Spur Center Problems

Hi, It seems like no matter what I do the spur center that came with my Rikon always ending up spinning in the end of the stock I'm turning. Am I doing something wrong or is it the spur center?

-TH

Reply to
thumphr
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Unless it is tearing up the end of the workpiece and spinning, it sounds like you have not seated it well enough. Take the center out of the headstock, put your workpeice, end up, on a hard surface, put the center against the wood and whack it a couple times with a soft mallet. The teeth should bite into the wood. Alternatively, saw a couple notches for the teeth to engage. WARNING: DO NOT DRIVE THE WOOD ONTO THE CENTER WHILE IT IS IN THE LATHE. SEVERE BEARING DAMAGE WILL RESULT. Also, do not hit the spur center with a steel hammer. Wooden or rubber mallet only.

Reply to
CW

Hi Along with setting the spur center as mentioned, Sometimes I find if you bring the tailstock up and tighten up very tight this causes resistances on your wooden piece so the headstock trys to turn against this resistance and evenually will spin in the wood. You can buy a live center for the tailsock or put a brass washer over the tailsock center before tightening it in.

Reply to
Moray

Hi T H

First off your spur centre should be sharp, if it isn't, file the sloping side so it is. As was said before, you can drive the spur in with a mallet, however you could start a split that way, so be careful, a better way might be a couple of saw cuts so your spur centre fits in it, and can have a good bite. Keep your tailstock centre so the wood is not loose, not a lot of pressure, but not loose either, and check this often. Last but not least, don't take big cuts, and make sure your gouge is sharp (SHARP sharp) :-)))

Have fun and take care Leo Van Der Loo

Reply to
l.vanderloo

Four-fanged centers want an X (only @90 degrees) on the end to seat the sides of the fangs against. As a lazy man, I prefer a two-fanged center which allows me to make a single cut. No worries about getting close enough to 90 to seat the others, no risk of splitting as you tap. The sharp center engages first, and maintains your mark, while the blunt - don't bother sharpening - fangs snug up to the sides of the saw kerf without risk of splitting. Remember, that's why they blunt the ends of nails rather than sharpening them - so they are less likely to split the wood.

Then you'll want to snug the tail up, not mash it, which can lead to flexing of the workpiece. Don't assume that doing it once is enough! When you stop the lathe to check turning progress, see if your fangs are still firm in their groove(s). if not, snug the tail up again, then back off a quarter turn.

So much for drive centers. Your problem could actually be at the other end. Pointed centers can wedge their way sideways as you turn and enlarge the hole enough to make the fit sloppy, allowing the sharp point to dig in farther, and thus loosening the other end. Cup centers make this much less likely, as well as preventing splits by riding the depressed ring you made when you tapped them in. Use the wooden mallet you turned as a project to do this, as others have mentioned.

Reply to
George

It's always hard to know what someone is doing from a usenet post, but I know I sometimes have this problem on green wood.

Most often, it's a direct result of one of two things- the first is that there is punky wood in the center, and the second is that I didn't strip off the bark (I rarely do) and put the drive center into the bark side instead of the cut side.

If you flip the work around in the second case, it usually reduces the chances of the center slipping. If it *does* slip, I've found that it is worthwhile to stop, remove the piece and clean the packed chips out of the drive center- a lot of times, they'll be stuck in there very tightly, and no amount of hammering or cinching the tailstock down will re-engage your spurs.

Reply to
Prometheus

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