Setting up my new 901

Newton Pens · Jan 9, 2014

So I got a Graversmith and 901 (yay!) except it doesn't seem to like cutting plastic. I can cut a line in aluminum and my old ancient pliers and other hard metals (well... sorta hard?). Just stick it, push my foot, and off it goes. All I have to do is steer. With acrylics is sort of just... sits there. Every now and then it'll take off, or seems like it does, but just for a second.

Any suggestions for optimum air pressure and SPM? I've had it at 19-20psi at 2300 and 3300 and 4200 spm and 6100 spm and dangit.... none of it feels right. I put the short spring in and tried at all spm as well, along with lower psi, around 12...

Help?

Thanks!

Sam · Jan 9, 2014

I never had much luck engraving plastics either. I've done it a few times and didn't like it one bit.

The air pressure should be set according to the manual and will not change unless you change springs or set the SPM extremely slow or insanely fast, then it might need tweaking. Try a variety of speeds and see which one works best, which you have already started doing.

Brian Marshall · Jan 9, 2014

Engraving plastics is part of making customized masters for pantographs we use for transfering...

I don't think I change anything much - outside of using gravers ground to fit the stylus of the machine that will be making the transfer?

May use a lighter handpiece and stroke? Pretty much just use whatever happens to be handy...

Brian

Newton Pens · Jan 9, 2014

If I have the settings "right" according to the book (which I did at first) could it just be a matter of finding the right geometry for the graver? Are there certain face angles that work better for soft metals rather than hard metals? Should I treat plastic like a soft or hard metal? So would a 45 degree face be better or worse than a 60 degree face? I know lots of experimentation is needed, but any advice to lead me in the generally right direction would be helpful.

I had one graver with a 60 degree face and I think I should have left it there. Maybe it was just in my mind, but it seemed like it cut the plastic better.

maako · Jan 9, 2014

I don't know if this helps but, I work on Aircraft and the windows are plastic, you need to dull the outer corners of the drill bit before drilling the plastic. if you dont it will shatter the plastic at worst or it wont cut a clean hole thru the window.

dlilazteca · Jan 9, 2014

Call me if you don't mind, I'm interested in tackling this problem. I'll send pm

Newton Pens · Jan 9, 2014

Thanks!

I'll call you tomorrow - in the meantime I'm going to play with it on about 500 spm at 12psi.

Southern Custom · Jan 10, 2014

I've had weird results every time I tried to cut plastic as well. I can tell you that you need an extremely solid mount for whatever you are cutting. Anytime the object you are engraving has give, or flex, then it will absorb the stroke of the graver. That sounds like why you are experiencing the graver sitting in place and then taking off.
Since your pens are plastic and the barrel is hollow, you have flex in the material. I'd suggest in addition to a good vise or mount, trying to find an arbor of steel that will fill your pen snugly. Then chuck it into a good solid vise or fixture. Oh, and try using high speeds and a standard heel instead of parallel.
Good luck with it! Let us know how the journey progresses.
Layne

Newton Pens · Jan 10, 2014

Thanks! As for heels - I'm still waiting on good diamond laps to come in the mail - right now I just have a sandpaper wheel (from my Delta belt sander - with wheel on the side) and it works okay - but I really need to practice the grs multi angle tool. My heels don't seem to turn out right. I must be doing something wrong.

I'll take pics when I get home tonight to show you what I mean.

I'm loving having a powered sharpening wheel. Very cool stuff.

Setting up my new 901

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