Cutting Circles in heavy Card board stock

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accooper

Well-Known Member
Anyone know of an easy way to cut circles in heavy card board stock?

Andrew

sj_h1

Well-Known Member
Pin a piece of string to the center and attach the other end an xacto knife. If you need it more precise use a piece of wood instead of a string, drill holes for the knife and pin( or nail) and use a screw to hold the knife in place.

MarkII

Well-Known Member
Here is my method: Draw or print out the circle. Cut out very carefully (freehand) with an X-Acto knife with a new, sharp blade. (A brand-new blade helps enormously. No matter how recently I changed the blade in my knife, I always cut out patterns, templates, circles, etc. with a new blade.) Clean up the edge as needed with some 320 grit sandpaper. Once you have done this a bunch of times, you won't need to do much clean-up.

I have built many cardstock models in the past five years, and in the process I have gotten pretty comfortable with cutting curves freehand with an X-Acto #1 knife fitted with a #11 blade. The practice effect of doing this a number of times really helps, and it seems to be sort of like riding a bike - once you get comfortable with it, you never lose the skill.

MarkII

brianc

Well-Known Member
Pin a piece of string to the center and attach the other end an xacto knife.
If you use this method, pay attention so the string doesn't wrap around
your knife and suddenly get shorter around the arc...

MarkII

Well-Known Member
If you use this method, pay attention so the string doesn't wrap around
your knife and suddenly get shorter around the arc...
Cool way to cut a spiral, though...

MarkII

powderburner

Well-Known Member
If you do some searches on the TRF1 archives using search terms like "circle cutter" or "Olfa" you should be able to pull up lots of old posts with advice on tools, techniques, etc.

Put a dot of superglue on the center of the circle to help keep the locater pin on the circle cutter from wandering around and making the circle sloppy. If it is thick cardboard, make a light pass with the circle cutter and finish with a hand-held Xacto.

Also, you should try just drawing the circles with a sharp pencil and cutting the discs freehand with a sharp Xacto blade. It won't take much practice and I think you will find that you can get darn close that way, especially if you are going to glue them in place anyway.

Wait until Hobby Lobby puts their picture framing matte board on sale (which they do about every other week) for half price. You can get a lot of CRs out of a 30 x 40 sheet, you get one side that is great for drawing and you get to choose your favorite pretty color for the other side.

OTOH, it is also dirt cheap to order a bunch from somewhere like Balsa Machining or Totally Tubular. Order in quantity (100 +) and some places give you a discount. Having a big box of lots of sizes of CRs sitting on the shelf, ready to go, is nice, and amazingly affordable.

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luke strawwalker

Well-Known Member
Here's how I do it...

Works like a champ... Hobbico Circle Cutter, got mine for $6 at LHS... (local hobby shop) Should be available at any good hobby shop or online. Later and good luck! OL JR MarkII Well-Known Member Here's how I do it... Works like a champ... Hobbico Circle Cutter, got mine for$6 at LHS... (local hobby shop) Should be available at any good hobby shop or online.

Later and good luck! OL JR
I have one of those, too, but I rarely use it. (In fact, it's been years since the last time.) It is great for cutting circles in thin paper, but in order to cut anything thicker, I have to put pressure on the cutting end. I do that by pressing on the cutting end with my free hand. This ends up throwing the whole thing off balance, and it is very difficult (nearly impossible) to keep the center point on the correct spot during the process. The last couple of times that I used it, I just scored the cardstock or cardboard with it, and then I finished the job freehand with my X-Acto. Subsequently, I dispensed with the initial scoring step, and just attacked the circles with the knife. My circle cutter has been sitting neglected in a box ever since. It's a nice concept; I just wish that I could find a better way to make use of it.

I think that the big problem is that it uses a straight horizontal beam that sits only a fraction of an inch above the paper. It is hard to exert leverage with that arrangement. With a traditional triangle compass, the pressure point is high up and midway between the center and the drawing (or cutting) tip. In that arrangement, it is possible to exert balanced pressure on both tips at the same time. Having the pressure point up high also gives you more leverage. This is the type of device that I have in mind:

It is available here.

MarkII

powderburner

Well-Known Member
It is available here[/URL].
If you are willing to spend that much money, have you checked out automotive tools called "gasket cutters"? They are made specifically for cutting precision circles out of thick material.

luke strawwalker

Well-Known Member
I tend to use my Hobbico cutter more like a fly cutter. I make multiple passes with light pressure, sorta 'twirling' it round and round, so to speak. It works ok...

Of course I have a REAL fly-cutter hole saw I got at Harbor Freight a couple years back that I use on wood and other 'heavy' projects... OL JR

MarkII

Well-Known Member
For fly cutters or gasket cutters, I need to have a drill press. I am still trying to save up enough money to buy one.

MarkII

accooper

Well-Known Member
B-4 I get a drill press I'm saving up for a bench sander.

Andrew From Texas

Micromeister

Micro Craftman/ClusterNut
TRF Supporter
B-4 I get a drill press I'm saving up for a bench sander.

Andrew From Texas
Andrew until then Powderburner & Mark have about the best suggestions, the Olfa cutter is by far my preference for heavy cardstock, Sho-Card and Railroad board (OD waterproof 14 and 28ply sho-card).
About the only thing we have to remember is to let the tool do the work, don't try to force it or it will undercut or "run out" of it's path.

Here are a couple other options for circle cutters i've used in the past. the big red handled thing is a Mat cutter for photo mounting picked up at Pearl discount Art Center. While it worked very well, I snapped the pot metal body cutting some thick 28Ply sho-card awhile ago and have not been able to find a replacement since Pearl Art Centers went out of business in my area.

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PemTech's Squeeze

Well-Known Member
I do a lot of cutting sometimes with an Exacto knife and I find that using a bit of leather to strop it really helps a lot. I just keep one handy and give it some wipes along the leather as I go and it really helps with the cutting.

I like the sound of a "gasket cutters" whatever that is though too for circles.

Stropping, you whippers snappers who don't know what it is, is using a plain ole peice of leather (hide, not suede) to sharpen an already pretty sharp blade. Instead of a whetstone, you run the blade at about a 45 to 30 degree angle along the leather, pulling backwards (go forwards and you'd cut into the leather). Yer grandpappies used it to keep their straight edge razors sharp, and the leather they stropped with to keep their kids in line.

So sayeth
Trudy
Pemberton Technologies Art Department and all around cheerleader

Peartree

Cyborg Rocketeer
Staff member
Global Mod
Andrew until then Powderburner & Mark have about the best suggestions, the Olfa cutter is by far my preference for heavy cardstock, Sho-Card and Railroad board (OD waterproof 14 and 28ply sho-card).
About the only thing we have to remember is to let the tool do the work, don't try to force it or it will undercut or "run out" of it's path.

Here are a couple other options for circle cutters i've used in the past. the big red handled thing is a Mat cutter for photo mounting picked up at Pearl discount Art Center. While it worked very well, I snapped the pot metal body cutting some thick 28Ply sho-card awhile ago and have not been able to find a replacement since Pearl Art Centers went out of business in my area.
Micro,

RangerStl

Well-Known Member
Stropping, you whippers snappers who don't know what it is, is using a plain ole peice of leather (hide, not suede) to sharpen an already pretty sharp blade. Instead of a whetstone, you run the blade at about a 45 to 30 degree angle along the leather, pulling backwards (go forwards and you'd cut into the leather). Yer grandpappies used it to keep their straight edge razors sharp, and the leather they stropped with to keep their kids in line.

So sayeth
Trudy
Pemberton Technologies Art Department and all around cheerleader

Knocks the burr off the fine cutting edge, and the unruly child!

Micromeister

Micro Craftman/ClusterNut
TRF Supporter
Micro,

Actually both ways John:
The smaller compass is setup strictly for matt cutting with a very thin very shape blade that fits in a recessed channel in one leg. While the 8" compass as round chisel cut blades that fit in the standard lead slots. Both were found at local art supply stores.

Trudy
Couldn't agree with you more on the stropping, I just finished making a new one for my Son-in-Law and have one handy just about everywhere in the house...even set up the better 2/3rds with one that now stays with the kitchen knifes butcher block set LOL!!!
I've made it a habbit every time I pick up an X-acto it gets stropped 8-to-10 passes each side before I start the project.
Adding a little jewelers rouge to the flesh side of your strop to really keep a razors edge on your cutting tools, Doesn't hurt to strop the circle cutters blades about 10 passes on each side each time you pick it up either

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accooper

Well-Known Member
Where can I buy a cutting compass like what you have shown? Please remember I live in South Texas.

Andrew

Micromeister

Micro Craftman/ClusterNut
TRF Supporter
Try any good Art supply store, some of the larger Craft type store like Micheals, AC Moore, or Pearl Discount Art Centers (I seem to recall they were based in Texas?) If no luck locally try www.dickblick.com on-line.

You might also look at framing shops as some of these cutters are used in cutting matt backgrounds for photos and pictures.

MarkII

Well-Known Member
Try any good Art supply store, some of the larger Craft type store like Micheals, AC Moore, or Pearl Discount Art Centers (I seem to recall they were based in Texas?) If no luck locally try www.dickblick.com on-line.

You might also look at framing shops as some of these cutters are used in cutting matt backgrounds for photos and pictures.
In addition to the sources that Micro mentioned, you can also order one online from Micro-Mark. (See the link in my earlier post. Or here.) With the exception of the Hobbico cutter, I don't really know how the price of the Micro-Mark compass-style circle cutter compares to similar products from other sources. If it is only a little bit more expensive, it might still be a suitable buy if you don't have ready access to one of the craft stores mentioned previously, or if the stores don't carry them. BTW, the compass-style unit isn't the only circle cutter that Micro-Mark carries; see this accessory for this item. (Yes, it's expensive, but it goes out to 6 feet! OK, probably way more than what any of us need.) But they also have this item, too, which is probably a bit more affordable.

MarkII

accooper

Well-Known Member
Those are some great ideas. I will check them out!

Andrew

luke strawwalker

Well-Known Member
For fly cutters or gasket cutters, I need to have a drill press. I am still trying to save up enough money to buy one.

MarkII
Check Harbor Freight, Northern Tools, Homier, or Cummings Tools... they have some VERY affordable drill presses that are satisfactory for hobby use...

I got my flycutter for about $9 at Homier... flycutters are kinda difficult to find in the regular hardware stores-- they want to sell you individual hole saw cups for$10 or more EACH... :y: And they're not even adjustable!

Anybody got a link to one of these gasket cutters somebody mentioned?? I goofed around on yahoo looking for them for a bit, but everything I found was in the $100+ range... sure made that$30 "drafting compass" style cutter look affordable!

Later! OL JR

powderburner

Well-Known Member
Anybody got a link to one of these gasket cutters somebody mentioned?? I goofed around on yahoo looking for them for a bit, but everything I found was in the $100+ range... sure made that$30 "drafting compass" style cutter look affordable!
Finding a gasket cutter in usable condition is not going to be cheap. Check ebay, and you might get lucky, but if the item is in good working condition you may end up bidding against a mechanic.

I would like to emphasize that I have had pretty good luck with simply drawing an accurate circle and using a free-hand Xacto to cut out the part. It's not as hard as you might think. Make the first pass (or two) with light pressure on the blade as you follow around the circle, without trying to cut all the way through. After I have the circle cut into one side of the material, I pick it up and "saw" the Xacto blade through the rest, working around the circumference and staying in the circular path already there. It takes a few minutes but it's the sort of thing you can do while half-watching TV or something. If you need a really precisely sized CR, you can still order them, but home-made CRs will do fine for 90% of your building.

And high-quality cardboard (smooth on one side for laying out patterns or laminating pre-printed paper patterns) is on sale for half-price this week at Hobby Lobby in the form of picture framing matte board. You can get a darned big sheet of the stuff for a few bucks, enough to last for years of making CRs.

luke strawwalker

Well-Known Member
Finding a gasket cutter in usable condition is not going to be cheap. Check ebay, and you might get lucky, but if the item is in good working condition you may end up bidding against a mechanic.

I would like to emphasize that I have had pretty good luck with simply drawing an accurate circle and using a free-hand Xacto to cut out the part. It's not as hard as you might think. Make the first pass (or two) with light pressure on the blade as you follow around the circle, without trying to cut all the way through. After I have the circle cut into one side of the material, I pick it up and "saw" the Xacto blade through the rest, working around the circumference and staying in the circular path already there. It takes a few minutes but it's the sort of thing you can do while half-watching TV or something. If you need a really precisely sized CR, you can still order them, but home-made CRs will do fine for 90% of your building.

And high-quality cardboard (smooth on one side for laying out patterns or laminating pre-printed paper patterns) is on sale for half-price this week at Hobby Lobby in the form of picture framing matte board. You can get a darned big sheet of the stuff for a few bucks, enough to last for years of making CRs.

Good tips...

I'd add that for folks who find the Hobbico-style circle cutters hard to use, there is another trick that's a hybrid of powderburner's method... use the Hobbico cutter to scribe the circle by making a couple passes, and then switch to a regular hobby knife to finish the job. The circle cutter should leave you a nice smooth even groove for your hobby knife to follow almost effortlessly to finish cutting them out. I've done that once or twice on really thick stuff...

Good luck! OL JR

MarkII

Well-Known Member
Good tips...

I'd add that for folks who find the Hobbico-style circle cutters hard to use, there is another trick that's a hybrid of powderburner's method... use the Hobbico cutter to scribe the circle by making a couple passes, and then switch to a regular hobby knife to finish the job. The circle cutter should leave you a nice smooth even groove for your hobby knife to follow almost effortlessly to finish cutting them out. I've done that once or twice on really thick stuff...

Good luck! OL JR
I was going to suggest that too, but you beat me to it. Good point!

MarkII

Micromeister

Micro Craftman/ClusterNut
TRF Supporter
Another thing I've found helpful on thicker stock and harder materials is to flip the material over when you've cut about half way thru to finish with most of the compass or bow compass type cutters. by that time you'll have already penetrated or have a very good dimple to locate center with.

Works on most woods, Polycarbonate and styrene plastics also.

MarkII

Well-Known Member
Another thing I've found helpful on thicker stock and harder materials is to flip the material over when you've cut about half way thru to finish with most of the compass or bow compass type cutters. by that time you'll have already penetrated or have a very good dimple to locate center with.

Works on most woods, Polycarbonate and styrene plastics also.
Probably with enough practice, you can do that reliably and accurately. Me? Well, I'd be too afraid that my cuts on each side wouldn't line up. And I'd probably be right. :bang:

MarkII

accooper

Well-Known Member
What is a flycutter and what is it for?

Andrew From Texas

brianc

Well-Known Member
What is a flycutter and what is it for?
A very small scalpel used by entomologists...