Parting off - having difficulty

[Evanism]

Hi all.

After a bit of an absence from the forum and turning, I'm back into it. The poor lathe gathered dust for 5 months while I worked on some commissions and illness.....

Annnnyway, I've done heaps of turning in the past, but one skill that has eluded me is getting a clean parting off for both ends on spindle work.

I was hoping somebody could point me to a good resource in order to learn to do it properly.

Many thanks in advance.

(damn I love turning. Did it all day today and it's wonderful)

[Paul39]

Starting on the tail stock side, I use a diamond shaped parting tool, freshly sharpened and resharpened when it slows from freely cutting. I go straight in a bit then go about half the width of the tool into the waste stock to widen the kerf then back and forth to enough to keep it in the lathe while I part the Head stock side.

Again with a freshly sharpened tool I do the head stock side as thin as I dare.

I then turn off the lathe and cut through the last nubs on each side with a metal cutting hack saw with a new blade used only for this purpose, (makes a smooth cut), and sand them to taste.

For a very thin kerf I made a parting tool from a 50 cent bread knife, grinding the sharp edge off and grinding the tip at about an 80 degree slant.

Photo below shows carbon steel diamond shaped, screwdriver that I used before I had any proper lathe tools, and bread knife.

The bread knife is not good for going very deep as it wiggles around. Up to about 25mm it slices in and makes a clean cut.

I have since acquired a nicer looking HSS diamond parting tool with a used set at auction. It cuts no better than any of the three in the photo in the cherry, walnut, and maple I normally turn.

With your thinly disguised concrete timbers in AU, they may not do as well.

The secret is practice, practice, practice. When I was having skew troubles, some advice from here and 25 hours in front of the lathe got me to the point where I make spindles for entertainment. I also have 50 to 75 nice tool handles. A hardware store will take some on consignment.

[pommyphil]

Taking 1mm off with the long point of the Skew should give you a polished finish on endgrain. Welcome back Phil.

[Mobyturns]

Pretty hard to part of both ends cleanly :wink:.

I've done a couple of long spindles that required drilling / turning on both ends of each piece - jointed flag staffs actually, where I used a bit of bush ingenuity to come up with a solution.

[chuck1]

When designing item add 10 to 15mm on each end to allow waste for clean up. If there is enough timber.
on newel posts with a ball I usually turn it down to about 10mm with the skew.. Then Saw the waste bit off and air orbital sand and hand sand.
be aware starting and stopping lathe with such a small diameter can twist and snap end off. .so you need to be sure all Turning and sanding is complete before reducing ends

[BobL]

This is probably complete heresy to hard core turners but here's what I do with small, short spindle work.
I put one end of the work into a chuck that has long nosed rawhide leather lined jaws and part the tailstock end of the piece - then sand and pre-polish in place
Then I turn the piece over and do the other end.
The grip afforded by the rawhide leather is impressive and is thick enough to cope with some taper on a piece the size of a chisel handle.
If the end of the piece is stepped I wrap leather strips around the recessed area to build up enough area for the jaws to hold firmly.

BTW that's not a clean part shown as the saw marks on the end of the piece are still visible :-)

http://www.woodworkforums.com/attachment.php?attachmentid=360429&stc=1

[Drillit]

Hello Evanism,
Good to see you back. If using long point of skew make sure it is sharp and that you rub the bevel against the piece, lifting handle as you go to effectively cut in an arc. If
using parting tool, you can drop the handle, rub the level, lift and push or go in horizontal again with a sharp tool. I have found that using a thin parting tool at relatively high speed seems to get
the best finish, putting to one side that some wood seems to tear more than others (e.g pine). Hope that helps. Drillit.

[Evanism]

BobL, we commit the same heresy, this is exactly as I do. :) The little nubs are then sanded off very quickly.

has been here a few times and I saw him use the skew... He just slid it down and it popped right off. I've never been able to repeat it. His result was polished smooth, as if cut by a laser, but mine has lines (and on pine) tiny tears.

Obviously my skews and chisels are sharp. This goes without saying. It's clearly a matter of technique to use the point or such, which I try, but I'd swear he used the middle of the skew.

Thanks to everyone's input. Last night I reviewed a few youtubes, but they all do the same as what I/we do, which is reduce the diameter slowly... But to get a clean cut, one must cut and polish... Almost like making a bead that reduces to zero!

[Evanism]

Forgot to mention, I'm turning between two centres. I think I'll turn one end round, then remount it in a chuck instead. This will let me get the bigger end smooth. :)

Off I go! Wish me luck!

[Skew ChiDAMN!!]

Just what sort of troubles are you having?

Heavy tear-out? This is usually caused by parting with a plunge-type tool (such as your stereotypical diamond parting tool, a square scraper or even a modified knife) in timbers that just don't like that.

A skew is ideal for these timbers, as it slices the grain rather than just scraping it out... but it does take a lot of practice to get it right.

I usually part with a 5mm square negative rake scraper or a modified carpet knife for thin kerfs but I 've also made a "compromise" parting tool for those timbers that just won't part cleanly without tearout.

It's basically an old screwdriver shaft that has been ground to a double-sided chisel point at one end. Then I used a chainsaw file to cut a cove in one of the bevels, so that the cutting edge has horns, rather like a beading tool. When sharpening, I simply touch up the flat bevel on the grinder. After a few sharpens, the 'horns' no longer become points and it needs a touch-up on t'other side with the chainsaw file to restore them.

In use, it's used as an ordinary plunge tool - it doesn't matter which way up - and the horns/points act as scribes (or mini-skews, if you prefer) to cut the fibres on each side of the cut just before the rest of the tool scrapes out the rest of the grain.

A skew is better, this requires less skill to use. ;)