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Too old to die young
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Discussion Starter #1
Hi

Could some of you guys have a look at my bowl turning photo album? I must be doing something wrong as the tool tips get very hot :eek: but cant figure it out myself.

Bob
 

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I couldn't really tell from your album how the gouge is working. When a gouge gets hot it's usually from turning dry wood with the speed to fast and possibly a dull tool. As a tool gets dull you put more pressure on the bevel trying to make it cut and it gets hot. Dry wood is worse. A turn a fair amount of dry cherry and the shavings are quite hot coming off the tool. this is with a very sharp gouge and moderate pressure. The culprit in this case is speed. The outer rim of the bowl is traveling pretty darn fast and the shavings tend to heat up. So much so that if it's a large bowl (16" or so) I have wear a glove on my left hand because the hot shavings get uncomfortable.
In that case sometimes I'll change the attitude of the gouge so it throws the shavings somewhere else but sometimes the direction I'm using the tool is just the most efficient way so I just put on the glove.
 

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Too old to die young
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55 Posts
Discussion Starter #3
Thanks John

I also put a glove on to guard against the hot shavings although received wisdom is that we should not wear gloves because of the risk of the material catching in the rotating work and causing injury - Hadnt thought about the speed but it's obvious when you think about it. I get the same effect when using sycamore. I will certaily try reducing the speed

I have tried different angles of tool presentation and wondered if I might be getting too much bevel rubbing contact.

I keep the tools sharp using a Robert Sorby sharpening system
http://www.robert-sorby.co.uk/universal_sharp_sys.htm
It is incredibly easy to use and I keep it set up within easy reach of the lathe

Thanks

Bob
 

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Bob,
Are you putting a lot of pressure on the tool? Riding the bevel in itself should not cause a lot of heat buildup. If your tool is sharp, it should take very little pressure at all to produce a nice cut. I turn a lot of exotics that are very dense and dry and haven't noticed any of the tool tips getting hot enough to notice.
Mike Hawkins:blink:
 

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Too old to die young
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Discussion Starter #5
:bangin: That is also a possibility. Thanks guys, keep bashing the knowlege in and it will stick eventually.

I will have to spend some time turning a bowl that I am not too bothered about the final shape so that I can try these different methods of adjusting speeds, angles and pressures.

Another thing I thought of: Is is there likely to be a difference between bowl gouges with a traditional grind as opposed to a fingernail grind? My bowl and spindle gouges all have fingernail profiles.
 

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It is possible but to a lesser degree. bowl gouges are often a more blunt grind than a spindle gouge. I have bowl gouges from 45 degrees to about 75 degrees and don't really notice a difference in how hot they get. It's mostly when I'm turning dense woods at high speed that I have the problem.
 
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