Turning Ebonite

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Amihai

Amihai

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Joined
Oct 8, 2021
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117
Location
Israel
Hello,
I'm used to turning wood. In fact, wood is the only material I've turned so far.

As part of my attempts at kitless pen making, I've tried to turn Ebonite without much success. I've several questions, which I hope you could answer:

What lathe speed is best for turning Ebonite? I turn my wooden pens at around 3,000 rpm, if that matters.

I'm using carbide cutters. Have the classic set of square, round and dimond shape cutters. What cutter is best for what operation?

Also, what's the best way to finish ebonite? I guess I can just wet sand with Zona paper?

Thank you very much,
Amihai Fishman.
 
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Hi, I usually turn ebonite at around 2000-2500 rpm for a pen. Most important thing is to go slow with sharp tools. The carbide cutters should work just fine. I use the negative rake cutters, both square and round.
 
If you are experiencing problems turning any material, I suggest you slow down. There's really no need to run the lathe above 1,000 rpm - all it does is make your first catch worse and arrive quicker.

You don't say which make of ebonite you are turning, and there are significant differences between manufacturers. Typically the German products (SEM, for example) are a little harder than the Japanese products. Both of those are better quality (meaning fewer pinholes) than the rods I bought from India. I have a couple of rods from China but haven't tried turning them yet.

I've used a skew with reasonable success, but also regular HSS scrapers, and a couple of scrapers I made myself from old files that I annealed in the oven then ground into a gentle curved shape. In my experience, it's better to use a curved scraper than a perfectly straight cutting edge purely to reduce the size of the bite it takes from the material. With a light touch, that doesn't matter so much.

Ebonite is kind of flexible, so the amount sticking out of the chuck (unsupported) is important. Too much sticking out will cause vibration and chatter. I use a collet chuck, so most of the rod is buried in the headstock until I have drilled and threaded the piece, then I put it on a pin-chuck which provides mechanical strength while I shape the outside of the parts (barrel or cap).
 
In my experience, ebonite is more difficult to turn than almost all types of wood. I turn this with a skew. This is two to three times slower for me than for wood. I only use a square carbide scraper for the very last bit. I take it out of the mandrel and turn it round with a carbide cutter. Speed is not that important to me. Still, I turn ebonite at about 1500 rpm
 
wimkluck said:
In my experience, ebonite is more difficult to turn than almost all types of wood. I turn this with a skew. This is two to three times slower for me than for wood. I only use a square carbide scraper for the very last bit. I take it out of the mandrel and turn it round with a carbide cutter. Speed is not that important to me. Still, I turn ebonite at about 1500 rpm
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I love turning ebonite. And it is very easy to cut nice threads on. I use sharp steel tools and turn at 1750 rpm not sure speed is that big of a deal, more a preference.
Jim
 
Ebonite is my favorite synthetic, it threads very well and turns easily. I have not found speed to be a factor. (I use a metal lathe)
Finishing black German ebonite is time consuming if done well but looks Awesome and holds its shine very well.
I dry sand, changing direction of sanding between every grit. Sand with each grit until there are NO marks from the previous one (unlike wood and most plastic) go through each Zona paper with this process. You will need to add a couple grits between the blue and red (?) because of the big jump it takes. then polish with very fine compound (Plast X is what I use)
I find the Japanese Ebonite to be a little softer and quicker to finish but it doesn't polish to the same level as SEM.
Stay away from Indian ebonite.
 
Amihai said:
Hello,
I'm used to turning wood. In fact, wood is the only material I've turned so far.

As part of my attempts at kitless pen making, I've tried to turn Ebonite without much success. I've several questions, which I hope you could answer:

What lathe speed is best for turning Ebonite? I turn my wooden pens at around 3,000 rpm, if that matters.

I'm using carbide cutters. Have the classic set of square, round and dimond shape cutters. What cutter is best for what operation?

Also, what's the best way to finish ebonite? I guess I can just wet sand with Zona paper?

Thank you very much,
Amihai Fishman.
Click to expand...
Amihai,
I use easy wood carbide with a negative rake. I run the lathe between 1800-2100 rpms. It turns very easy and polished to a matte sheen.
 
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