Alright Gang….
What is the best way for me to mark and cut a 30″ circle on 3/4″ plwood?
Need some help. Just a weekend warrior…..
Alright Gang….
What is the best way for me to mark and cut a 30″ circle on 3/4″ plwood?
Need some help. Just a weekend warrior…..
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Replies
a yard stick and two nails. one at one inch, the other at 16 inches..schwing it round, then get a 40,000 $ water jet CNC to cut it out.
Spheramid Enterprises Architectural Woodworks
"Sell your cleverness, Purchase Bewilderment"...Rumi
And where would you be gettin' this cheap water jet,friend?
EBay...(G)
Spheramid Enterprises Architectural Woodworks
"Sell your cleverness, Purchase Bewilderment"...Rumi
Yeah, I think he missed a zero!
You could use a router, that would give you the cleanest, most accurate circle. Or if you don't have a router or the bit, you could put a nail in the center that you want, then use a string and pencil to mark you circle, then cut it with a jig saw. Below is a link for how the router would generally set up.
http://www.garymkatz.com/Tool%20Reviews/PCRouterFence.htm
Do you have a router?
Mount the router on a trammel or swing arm. Drill a smal hole on the trammell 15" from the edge of the router bit.
A nail through the nail hole of the trammel set in the center of the circle...fire up the router, plunge it in, and cut the circle.
For a 3/4" depth might want to make three 1/4" deep passes. It's easier on the router and bit.
On the last pass, you might need to do it in a couple of starts/stops and shift your work to make sure you're not cutting through the support table below.
My preference:
First rough cut the circle slightly oversized (1/8" to 1/4" radius larger) with a jig saw, then use the router set at full depth (one pass) to clean up the edge to your desired 15" radius.
I've also cut circles with the router inverted in a router table while swinging the piece around a pivot point.
If you don't have a router, use the CNC water jet that Sphere mentioned.
Do you have a router?
I really like the "woodslicer" BS blades from Highland Hardware, I did some serious sawing with this one ( about 30 bucks) that I got, man, they are sweet.
Same deal, pivot on ext. table.
I doubt he has a BS tho'.
One can also attach a jig saw like you said to a trammel, thats what I have resorted to in the past.
As amatter of fact, b4 I could buy a BS, I had a jig saw mounted upside down on an old sink cut out over a 55 gal drum for cutting curvey stuff.
Mother of invention and all that.
Spheramid Enterprises Architectural Woodworks
"Sell your cleverness, Purchase Bewilderment"...Rumi
Thought about the "weekend warrior" comment...
If you don't have anyhting but a circular saw, then mount the circ saw on a swingarm. Set the pivot point 15" from the edge of the blade.
Set the saw to cut about 1/8" deep and swing a circle.
Set the depth to 1/4" deep and repeat.
Repeat increasing the depth of cut 1/8" each time.
Support the waste for the last cut so it doesn't jump and bind the blade.
The edge will probably need cleanup with sandpaper, but the method should work.
You ever try one of those triangular blades for a circ saw? remember them? supposed to allow curves...
Spheramid Enterprises Architectural Woodworks
"Sell your cleverness, Purchase Bewilderment"...Rumi
I remember them, but have enver used one.
I've cut a fair number of cured pieces with a circ saw and a regular blade.
Easier to do if rough cut first, have to be a little mo'beddah carful if plunge cutting.
Looks like they're still making them.
HERE IS HOW AND WHY IT WORKS!!!.
LOL...Thank ya very mooch..looks scary if not, iffy to me.
Spheramid Enterprises Architectural Woodworks
"Sell your cleverness, Purchase Bewilderment"...Rumi
Those things work fine for rough carpentry Sphere.
I used to use a router and trammel. I tried those weird blades. They worked fine, but took an extra minute because I had to switch the blades (twice). Now, I just use my regular saw.
Those weird blades do have one very good advantage. They can cut a much tighter radius than a regular 7.25 marathon.
If this 30" circle needs a finish edge, I'd use a router. If a rough edge is fine, I'd just mark it and cut it with the sidewinder.
blueJust because you can, doesn't mean you should!
Warning! Be cautious when taking any framing advice from me. There are some in here who think I'm a hackmeister...they might be right! Of course, they might be wrong too!
Anyone else notice that Alan seems to have bailed on this project? I guess he never got a round to it.
I tried that. Problem was that the belt got loose with the table upside-down like that.It was also a little hard to move it around.
By far... rough cut it... then router with a circle guide.
I seem to remember seeing 30" x 3/4" plywood circles for sale at my local Menard's lumber yard, in the same part of the store where they sell plywood shelves. It may be worth checking at your local big box store - I'm sure they're more expensive than making your own, but it would be a lot less trouble.
Cutting circles in plywood always reminds me of this story I posted last month.
55087.7 in reply to 55087.4
I just read about two construction workers who made the 2001 Darwin Awards; they fell to their deaths after cutting a circular hole in the floor, while they were standing in the circle.
"Of course I know this defys the laws of gravity, but fortunately I never studied law"
Mr T
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