[kreativjustin]

Hey, I'm not sure if I got this in the right place, but here we go.

I'm running .500" D2 locator pins on a Hardinge CNC Lathe. I'm going to be reaming on center, a .2505" hole at .625" depth. I haven't done too much reaming in CNC machines, usually I'll bore it. What should my feeds and speeds look like for reaming on my lathe? I won't be doing this til later in the week.

It would be helpful if someone can give me a 'Rule of Thumb', or at least how you figured out the feed and speed. Last time I tried on aluminum, it blew the hole over decently, and I'd rather not repeat that lol.

[Jim Dawson]

I normally use 50% of the drilling SFM for reaming, but double the drilling feed/rev, especially in D2. When close coupled a reamer makes a pretty good boring bar rather than following the hole, which will cause it to cut oversize. Normally in a CNC lathe the cutting portion of the reamer needs to be pretty close to the tool holder just due to space constraints so not able to flex using the full length of a chucking reamer shank.

The fix is to use a floating reamer holder to allow the reamer to ''flop'' around a bit so it will follow the hole.

Since you are only going 0.625 deep, boring the hole might make sense. I have used a 2 flute end mill as a boring bar for shallow holes, just set up with one flute tip as the cutting edge. Just grind clearance on the endmill if needed.

[rcs60]

Jim is correct
i usually use 60% of the drill sfm for the material i am doing and .001-.002 ipr per flute
on the chnc the only way i had a reamer work was to stick it out as long as i could to allow so that it could bend to the hole as the tool holders and bushings don't allow much flexing
Hardinge does sell an eccentric 1c collet tool holder that can be used to set the tool on center but i never found it ti be cost effective and just bored the parts

[kreativjustin]

I've used the 1/2 the speed, twice the feed method in the past. That's how I blew the aluminum over lol, that was on the CNC Mill though. For the lathe, I use ER collet tool holders on the turret and indicate zero in, never had trouble holding center with them that way. I do have to cut shanks down on the lathe to get them to fit closer to the tool holder.