Cutting Styrene Round

[Horrorshow]

I need to cut some round styrene pieces as headlight covers for a NASCAR build. Any suggestions?

 

[64SS350]

Paper punch, disc cutter punch(check eBay), drafting templates, find a dowel rod the size you want (of wood, steel,??) lightly glue to it's end and sand around it.

Hope this helps 

[NOBLNG]

Michaels has these in the leather working section.

[Fat Brian]

I start with a square the size I need then clip the corners into an octagon and then just sand it round. This way I can make them whatever size I need without a tool.

[Ace-Garageguy]

For rounds too small to use a circle-cutter (compass) or too big for my Stanley multi-punch, I use these old-school "gasket punches", a tool that's been around now for probably 100 years.

Below is the Stanley punch for small holes and rounds.

[stitchdup]

leather punch for up to 5mm, around 12 bucks in the hobby shop and does sizes from 2mm up to 5mm.

 

[slusher]

the standard paper punch in school supplies at Walmart is ther perfect size !   I have one..

[atomicholiday]

I’ve been wondering about this topic too.  Would something like this punch & die set work?  I’ve used them in the past with sheet metal, but never plastic.

Also wondering if the same thing would work for round decals?  Or would they paper just tear?
 

Edited July 13, 2023 by atomicholiday

[PHPaul]

A Whitney Punch  works great for thicker plastic and metal.

[peteski]

3 hours ago, atomicholiday said:

Also wondering if the same thing would work for round decals?  Or would they paper just tear?

That depends on how  precise the fit of the punch and die is.  If they have very close fit then they can punch even very thin materials, but it the fit is too sloppy, then the thin punched material will tear or even stretch.

[TarheelRick]

Bought a set of these at Harbor freight and there is one size in there that works perfectly for headlight covers, of course depending on headlight size and whether one light or two.

[NOBLNG]

2 hours ago, PHPaul said:

A Whitney Punch  works great for thicker plastic and metal.

It will indeed punch holes in metal up to 1/16 thick or so. But the punches have a center point on them which distorts the slug. OK if you want the hole, NOT good if you want the punching.

 

Edited July 14, 2023 by NOBLNG

[Straightliner59]

These are essential, if you're a scratchbuilder. I also have a set that screw into a handle, similar to these. I have an old Waldron punch and the Micro Mark set with the plexiglas guide. I also have a few I've made.  Different punches work better for different purposes.

[LDO]

I like this one. It goes from 1mm to 50mm. I made a bunch of discs to mask road wheels for a tank, while painting the rubber “wheel” on the outside diameter. These were made from magazine subscription cards.
 

I tried cutting a smaller one that is 1/24 car headlight size. For that I used .020” Evergreen sheet styrene. I had to turn it a bunch of times to cut through .020”. I think .010” would be better, but I don’t have any right now. This is not the only brand for this type of cutter. I don’t remember the prices. 
 

Some notes on using it; the bottom is covered with non-stick pads that are included. These are not optional. The tool will try to move the paper or plastic being cut. The entire base should be on what’s being cut, the blade can move the material around. Also, the next circle can’t be too close to the last for the same reason (when cutting paper). I think that .020” is the thickest that can be cut, at least for smaller diameters. For larger diameters, a compass type cutter is better, and easier to set for the proper size. (Divide desired diameter in half, then use a caliper to make two holes in paper, then set the compass point and blade in the holes).That’s really darn close to the desired diameter. 

Edited July 15, 2023 by LDO

[Chariots of Fire]

Simple tool.  Take a piece of brass tubing and taper the ends so that it is thinnest on the inside.  Use a piece that suits the diameter you need.  Place it on a piece of flat thin evergreen and hit it with a hammer.  You'll have a round headlight cover.

[Bainford]

48 minutes ago, Chariots of Fire said:

Simple tool.  Take a piece of brass tubing and taper the ends so that it is thinnest on the inside.  Use a piece that suits the diameter you need.  Place it on a piece of flat thin evergreen and hit it with a hammer.  You'll have a round headlight cover.

Yes, an excellent and inexpensive solution. I have a selection of brass tube punches I've made, some sharpened on the outside and some sharpened on the inside, depending on whether I want the hole or the disc. If I want the disc, I use a punch sharpened on the outside to avoid distortion of the disc during the punch operation.

Having said that, the Dspiae tool posted above is quite intriguing. 

Edited July 21, 2023 by Bainford

[LDO]

One disadvantage of the DSPIAE* tool is that it’s “centerless”. It does a great job of making circles, but it can’t make a circle with a centered hole (think of a vinyl record). I drove myself batty and wasted three sheets of styrene trying to make it work. It is also difficult to get a circle to an exact diameter (if you measure with a ruler, it’s ok. If you use a dial caliper, you’ll need cut several circles, chasing the right diameter with each try).

*I’ve heard the name pronounced as a word, like “Display” minus the L. 

[NOBLNG]

1 hour ago, LDO said:

One disadvantage of the DSPIAE* tool is that it’s “centerless”. It does a great job of making circles, but it can’t make a circle with a centered hole (think of a vinyl record). I drove myself batty and wasted three sheets of styrene trying to make it work. It is also difficult to get a circle to an exact diameter (if you measure with a ruler, it’s ok. If you use a dial caliper, you’ll need cut several circles, chasing the right diameter with each try).

*I’ve heard the name pronounced as a word, like “Display” minus the L. 

Here are some ideas for finding the center of a circle.

http://www.modelcarsmag.com/forums/topic/157592-simple-centre-finder/#comment-2334317

Edited July 21, 2023 by NOBLNG

[bobss396]

I save unused kit headlights. I have sanded off the texture and used that as covers.

When I worked for a living, I was going past the punch press scrap bin, I found a bunch of round blanks that measures around .270", perfect for old NASCAR builds.