Cutting internal Keyway

CAMCOMPCO · 2006-11-28T12:42:56+00:00

Hi all,I am trying to cut a 2 inch internal keyway into some CRS and am havingsome trouble. I have an Atlas 7" shaper and have ground a bit out oftool steel (kiln hardened after grinding). The issue is that I getdeflection because of the tool being a bit over 2 inches long. What'shappening is that the keyway is being cut just fine at the beginning ofthe hole but is deflected down to nothing by the time the cutter getsto the other side of the hole (2" further). I am using 1/2 inch toolsteel and thought that it should be strong enough to not deflect. Do Ineed to make the cutter out of 3/4 inch steel? If so, how would onecut a keyway into a 5/8" hole (2 inches long)? Should I make my cuttingtip smaller (width), right now it is .25" wide (the width of the keywayI need.Any help would e greatly appreciated.I had one idea, that was to anneal a file, cut it, drill holes in it,make a new clapper attachment to hold the file with screws through theholes I made in the file and file away the group....in effect,converting the shaper into an automatic file...just seems like I shouldnot have to do that.Thanks againJohn

Nov 28, 2006 22 Replies

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Grant Erwin 19 years ago

I always heard shapers would do better cutting a keyway if you ground the tool so it cut when you pull it, and mount the tool so it cuts on the top, and have it cut on the return stroke. You have to do some thinking to get your cutting speed right, because of course the ram travels faster on the return stroke.

Ever since this thread started I've been trying to remember where I heard/read that. But I just can't quite remember. Nor do I have any links, pictures, descriptions or accounts whatever.

Grant

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Gunner 19 years ago

Be sure of course..to clamp the clapper so it doesnt move, when slotting.

Rule #35 "That which does not kill you, has made a huge tactical error"

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Gunner 19 years ago

Hanging around in old oil field shops, Ive seen shapers running both ways. The issue is..if its a blind slot. Open on one end, or on no ends. When you push the chip load towards a blind end..chips tend to stack up. So lots of guys will drill/mill a hole at the end of the slot, to allow the chips to break off and have some place to go. In this case, using conventional shaping...ie using the down feed, yes..drawing the chip back towards the shaper works well indeed..as you are pulling the chip out of the slot. If the OP had a bar thick enough, and with good tool geometry..drawing would be a good thing but keep in mind..you are plunge cutting..and it requires a much different tool form as your back relief becomes an issue in a shaft. Inside slots..work ok either way. I slot forwards, simply because of the hassle of adjusting the return stroke speed..which is the cutting speed on a draw cut.

All of this is the reason shafts are generally milled and IDs are now mostly broached

Chuckle

Gunner

Rule #35 "That which does not kill you, has made a huge tactical error"

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