Re: Making a radius punch and die
Originally Posted by
Jim27
Two edges were cut with some sort of torch. I can grind off a bit to get through the harder part although it doesn't seen much harder. How deep should I grind to get through the hardness?
If you can mill through it then you may not have to worry about it. I normally grind back to the base metal, just take the rough edge off. If you can make the first pass well into the base metal, then you may not need to worry about grinding.
I got a 1/2" cobalt rougher (actually 2 in case I break one...). Next issue I see is how to mount this to cut clear through. It is bigger than the table is wide so I can only clamp at the ends without some fixture. I am thinking I could space it off the table with some scraps of 1/2" aluminum or something similar. Then mill a slot half way across the plate. I could then put a clamp or clamps in that slot and mill the rest of the way. If I put the T slot nuts in place before starting I might even be able to add the clamps without loosing my location.
I am thinking I want to make the cuts in the X direction so I can use the power feed to get even feed. If I do that perhaps I could center the cut over the table and use the outside T slots to clamp and not have to change anything while cutting. But there will be a fair amount of metal hanging off the table. I am thinking I should still mill part way and put a clamp in the center slot to help support things but maybe I am being overly cautious.
Planning to do this manual lube/coolant. The mill doesn't have coolant system but I can give it a shot occasionally.
Sounds like a plan. Many times I pre-stage T nuts. If there is a danger of filling the T nut with chips, screw a set screw into the T nut to keep the chips out until you are ready to use it. Cutting with the X axis is the normal way of doing it. Overall the setup is dependant on the workpiece, machine the work in your head and know what you are going to do before start making chips. A little air would be helpful to remove to the chips. Spacing the work off of the table will help in this regard also, gives the chips somewhere to go.
I am not really concerned about edge finish. How rough is the finish going to be? I could clean it up with a standard mill but will skip that unless it is really rough.
Not that rough, but it depends on whether you are using a coarse, fine, or finishing rougher. Maybe make a test cut and then decide if it is acceptable for the final finish.
Originally Posted by
Jim27
What feeds and speeds for the 1/2" cobalt rougher taking a full width cut? Climb or conventional milling on the edges (on the full width cut it doesn't matter because both sides are cutting)?
About 400 RPM, maybe about 2-4 IPM. I would hand feed, it that way you can feel when the machine and cutter are happy. If you're careful and the machine is stable enough, you can make the full 1 inch DOC with a 1/2 rougher. Watch the color of the chips, silver to gold is OK, blue is getting a bit hot for that setup. As you say, making a full width cut, direction doesn't matter, but on the edge, on that machine you will want to conventional cut. Except for very light cutting, climb cutting requires near zero backlash.
Jim Dawson
Sandy, Oregon, USA