# metal lathe-acrylic turning



## nsfr1206 (Sep 18, 2011)

I would like to try turning a pen with my metal lathe. What cutter would you use for acrylic? I have hss and carbide cutters. Any special grind or relief angle? Or just go at it like I was cutting metal?


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## cwolfs69 (Sep 18, 2011)

*sharp tools*



nsfr1206 said:


> I would like to try turning a pen with my metal lathe. What cutter would you use for acrylic? I have hss and carbide cutters. Any special grind or relief angle? Or just go at it like I was cutting metal?



since acrylics is a very soft material, relatively speaking compared to metals, you need sharp very positive edge cutting tools. radius noses as well will help with finish. myself, i would use high speed steel so that i could sharpen easily on my grinder and shape special form cutting tools. i would get some scrap pieces and practice with several shaped tools to see which works best for you. i also would try to get some ground with chip breakers in them to alleviate the long stringy chips that will be created. carbide will work but you would need special grinding wheels to sharpen or make form cutting tools.  
again if you PM me or give me a call i will be more than happy to help with the tooling. easier to do if i can get specifics on machine. 

thanks
Charley


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## KenV (Sep 18, 2011)

radius tipped HSS tooling seems to work well for me.   The tooling will not cut as smoothly on acrylics as it will on metals -- that is you will still need to finish/polish the turned blanks.  

Dust collecor or vacuum to collect the stringy swarf is handy.

Note that you will generally be producing more straight sided pens unless you are using CNC or are very smooth at turning hand wheels.   

there is a lot of variation in the plastics used in pen blanks, but in general moderate feeds and taking time works better.  Some blanks are very easiy to cut and some are brittle.

Have fun and share your successes here.


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## Curly (Sep 18, 2011)

In addition to what has been said, lubricating improves the machined surface. Something along the lines of Pam or cooking oil applied with a small brush.


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## Chthulhu (Sep 18, 2011)

You can get all sorts of interesting curves from a metal lathe, but it's a good deal more work: you have to plot out the cut depths needed to reach the various diameters along the curve, cut to those depths (usually with a parting tool), then file or sand the ridges off to leave a smooth, unstepped surface.

Or you can install a freehand tool rest ( http://littlemachineshop.com/products/product_view.php?ProductID=1685&category=1 as an example ) and use your woodturning tools.


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## nsfr1206 (Sep 18, 2011)

I won't be replacing my wood lathe. Just wondered about doing some straight pens.


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## Chuck Key (Sep 18, 2011)

Tapers, following template curves and spiral ropes twists are also possible on the metal lathe.

Chuckie


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## Texatdurango (Sep 18, 2011)

nsfr1206 said:


> I would like to try turning a pen with my metal lathe. What cutter would you use for acrylic? I have hss and carbide cutters. Any special grind or relief angle? Or just go at it like I was cutting metal?


 
David, If you use the little triangular indexable cutters with the 7/64" hole I could wholeheartedly recommend a cutter I just bought yesterday. I've been wanting smoother cuts on aluminum so ordered some of these from Shars tooling and WOW...... the difference (without doing anything else) between the carbide cutters I have been using and these is daylight and dark!

I grabbed a piece of acrylic that I previously rounded with a carbide cutter and turned a bit on the end with the new cutter. This photo isn't the best but I made one cut then another shaving off just .001" then took it to the buffer without sanding, it was THAT smooth!

If interested, it is a TCGX-LH cutter for aluminum, Shar's http://shars.com part number is #424-1660. This will be a hard cutter to beat for acrylics... and aluminum!


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## nsfr1206 (Sep 18, 2011)

Thanks for the info everyone. Now I would like to upgrade my lathe!


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## SteveWatson (Sep 21, 2011)

I used my metal lathe to make one pen just using the slide.  It turned out nice, straight and concentric but after looking at some of the other pens I made on a wood lathe it just didnt have the same "character" with the nuances you get cutting by hand.  I made a tool rest to use the metal lathe by hand and use it for acrylics since the speed control is so much better than on my wood lathe but that is just my observation and personal opinion.  Nice thing about making pens is you get to make them however you like!


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## cwolfs69 (Sep 21, 2011)

the metal lathe is harder to do contours and such than with a wood lathe. however, for small metal parts, to trim pen parts, metal turning etc. they are great.


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## Kaspar (Sep 23, 2011)

RE: Curves and such.  I believe these are going to be available soon (Ignore the dates on the web pages: that went out the window long ago.)  They are, as I understand it, a new twist on an old idea.  

When I get one, I will be posting a review in the appropriate forum once I've tried it out.


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## Kaspar (Sep 23, 2011)

nsfr1206 said:


> I would like to try turning a pen with my metal lathe. What cutter would you use for acrylic? I have hss and carbide cutters. Any special grind or relief angle? Or just go at it like I was cutting metal?



BTW, I use indexable gold ti finished carbide cutters.  Inserts are dirt cheap, last forever and, depending on how you angle them, make excellent deep and finishing cuts.


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## Haynie (Sep 23, 2011)

The website does not show that cutter.  Where did you pick it up?

Found it.  Great price too.



Texatdurango said:


> nsfr1206 said:
> 
> 
> > I would like to try turning a pen with my metal lathe. What cutter would you use for acrylic? I have hss and carbide cutters. Any special grind or relief angle? Or just go at it like I was cutting metal?
> ...


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## nsfr1206 (Sep 23, 2011)

That dream cutter sounds neat. When will they be available?


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## Kaspar (Sep 23, 2011)

Don't know for sure, but I have heard the first production run is done.  I believe they have to update the website and put up some tutorials and then I think they'll be ready.  

I've been salivating over that thing since I saw it.  It looks like an easy way to do tapers (over pen barrel length distances) at any angle for one thing.  And it looks like it will give metal lathe users some of the free hand fun of the wood lathe, but with more precision.  And it looks tailor made for making spherical or ovoid bottle stoppers very quickly.


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