latest piece

[badgaz]

Howdy folks
Here's my 4th attempt at turning. I completed it whilst that horse race was on.
Jarrah handle for pen mill.

I'm surprised at how easy a hardwood like jarrah was to turn. Finished in turps and linseed oil.

Can anyone explain the best way of driving a drive centre into hardwoods like jarrah.
I can see after time and a few good belts with a mallet the end will start to mushroom.
To achieve a deeper purchase into the wood I marked the end with the 4 prong drive centre and deepend the grooves with a screw driver, this gave me about 1/8" bite into the wood.
Is there a better way or an alternative drive centre for hardwoods?

[Manuka Jock]

Gaz,
my experience with drive centers and hardwoods leads me to think that there must be some that are made for the job .
The conventional 4 spurs ones are ok for softer timbers , but I have had hard dry stuff start to split when tapping them in , so I too await the incoming info :)

[Robomanic]

I can't really offer a technique, more a purchase. I made a steb-center type drive in high school, and use it for everything. They are great for hardwood because the center cone pushes back on a spring, and on softwood they don't drift off to the side following the soft growth rings. Carba-tec and others have them.

http://www.carbatec.com.au/woodturning-tools/drive-spurs-live-centres/carba-tec-drive-centres/carba-tec-steb-style-drive-centre

A couple of drawbacks;
- They don't cope with blanks that don't have square faced ends because the whole ring can't engage and could lever itself of the spring loaded cone

- The spring can place excessive pressure on thin pieces - at this point I am probably using a jacobs chuck or scroll chuck.

[orraloon]

To get a purchase for the drive center saw a cross (x) in the end of the blank then tap the center in with a rubber mallet.

[badgaz]

Robomanic
I've had my sights on a steb-centre because of is reputation to hold the piece. It follows to have variety of centres for different jobs...off to CT again.

orraloon
Excellent tip. So simple!:2tsup:
I had a saw in my hand whilst trying to figure it out too. I was ready to cut the waste off and start again, then put it down and grabbed a screw driver.Typically, the answer was staring me in the face the whole time.

Cheers
Gazza

[TTIT]

Robomanic
I've had my sights on a steb-centre because of is reputation to hold the piece. It follows to have variety of centres for different jobs...off to CT again......Wouldn't be in too big a hurry - I've got one you can have real cheap! They make a better hole-saw than they do a drive-centre - IMHO . . . . . . . . . . . . . back to my cupboard now :B

[Robomanic]

Wouldn't be in too big a hurry - I've got one you can have real cheap! They make a better hole-saw than they do a drive-centre - IMHO . . . . . . . . . . . . . back to my cupboard now :B

At the risk of hijacking the thread - what don't you like about it TTIT?

[powderpost]

Vern, try this. Bore a small hole to accommodate the spur centre. Drive the spur centre into the wood with a soft mallet (brass, nylon or make a wooden mallet). Check the edges of the spur "cutters". If they are blunt, sharpen them on the grinder. A new spur drive seldom has sharp edges.
Jim

[TTIT]

At the risk of hijacking the thread - what don't you like about it TTIT?It might just be that I'm too greedy or something but I find that no matter how I set it up it always starts slipping when I'm roughing down and all those sharp little teeth start boring a hole :~. So many short teeth just don't seem to dig in far enough (for me) :shrug:


Vern, try this. Bore a small hole to accommodate the spur centre. Drive the spur centre into the wood with a soft mallet (brass, nylon or make a wooden mallet). Check the edges of the spur "cutters". If they are blunt, sharpen them on the grinder. A new spur drive seldom has sharp edges.
JimNot a normal spur Jim - the Steb-centre teeth are sharp short and many and the centre is spring loaded.

[hughie]

Not a normal spur Jim - the Steb-centre teeth are sharp short and many and the centre is spring loaded.

dont like em either......

[Robomanic]

The teeth on mine (custom) would be at a diameter of 20mm, which I think is about the same. My teeth are at a finer pitch so there are more of them, but maybe the difference is in their sharper angle allowing them to bed in better and their faces are closer to 90*? I was glad when I didn't have to bother with the saw but it does work well, and you get a good lead in for the center cone where they cross if the cuts are the right depth.

[Manuka Jock]

My experience is that the spurs will bed themselves in firmly to the northern hemisphere woods ,
but with the Australasian hardwoods , they chatter and chew out under stress .

[powderpost]

Yep, I had a steb centre and disposed of it a long time ago. My comments were directed at the traditional four "cutter" spur drive.
Jim