doublegunshop.com - home Forums General Discussion DoubleGun BBS @ doublegunshop.com Ever mill a SxS raised rib to sunken rib insitu?

Marc,
Any radius is possible. Simply use a convex side milling cutter (horizontal mill cutter) and a horizontal mill or a stub arbor in a vertical mill and tip the barrels up. By using a cutter of just the width needed to cover the widest point of the rib, you can then grind any radius on the cutter desired and still not hit the barrels. I know not everyone has the equipment, but I'm just stating what is possible if you're willing to pursue it.

I almost forgot, tipping the head on a verticle mill with a square cornered cutter will also allow you to cut a larger radius with a smaller diameter cutter. You can only use a certain portion for producing a true radius (or very close to it) because it forms an elipse when the head is tilted.

So, for a test of this, tip the head of the mill with a, say, 3/4" endmill in it about 30 degrees. Then cut test part. You'll get a pretty large radius in about the middle 1/2" and then the raduis tightens up quickly around the edges. Somewhere you can find a formula for this process that will produce the desire radius. I've used it many times in the past (20 or more yrs ago).

If you use a ball endmill to cut the rib, tilt the head similarly to above such that the center of the endmill doesn't cut a little swirl down the middle of the rib.

Chuck
Now you talking. Tipping the head to the side on the milling machine is the way to go.
If you have a Bridgeport type Mill.
Also drilling a hole midway down the rib you can install
a small sight that will look like it belong there
Casey

Casey,
I recall cutting something like a 24" radius on a Bridgeport (glorified drillpress) with a large (10" ish?) flycutter tipped at an angle.

Would you cut it with the head at an angle from the begininng, or would you mill the raised rib down close to the barrels with a small diameter end mill and then swap to a larger diameter cutter with the head kicked up?

I'd tip the head and cut a practice piece and use an optical comparator or other (string or trammel cut template for a radius gauge) method to check the radius and then set the barrels and cut them with some shallow cuts and keep going down to the depth of choice.

Marc, this is just a thought, if the rib has a center bead, just remove the center bead and see if the rib is hollow. You should be able to see just about how thick the rib is at near the center point.

I'm NOT a metalsmith as you are aware so this is just a guess on my part.

Marc
With this setup you make a final cut .002/.003 deep and very
good feed rate to make the rib finished with a nice tool marks
Casey

Doug-

no center bead, but great idea though!

Casey-

What feed rate would you reccomend? I plan on using just a plain ol' 4 flute carbide end mill. Well, of course I coule use HSS as well.

Marc,

Just to give you an idea of a light set up, here are pictures of my
Manufrance Ideal's barrels:


JC