What am I doing wrong

[Daven]

Turned a bowl yesterday in Oak (first one for many years) but I couldn't stop getting some tear out on the grain ends - is it a case of better sharpening of the tools (was getting some shavings so thought they were fair) or is it the wood, speed (was slow as it was about 10") or just bad technique?

I used a gouge and then a scraper to finish - some of the dinks came out during sanding but could have been better!

Cheers

Dave

 

[Bodrighy]

IME oak is not the easiest wood to turn. You need really sharp tools and a gentle touch. Most of the oak I have used has been from old furniture so as dry as a bone, don't know if this applies to wet wood.

Pete

 

[user 5053]

Yes, its down to correctly sharpened tools and a good smooth positive technique that only really comes with practice.

 

[Argee]

As has been said, sharpness of the tools is paramount. If you're getting tear-out on the endgrain, what this shows is that, although the tool will cut with the grain, it won't cut across it - therefore, most likely it's not sharp enough.

You can expect the endgrain to be more difficult to cut cleanly, but a slow speed won't help either. Run the lathe as fast as you're comfortable with, once you've got the bowl into balance and are sure of its mounting.

Ray.

 

[Scrums]

Yup I'd agree with what's been said - Oak isn't very good for bowls, OK for spindle work when necessary. In my experience you never get 'twirls' of spiral shavings coming off Oak - just flakes and even when finished well it still has a slightly pitted and porous look.

As for speed - fastest you can go once you get the blank into balance.

Tool edges as always need to be sharp, don't get too hung up on the type /style of grind or the angle though, you'll find that by adjusting your presentation of the tool to the work you'll be able to pick up a cut and follow it down the bowl.

Chris.

 

[Daven]

Many thanks all - will keep practicing my sharpening then :wink:

The Oak was given to me as 3 round blanks of different sizes so I can keep trying (I like jumping in at the deep end!)

Regards

Dave

 

[CHJ]

Dave, try moistening the end grain area with finishing oil or water before and during the last few cuts, see if this reduces the tear.

You can also try sanding sealer just before the last fine cut.

Tear effects can be very deep and a poor cut early on can reflect down 5-6mm deep.

Sharp tools as everyone says are a must though, try and angle your cutting edge so that it is shearing across the lie of the grain instead of at 90 deg. (slicing as oposed to chopping)

Re using the scraper, unless used in a shear mode, and again with a fresh sharp edge it is likely to exacerbate the problem rather than reduce it.

 

[Daven]

Thanks Chas,

Re-sharpened, turned the speed up and had another go - a lot better!

I did use a drop of BLO on the end grain and it made the cut easier so big thanks to all for the tips :wink:

Regards

Dave

 

[robo hippy]

I agree with what has been said. Also, there is a difference between roughing cuts and finish cuts. Roughing is getting all of the waste out of the way, and they can be heavy and coarse, and will lead to more tear out. As you get closer to final form, your cuts get lighter and more gentle so there is less tear out. Roughing cuts are more of a scraping cut, and finish cuts are more of a shear cut with the tool, either a gouge, or a scraper held at an angle to the wood. I can get equally good cuts with a freshly sharpened gouge or scraper (I do prefer a good burr on my scrapers). Your finish cuts should result in little whisps of shavings floating in the air. Of course, some woods are more likely to tear than others, and oak is one of those.

Dry wood will tend to tear more than green wood, and as near as I can tell, this is because the wood is lubricated with the moisture that is in the wood. Wetting the wood helps this, just get it damp with water, oil, or sealer, let it sit for a minute or two, then use very light cuts to remove the wet stuff. If the tear out is bad, this can take several applications. Getting the wood wet doesn't hurt the wood because you end up cutting away all of the wet stuff.

robo hippy

 

[loz]

BLO on the end grain and it made the cut easier

BLO ?

 

[CHJ]

Boiled Linseed Oil

 

[loz]

Ah - Thanks - ( Just googled the usage ) - My Vocab grows daily !

 

[Daven]

Ah - Thanks - ( Just googled the usage ) - My Vocab grows daily !

Shhhh Loz don't tell anyone but up until two weeks ago I didn't know what BLO was either - just trying to sound like I know what I'm doing!! :roll: :lol:

Also thanks robo hippy - had yet another practice last night and was a lot better (still not as good as the bowls I have seen here of course) but not bad for a beginner!

Still trying to get the sharpening right and recognize when the chisel has gone dull!

Regards

Dave

 

[CHJ]

Still trying to get the sharpening right and recognize when the chisel has gone dull!
Regards
Dave

That's easy :roll: it was about three cuts ago :lol:

 

[Daven]

Still trying to get the sharpening right and recognize when the chisel has gone dull!
Regards
Dave

That's easy :roll: it was about three cuts ago :lol:

So true! :lol: