Chisel questions +

[Chasboy1]

Hi folks, I haven't been around for awhile, in good weather its car show/cruise season and once "the brine" is on our roads, my Corvette stays home.
I decided that rather than use certain shortcuts for rounding a blank, I'm going to use 'big boy' techniques and use my lathe chisels to do the job. I have a square and round tip carbide tipped tool from John at NCWoodturning tools. They are worth the money and since I work primarily with acrylics I like the fact that they don't dull easily.
My question is I've seen info regarding negative rake carbide tips. I was having a problem with frequent chipouts and for the heck of it tried the tool upside down, thinking I was giving it a sort of negative rake. I must say the cut was smooth but did not cut very fast. Was I fooling myself in this regard?
Another question is tool angle as it approaches the work. I heard that it was different for carbide but I don't remember what it was. The carbide tool shaft is much thicker than my old ones and the cutting tip is at the top, which adds to my confusion.
That's about all I can remember for now.
thanks everyone1

 

[Dale Allen]

I use my carbide tools for wood and plastics. When I use them on the length of the blank I tilt the blade to about a 30-40 degree angle.
This helps prevent the blade from catching. And when I use it flat against the side of the blank or when trimming the ends, I make sure the blade edge is just below the centerline and that the tool rest is as close to the blank as possible. In this way the tool is less likely to catch and dig in because the support center is so close to the cut and it takes much more force to tilt the tool up, which is what causes the catch and gouge.

 

[robutacion]

Hi folks, I haven't been around for awhile, in good weather its car show/cruise season and once "the brine" is on our roads, my Corvette stays home.
I decided that rather than use certain shortcuts for rounding a blank, I'm going to use 'big boy' techniques and use my lathe chisels to do the job. I have a square and round tip carbide tipped tool from John at NCWoodturning tools. They are worth the money and since I work primarily with acrylics I like the fact that they don't dull easily.
My question is I've seen info regarding negative rake carbide tips. I was having a problem with frequent chipouts and for the heck of it tried the tool upside down, thinking I was giving it a sort of negative rake. I must say the cut was smooth but did not cut very fast. Was I fooling myself in this regard?
Another question is tool angle as it approaches the work. I heard that it was different for carbide but I don't remember what it was. The carbide tool shaft is much thicker than my old ones and the cutting tip is at the top, which adds to my confusion.
That's about all I can remember for now.
thanks everyone1

G'day,

I was trying to find some pics of inserts/tools showing clearly the difference between rakes angles on tools I couldn't find anything I liked so I make one myself, I hope it gives you a clear exemplification of regular and negative rakes so, you cutter turned upsidedown is far from being ideal or effective.

As for the "correct" angle of approach, the banjo has to be adjusted depending upon the chisel shaft size, centred or just below it is the norm.

Hope this helps.

Cheers
George

 

[Woodchipper]

once "the brine" is on our roads, my Corvette stays home

Fiberglass doesn't rust like metal. Had a '66- if I still had it I could sell it and pay off my house and car. Used to live across the Hudson River in Queens, NY.

 

[Dale Allen]

The 'banjo' supports the tool rest and has nothing to do with the vertical position of the tool. It does position the tool with respect to the support position of the tool. Proper references make things clearer.
I guess a picture is needed in some cases to better clarify.

 

[howsitwork]

I was a bit confused by georges diagrams as , to me , they look the wrong way round ( maybe that's me , no offence George ).

Dales picture and diagrams show it correctly.

Skewing. or angling the tool sideways as per his picture gives a shearing cut with the tool and should work well on plastics or difficult woods.

It's always worth trying to cut at centre line if you can as then there is good clearance pounder the tool and there is no , or rather less force on the tool from the work tending to lift itself over the cutting tip as you work. if you cut above centre line you are effectively pushing the tool into the work and taking a big bite rather than cutting it.

 

[Chasboy1]

Fiberglass doesn't rust like metal. Had a '66- if I still had it I could sell it and pay off my house and car. Used to live across the Hudson River in Queens, NY.

Body is plastic, yes, frame is steel. Besides, it's bad enough to inhale the powdered brine, don't need to fight it on the car in the winter.
I'm from Queens, born in Jackson Heights, moved to Peekskill as a baby, most of my cousins from that side are still there.

 

[Chasboy1]

Thank you guys, that all makes sense, including the pic of the shearing cut, which I never thought of doing with a carbide cutter.

 

[Chasboy1]

Are carbide cutters standardized that they can fit a variety of vendor's handles?

 

[Woodchipper]

Lived in Elmhurst. Not too far from JH.

 

[penicillin]

Are carbide cutters standardized that they can fit a variety of vendor's handles?

No. Some are interchangeable, some are not.

First of all, carbide tips shapes are specific to the tool handles that fit them. I have three Rockler carbide tools - square radius, round, and diamond. None of the carbide tips will fit into the "wrong" handles. The back part of the tool "receptacle" is shaped perfectly to match the back of the carbide tip and support it. The shape and bevel angle are a perfect match to provide perfect support for the back of the carbide tip. Rockler sells a square carbide turning tool. Despite its similarity to my square radius tool, my square radius carbide tip will not fit into the square tool, and the square carbide tip is not a good fit in my square radius tool either.

Even if you match the basic tool shape, the size must also match. For example, round carbide tips come in different diameters, and you must choose the correct one for your round carbide tool. The other carbide tip shapes come in different sizes as well. A given manufacturer may make more than one size of tip in a given shape - full size AND mini size, for example.

The manufacturers want to convince you to buy their brand of tip for your tool, but there are good third-party sources for carbide tips.

Arizona Carbide has a cross-reference chart, mapping different carbide tools to their carbide tips. Arizona Carbide is one of the active vendors here on Penturners.org. The chart is multiple pages and kinda' painful to use, but it works. If you find a tip you like, you can see what other tools use it.
https://azcarbide.com/cross-reference-chart

Finally, you can resharpen your dull carbide tips. I flip them over and flatten the tops on diamond stones. I won't say that they are as good as "factory fresh", but it certainly extends the life of your carbide tips.

 

[Jsavage4]

I was having bad chatter and chip out with my new negative rake tool. I called the manufacturer and was told that I need to run my lathe at maximum RPM and that should solve my problem. Haven't had a chance to try it out.


Sent from my iPhone using Penturners.org mobile app

 

[TonyL]

Body is plastic, yes, frame is steel. Besides, it's bad enough to inhale the powdered brine, don't need to fight it on the car in the winter.
I'm from Queens, born in Jackson Heights, moved to Peekskill as a baby, most of my cousins from that side are still there.

I'm another Elmhurst (now changed to Middle Village) native (Born Ridgewood, Queens). Took the Q45 many times from Roosevelt Avenue to Eliot - sometimes walked when it was late the the buses ran infrequently.

 

[Woodchipper]

Plastic or fiberglass? Mine was FG.

 

[Chasboy1]

Plastic or fiberglass? Mine was FG.

Depends on the year. I know the first gen was fiberglass, I've seen enough loose body parts at Carlisle to know. Not sure about the rest

 

[Woodchipper]

Mine was a '66 model.