylon string and chased that with CA glue. I have it set so the blade is maybe 1/4 inch above center. If you have it exactly on center, you will be below center when you get near the end of the core due to the down pressure from the cutter when under load. Try removing the nub left when the core pops off to see what I mean. You don't want scrapers below center at any time with turning bowls. Alternative would be to raise the tool rest in stages as you get closer to the center.

robo hippy