Advice turning Tru-Stone

[Dustman]

I am about to turn a 7/8's tru-stone blank for a Majestic pen as a gift. I have never turned Tru-Stone and would like advice on spindle speed and cutter. I have regular square carbide PSI cutters and a negative rake cutter from PSI. As you probably know, they don't offer much advice for anything they sell.

And, I've been making pens off and on for about a year, mostly as gifts. For the most part they have turned out pretty well but I haven't been able to find anything I would consider reliable about spindle speed. Is there a real difference between wood and acrylic? Tru-Stone? The largest blank I have turned has been one inch but most have been 5/8ths and 3/4ths. Thank you in advance for your advice.

 

[jttheclockman]

Not all truestone is the same consistency. Some have more harder stone dust and others are just all acrylic. Turn as if any other material and for speed that is a subjective thing I turn at highest speed for everything that whatever my lathe is set at. Never looked to see what that is. Truestone polishes up very nicely and looks great on higher end kits like the Majestic. I always turn down my blanks with round carbide cutter and clean up with a well tuned skew. Just the way I do things and has worked well. Here are a couple truestone pens that are my favorite colors.

 

[gbpens]

Keep in mind there are TWO levels of hardness in Trustone. The softer one a 75-25 pigment to resin and the harder one is 85-15 pigment to resin. You can use HSS on the softer but carbide is recommended for the harder version. If the material comes off in ribbons it is the softer version. Usually these are the turquoise or white versions, The remaining colors are usually the hard version.

 

[RunnerVince]

I've found sharpness of the tool to be far more important than spindle speed. That's sort of universal, regardless of the material I'm turning. Beyond that, I'd say get the blank round and then do a little experimentation while you have excess material to work with. That way you can find the tool/speed that works for YOU. I rarely use a scraper for anything, yet others swear by them. Same for carbide. I have a 3/8" bowl gouge and a couple skews (nothing fancy...Benjamin's Best from PSI) that I keep sharp, and they work great for me on just about everything.

 

[Dustman]

I've found sharpness of the tool to be far more important than spindle speed. That's sort of universal, regardless of the material I'm turning. Beyond that, I'd say get the blank round and then do a little experimentation while you have excess material to work with. That way you can find the tool/speed that works for YOU. I rarely use a scraper for anything, yet others swear by them. Same for carbide. I have a 3/8" bowl gouge and a couple skews (nothing fancy...Benjamin's Best from PSI) that I keep sharp, and they work great for me on just about everything.

Thank you, Vince. Much appreciated.

 

[randyrls]

Al; Like others have said, Trustone will vary from very soft to hard as diamond depending on the material. I take my disk sander and round the corners. It doesn't have to be perfect, you just want to get rid of the sharp corners. Then use a carbide round bit below center. The lower on the blank the more aggressive is the cut and the more stress you put on the blank. You should get endless streamers; If you get pits in the material and hard nits coming off the blank, vary your technique. The tool at the bottom is the one I most often use for Trustone and most synthetics. Carbide can be honed (sharpened) with a diamond card easily.

 

[montmill]

Randy, is that a Hunter tool? It looks like his style. Hard to learn I'm told but a beautiful finish. You actually cut with it rather than scrape they say.

 

[Ted iin Michigan]

I've turned quite a bit of Tru-Stone and there are a couple things I'd like to add that are important.
First - the material will overheat FAST when you are drilling, VERY easy to mess up an EXPENSIVE blank here. Take it easy and stop and let things cool down COMPLETELY - several times. Sharp drill bits will help but they dull quickly.
Second - Although the material is slightly troublesome to turn (I ALWAYS use carbide), oversanding is VERY easy to do. I hardly ever use carbide on anything else.

 

[KMCloonan]

I usually work my way up through a range of drill bit diameters, starting pretty small and increasing by 1/16" with each increment. This minimizes the amount of material removed with each drill bit, which also reduces heat buildup. I also drill at a slower speed, and regularly cool the drill bit with a cool damp rag. You want to avoid heat at all costs.

Once I have the blank drilled and tubed, I turn at a normal (high) speed, but keep an eye out for heating up of the cutter. I use a round negative rake carbide. Take your time and things should work out. Try to hurry, and you may run into problems.

 

[TellicoTurning]

I don't think I've turned Tru-Stone in years... probably over 15 years back, but I learned to turn all plastics with a skew.... at high speed but watching the presentation of the skew closely. It's been so long though I really don't have any advice to offer. I actually quit turning pens about that long ago.

 

[umbert]

Turned few TruStones myself too, always used carbide.
NOW, I always worry more about drilling thru it then turning it.
After few of the blanks cracked, broken, now I ALWAYS butt end some wood where the drill bit exits. Usually I tape blue tape to the exit side of the TruStone and then tape the sacrificial wood with another piece of blue tape I may be overthinking it but since I'm doing it, never had a cracked end. Also, using 2-3 different diameter bits helps, rather then 1 final diameter one.

 

[ed4copies]

Don't drill through!

Cut your blank longer than needed, then stop your drill bit about an eighth inch BEFORE it would exit. Take the blank to the bandsaw and cut off the end--much less likely to ruin the blank.