Avoiding cracks in spindles from a tad much tailstock pressure...

[Skew ChiDAMN!!]

I'm sure it's a problem we've all had at some time or another; turning a very thin spindle (or perhaps it's a brittle timber) and tightening the tailstock that wee tad too far and.... CRACK!

Normally, if I suspect there's a likelihood of this when turning knitting needles, lace bobbins and the ilk, I'll wrap the end with wire. For larger spindles I'll use hose clamps. Today, when turning some brittle cedar at work, I didn't have access to any of this type of kit. Sadly, I ruined a couple of blank... any more than the lightest pressure from the tailsock and the stuff splintered horribly, don't apply the pressure and the blank'd fly over my shoulder at the first touch of the tool. :sigh:

Then I decided to mark the centre & drill a small hole to drive a short (1/2") posidrive screw in, giving the tail spur something to register into without wedging the grain apart.

Waddya know? It worked! :hpydans2:

I have no problem seeing myself doing this again at need, instead of the wire wrap/hose clamp method.

[Christos]

Thanks for sharing this idea. Something to keep in mind.

[powderpost]

That is the very reason I use a revolving cup centre, instead a cone.

Jim

[Mobyturns]

Ive been using the predrilled hole centre for a long while. Works well with a small custon live center.

[Beedeejay]

It depends on the size of the item being turned but i prefer to use steb centres now for spindle turning, i find i get a good bite into any timber i have tried with them..
cheers Ben

[JDarvall]

I've noticed a screw drive with a pilot hole works only really with a dense timber… If its soft the screw tends to rip the thread out of the wood.

The most reliable method with a regular drive, if its workable with what your doing, is to just have buffers at the drive or tail if your worried, that you cut off latter.

I think we are talking about the same thing.

Just an opinion. Not an expert at being on the same wavelength. 2 cents worth.

[KBs PensNmore]

At our local wood turners meeting a few months back we were shown how to make a TREMBLER which can be a goblet with a base but the stem is about 2mm thick and what ever length 300+. The secret was to make some steadies with 3 screws on each equal distance around, using waxed string, it was wrapped around so that the string supported the thin spindle. Should be something on Google about turning tremblers, I think they got that name from your hands trembling that you're going to stuff it up!:D
Kryn

[Skew ChiDAMN!!]

That is the very reason I use a revolving cup centre, instead a cone.

For large spindles I use cups, but mine are all hollowed in the centre for drilling though the tailstock. Not ideal for holding smaller pieces. :wink: One day I'll buy/make something suitable, but until then...


I've noticed a screw drive with a pilot hole works only really with a dense timber… If its soft the screw tends to rip the thread out of the wood.

The most reliable method with a regular drive, if its workable with what your doing, is to just have buffers at the drive or tail if your worried, that you cut off latter.

I think we are talking about the same thing.

Yes, I think you know what I'm talking about. But I'm using the screw on the tailstock end, not on the drive end. (I use pin-jaws on the chuck to drive it, to avoid this whole problem) The thread doesn't need to "bite" into the wood... it can be only a press fit into the hole, as the tailstock will hold it there. Just so long as the screw doesn't wobble around in the hole.

My problem with these particular blanks was the cedar had long, straight grain and once it cracked it split down the whole length, like splitting it with a hatchet. So leaving waste on the ends just gave it more timber to throw in the bin when it all went tits up.


At our local wood turners meeting a few months back we were shown how to make a TREMBLER which can be a goblet with a base but the stem is about 2mm thick and what ever length 300+. The secret was to make some steadies with 3 screws on each equal distance around, using waxed string, it was wrapped around so that the string supported the thin spindle. Should be something on Google about turning tremblers, I think they got that name from your hands trembling that you're going to stuff it up!:D
Kryn

:yes: I've tried my hand at a couple of trembleurs in the past. Not that any were what I'd call successful, (ie. survived long enough to be called finished! :rolleyes:) as timber selection is very, very important there - you need long, straight grain - and I tend to use scraps and construction offcuts that do NOT meet that requirement when I play around. :- Still, they are definitely fun to make and one day I'll attempt one in a more serious manner.

I've also made several string steadies to go with my wheeled centre steadies, but they're only really useful when you have long blanks. For a blank that's only, say, 200cm long then a steady becomes more hassle than help. IMO, anyway.

[JDarvall]

Yes, I think you know what I'm talking about. But I'm using the screw on the tailstock end, not on the drive end. (I use pin-jaws on the chuck to drive it, to avoid this whole problem) The thread doesn't need to "bite" into the wood... it can be only a press fit into the hole, as the tailstock will hold it there. Just so long as the screw doesn't wobble around in the hole.

My problem with these particular blanks was the cedar had long, straight grain and once it cracked it split down the whole length, like splitting it with a hatchet. So leaving waste on the ends just gave it more timber to throw in the bin when it all went tits up.



I get what your saying…. I do think though its still worth a go. A long enough buffer thats not sized down (still at its thick roughing in diameter) say about 20mm long right on the tail shouldn't split in my opinion, even though its soft. I do that with jacaranda for stretchers in my stools all the time. And its as soft as cedar and no splits. With the jacaranda stretchers, right on the tail, I have a buffer only about 10mm long thats around 20mm diameter before reduced to 8mm diameter for about 25mm (the 8mm is kept as part of a counterbore joint). After I'm done I just cut off the 10mm buffer at the change in diameter with a japanese saw.

suppose it depends on other factors you'd be more aware of than me in your particular situation. Like overall length etc. Or maybe your cedar splits more than I realise.

just an opinion. Not an expert on buffers. 2 cents worth.

Just thought of another way, but probably not practical for what your doing. Buy a say 5/16" verities power tenon cutter. uno those bits you stick in cordless drill. Ruff by eye a 5/16" diameter on the end….then stick that 5/16" diameter into a hollow cup live centre. Never split. I do that sometimes.