Table Shear Question

[Dee Gallo]

I have a Table Shear which came with my used laser and I didn't really think I had a need for it. Recently, I needed to cut some acrylic to fit into my laser and thought I'd try it, since the guy said it was a plastic shear. It cut the 1/8" alright, but on the drop off piece (luckily not my workpiece) the plastic is cracked in a few curved lines, ruining it for any future use.

This is a 12" shear from JDS. The manual does not say anywhere what is it supposed to shear. Does anyone know more about this tool?

Thanks for any help, dee

[Richard Rumancik]

Dee, I'd be reluctant to shear 1/8" acrylic. I don't have the specs on the shear itself, but acrylic in my opinion is too brittle for this.

I think you may have success with thinner acrylic (say .020 - .062") like the Rowmark types. Also ABS would probably cut will as it is rubbery. Some of the modified acrylics might shear okay. PETG if you ever use it would shear okay.

You should check the edge of your workpiece under magnification to double check there are not micro-cracks starting. (Hope you don't find anything . . . )

[Joe Pelonio]

I agree with Richard, it's meant for engraving material. You can just use a table saw, circular saw or even jig saw to cut acrylic. 1/8 or less can even be scored and broken but it's not 100% reliable. The easiset thing is to find a supplier that cuts free and order it to fit the laser.

[Dee Gallo]

Thanks, guys!

Joe- By "engraving material" do you mean metal? Wood? Something not so brittle or flexible?

We have an excellent DeWalt table saw - any special blade needed? Or will the acrylic ruin a good blade in any way - like gum it up? My husband would kill me if I ruined his expensive wood blades. :eek:

[Mike Null]

Dee

Freud makes an excellent blade for plastic and aluminum. It is not good for general wood cutting so expect that.

Unfortunately the number is worn off mine but it is an 80 tooth thin kerf blade. Use a zero clearance insert. Support the cut line with masking tape if your edge isn't smooth enough.

It is possible that your JDS cutter is for metal. The blades are usually inter-changeable. If you buy the saw blade you will still need a metal shear.

[Joe Pelonio]

Thanks, guys!

Joe- By "engraving material" do you mean metal? Wood? Something not so brittle or flexible?

We have an excellent DeWalt table saw - any special blade needed? Or will the acrylic ruin a good blade in any way - like gum it up? My husband would kill me if I ruined his expensive wood blades. :eek:
I mean Rowark and IPI plastics. Softer ones like styrene you can easily score and bend.

Like Mike said, you need a special blade or it will gum up. It may be best to use a sabre/jig saw where it's easier and cheaper to replace the blades, and just clamp on a straight edge for a nice straight line. Even those require a blade with medium teeth, plywood blades will get hot and gummy, large teeth will break out bits on the cut especially when you first start.

http://www.rplastics.com/plastictools.html

[Dee Gallo]

Thanks Mike, I'll order a new blade. We use Freud blades and they are excellent. Thanks for the tip on protecting the edge with tape first!

-dee

[Bill Morrison]

If a Borg is near you they have a blade that is red, called Diablo and it has a 3/16 inch kerf which does the job just fine. It's an 80 tooth super fine finish blade. I've never heard of the brand but it does work. It's 50 bucks which is not much but I was there and thought I'd give it a try. I haven't had any problems with it. Might be quicker than ordering one.

Bill

[Mike Null]

One of the secrets to the plastic/laminate blade is what is called the rake. Wood blades have a tooth that's angled forward sharply in the direction of the cut. The laminate blades have a very shallow rake, almost negative. A lot of wood blades have alternating bevel teeth. These are almost guaranteed to chip plastic.

[Dee Gallo]

One of the secrets to the plastic/laminate blade is what is called the rake. Wood blades have a tooth that's angled forward sharply in the direction of the cut. The laminate blades have a very shallow rake, almost negative. A lot of wood blades have alternating bevel teeth. These are almost guaranteed to chip plastic.


Hmmm. makes sense. That must be why I saw some guys using the blade backwards to cut vinyl siding?

I'll check out the borgs near me for plastic/laminate cutting blades and see what they have - faster than ordering and cheaper with no shipping, thanks!

[David Lavaneri]

Dee,

You can tell if your table shear is meant for cutting plastic or metal by looking at the top blade.

If the top blade is essentially square, it's a metal shear. If it's a sharp, knife blade, it's meant for plastics.

There are "hybrid" blades, but as in so many things where you're looking for for one item to pull double duty, they do a fairly poor job, compared to a dedicated blade.

In the awards and engraving business, a typical way to cut rigid acrylic would be with safety saws, which come standard with carbide-tipped blades. Another way, would be to use a typical table saw, fitted with a carbide-tipped blade.

David "The Stunt Engraver" Lavaneri

[Albert Nix]

I went by the local glass shop and had them order me a scoring tool for acylic. You just pull it along a straight edge and snap it. It works fine on 1/8 but take several strokes to cut any thicker.

[Dee Gallo]

I looked at the blade - it's pointy like a knife, so I guess it's made for thin plastics. That clears THAT up!

I have one of those had held plexi cutters, but did not get great results with it. Although, the truth is I only need it to cut a "general" size, since my laser will do the actual shape cutting so edge quality is not that important.

In the end, I went to the borg and bought a cheap plastic/veneer/laminate cutting blade for my table saw for $10. It should last for maybe 50 cuts, which is plenty since I will only be cutting a few 24" pieces down to 14". I already have 12" x 12" pieces of cast I got from Delvies (by the way, Brian, 3 days shipping to NY!) which is very nice stuff!

Many thanks to you experienced guys for the help, dee