Curved profile on a manual mill?

[Spookydad]

I am fairly new to milling and could use some help. I have a SX3 manual mill with DROs

I have to make a few of these parts. The dimensions are not super critical, but the 5/8" end has to fit into the end of some galvanized electrical conduit. So I end up grinding off a little to make it fit.

Do I need a rotary table?



Thanks

Neil
The image is also here:
http://i13.photobucket.com/albums/a2...0mill/tang.jpg

[v860rich]

Does your DRO have an arc machining function? If so try this link if you don't know how it works, it should be close to the same procedure no matter who the mfg. is.

http://dropros.com/DRO_PROS_Digital_Readout_Videos.htm

Almost forgot, yes you could use a rotary table

THANX RICH

People say I'm getting crankier as I get older. That's not it. I just find I enjoy annoying people a lot more now. Especially younger people!!!

[Spookydad]

No. I have two simple single axis DRO's with no built in functionality other than to zero it out. ;-)

Neil

[jugs]

A rough & ready way if you don't have a rotary table -

A
-clamp a milling sub-table with locating mandrel (bit of scrap bar/plate tapped to take a ¼" shoulder bolt with some washers to lift work above sub-table).
-center spindle over mandrel & ZERO,
-wind out Y axis 0.478" + ½ dia of your cutter & ZERO,

B
-wind out some more (for clearance),

-drill ¼" hole 0.55" from the end of a 3' length of 1" x ¼" bar.
-mount bar on mandrel so long side is on your right & clamp up using spring washer so it's tight but movable.
-start machine & wind to ZERO (cutter will now be......cutting )
-slowly pull bar toward you & you are cutting an arc, continue moving clockwise till you've done 180°.
-remove, cut off component length & repeat from B

[Spookydad]

That sounds simple. ;-)

I will give it a shot and see how it goes. I was planning to print out a pattern on paper and then glue it to the stock. Then I can eyeball the second part of the curve. I will finish it up on the sander.

Neil

[loose nut]

Look at the bottom (post # 9) of this thread, they want a similar operation. It shows a similar method to what Jugs is talking about.

http://bbs.homeshopmachinist.net/showthread.php?t=51690

[Paul Alciatore]

Just a thought, you could go to a lot of trouble getting that "right", whatever "right" means. But you specify the material as aluminum without calling for any particular alloy. I would try to make one pattern and use a router with a carbide cutter and ball bearing guide to make the basic profile. There is a 1/4" hole that could be drilled in the blanks and used to bolt it down to the pattern. This pattern would be set about 1/2" to 3/4" below a cutout in a surrounding table area for the router base to ride on to leave clearance for the hold down bolt. The pattern could be aluminum while the platform it is mounted in could be wood or particle board. Then the router could make fast work of cutting it with no chance of going too deep. The two inside corners could then be cut on a mill with a bunch of them stacked with the square ends pointing up. This would be far faster than trying to do that profile in a manual mill. Find an aluminum alloy that cuts well with a high speed router bit.

[Toolguy]

6061 T6 works fine for that. I cut it with router bits quite often, both on the router table with a ball bearing pilot and on the CNC mills without a pilot.