how do I cut a 6-1/4" hole (not circle)
 

I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

Use your collars. Lay out your desired opening on a sheet of template
material. Now determine your bit/collar difference for cutting. Say you're
using 1/2" bit and a 3/4" collar. Nail your fencing strips 3/4" away from
the layout lines. Now cut the pattern (it'll be 3/8" too large in both
dimensions), remove the fences, use your new template to cut your openings,
which will, of course be 3/8 smaller because of the bit/collar difference. .

wrote in message
...
I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

On Thu, 09 Dec 2004 04:17:11 -0700,
wrote:

I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

Get a circle cutter for the drill press. It cuts holes or circles.
Run it at a slow (~400 rpm) speed, use clamps, and be careful.
Depending on the size, a lathe works well too.

Teach me to change dimensions in mid-thought. Change the 1/2 bit to 3/8.

Or, use 1/4 differences with the 1/2 bit.

"George" george@least wrote in message
...
Use your collars. Lay out your desired opening on a sheet of template
material. Now determine your bit/collar difference for cutting. Say
you're
using 1/2" bit and a 3/4" collar. Nail your fencing strips 3/4" away from
the layout lines. Now cut the pattern (it'll be 3/8" too large in both
dimensions), remove the fences, use your new template to cut your
openings,
which will, of course be 3/8 smaller because of the bit/collar difference.
..

wrote in message
...
I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

A plunge router with straight bit and circle cutting jig is about as
sharp and clean as any method you might try and better than most. I
use a Dewalt 621 router, a 1/2" straight bit, and a Jasper circle
cutting jig. I've cut numerous holes for dust collection using this
method. You can make your own circle cutting jig from a flat sheet
material like MDF, tempered hardboard or plywood. The method is
precise enough, that I don't think you need to cut all your holes
simultaneously. Most jigs work off a small pilot pin located at the
center. If you drill this pilot hole in all your stock simultaneously,
then cut your circles individually with the router, the holes will line
up with each other.

The small Jasper circle jig is available from Woodcraft. It has
settings for holes 1" to 7 1/2" in 1/16" increments.

Bob

Circle cutter on a drill press works great and gives really clean
holes

John

On Thu, 09 Dec 2004 04:17:11 -0700,
wrote:

I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

I've read mixed reviews on cutting holes with a drill press in the rec
archives. I'm sure not all circle cutters are created equal. What
brand do you use and recommend?

Bob

On 9 Dec 2004 07:00:41 -0800, "Bob"
wrote:

I've read mixed reviews on cutting holes with a drill press in the rec
archives. I'm sure not all circle cutters are created equal. What
brand do you use and recommend?

Bob

Many stores sell circle cutters (Home Depot, Lowes, Sears, Ace,
hardware stores, etc). Look at the package and find out where it is
made. Made in USA, made in Canada, made in Germany are usually good.
Lowest quality (for machined tools and castings) is "Made in China."
A circle cutter is about the most risky thing on a drill press, so
think carefully during setup and operation.

Is the 6.25" diameter, 3-1/8" radius going to be a challenge?

My PC690's baseblate is 5-3/4" dia. I'm going to be pivoting very
close to it's edge.



On 9 Dec 2004 06:52:41 -0800, "Bob"
wrote:

A plunge router with straight bit and circle cutting jig is about as
sharp and clean as any method you might try and better than most. I
use a Dewalt 621 router, a 1/2" straight bit, and a Jasper circle
cutting jig. I've cut numerous holes for dust collection using this
method. You can make your own circle cutting jig from a flat sheet
material like MDF, tempered hardboard or plywood. The method is
precise enough, that I don't think you need to cut all your holes
simultaneously. Most jigs work off a small pilot pin located at the
center. If you drill this pilot hole in all your stock simultaneously,
then cut your circles individually with the router, the holes will line
up with each other.

The small Jasper circle jig is available from Woodcraft. It has
settings for holes 1" to 7 1/2" in 1/16" increments.

Bob

George,

how do I get the round template to start with?

rough out w/ jigsaw then sand? just curious

On Thu, 9 Dec 2004 07:42:31 -0500, "George" george@least wrote:

Teach me to change dimensions in mid-thought. Change the 1/2 bit to 3/8.

Or, use 1/4 differences with the 1/2 bit.

"George" george@least wrote in message
...
Use your collars. Lay out your desired opening on a sheet of template
material. Now determine your bit/collar difference for cutting. Say
you're
using 1/2" bit and a 3/4" collar. Nail your fencing strips 3/4" away from
the layout lines. Now cut the pattern (it'll be 3/8" too large in both
dimensions), remove the fences, use your new template to cut your
openings,
which will, of course be 3/8 smaller because of the bit/collar difference.
.

wrote in message
...
I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

Did any one notice in the subject line that he says "not a circle"

Circle cutter on a drill press works great and gives really clean
holes

John

On Thu, 09 Dec 2004 04:17:11 -0700,
wrote:

I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

Sorry, I saw the "(not circle)" and assumed it was not going to be a circle.

No problem starting with a trammel point to cut a female template, though.

No problem with a circle-cutting jig and a bandsaw to cut a male jig.

Allow your offset for the collar, and note that you cut in opposite
directions with the router when using female versus male jigs.

wrote in message
...
George,

how do I get the round template to start with?

rough out w/ jigsaw then sand? just curious

On Thu, 9 Dec 2004 07:42:31 -0500, "George" george@least wrote:

Teach me to change dimensions in mid-thought. Change the 1/2 bit to 3/8.

Or, use 1/4 differences with the 1/2 bit.

"George" george@least wrote in message
...
Use your collars. Lay out your desired opening on a sheet of template
material. Now determine your bit/collar difference for cutting. Say
you're
using 1/2" bit and a 3/4" collar. Nail your fencing strips 3/4" away
from
the layout lines. Now cut the pattern (it'll be 3/8" too large in both
dimensions), remove the fences, use your new template to cut your
openings,
which will, of course be 3/8 smaller because of the bit/collar
difference.
.

wrote in message
...
I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,

It shouldn't be a problem. If the work piece in which you are cutting
the hole is small (providing little support for the router), you can
place some supporting stock around it. I usually use a piece of 3/4"
plywood as a base, then place the workpiece and some auxillary support
stock on tope of the plywood base. I'll use carpet tape and/or brads
to hold everything in place. I'll also use F-clamps to hold the base
on the bench. The base is sacrificial. I make sure that the center pin
goes through the workpiece and into the plywood base. This prevents
accidents when you cut through on the last pass with the router.

Your question is a good one, because the success of cutting clean
circles with a router is totally dependent on everything being locked
down tight. Don't depend on holding it with your hands.

Bob

Can't you use a circle cutter to cut a hole?

Bob

Bob

Don't even remember the brand, but the key is to run the drill press
slow, and FEED the circle cutter slowly to get a good clean cut.

John

On 9 Dec 2004 07:00:41 -0800, "Bob"
wrote:

I've read mixed reviews on cutting holes with a drill press in the rec
archives. I'm sure not all circle cutters are created equal. What
brand do you use and recommend?

Bob

On Thu, 09 Dec 2004 21:27:10 GMT, max vaguely
proposed a theory
.......and in reply I say!:

remove ns from my header address to reply via email

Did any one notice in the subject line that he says "not a circle"

Yeah, but I for one am not sure what _is_ wanted.

Round is a bit hard with this method.

"George" george@least wrote in message
...
Use your collars. Lay out your desired opening on a sheet of template
material. Now determine your bit/collar difference for cutting. Say
you're
using 1/2" bit and a 3/4" collar. Nail your fencing strips 3/4" away from
the layout lines. Now cut the pattern (it'll be 3/8" too large in both
dimensions), remove the fences, use your new template to cut your
openings,
which will, of course be 3/8 smaller because of the bit/collar difference.
..

wrote in message
...
I'm building blast gates.

I need to cut some clean 6-1/4" (or thereabouts) holes. Ideally, I'd
cut through the 3/4" + 1/4" + 3/4" at the same time to get a perfect
fit.

I'm guessing the router is the way to go, but can you lead me to some
hints and tips, pictures, or other suggestions?

Thanks,