How to machine this part?

[great white]

I'm making some forming dies and can't quite figure out how to make a part (somewhat) accurately.

The part looks like so:



The part in question is the long square stock with the radius cut into it. The radius is roughly 1 1/8".

What I've got to work with is my dovetail mill and my Atlas 10F.

I though maybe boring a piece of square stock and splitting it in half, but i don't have the ability to bore that deep. Same with drills.

If I clamp it to the bed of the mill, I can't seem to picture how to cut the long radius in the square stock because I can't see how the quill rotation can operate a tool to cut in that direction.

Anyone with a little more experience than me (which wouldn't take much!LOL!) want to make a suggestion?

 

[WobblyHand]

I'm making some forming dies and can't quite figure out how to make a part (somewhat) accurately.

The part looks like so:

View attachment 421822

The part in question is the long square stock with the radius cut into it. The radius is roughly 1 1/8".

What I've got to work with is my dovetail mill and my Atlas 10F.

I though maybe boring a piece of square stock and splitting it in half, but i don't have the ability to bore that deep. Same with drills.

If I clamp it to the bed of the mill, I can't seem to picture how to cut the long radius in the square stock because I can't see how the quill rotation can operate a tool to cut in that direction.

Anyone with a little more experience than me (which wouldn't take much!LOL!) want to make a suggestion?

Going to say, I know less than you, but ball mill?

 

[great white]

Going to say, I know less than you, but ball mill?

an 1 1/8" ball mill?

 

[WobblyHand]

an 1 1/8" ball mill?

Hmm, missed that. How about something like a router bit with the correct profile? Similar to: https://www.woodcraft.com/products/...004269702d6582000e8d,5b17dc28776f6f59d0001739
That one is a 1.25", maybe you could find 1.125".

 

[jwmelvin]

Going to say, I know less than you, but ball mill?

That’d be a huge tool for one pass, but what about a bunch of long passes like a CNC would do. You could rough with a regular end mill then switch to a ball end mill for finishing. Spacing of passes depends on what you need for surface. Maybe smooth with a file or sander?

 

[jwmelvin]

Or, cut a piece of pipe and weld it in a channel?

Or, line bore on the lathe?

 

[WobblyHand]

That’d be a huge tool for one pass, but what about a bunch of long passes like a CNC would do. You could rough with a regular end mill then switch to a ball end mill for finishing. Spacing of passes depends on what you need for surface. Maybe smooth with a file or sander?

Using the technique that @jwmelvin wrote, with a round nose router bit? Rough it first then finish with the router bit?

 

[ttabbal]

Can you tilt the head on the mill? If so, you could make a fly cutter that has the right radius. That would work with a right angle attachment on the mill as well.

Whatever you use, removing the bulk of the material with a normal end mill is probably a good idea.

 

[jwmelvin]

Can you tilt the head on the mill? If so, you could make a fly cutter that has the right radius. That would work with a right angle attachment on the mill as well.

I was wondering about this, but to get the desired shape, the cutter's rotation axis needs to be parallel to the workpiece; I don't think there'd be enough clearance even with a right-angle attachment.

You could approximate it with the tablesaw method of cutting coves...

 

[great white]

Can you tilt the head on the mill? If so, you could make a fly cutter that has the right radius. That would work with a right angle attachment on the mill as well.

Whatever you use, removing the bulk of the material with a normal end mill is probably a good idea.

only tilts 45 degrees from vertical. I suppose you might be able to make that work, but the angle seems like it would muck things up.

I have thought of maybe clamping the workpiece to the table and running a cutter along a side of it, but I'm right back to needing a tool that will cut a full 1 1/8" for at least a finishing pass. The tool rotation direction just seems wrong no mater how i look at it.....