Turning Brittle Acrylics - International Association of Penturners
     International Association of Penturners
Pens for Service Members
Support The IAP

Go Back   International Association of Penturners > Community Forums > Penturning
  Forgot Password
Register FAQ Members List Search Today's Posts Mark Forums Read
Penturning General penturning discussions not specifically addressed in one of the specialty forums.

Logged on members can hide ads!

Welcome to penturners.org!

You've found the home of The International Association of Penturners. You are currently viewing our site as a guest, which gives you limited access to view discussions, photos, and library articles.

Consider joining our community today. You'll have full access to all of our content, be able to enter our contests, find local chapters near you, and post your questions and share your experience with our members all over the world.

Membership is completely free!!

If you have any problems with the registration process or your account login, please contact us.

LinkBack Thread Tools Display Modes
Old 10-31-2017, 03:42 PM   #1 (permalink)
Join Date: Nov 2015
Location: Lago Vista, Texas 78645
Posts: 33
Photos: 0

Default Turning Brittle Acrylics

I turn a lot of acrylic blanks and I use carbide tools exclusively for all of my wood and acrylic turnings. I ran in to chipping and breaking problems some time ago trying to turn Mica blanks from PSI and got so frustrated that I just don't buy them anymore. I recently had a similar problem with Rhino blanks but I sped the lathe up a little and took much shallower cuts and took my time (after reading reviews) and was able to get the desired result. Now I am REALLY having a problem with Stars and Stripes blanks (also from PSI). When I read reviews they all say how hard these are to turn without chipping and cracking. To try something new, this weekend I purchased new Woodpecker tools because they have a 45 deg. bevel on the shaft and I thought that it would help me "cut" the blanks instead of "scraping" them. I have the lathe at around 3,000. The Woodpecker carbides are really very sharp and if I go really slow I can get them close. I read a couple of reviews that suggested using dull tools! I don't know how to do that because I buy carbides because they are always sharp. The last two blanks that I made I roughed them with the tools and they were chipped a bit. I then resorted to a Dremel rotary sanding disc to get them down close to size and below the chips and then very slowly and with really shallow cuts I was able to use the 2 deg radius scraper to finish them good enough for final sanding. Every single one of these I turn has chipping problems no matter what I try. I bought a bunch of these for my American Patriot and Salute to Troops pens and am hoping that someone out there has a magic bullet idea that will keep me from breaking these things because they are strikingly beautiful when they are done.
Likes: (2)
mikefoye is offline   Reply With Quote Top
Old 10-31-2017, 04:20 PM   #2 (permalink)
Join Date: Nov 2010
Location: Buena Park, California, USA
Posts: 204
Photos: 0


My only luck with the brittle acrylics is to use a REALLY sharp HSS spindle roughing gouge (my normal pen turning tool of choice), not carbide, and use on an angle to cut and not scrape. Also, high RPM helps, but not trying too push to fast or hard on the tool; there is a certain "feel" when the cut starts to slice shavings. I still might get sections that chip out, but its very minor and after sanding through the grits, a little CA will eliminate. I would practice on some less-critical acrylic blanks to get the feel with the roughing gouge before finishing your expensive blanks.
Likes: (1)
Bill in Buena Park is offline   Reply With Quote Top
Old 10-31-2017, 05:11 PM   #3 (permalink)
Ted iin Michigan's Avatar
Join Date: Feb 2010
Location: webberville, mi
Posts: 1,434
Photos: 1


Hmmmm - interesting experiences. I've turned a lot of the same type of materials - hope my following comments help.
After doing many I've settled in on using a non-high speed steel spindle roughing gouge (not a skew) on those type materials. I sharpen on a Work Sharp with a jig I made or on my low speed grinder. Either way gives a decent edge. If it's a material that I know is particularly sensitive, I may sand the edges and get the blank to a very rough round shape. Then I'll turn at about the same speed you do. I keep my tool rest at a height that presents the edge pretty well centered - but not high. I try to keep the bevel as close to the material as I can.
I've been pondering why I prefer this gouge (just a HF that was part of my first set) and I think it might be partly due to familiarity, partly because it has a pretty short handle and maybe partly because I can get a nice edge on it that doesn't stay super sharp for very long. I'll resharpen every other pen or so.
I know it's not the carbide you are using but my experience is that carbide works nicely on things such as TruStone but I prefer steel on just about everything else.
Hope this helps
Ted in Michigan
Go Buckeyes!
Ted iin Michigan is offline   Reply With Quote Top
Old 10-31-2017, 10:27 PM   #4 (permalink)
Join Date: Mar 2012
Location: Waxhaw, NC
Posts: 452
Photos: 21


Don't resist using a skew chisel... Right tool for the job. Once you get it down you won't look back. I love my carbide tools, I've used them for 10 years... But when I turn acrylester and a few others I use a gouge and skew and they get the job done without drama
Likes: (1)
McKenzie Penworks is offline   Reply With Quote Top
Old 11-01-2017, 07:25 AM   #5 (permalink)
WriteON's Avatar
Join Date: Aug 2013
Location: Lake Worth, Fl
Posts: 1,122
Photos: 0


No Mica’s for me. Not my faves. However if you strike like a snail with air brakes with sharp tools they are manageable.

Current set up:
a pair of Jet 1015VS
Jet 1221VS
MidAmericaPool professional pool cue repair lathe
WriteON is offline   Reply With Quote Top
Old 11-01-2017, 12:08 PM   #6 (permalink)
elyk864's Avatar
Join Date: Jun 2017
Location: Phoenix, AZ
Posts: 207
Photos: 1


I turn a lot of acrylics and use carbide tools with very little problems now. I would experiment with the angle of attack. I will have the tool at almost a 45 degree angle up, to the point where I am making contact below the center line of the blank. If that all makes sense. You will then need very very little pressure to make cuts.
elyk864 is offline   Reply With Quote Top
Old 11-01-2017, 12:29 PM   #7 (permalink)
Join Date: Mar 2011
Location: Glastonbury CT
Posts: 725
Photos: 0


I knock the corners off and round using a round carbide with the dished top side not just a flat carbide cutter. If I go slow it gives me nice ribbon after the blank is round. Than I use a skew on its edge as a negative scraper to get rid of the chipping and chatter. Be careful on two part pens because the middle will vibrate as you get far away from the head stock. Than I finish up with my 80 grit gouge :-) to get to final size. Hope that helps.
raar25 is offline   Reply With Quote Top
Old 11-01-2017, 10:24 PM   #8 (permalink)
TattooedTurner's Avatar
Join Date: Aug 2016
Location: Surprise, Arizona
Posts: 1,154
Photos: 264


Originally Posted by Ted iin Michigan View Post
I've been pondering why I prefer this gouge (just a HF that was part of my first set)...
I use an ultra cheap HF spindle gouge that came in my first set of tools on really brittle stuff. I don't know why, but it seems to do the best job in spite of the fact that it's useless for just about anything else. I reground the tip to more of a detail gouge shape (by accident) and dang if it didn't start slicing through the brittle stuff like that's what it was made for.
TattooedTurner is offline   Reply With Quote Top
Old 11-02-2017, 09:15 AM   #9 (permalink)
Woodchipper's Avatar
Join Date: Mar 2017
Location: Cleveland, TN
Posts: 2,051
Photos: 1


raar25, I might do the blanks as a separate operation for turning.
TatooedTurner, your post has me thinking. Scary, isn't it?
To err is human; To really mess it up, you need a computer.
Woodchipper is offline   Reply With Quote Top
Old 11-03-2017, 12:43 AM   #10 (permalink)
TattooedTurner's Avatar
Join Date: Aug 2016
Location: Surprise, Arizona
Posts: 1,154
Photos: 264


Originally Posted by Woodchipper View Post
raar25, I might do the blanks as a separate operation for turning.
TatooedTurner, your post has me thinking. Scary, isn't it?
I hear you. Between casting and turning, I've gotten very lucky at times completely by accident. It seems Ted and I have both gotten lucky using cheap HF tools on the brittle stuff. Maybe because they don't sharpen to as good of an edge?
TattooedTurner is offline   Reply With Quote Top
Related Content
Logged on members can hide ads


Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

All times are GMT -5. The time now is 08:39 PM.

Powered by vBulletin® Version 3.7.6
Copyright ©2000 - 2018, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0

Content Copyright © 2003-2018 by Penturners.org, LLC; All Rights Reserved
Terms Of Service   Acceptable Use Policy