Finish On Endgrain

[adrian]

This was a small bowl made out of some of the local hardwood. As you can see, there is a problem with the finish on the endgrain. It's the same on the other side of the bowl. It was one of the first things I did so I put the bad finish down to inexperience and blunt tools but I got myself some lumps of the same timber and began to turn them a year later with the same result. The only tool I have been able to get any half way decent finish with is a round scraper held on a 45deg angle. What tools do others get the best finish with on the outside of bowls?

[RETIRED]

What grit did you go down to?

[adrian]

What grit did you go down to?
I've used 80, 120, 240, 340, 0000. The damage done by the chisel seems to be very deep and sanding just doesn't seem to have any effect. The finish on the other sides is like glass so I don't think it's tool technique.
It's what prompted me to post the thread about the shallow hybrid gouge that Mike Darlow mentions on his DVD. He seems to equate it's finishing qualities to that of a skew which is not a recommended chisel on bowls.
At the moment, all my gouges, with the exception of the roughing gouge, are 12mm or less and seem to cause subsurface damage on endgrain.

[RETIRED]

I've used 80, 120, 240, 340, 0000. The damage done by the chisel seems to be very deep and sanding just doesn't seem to have any effect. The finish on the other sides is like glass so I don't think it's tool technique.
It's what prompted me to post the thread about the shallow hybrid gouge that Mike Darlow mentions on his DVD. He seems to equate it's finishing qualities to that of a skew which is not a recommended chisel on bowls.
At the moment, all my gouges, with the exception of the roughing gouge, are 12mm or less and seem to cause subsurface damage on endgrain.
The standard gouges ( which Darlow calls a Hybrid Gouge, Why I do not know) are technically spindle gouges.

However, I sometimes use a 3/8 spindle gouge on bowls as its fingernail shape seems to cut better.

I hate to be a nark here but it does boil down to technique if you have chisel marks or gouges in the timber.

Try this: increase the speed (gradually, one speed at atime) until it vibrates the lathe. Make sure that it is well mounted in the chuck. Back it off one speed.

Move the toolrest in to within half an inch a fraction below centre. sharpen the chisel, either a small bowl gouge or small spindle gouge. Moving slowly and keeping the bevel rubbing the whole way start from the smallest diameter to the largest on the outside. This keeps the fibres supported while cutting. Inside is opposite.

Take light cuts and do it as many times as it needs to get a reasonable groove free finish.

I must admit that I have an advantage here as my lathe has reverse and makes sanding relatively easy.

Start sanding. If you have a rotary sander all the better. Sand until ALL marks have gone. Move to the next grit and repeat until the lines from the previous grit have gone. Next grit etc.

The quarter grain which is where the trouble is will always take a little more effort sometimes stopping the lathe and hand sanding that area.

Do not use much pressure or a pad under the paper as you run the risk of getting heat cracks in the timber. If you burn your fingers it is too hot.

Sand paper is a cutting tool and goes blunt. If it stops sanding and the marks are still there get new paper.

HTH.

[Cliff Rogers]

.... What tools do others get the best finish with on the outside of bowls?Depends on the timber & the grain.
That bit looks like it has a problem in the softer wood.
How old is the timber?
Is there any chance that the softwood is starting to rot?

I use a bowl gouge with long sweep back edges & to get a fine shear-scrape finish, I roll it over & bring the handle around toward me so that just the bottom long edge is in contact with the timber.
This gives a very fine scrape similar to your round nose scraper at an angle.

[La truciolara]

amazing (I should say annoying) effect!
Several possible reasons from the picture (it is always hard to guess)
The defects are quite horizontal , therefore I doubt it is because of a bad handling of the gouge.
In addition on the picture it looks like the defect is not on all the surface but just on one segment of your vase. If that is the case, may be the piece was no longer entered on the lathe.
If it was centred… may be you insisted too much with the 80 grit which went too deep and not enough with the others.
Again, I am just guessing

[gatiep]

I'm with & Cliff on this.

If all alse fails ( the above mentioned tool techniques won't fail ) then sand locally with the lathe stopped and 80 grit paper on the end grain only. If it is really bad, put your pride in your pocket and use a 60 g or even 40 grit "gouge" ( lol ) again locally, even if it means using 3 meters of it, then work up to 80 grit on the end grain only. Once you have the endgrain 80 grit smooth with no tear out, spin up the lathe and sand through the grits 80,120,180,240,320,400 etc as said.
With the right technique, light cuts, sharp tools ( throw in lots of patience as well ) you'll soon find that the endgrain cuts almost as smooth as the side grain.
Practice, practice, lots of patience and with more of all that, soon you'll find that it gets better and better. Never accept that an ' ah thats OK ' finish is good enough. Also, if you use a chuck, finish inside the recess properly as all people, for a reason unknown to me, will pick up your project and look at the base first!
Preservere!

[adrian]

Depends on the timber & the grain.
That bit looks like it has a problem in the softer wood.
How old is the timber?
Is there any chance that the softwood is starting to rot?

I use a bowl gouge with long sweep back edges & to get a fine shear-scrape finish, I roll it over & bring the handle around toward me so that just the bottom long edge is in contact with the timber.
This gives a very fine scrape similar to your round nose scraper at an angle.
The timber came from local log dumps and has probably been on the ground for less than six months so it's in pretty good condition.
I don't have a problem on any other timber. I get a good shiny, unmarked finish (inside and out) with my existing tools on all other projects but this timber is proving difficult on the sides where the endgrain is near 90deg. This would tend to indicate that my toolwork and sanding are good enough.
That's why I asked what other people use ie: their favourite tool. (type and size)
My main problem is that apart from my carbatec HSS set I only have small spindle gouges(12mm or less) and one small bowl gouge.
I'm saving up for some new Hamlet or Crown chisels in the larger sizes and am leaning toward the Euro style gouge such as the Crown 2325 and the Hamlet German style gouge such as the HCT077.

[PAH1]

Adrian,

I think that you will find those are really spindle gouges rather than bowl gouges. A good shear/ bowl scraper is a good investment, although they can be made easily from HSS blanks available froma range of suppliers. Some timbers lift that section of grain and there is little that you can do about it, gatiep is right when he says get into it with the sandpaper. Depending on what you have done with the base try throwing it back on the lathe and re-sanding it, some grains take a while to lift but can be worn down again by putting it back on the lathe.

[rsser]

You've got the tools you need.

Do more of the scraper at 45 degrees as you've already found, or follow 's instructions carefully with your bowl gouge. If the small one is your only one (not that 12mm is all that small), get your rest as close as you can to the bowl and take LIGHT cuts. Point the flute in the direction you're cutting. Play around with the angle that the edge meets the piece.

Apart from that generic hardwood is often p*ss-poor timber to turn - coarse and/or brittle; grain tear out is common - but to master it you will be learning valuable techniques.

[adrian]

I just had another go at it.
I tried sanding for about 5 minutes, refreshing the paper frequently and there wasn't one speck of improvement. Then I stopped the lathe and sanded hard with 120 grit across the piece (headstock to tailstock) for about a minute and then turned the lathe back on (1200rpm) and sanded with the same 120grit for a short time. The surface improved a hell of a lot. I did that a couple of times and the problem grain disappeared on the section I used that method.
's suggestion about stopping the lathe and using a rotary sander gave me the clue. I needed to get at the grain from a different direction.

[adrian]

Adrian,

I think that you will find those are really spindle gouges rather than bowl gouges. A good shear/ bowl scraper is a good investment, although they can be made easily from HSS blanks available froma range of suppliers. Some timbers lift that section of grain and there is little that you can do about it, gatiep is right when he says get into it with the sandpaper. Depending on what you have done with the base try throwing it back on the lathe and re-sanding it, some grains take a while to lift but can be worn down again by putting it back on the lathe.
Yes, the ones I mentioned are spindle gouges. I was very impressed with the closeups of the surface of a bowl when Mike Darlow used various gouges and then used a very shallow fluted spindle gouge that was ground like a scraper. The finish he got was noticeably better than the other chisels he used and I'm assuming that he wouldn't have been using blunt tools or had questionable technique.
You're right about the scraper. The Crown 2565 Bowl Finishing Scraper is another tool I want in my toolbox.

[rsser]

Adrian: slow the lathe down a lot; 1200 is way too fast for an abrasive to cut on a bowl.

[Cliff Rogers]

Yeah, it might be bouncing right over the crook spot.

I have had luck fixing torn end grain with the lathe stopped.

Hit us with another picture once you've sorted it out.

[powderpost]

For difficult timbers I use a shear scrape cut using a 1 1/4" heavy duty round nose scraper held on an angle, not flat on the toolrest. Good idea to find someone that can demonstrate the technique as it can be a little frightening. I have also made scraper tools by silver soldering heavy duty high speed hacksaw blades to mild steel blanks. That can save lots of money and produces very good scrapers.
Jim

[adrian]

For difficult timbers I use a shear scrape cut using a 1 1/4" heavy duty round nose scraper held on an angle, not flat on the toolrest. Good idea to find someone that can demonstrate the technique as it can be a little frightening. I have also made scraper tools by silver soldering heavy duty high speed hacksaw blades to mild steel blanks. That can save lots of money and produces very good scrapers.
Jim
Yes, that's the way I was able to improve the surface slightly on this timber. It's the reason why I'm going to get the chisels I mentioned above because although it is an effective method it's not really an appropriate use of the scraper.

The only thing I hate about woodturning is the same thing I hate about any hobby. It gets so damned expensive. When you grind a particular profile on your chisel you sometimes find that it's not quite right for other jobs (and timbers) so you find a need to buy another chisel. It would be nice if we could all get away with having the same set of five chisels for all jobs but after a while the challenge of getting a finish off the tool that doesn't need sanding means that you always have your hand in your pocket.

[powderpost]

Shear scraping is really a finishing cut and will take a while and numerous sharpenings to remove torn grain. A sharp chisel will take off shavings and it is still better than sanding. The need for more "special" shaped chisels and the cost led me to making my own scrapers using mild steel blanks with silver soldered heavy duty hacksaw pieces on the top. The HHS hacksaw blade provides a very good cutting edge.
Jim

[adrian]

The contintal gouge and the grind is described at the end of this link. http://www.woodcentral.com/newforum/grinds.shtml

[Cliff Rogers]

Good link, my grind looks like the one that Dave Peebles uses.