I'm okay with the "carbide == C++" assertion, but only in that both are tools I have no interest in using again.
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Unpopular Turning Opinions...
- Thread starter John Ames
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I'm okay with the "carbide == C++" assertion, but only in that both are tools I have no interest in using again.
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I used to be anti-carbide then I got gifted a couple of Hunter carbides to use in my Bosch hollowing bars.
They worked fine but were too slow at removing material for me to use over HSS cutting tips.
Then while working on a box that was stubbornly refusing to cut cleanly on the inside, I grabbed the straight hollowing tool with the carbide. Cleaned the inside quite nicely.
Shortly afterward, I was givena #4 Hunter. Used it finishing some goblet cups. Great finish! Great tool,
Now the Hunter carbides are permanent option in my finishing tool arsenal.
Thanks for the mention, Michael. You are correct, while I do use HSS gouges and cupped carbide tools, I primarily use carbide scrapers to make my forms. As to whether the work is "amazing", that is for others to judge.
LOL, I hear that. If I'm going to sit down and write myself an app today, it will be in C#.
At about 14.5 min in the video Bill linked to the demonstrator specifically warns about the problem using free cutting, cupped carbide and the likelihood of major catches. That's what I meant about the difficulty of learning to use carbide. When I mention using carbide I don't mean Hunter flat top carbides and their usage.
The cupped inserts were designed for aluminum cutting in machine tools with the insert mounted flat for best cutting action. The ideal woodturning insert styles are the diamond type with a small nose radius. With small nose radius the length of the cutting edge in contact with work is small. They do a good job cutting against the grain and through knots. Google on videos of production wood lathes making spindles to see no concern about grain direction.
It takes special considerations to use the cupped inserts to their best advantage.
BTW, why do you suppose the demonstrator started with a square block instead of rounding the blank on his bandsaw? He's creating a mass of chips and dust while bandsawing would only leave 4 small chunks. And that extra turning is contributing to dulling of tools (especially with HSS). It seems starting square is very common. Last time I asked about this the responses were it takes too much time to use the bandsaw.
The cupped inserts were designed for aluminum cutting in machine tools with the insert mounted flat for best cutting action. The ideal woodturning insert styles are the diamond type with a small nose radius. With small nose radius the length of the cutting edge in contact with work is small. They do a good job cutting against the grain and through knots. Google on videos of production wood lathes making spindles to see no concern about grain direction.
It takes special considerations to use the cupped inserts to their best advantage.
BTW, why do you suppose the demonstrator started with a square block instead of rounding the blank on his bandsaw? He's creating a mass of chips and dust while bandsawing would only leave 4 small chunks. And that extra turning is contributing to dulling of tools (especially with HSS). It seems starting square is very common. Last time I asked about this the responses were it takes too much time to use the bandsaw.
I have only experimented with hollow forms. I'm pretty sure I would use a carbide swan neck to hollow once I start making some of those.
That’s fair. Conventionally, at least in my experience and exposure to the lingo, unless you specify “cupped”, the term carbide usually refers to flat non-cupped. Flat carbide vs cupped carbide are two completely different beasts. Cupped carbide does have a steeper learning curve than flat carbide, and yes, the catches can be spectacular. One of the worst catches of my life was soon after purchasing a Hunter Badger. I was hollowing something relatively deep, and I presented the cutter completely open and BAM! One of those experiences where you turn off the lathe, take a few breaths, and really analyze what just happened. Hasn’t happened since, but I’ll never forget it.
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Those are effective tools.
I do mostly face grain hollowing on my bent tool I sharpen a 3/8” down the leading side of the cutter
. This lets me take a 1/4” cut. With a carbide I’m limited to about an 1/8”
I didn't even know about cupped carbide until this thread.
Dave Landers
Beta Tester
During my career, I've done FORTRAN, C, C++, Java, JS, Ruby, Scala... and a whole lot more I'd just as soon forget.
Now, if I find myself thinking about writing an app, I stop and re-evaluate that thought.
Did you like it or just endure it? Some folks that really don't like programming can still make a career out of it. One of my interview questions is, "Do you like programming?" If the candidate has a lukewarm response to that question I'll probably keep looking.
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FORTRAN. Brings back a fond memory - got to go to England to put a program on an Airforce computer, a relic PDP that only had paper tape input. Lucked into finding an DoD engineer with a near identical relic he scrounged for his lab that had a card reader, paper tape punch, and a Fortran compiler to make the binary. So with his help off I go with spools of paper tape in my carry on.
Dave Landers
Beta Tester
Loved it - enjoyed creating elegant solutions to the puzzles. But I have moved on.
I've heard tales of punch cards for programming, but never had to endure it. Closest I've come is using a "cards" statement in SAS to read in hard coded data.
Circling back to the topic, progress is great. Otherwise we would be turning on spring pole lathes with hand made gouges.
I've seen videos of artists using woodworking machines poorly or inefficiently and still make beautiful pieces. If a turner uses carbide they can still make exception turned pieces.
Michael Brolly is a self-admitted poor traditional turner. He taught himself how to turn and mostly uses scrapers (not carbide though, if I remember right). He still produces amazing turnings.
Circling back to the topic, progress is great. Otherwise we would be turning on spring pole lathes with hand made gouges.
I've seen videos of artists using woodworking machines poorly or inefficiently and still make beautiful pieces. If a turner uses carbide they can still make exception turned pieces.
Michael Brolly is a self-admitted poor traditional turner. He taught himself how to turn and mostly uses scrapers (not carbide though, if I remember right). He still produces amazing turnings.
In my past life on the west coast I would turn bad wood. Didn’t like it, but you turn what you can get.
Then I moved to Western Pennsylvania. The first load of firewood I had delivered was oak, cherry, maple and locust. I knew I’d gone to turner‘s heaven.
If given a choice, life is too short for bad wood.
Then I moved to Western Pennsylvania. The first load of firewood I had delivered was oak, cherry, maple and locust. I knew I’d gone to turner‘s heaven.
If given a choice, life is too short for bad wood.
--some of which can't be made with any other tools. 🙂
Well, not sure I agree. There is a learning curve with any tool. Learning to do enough to get by is not too difficult, other than mental blocks. Learning to be good with any tool does take a lot of practice. Many do not bother much with scrapers, but if you have seen me turn, or watched my videos, I do things with scrapers that many will say, "I may have to rethink my position on scrapers". That is the whole point of experimenting to find out what works best for you.
robo hippy
Maybe it's worth clarifying. I meant scraper in the sense of a flat carbide insert (I just wrote scraper there to mean I'm not talking about cupped carbide). HSS scrapers...the sky is the limit. And yes, there is a steep learning curve to using those well, and spectacular catches for not using them well.
Edit: Never mind, I found it.
Reed, can you post an example of one of your videos showing your scraper use? I'd like to see that. 🙂
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When I worked at a national lab, the physicists there referred to their simulation scripts (now mostly in Python) as "decks", as in a deck of punch cards.
There is an equivalent statement "datalines" in SAS but that is almost twice as long to type. Saving a fraction of a second the one time a year I use it is worth looking like an old-timer.
Kent, here is one:
View: https://www.youtube.com/watch?v=T4MKTOutZ3w
I was chatting with Russell Neyman up in Washington about this very thing. There always seems to be a lot of conversations and myths about what scrapers can and can't do. I watched a turner, Fred Uggla down in Roseburg and he turns light houses with finials using only the Big Ugly tool. I have him up on You Tube as well, mostly for historical purposes. One turner in our club also uses the Big Ugly tool to turn light houses. There are so many different ways to apply a cutting edge.....
robo hippy
I was chatting with Russell Neyman up in Washington about this very thing. There always seems to be a lot of conversations and myths about what scrapers can and can't do. I watched a turner, Fred Uggla down in Roseburg and he turns light houses with finials using only the Big Ugly tool. I have him up on You Tube as well, mostly for historical purposes. One turner in our club also uses the Big Ugly tool to turn light houses. There are so many different ways to apply a cutting edge.....
robo hippy
Almost the same experience I had. I more or less gave up on the tool until a turner who does beautiful segmenting and hollow forms kindly educated me.
Woodturners introduced new terminology (and confusion) to carbide inserts used in turning. Carbide inserts have a long history in the metalworking industries. "Flat top" and "cupped" are not terms used in metalworking to describe inserts. It's been many years since I've seen any metalworking turning inserts with a flat top. When flat top inserts were readily available they were mounted such that they had a top rake. That mount created a "high positive" cutting situation for soft materials. The cup in inserts would be considered a deep chip breaker used in softer metals such as aluminum were a problem has always been the dangerous tangle of long chips you want to avoid.
The technology in carbide inserts has come a long way in recent years. The so called "cupped" inserts with their razor sharp, mirror polish were not possible a few decades ago.
I've referred to the ideal carbide insert for woodturning as "high positive" insert mounted flat. The problem is they're extremely aggressive and will self feed with a resulting major catch if not used carefully.
Interesting information Doug, thanks. I’m not privy to the metalworking side of things at all (though if I had the space I would absolutely love to be).
Looks like a purchased block (most I’ve seen are square vs round). Its a smaller piece that doesnt take long to round. Could be like me, ie doesnt have a large bandsaw. For large pieces it can save time to bs round for bed clearance - I spend time trimming corners for clearance.
Taking a square to round does use more tool life, but its cheaper than a large bandsaw that I dont have room for.
Perhaps better stated as the best wood cutting insert, but not applicable to hand held tools due to the aggressive self feeding nature of the design…
As you can buy the inserts very cheaply these days, they can be incredibly cheap if you have the wherewithal to make the rest.
Although I use mostly conventional HSS tools I’ve made loads of carbide tools including a few “experimental”.
If you’re referring to the cupped RCGT type inserts, then yes, they can be a bit grabby. The general advice is to present the tip at an angle. Some tools with this type of insert actually have it mounted at a 45° angle.
I made my own hollowing tool in which you can adjust the angle of the cutter and lock it in place whilst still keeping a flat on the tool rest. It’s unique as far as I’m aware in that I chose to use Hexagonal bar stock. I guess someone will copy the idea.
Cupped carbide inserts for turning plastics and light alloys. They are available in 06, 08, 10 & 12mm diameters. You need to check the specification though as not all have a sharp edge. The sharp ones work great on wood and last ages.
As much as I use scrapers, I have never understood the 'self feeding' description that seems very popular/common. Many scrapers are huge, which is a point I make in my Scary Scrapers video. I have never noticed any of the ones I use, with burnished burr, grinder burr, or burr honed or stropped off. As near as I can tell, the main 'catch' reason most have when turning bowls is too big of a scraper so you end up putting too much cutting edge into the wood at one time, and also when sweeping across the bottom of the bowl and coming into the transition, if you don't pivot the tool, you can again get too much metal into the wood. I can see where that might be called 'self feeding'...
robo hippy
robo hippy
carbide cutters have their own vocabulary and designations... RCGT is one specific cutter type. If you want top start down the rabbit hole of carbide insert vernacular/designations start here:
http://www.carbidedepot.com/formulas-insert-d.htm
http://www.carbidedepot.com/formulas-insert-d.htm
Spending any thinking about what is in other peoples mind is overthinking and only leads to some kind of feelings that are not happy. Why would you do that to yourself? Let them be. Also, Cool = Cool. haha. I like that. IMHO: Outcomes are waypoints and not important. I try to focus my mind on my journey. Enjoy what ever tool, approach, practice you can and want. Please share it with me too! Haha.
Also: Ive been looking for a source for tantung steel or perhaps Stellite (which I think is perhaps a brand name for tantung?)
My googling skill is pretty weak, I think.
My googling skill is pretty weak, I think.
Nope, not referring to the round types inserts. They have too much cutting edge length of contact which increases the chance of a catch. 30 degree high positive (or cupped in woodturner terminology) diamond would be the ideal wood cutting tool. And when you mount them at an angle you're defeating their free cutting design. Mounting at 45 degrees and you're in negative rake scraper category.
Example: Using a 1/4" round insert taking a 1/16" depth of cut by my calculations you have .131" length of cutting edge contact. Using a 30 degree diamond and .010" nose radius with the same depth of cut only .077" cutting edge length in contact. The shorter the length of contact the better the tool will do in difficult grain and knots. In flat grain turning you have a good deal of micro tool bounce with a hand held tool twice in every revolution of the work. The smaller the work contact the less bounce. Tool bounce leads to micro tear outs.
The issue comes down to how to use the high positive inserts the way they were designed to be used without catches. Severa; ways, keep the tool shank rigidly horizontal on the tool rest, hood type depth limiter on top of insert, use some sort of tracing template to limit depth of cut. and so on. But using a template will no doubt have the purists claiming that's not real woodturning.
Crown in the UK have done so!
Have a look at this video to see what I mean. Used at an angle these inserts cut very well. Carbide inserts like these are not normally used with any type of limiter. I have seen that type of thing on HSS cutters with larger steeper cutting surfaces.
Simon Hope was I believe one of the pioneers in the UK to offer these type of hollowing tools using RCGT type cutters.
Your One-Stop Woodturning Shop | Hope Woodturning
hopewoodturning.co.uk
This is the hollowing tool I made a while back. Several guys at my club tried it out and they were impressed with it. The tip can be rotated and locked at any angle.
Hunter manufacture a large range of tools with RCGT type inserts.
huntertoolsystems.com
Hunter Tool’s How-To Videos - Hunter Tool Systems
The following videos are sample demonstrations of our Hunter Carbide Woodturning Tools.
huntertoolsystems.com
Hunter round bar is started at 37 to 45 degree angle and once engaged can then be leveled somewhat. The Viceroy has a small carbide <#2 i think,mounted on a square bar at an angle. This small carbide is aggressive but great for hollowing . The larger cups #4 or #5 is better for smoothing but if angled approach is wrong will give a humdinger of a catch. These carbides cut rather than scrape.
Of note on my round bar I marked the top dead center so I know how it is oriented inside a hollow form.
Of note on my round bar I marked the top dead center so I know how it is oriented inside a hollow form.