[AshleyJ]

Ok, let's be a bit more specific then the thread title...

I'm working with 1/8" thick cast acrylic sheet. I've never used the stuff before.

First project is a cursor that will travel over a measuring tape on a jig... cut the acrylic about 4" long and 1" wide; score a line down the center of the length and put red ink in it before removing the protective film; route a 1/8" slot about 5/8" wide at each end to receive the machine screws that will mount it with a little adjustment room for calibration.

So the question is what should an acrylic newbie know about blades and bits before doing this project?

Regarding saw blades...

• I'm very tempted to make the cuts with the Diablo 40 tooth blade in my saw (this blade).
• I've done enough reading and youtubing to know that the perfect blade would have more teeth like this one.
• And I wonder if the difference is worth $50. All opinions welcome.

Then there's the slots I need to route at each end so the acrylic piece can be adjusted side to side.
I don't have any bits that small, so I'm looking at 1/8" bits, both straight and spiral upcut, including these choices:

• Bosch 1/8-in Solid Carbide Straight Bit, here.
• Bosch 1/8-in Carbide Tipped Upcut Spiral bit, here.
• Freud 1/8" double flute straight bit, here.
• Whiteside RU1600 1/8-in solid carbide spiral up-cut, here.

Any wisdom is welcome, and thanks in advance!

 

[Stick486]

There are several ways to cut acrylic, but regardless of which method you use, you will want to prevent your cutting tools from becoming a source of damaging heat.*
Use a table saw, preferably with a carbide-type blade with 10 teeth per inch.*

Choose a saw blade that is designed for cutting acrylic. *
The blade’s teeth should be fine, of the same height, evenly spaced, with little or no set.* Be sure to feed the acrylic into the saw blade at a steady rate — feeding it too fast or too slow can cause the edge of the material to melt.
Thin pieces of acrylic (1/8″ or less in thickness) can be scored like glass using a scribing knife, metal scriber, awl or utility knife, and snapped apart.

Note:
This process does not work well for long cuts and may not leave an edge that is flat enough for capillary gluing...

Regarding saw blades...

I'm very tempted to make the cuts with the Diablo 40 tooth blade in my saw (this blade).
I've done enough reading and youtubing to know that the perfect blade would have more teeth like this one.
And I wonder if the difference is worth $50. All opinions welcome.

the 40T blade is a poor choice...
it will chatter and ''grab'' your plastic...
you need to remember that acrylic is nick sensitive and the nicks will cause/lead to cracking/splitting under tension/compression....

 

[Stick486]

Use an O‑Flute Up Spiral Bit for the slot....

use this bit to cut your plastic and not the TS...
allow the bit to cool off from time to time to avoid heating the acrylic....

Note:
you need to remember that acrylic is nick sensitive and the nicks will cause/lead to cracking/splitting under tension/compression....

polish all cut edges w/ mega fine wet sand paper..
lightly RO the right angles w/ sanding...

 

[Stick486]

First project is a cursor that will travel over a measuring tape on a jig... cut the acrylic about 4" long and 1" wide; score a line down the center of the length and put red ink in it before removing the protective film; route a 1/8" slot about 5/8" wide at each end to receive the machine screws that will mount it with a little adjustment room for calibration.

score your line and fill it w/ tinted acrylic cement....

 

[Stick486]

how about polycarbonate instead of acrylic???

.

 

[Cherryville Chuck]

I just looked up Freud's plastic cutting blade and it's similar to a melamine cutting blade. The blade would need to be near zero or negative hook angle to avoid the grabbing that Stick mentioned. I also recommend a zero clearance saw insert. I see that Freud has a 7 1/4" melamine blade and you can run it on a table saw, it just won't have much depth of cut but you don't need much for your job. It might be cheaper. You can also scribe through a sheet with a laminate cutter manually which is only a few dollars but you'll need to work at smoothing the edges or use a router to trim them.

 

[Stick486]

You can also scribe through a sheet with a laminate cutter manually which is only a few dollars but you'll need to work at smoothing the edges or use a router to trim them.

Downshear Helix Flush Trim Bit followed w/ mega fine wet sand paper..

 

[sreilly]

As much as I appreciate the need/want to make your own I looked at this once myself and having replaced my Sawstop fence with an Incra I remembered that I already had the lens I needed on the unused fence. See if this part fits your needs and maybe save some money for other tools/blades/bits you need. Here's a picture of it as well and for $7 plus shipping maybe a good deal. If you need dimensions let me know and I'll measure it for you. I used this on my monster table saw sled for the very same reason.

 

[Danman1957]

Chuck,
I have used my 100 teeth Melamine blade on Plexiglass with good results. I also use a fine tooth metal jigsaw blade for cutting curves.

Dan

 

[AshleyJ]

@sreilly, that's a great suggestion, thank you!
I would very much appreciate dimensions if you could send them.
Again, thank you!

 

[sreilly]

2.5" wide by 2.25" tall

Forgot to mention it has a magnifier circle to help read the tape measurements as well.

 

[TenGees]

...I also use a fine tooth metal jigsaw blade for cutting curves...

I've found that a jigsaw can be troublesome by welding the cut back up if the blade gets hot.

 

[sreilly]

Forgot the picture.........