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26th August 2013, 02:54 PM #1Retired
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trouble with the insides of bowls
Hi all,
Hoping for some advice and wisdom.
I'm having a bear of a time with my bowls and cups. The outsides and rims are perfect, but when it comes to the insides... well, its a disaster.
I end up spending too much time grinding out chunks with sandpaper and I cant get my chisels NOT to catch, gouge or rip out a chunk. The pictures are a demo with a timber found from a generic hardwood sleeper and the small bowl is Camfor Laurel. Both are dry.
I've tried speeds from 300 to 1600 in increments of 200 rpm (this was done on a cougar 350EVS). The bowls are very firmly secured with a SuperNova2 chuck with 50mm jaws. The bowls are round and there is no vibration. The tools are sharp (or at least I think they are once they come off the slow speed water grinder). I've tried every imaginable angle of approach. I've also turned the headstock 45 and 90 degrees to see if its the angle. BTW, I'm truly ambidextrous, so it doesn't matter which hands or hold I use... if its the technique.
Below is a picture of my chisels labeled. I have tried them all and all have either caught, given me hell or are simply not the right tool.
bowl1.jpg bowl2.jpg chisels.jpg
Should I buy a new/better/bigger/different bowl gouge? I frequently use #4 (a 3/4" bowl gouge), #5 (unknown and appears to be COMPLETELY useless for any form of lathe work)
Its almost like I need something like a gouge that looks like a huge letter-P .... where the curved part of the P is a scraper?
All wisdom most welcome. I've done 20-odd bowls in a variety of methods and I am getting absolutely no closer to being satisfied with the inside finish.
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26th August 2013, 03:41 PM #2Retired
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Blunt tool and wrong presentation would be my first guess. Wait until next week.
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26th August 2013, 03:44 PM #3Retired
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PS, Don't use no 7. It is a normal chisel and may come off the handle.
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26th August 2013, 04:34 PM #4
Of course you are going to get someone that does something different and use a tool that you do not have. I have used a square scrapper for the bottom of the few bowls that I made. The last two I have done I used a square then round nose scrapper towards the sides.
So far not many catches or much in terms of hills or valleys.
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26th August 2013, 05:43 PM #5Retro Phrenologist
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It's a bit hard to tell from the photo, but #4 looks like a spindle gouge and would not work well inside a bowl. # 2 looks like a bowlgouge . #5 looks like a scraper of some sort which should work OK if it is sharp.
Also, the bowl in the first pic looks fairly deep, the end of the chisel is going to be a long way from the tool rest,it wouldbe hard to control.____________________________________________________________
there are only 10 types of people in the world. Those that understand binary arithmetic and those that don't.
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26th August 2013, 08:42 PM #6
hi evan,
no.5 and no.12 i would be using,and try to put your rest inside
the bowl and keep it as close as possible,as you go in deeper
what are you using to sharpen your chisels?
when you get to the last pass,sharpen up again
just my 2 bob,s worth ,hope it helps
cheers smiife
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27th August 2013, 07:33 AM #7
Go to Glenn Lucas - Rough Shaping a salad bowl - YouTube and watch all of Glen Lucas' bowl videos. Will get you going in the right direction.
No's 3 & 11 are spindle roughing gouges - and are high risk choices for bowl work, so do not use them for roughing bowl blanks.
4, 5 & 12 would be my preferences from what you have for bowl work. However #4 appears to have a rather shallow flute for a std bowl gouge and may actually be a Sorby - Long & Strong which is intended for spindle work. In any case the grind / sharpening of the nose profile seems rather squarish for typical bowl use.
If you can get with or another skilled bowl turner jump at the chance,
Tool grinds.jpg
These are some of my tools, bowl gouges on LHS - spindle tools on RHS which are widely considered unsuitable and unsafe for bowl work.
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27th August 2013, 08:45 AM #8SENIOR MEMBER
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inside of bowls
I think that you should wait and see Ian as he has suggested. I also think the problem could be multi-faceted.
Tools, edge (grind & sharpness), and presentation. From what you have shown
it seems that you are ready for finishing and that would normally mean proper use and presentation of scraper
with burr and trailing position. However, in view of what you have said the problem may be more fundamental
given that some of the tools may not be proper turning tools or sharpened as turning tools. This can sometimes happen if they were used for
e.g carving. Drillit.
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27th August 2013, 09:06 AM #9Senior Member
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I think you need a hands on lesson. Generally for bowls, I use 2 gouges. One with about a 45 degree bevel which is fine for the outside of the bowl, and down the wall on the inside of a bowl. The other has a 60 to 70 degree bevel for going through the transition and across the bottom. You can't really see the inside the way you can the outside when turning it, so it is done more by feel. The steeper the sides are, the more difficult it is to go through the transition and across the bottom. I have a couple of clips up on You Tube as well, type in robo hippy
robo hippy
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27th August 2013, 01:49 PM #10SENIOR MEMBER
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I have this same Robert Sorby tool set. #4 is a 3/8" bowl gouge and does quite a nice job but is slow at times because it is small.
#2 is a 1/4" spindle gouge, and is actually quite flat. It is quite a narrow fluted tool, and with the factory standard (fairly straight) grind pattern could result in some nasty dig-ins if used inside a bowl. The instant you get the right part of the tool on the timber, you are bound to be within about 1mm or so of the corner of the tool touching the inside of the bowl. It works great as a spindle gouge but steer clear of using this in any sort of concave (bowl inside) with that grind pattern.
# 5 is a great little scraper. The problem might be that it is too far into the bowl (compared to tool rest location) and can't control properly. Also I have noticed that this scraper will do serious damage in very little time. I am new to turning, but I find that it is generally much safer for me to use my large scraper than # 5 on bowls.
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28th August 2013, 10:32 AM #11Senior Member
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Can I suggest ?
That instead of buying a new gouge that you invest your money in joining a woodturning club.
All the clubs I know have experienced turners who are willing to pass on their knowledge.
I think the best way to learn is from a "hands-on" session with one of these guys.
You will not regret the joining fee I can assure you.
HTH
ColChucks are like potato chips....you can't have just one.
www.bouvardbush.com
http://www.mandurahwoodturners.com/
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28th August 2013, 10:49 AM #12Novice
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29th August 2013, 06:57 AM #13GOLD MEMBER
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Echoing some of the above; 15 to 30 minutes instruction and demonstration of sharpening and an hour or two of same on turning will save you days and days of trial, error, and frustration.
Your #2, assuming it is a 1/2 inch bowl gouge and #12 half round scraper are all you need to make bowls, other than a tool to make the foot for the chuck. A screw driver ground to taste or a skew will do that.
The #4 looks like a roughing gouge ground straight across. That is 100% guaranteed to catch if brought even near the inside of a bowl.
There are 5/8 and 3/4 inch bowl gouges, but until you have spent 50 to 100 hours using a 1/2 inch bowl gouge they are hard to control. The bigger the tool and the farther away from the tool rest, the more force is on the handle. You should have at least three times the length of the tool behind the tool rest as you have in front.
That's why the guys & girls who make big deep vessels have 5 to 7 foot handles on their tools. They will also have a 1 inch bar and an itty bitty cutter on the end.
Find some reasonably hard close grained clear timber, 6 - 8 inches in diameter and 3 - 4 inches thick. Make a shallow bowl using the 1/2 inch bowl gouge inside and out, and the half round scraper inside. You may use the straight across scraper on the outside.
This will give you practice and not be prone to tear out that you would get from crazy grain, or soft wood.
Sharpen the bowl gouge using a jig to get a mild fingernail grind. The straight across grind will catch the wings inside the bowl, and the Ellsworth or Irish grind will be quite aggressive and prone to catching.
Sharpenig: http://www.ghwg.ca/techniques/sharpeingwithjigs.pdf
Grind the scrapers up side down so you get a nice burr and use them in the trailing position - nose pointing down where it meets the bowl.
Resharpen often, as soon as the tools stops making shavings, it is time. Make a mark on your bench or lathe bed so that you get the bowl gouge sticking out of the jig the same each time.
The jigs that come with the Tormek are wonderful. I have a Tormek but mostly use a dry grinder, 1725 RPM, 8 inch wheel, and the Wolverine system with the fixed predecessor to the vari-grind jig. The grinder is at the end of the lathe and I can stick the bowl gouge in the jig do a swipe on the grinder and be turning in about 45 seconds.
Deep bowls are difficult as you have to twist the bowl gouge when transitioning from the bottom to the side. You can use a scraper to make a bowl. See Robo Hippy's videos and posts.
Hope the above helps.So much timber, so little time.
Paul
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29th August 2013, 09:19 PM #14
Looking at all the tools you have none of them are a bowl gauge
1 Skew
2 Spindle
3 Roughing
4 Spindle
5 Round nose scraper
6 Parting tool
7 Wood chisel (do not use for turning)
8 Not sure but looks like a scraper
9 Nut sure
10 Not sure but looks like skew
11 Roughing gauge
12 Round nose scraper
13 Skew
Numbers 2 and 4 I have labelled as spindle because of the shape of the flute and also they are too short for Robert Sorby bowl gauges not just in the blade but the handle as well. Check the end profile of the spindle gauges against bowl gauges you can also see the difference
The picture below shows a spindle on the right and a bowl gauge on the left.
DSCF2138.jpg
I would suggest that a bowl gauge is on the to buy list either a 3/8" or better still a 1/2" one.
And as many have suggested find someone to guide you.
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