Any tips on turning plastic pens?

[Stephen Saar]

I tried turning some plastic pen blanks today, but I got horrible results. A ton of chip out on the plastic almost anyway I tried to cut it. I tried different speeds, but didn't run in to anything magical. At first I was just using a basic roughing gouge, then I tried a scraper, and finally a bowl gouge. If I went super slow with the cut then I didn't seem to have any real problems, but it was very very slow. Maybe that's just how you have to work with plastic, but man that was a pain. Any great tips on dealing with it?

Thanks.

-Stephen

[Dan Hintz]

What kind of plastic? Are you sure you're tools were sharp?

[David E Keller]

Super sharp tools and light cuts... I think the acrylics are generally much tougher than wood for pens. I tend to use high speeds and sharpen often with acrylics. Some of the acrylics are easier than others. I prefer a spindle roughing gouge for rounding the blank and a skew chisel for the remaining cuts, but there are 1,000 tools that will do the job.

[Scott Woodson]

What kind of plastic? Are you sure you're tools were sharp?

I would foot stomp Dan's comment...Tools gotta be sharp, when sanding you can't let the paper get hot as it will continue to scar the plastic and not polish up as nice.

[Steve Kennedy]

Helps to keep your tool rest real close to the blank too..

[John Hart]

I use a skew...and keep it sharp the whole time. I sharpen when I'm turning plastic more often than when turning anything else.

[Ken Fitzgerald]

Sharp skew....when sanding, use micro-mesh and wet sand using water as a lubricant.....

When drilling, use a sharp bit ......go slowly...Make the blank 1/4" minimum longer than you need in case it blows out the bottom when drilling...I will typically drill 1/8"-3/16" and then back out of the hole to clear the cuttings and repeat until finished drilling......don't hurry as bound cuttings and speed create heat....heat is your enemy.

[John M. Smith]

I use a hunter carbide tool. Lathe speed as fast as it will go. I've done about twenty without sharpening. Wet sand up to 600 grit, and then the micro sanding pads, and plastic polish.

[Mark Hix]

I go as fast as possible and usually just use a skew. Occassionally, I will use something else to knock the corners off. Light cuts, sharp, tool rest as close as I can, keep the tool moving. Use sandpaper like your neighbor gives it to you for free...don't skip a grit. If your interested, PM me and I think I have a link for an excellent video (free!) that might help.

[Donny Lawson]

I use a 3/8 spindle gouge and make sure it is sharp. Always take light cuts and go slow. Wet sand through 12,000 grit and add a coat of HUTs plastic polish and you will have a glass like finish.

[Stephen Saar]

Thanks for the tips. I'm not sure the type of plastic, I think it was acrylic based on how it broke off, but I'm not sure. It was just a pen blank I picked up at Rockler. My tools were pretty sharp, but maybe I needed to sharpen them even more. Sounds like my speed might not have been as high as it should have been. Well I'll try again sometime and hopefully it will go better.

Thanks for all the tips.

-Stephen

[Lupe Duncan]

Inlace acrylester is very "chippy". sharp tools slow cuts and high rpms.

[Bernie Weishapl]

High speed, a skew, and wet sand to 1000 grit. I then buff with tripoli, white diamond and then Ren wax.

[James Combs]

Sharp skew....when sanding, use micro-mesh and wet sand using water as a lubricant.....

When drilling, use a sharp bit ......go slowly...Make the blank 1/4" minimum longer than you need in case it blows out the bottom when drilling...I will typically drill 1/8"-3/16" and then back out of the hole to clear the cuttings and repeat until finished drilling......don't hurry as bound cuttings and speed create heat....heat is your enemy.

Ditto everyone's comments on sharp tools and fast speeds. Adding to Kens comment on drilling. I was drilling out a couple plastic blanks to 27/64" the other day and it struck me that maybe a coolant would help. Coolants are used extensively in drilling metals so I tried using water in the drill hole to keep the bit cool. It worked great for those two blanks. No heatup of the drill it barely got warm, no blowout at the bottom and a very smooth bore hole. I will continue the method for future plastic blanks. I have a plastic bottle of water I keep at my grinder that has a very small pinhole in it's nozzle so the amount of water it squirts out is limited. That is what I used to avoid getting water all over the drill press. Just a few drops every few seconds did the trick.

[Dave Bell]

This is what experience, reading and training has taught me.....well that and the no stomping rule!

Correct, high speed for turning and a 3/8" or 1/2" spindle gouge (sharp....nothing less), the skew is for getting the convex profile and flat sections proper. Concave sections need to be prepared with the spindle gouge and sanded to the finished profile (especially acrylester). Yes the tool rest must be a close as possible, this reduces vibration by providing better support due to less of the tool hanging over the rest. The spindle gouge when used properly can make gentle cuts with a lot of detail if desired. If you have to "force" the tool through the material, it most likely needs to be sharpened. If your unsure if your tool is sharp or not, them most likely it is not sharp. Seek some advice on sharpening your tools properly and then get the same advice on how to use the sharp tool. I wish I had been shown this at the start. As for the Skew.....it's hard to master and many turners (novice) shy away from this tool because of the problems associated with being able to use it properly. One word for the Skew and how to use it.....lots of practice folks. As for what the Skew can do......besides acting as a scraper.....it can actually cut the material leaving an almost polished finish requiring very little finishing to get to completion. As for turning the so called "plastics", don't be confused about your tool not being sharp because these materials cut slower than wood. Cut from the end of the blank moving inwards to teh center. Yes, it goes against the rules, but it also prevents blanks from blowing out on the ends. Take your time....it's not a race!!!!

As for drilling, the best way to avoid chipping or blow out is to drill the blanks from each end in steps (smaller to larger drill sizes) and then drill the final size in one pass. (Hmmm, Sort of sounds much like the turning method mentioned above.....coincidence?....)The speed must be under 500 rpm.......all types of blanks, wood, acrylic, silmar 41, acrylester, epoxy resin and alumilite. If you can afford them, the final pass of the drilling process is to pass a reamer through the blank, but this is something more for multi-composite blanks like "worthless wood" blanks which are composed of wood and a resin based medium such as acrylic. If you want to understand how to drill an accurate hole, research "gun drilling" and use the methods mentioned. This is one of the most accurate methods for drilling holes.

Note, there are many different types of blanks that people claim to be acrylic, when in fact they are not acrylic at all. This is a generic term given to pen blanks much like the term PR. If you doubt me....go research this for yourself.

Sanding......coarse grits....higher speeds, fine grits...slower speeds, it only makes sense. The grit fills up faster with finer grit and under high speeds, this leads to friction (heat) which causes the sanding medium to clog up and in turn, the heat melts the resin material and forms circular rings around the blank of resin build up. Whenever possible wet sand the finishes as this provides a cooling effect, it helps keep the sand paper from clogging up and it also provides a slurry which aids in the smoother finish desired (much like polishing). Avoid abrasives like garnet paper as they tend to release the grit into the slurry and end up creating more scratches (deeper) into the material that your trying to finish. #0000 steel wool.....works great, if used properly. It also acts the same way that sand paper does in relation to the grit size and clogging up. The down side of steel wool is that it leaves small hairs that can be a nuisance when it comes to removal and to the appearance after applying your finish.

As for carbide.......expensive, but well worth it in the long run.

I hope this helps those who want to get the most out of it and those who want to read further about it.

Dave