Tooling Help

I need to remove corrosion around a 3.5" diameter hole by machining a 4"-4.5" "counter bore" around the hole until the corrosion is gone. What type of tool/ method can I use for this? I'm using a manual mill.

Does it have to be round or just "kinda round"....??

doesn't have to be perfect. its getting filled back in and re-machined to spec

So can you just use a 1/2" endmill and do a little dance around the edge of the hole?

Tobes said:

I need to remove corrosion around a 3.5" diameter hole by machining a 4"-4.5" "counter bore" around the hole until the corrosion is gone. What type of tool/ method can I use for this? I'm using a manual mill.

Click to expand...

You can use a boring and facing head in the mill to create a professional looking counterbore which could be filled with a washer. Those heads are expensive, so not every shop has one.

If filling in the removed material with weld, the machined-out portion need not be all that round and flat.

Larry

If you have one, a rotary table will allow you to remove more metal and faster than a boring head because you can use a regular end mill of your choice. Make one end of a plug fit the center hole of the rotary table, the other end fits the hole in the workpiece, it's now centered for rotation concentric to the existing hole. This can be used for future jobs too with a reamed center hole. Remove the corrosion to the diameter and depth of your choosing. Just don't try climb milling on most rotary tables, use conventional milling with the lock slightly on to dampen vibration. Once you make the "locating plug" you can be cutting chips in about 15 minutes. You can even crank the head over for an angled wall (draft) or use a ball end mill if you wish. Hope this helped.