Cutting angles using carbide tools

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TonyL

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Hi again!
Looking to benefit from your experience and different opinions.

I use a carbide tools (square roughing and round finishing) to make my acrylic pens What is the proper cutting angle? I do approach the blank from above and lower it to cut the blank. Is 90 degrees (blade to blank) the correct angle? Do you want to make contact with the blank along its center (above or below). Thank you.
 
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1080Wayne

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I think you have to determine what works best for you . I cut below the blank centerline , generally using the tool as a skew rather than as a scraper , so it is angled to the blank , with the contact point in the middle of the cutting edge . That may work best for me because I have my lathe 4 or 5 inches higher than what is generally recommended , which allows me to stand perfectly upright while turning .
 

TonyL

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Thank you. As a novice and will start at 90 and in the center, and see where that takes me.
 

plano_harry

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Tony, I generally have my handle level with the point of contact on the centerline or above. I have the handle rotated between 30 and 45 degrees so I am not presenting the cutting edge flat (as discussed in the previous thread and Chris' picture) This takes the impact pressure off which I find especially helpful when rounding. Holding flat would tend to knock the corners of the blank completely off. DAMHIKT

From that starting point, I will vary the angle of the tool to the centerline between 90 - down to maybe 75 (Looking down from above) This allows me to effectively control the bevel of the cutting edge (I think - although some who know more than me about this topic might disagree) and adjust it to fit the material. This seems to be especially important in plastics as different resins behave differently. You just have to see what feels best for that blank. You can still start out riding the bevel, even with a carbide, which is helpful for new turners to learn control of the tool.

Also, for pens, it seems like most of us feel comfortable between 2,000 and 3,000 rpm. I started off a lot slower out of fear and not knowing what I was doing. When I increased the speed, my turning got better.
 

TonyL

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Thank you Harry. I am really looking to try a finishing technique (tool handling) that eliminates those circular scratches. I get 75% out and the rest real light with wet sand, micro mesh, BG rouge/wheel etc. It would be nice to not start with them at all or less.

Thank you!
 

flyitfast

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Take a look at the Easywood Tools website. Products « Easy Wood Tools They have several very good videos on the best way to use the carbide tools. Also, check out Youtube. They have many demos on the tools. Capt. Eddie is also a good resource.
Pictures are worth a thousand words...................and they go well with all the good suggestions above.
gordon
 

Cmiles1985

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I bought the square cutter and used it once. I replaced the cutter with the R2 rougher, and I've enjoyed using it more. The first few pens I turned with it, I really enjoyed it... Then I sharpened my gouges. A couple of the last few pens I have rounded with a large gouge and turned to shape with a smaller gouge. I do still use the carbide tool at times to see what works better with which material. For instance, the desert ironwood bolt actions I turned last night went wonderfully with the carbide tool and poorly with conventional tools.
As for angle, I try to hold my cutter perpendicular to the rotational force with the point of contact barely below the centerline.
 

plano_harry

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Once you have it close to final diameter, drop the edge down horizontal for very light scraping cuts to smooth out the ridges. Although the round cuter is labeled a "finisher" to me, the radiused square cutter is easier to get a perfectly flat turn than a round cuter which can wander in and out and create waves. It is really about what you get used to and get confident with. I started out with an R2 (edges have the curvature of a 2" radius). I avoided moving to an R4 because that seemed to require more skill. Now, I am perfectly happy with it. Round would be nicer for inside curves, but we don't do much of that on pens.

Assuming you have your turning smoothed out pretty well, the circular scratches can be eliminated by stopping the lathe and sanding longitudinally between each change in grit. Always sand acrylics wet and wipe off the current grit slurry before moving to the next finer grit. You will be a happy guy! If you have problems with one or two errant scratches in your acrylic, get rid of the sandpaper and switch to abranet - no scratches -- before moving on to micromesh and or the buffer.
 

TonyL

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Getting better. Thanks for your help.

Thank you. At the suggestion of another member, I watched a Ed Burns (Exotic) video. I was not spending NEARLY as long sanding out of fear that it would create more scratches (in one of Ed's video's, he only dry sand and then buffs). I did want he did (but tried wet and dry), Gross' scratch remover, and then the rouge buffing wheel, and I got my best finish ever. I was simply was under sanding. I also think I may be looking for an electron microscope-friendly finish. May not be possible (yet :).

Thanks again!
 

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Quality Pen

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Thank you. At the suggestion of another member, I watched a Ed Burns (Exotic) video. I was not spending NEARLY as long sanding out of fear that it would create more scratches (in one of Ed's video's, he only dry sand and then buffs). I did want he did (but tried wet and dry), Gross' scratch remover, and then the rouge buffing wheel, and I got my best finish ever. I was simply was under sanding. I also think I may be looking for an electron microscope-friendly finish. May not be possible (yet :).

Thanks again!
I'm pretty new too, and one of the big differences we noticed is that more sanding provided our biggest improvement. When we started we would hit all the micromesh start to finish, but only when we added more time to it did it really start to turn out great.
 
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