Woodruff cutter or EM?

[orionstarman]

I have to cut a .250" wide by .125 deep by 8" long slot down the center of 6 pieces of .500" square 4140. Now I was thinking about using a HSS woodruff cutter, but I don't what kind of feed and speed to use. Or would a .25" carbide EM do the job. I'm thinking the EM will give out before I get all 6 pieces done. Any thoughts?

[Andre' B]

Forget about the woodruff cutter for slotting, they are really only good for cutting woodruff keys.
You maybe can get away with one for such a shallow depth of cut for me at least they have always been less then ideal for slotting.
Since they are not side cutting unless the spindle is perfectly perp to the motion when cutting a long slot they tend to move in or out of the tool holder, or move the part, or put a lot of unneeded stress on the machine.

I would use 2 15/64 carbide stub end mills.
Grab a used but still usable one and run it down the center, (actually about 0.002 off center to account for tool deflection).
Put in a new unused tool and make a pass down each side of the slot, this way you get a nice finish and you can make the slot the exact width you want.

Other then operator error the end mills should do all 6 parts and still have plenty of life left.

Alternately, get a proper staggered tooth side cutting slotting saw and an arbor, but the end mills will likely be more useful for other jobs.

[Geof]

Andre'B is quite correct about using an endmill smaller than the slot, not a Woodruff cutter; in 4140 I think the Woodruff would die very quickly, they are only HSS.

But his general statement is not entirely correct; Woodruff cutters work like a hot **** for slotting...in 6061 . We have several parts that get a 1/8" wide, 1/8" deep groove around a 3-1/8" semi-circle and this is done with a Woodruff cutter; I cannot imagine any other way to do it on a VMC.

The picture shows the part and the end of cutter still in the groove. This happened one time when we had a blip in our electric supply; the machine was part way round the cut when the blip happened and it just zoomed off diagonally across the part before alarming and stopping.

[dertsap]

keyway slot ??


a decent carb tipped woodruff would eat thru 4140 quite easily ,
best alternative would 3/16 endmill , use coolant high speed and feed and ramp it .02 -.03 , you hit the speeds and feeds right it will last the run and won t take too long ,

well , unless it's a few thousand pieces

[Geof]

Originally Posted by dertsap ......a decent carb tipped woodruff ......

Do you have a supplier name? I looked briefly once and did not have any luck.

[dertsap]

i'll try to find out where we purchase ours from ,kbc on Annisis has them , bit pricey ,it won t let me save the link direct to the cutter page , search woodruffs and you'll see the ones from rock river tools
http://www.kbctools.com/can/main.cfm

[big_mak]

http://www.iscar.com/ProductLines/Pr...ineDetailID/13

I'm surprised you haven't looked @ iscar's slotting solutions Geof.

[Geof]

Originally Posted by big_mak http://www.iscar.com/ProductLines/Pr...ineDetailID/13 I'm surprised you haven't looked @ iscar's slotting solutions Geof.

I think I did and the smallest OD was too large to fit. We machine the parts side by side on a length of extrusion.

We use mostly Iscar and have their catalogues and know I had a logical-at-the-time reason for not getting theirs.