How do you get perfect rounded corners using a router?
 

I have a print that requires me to put an interior hole in a part. It
requires all four corners to be rounded to a 1" radius. How do I do
that without having to buy a 1" drill bit and then having the router do
the straight part?

Also, on a different part, I am required to have all four exterior
corners rounded. How do I do that? Is there something on the market
that will work? I looked into the "route a corner", but it is
unsuitable for a 1" radius. An earlier post mentions the "radius
guide" from Woodhaven, but I was unable to find it on their website.
Any help would be appreciated. Thanks!

funster apparently said,on my timestamp of 23/01/2005 7:08 PM:


Any help would be appreciated. Thanks!


Drill a suitable hole in MDF, then use that as a template
guide for your router? You may need to work out a
proper diameter for the hole depending if you're
using a bearing bit or a template guide bush, but
it will do the job.

--
Cheers
Nuno Souto
in sunny Sydney, Australia
am

One option for both would be to make (or buy) a router trammel which
would give the router a pivot point.

I would make a template for the interior hole by using the trammel for
the corners connecting them with straight cuts as required. Use the
template as a guide for a pattern bit to cut the actual interior hole.
Make the template large enough to get a couple of clamps on it that
don't interfere with the router.

For the exterior corners, again make a template with the trammel and
use a pattern bit. For these radii cut as much of the corner off with
saw as you can. Make very light cuts with the router. This type of
operation can catch the wood and cause large chip out. That will make
you think bad things.

Suggestion, go buy some 1/2" MDF and keep it around for template stock.
You can buy a lot of MDF for the price of most store bought templates.

Sometimes with woodworking you just have to break down and
buy the tools and machines required to do whatcha wanna do.

Otherwise everybody'd being doing it.

UA100

On 23 Jan 2005 00:08:51 -0800, "funster" wrote:

|I have a print that requires me to put an interior hole in a part. It
|requires all four corners to be rounded to a 1" radius. How do I do
|that without having to buy a 1" drill bit and then having the router do
|the straight part?

I think that if I wanted a 1" *radius*, I'd use a 2" *diameter*
Forstner bit.

Or use this: http://www.woodhaven.com/detail.aspx?ID=1863
|
|Also, on a different part, I am required to have all four exterior
|corners rounded. How do I do that? Is there something on the market
|that will work? I looked into the "route a corner", but it is
|unsuitable for a 1" radius. An earlier post mentions the "radius
|guide" from Woodhaven, but I was unable to find it on their website.
|Any help would be appreciated. Thanks!

http://www.woodhaven.com/detail.aspx?ID=170

"funster" wrote in message
ups.com...
I have a print that requires me to put an interior hole in a part. It
requires all four corners to be rounded to a 1" radius. How do I do
that without having to buy a 1" drill bit and then having the router do
the straight part?

Also, on a different part, I am required to have all four exterior
corners rounded. How do I do that? Is there something on the market
that will work? I looked into the "route a corner", but it is
unsuitable for a 1" radius. An earlier post mentions the "radius
guide" from Woodhaven, but I was unable to find it on their website.
Any help would be appreciated. Thanks!

1. Remove the word "perfect" from your vocabulary. Just flush it out of your
brain.
2. For the inside hole, buy a hole saw and 1" bit. Should be about $20 for
both, and you'll have the saw next time, just add other bits as needed.
3. As for the outside, see #1 first. Then use a saber saw, band saw or
router to carefully cut the corner just outside the line you've (yuve, Don)
drawn with a compass. Then sand/file to the line. If it ain't close enough
to within 1/100, see #1 again.
4. Relax--part of the satisfaction in the hobby is knowing that what you do
is mos def not machine made.

Bob

A 1" drill bit would give you a 1/2" radius.

"funster" wrote in message
ups.com...
I have a print that requires me to put an interior hole in a part. It
requires all four corners to be rounded to a 1" radius. How do I do
that without having to buy a 1" drill bit and then having the router do
the straight part?

Also, on a different part, I am required to have all four exterior
corners rounded. How do I do that? Is there something on the market
that will work? I looked into the "route a corner", but it is
unsuitable for a 1" radius. An earlier post mentions the "radius
guide" from Woodhaven, but I was unable to find it on their website.
Any help would be appreciated. Thanks!

"funster" wrote in message

Also, on a different part, I am required to have all four exterior
corners rounded. How do I do that? Is there something on the market
that will work?



You can use a 2" dia round over bit. Hold the pice on edge to make the 1"
radius.
If you are not willing to buy a drill bit, I doubt that you'd spend $40 for
the router bit though.

Another way is to marke them with a pencil, cut the rough part with a jig or
bandsaw, then finish on the belt sander. Youjust put one edge against the
belot and rotate the piece until you are parellel on the other edge and it
will blend in perfectly.

"funster" wrote in message
ups.com...
I have a print that requires me to put an interior hole in a part. It
requires all four corners to be rounded to a 1" radius. How do I do
that without having to buy a 1" drill bit and then having the router do
the straight part?

Also, on a different part, I am required to have all four exterior
corners rounded. How do I do that? Is there something on the market
that will work? I looked into the "route a corner", but it is
unsuitable for a 1" radius. An earlier post mentions the "radius
guide" from Woodhaven, but I was unable to find it on their website.
Any help would be appreciated. Thanks!

Even though I have a router and template set, there are some things I just
won't use it for. It takes a lot of set up time to do small jobs. Unless
its something that just has to be near - perfect, I might use hand tools
instead. Its amazing how much you can do with a good half-round rasp and
some sandpaper and a coping saw. A small drum sander bit in the drill press
is also handy for shaping.

Bob

Many wood working catalogs have router corner TEMPLATES (for outside
AND inside curves) and after years of jig saw/bandsawing, I went with
the templates. Gives really GREAT results and totally repeatable and
identical

Same templates work on BOTH situations

John

On 23 Jan 2005 00:08:51 -0800, "funster" wrote:

I have a print that requires me to put an interior hole in a part. It
requires all four corners to be rounded to a 1" radius. How do I do
that without having to buy a 1" drill bit and then having the router do
the straight part?

Also, on a different part, I am required to have all four exterior
corners rounded. How do I do that? Is there something on the market
that will work? I looked into the "route a corner", but it is
unsuitable for a 1" radius. An earlier post mentions the "radius
guide" from Woodhaven, but I was unable to find it on their website.
Any help would be appreciated. Thanks!

Thanks Everyone for the advice.

I just love workshop gizmos, so I'll probably get the template from
Woodhaven. (I couldn't find it on their website until someone attached
a link here).

Woodworking drill bits are much more reasonably priced as compared to
metal working bits.

Just go to McMaster.com and you'll see that you can spend up over $70
for a high end metal cutting 1" bit. So, drilling out the interior
rounded corner is an option.

I just got back from Home Depot and I was going to split with $30 or so
for a template bit from Porter Cable. Since they keep the expensive
stuff locked up and no sales help anywhere, I didn't bother. Then I
went into their aisle which contains birch plywood. Man that stuff was
warped!! Anybody know where to get quality 3/8" thick birch plywood?
This is for a homebrew computer controlled engraving machine, so warped
won't work. So far it's in the "gather the materials" phase. See
www.hobbycnc.com for more info if you'd like.

Mcmaster has just about everything, including the highest prices around. It
pays to look elsewhere.

"funster" wrote in message
ups.com...
Thanks Everyone for the advice.

Just go to McMaster.com and you'll see that you can spend up over $70
for a high end metal cutting 1" bit. So, drilling out the interior
rounded corner is an option.

"funster" wrote in message

Just go to McMaster.com and you'll see that you can spend up over $70
for a high end metal cutting 1" bit. So, drilling out the interior
rounded corner is an option.

Keep in mind that a 1" radius corner needs a 2" bit.

Then I
went into their aisle which contains birch plywood. Man that stuff was
warped!! Anybody know where to get quality 3/8" thick birch plywood?
This is for a homebrew computer controlled engraving machine, so warped
won't work. So far it's in the "gather the materials" phase. See
www.hobbycnc.com for more info if you'd like.

HD is a crap shoot on the quality. I hot a beautiful piece last week, but
I've walked away empty a few times. For your needs maybe a Baltic birch
ply would be better. Try a wood dealer rather than the big box stores.

"Edwin Pawlowski" wrote in message
. ..

"funster" wrote in message

Just go to McMaster.com and you'll see that you can spend up over $70
for a high end metal cutting 1" bit. So, drilling out the interior
rounded corner is an option.

Keep in mind that a 1" radius corner needs a 2" bit.

WOW! And to think, the best-quality holesaws run ten bucks or less. Seems
you could do a lot for 70 bucks.

http://www.toolking.com/dewalt/view.asp?id=2386