Ribs, rubs and things falling off

[Mike Minto]

Sometimes when I'm turning a spindle, my tool will bounce some over the surface I'm working. Upon turning off the lathe, I find I have ribs, or spiral raised marks along the work. What causes this? I'm thinking the surface of my gouge might be round instead of flat, is that possibly the cause? Also, I wonder if I don't have a bad batch of epoxy - do you all ever have trouble with your glue blocks coming off your forms? Seems to happen to me about 25% of the time, which is very disconcerting. I can usually tell when it's about to happen, as I hear and feel a low, rapid vibration - but not always.

[Tim Rinehart]

I think...yes, that's dangerous, that the ribbing results from a combination of a tool that needs to be sharper and pushing too hard. I can at least confirm that this happens when I get lazy about sharpening my tools and try to overcome by brute force so to speak.

I don't use glue blocks much, but if you've got good flat surfaces, and using CA...if the super thick variety, it may not get enough penetration to help bond. Again, I'm not best on this, but perhaps a description of what you're doing will help too.

[John Hart]

It's the same reason as pot hole or ripple progression in a dirt road. Bounce.

I would suspect flex in the spindle..combined with pushing too hard or a sharpness issue too.

Sharp tools, light touch..and maybe a steady rest?

[Steve Schlumpf]

I agree - less pressure when rubbing the bevel, lighter cuts and sharp tools.

[Mark Hubl]

I think JH put it pretty well. Combo of these. How long was the spindle? And what was the diameter? I would suspect the epoxy if it is old, but I would also question what are the two woods being glued together. Was one of them an "oily" wood. I have just used titebond for blocks. I am too lazy and cheap to use epoxy on them.

[Mike Minto]

I've had the 'ridges' appear in the middle, as well as near the headstock, so don't know about that making a difference. Bounce and bad profile on the grind, perhaps. No oily woods, just domestic hards. Fairly new epoxy, too. Think I'll go back to tightbond and quit being in a hurry about it. I have had better luck with CA than epoxy, too. Thanks.

[Cathy Schaewe]

I have experienced this several times, in two vastly differing situations. Sometimes when cutting green wood thin, out toward the edge. I've attributed this(whether correctly or not) to the wood flexing. The second situation is when the wood is dry and really, really hard, and I've figured that's the tool (dull perhaps) bouncing off the hard wood. Sometimes sharpening helps, sometimes not. :(

FWIW.

[Neil Strong]

I would suspect flex in the spindle..combined with pushing too hard or a sharpness issue too.



Ditto

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[Jake Helmboldt]

Ditto

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Ditto, Ditto

I find when that happens I'm either pushing too hard and/or not sharp enough. As Richard Raffan says, let the wood come onto the tool. I find if I ease up and sharpen I'll get a nice clean cut. With the ribs/ridges the more I try to get rid of them, the worse they get (self perpetuating), until I ease off the cut.