[danrudolph]

Do any of you use your cutoff tool to create a chamfer or radius on the part before cutoff?

I've never has this work for more than a handful of parts before chipping the cutoff tool edge and leaving a pip on the part, even with very conservative feeds. I always plunge and make relief for making the chamfer.

I use mostly 1mm and occasionally 2mm wide tools on 303, 316, and 6Al-4V. Even running delrin, I have very inconsistent chamfers using the cutoff.

I've finally given up and will never attempt it again. I use a backturn or a groove tool to create any chamfer and only move my cutoff in the X axis, never Z.

Any of you get the cutoff tool to chamfer and not chip the edge?

[beege]

Do any of you use your cutoff tool to create a chamfer or radius on the part before cutoff?

I've never has this work for more than a handful of parts before chipping the cutoff tool edge and leaving a pip on the part, even with very conservative feeds. I always plunge and make relief for making the chamfer.

I use mostly 1mm and occasionally 2mm wide tools on 303, 316, and 6Al-4V. Even running delrin, I have very inconsistent chamfers using the cutoff.

I've finally given up and will never attempt it again. I use a backturn or a groove tool to create any chamfer and only move my cutoff in the X axis, never Z.

Any of you get the cutoff tool to chamfer and not chip the edge?

What kind of insert are you using for parting? We almost always chamfer or radius as part of the cutoff cycle. Plunge to just beyond where the chamfer will end, then back out and turn the feature toward center, using the face of the tool, never the side

[MCImes]

I chamfer/rad with my cutoff thousands of times per week. the cutting block of my cutoff looks like this:

(.187 stock, .010 chamfer)

T0505 (iscar 2mm cutoff)
G0 X.21 Z1.00
(skipping over some code...sub approach, sync, chuck sub)

G1X.150F.0015(PLUNGE)
X.2F.02
W-.030(BEGIN OF CHAMF)
X.193(ABOVE STOCK)
X.187W.020F.0009(BURR PREVENTER/RAMP IN)
U-.020W.010F.0005(CHAMF TO OAL)
X-.05F.0015T0 (CUTOFF)

On one machine I use a NTK .060" wide cutoff that comes to a sharp point. This one is more succeptable to corner chipping. Ive noticed that sometimes when I touch off the tool it will move a couple/few thou so if you rapid too close to the stock it will hit and chip the edge. In that case I cheat my numbers a few thousandths and just change the nnumbers to something like this:

X.200(ABOVE STOCK) (CHEATED)
X.192W.020F.0009(BURR PREVENTER/RAMP IN) (CHEATED)

The other cutoff I use is an Iscar Tang grip 2 or 3mm cutoff that has a .004 corner rad. I strongly prefer this tool over a sharp point cutoff. It is extremely consistent with the cutoff chamfer/rad. I have put up to a .125 rad on the end of the part with the 2mm tool. In that case I did 4 plunges to clear stock so it was only cleaning up a little material on the final G2 move. Also you can push the iscar cutoffs a lot harder. I use .001-.002ipr with the 2mm and .0015-.003ipr with the 3mm.

So try a cutoff/insert with a small corner rad and you'll never have this issue again! (you'll have to cheat your cutoff numbers slightly as it is easier to do that than using cutter comp on the cutoff, in my oppinion)

[Ned-Dragon]

G0X.280 Z? T1
X.195
G1X.167F.000
G0X.237
W-.035
G1X.167W.035
X-.05
"not possible to make radius"

=============

blending radius with chamfer
change Z
G0X.280 Z1.01 T1
X.195
G1X.164F.000
G0 X.187
Z.9988
G2 X.1852Z1.0009 R.003 F.000
G1 X.1688Z1.0091
G2 X.1645Z1.01 R.003
G1X-.05

[danrudolph]

Ok, well the one part that was chipping cutoff tools has been resolved. I was using a 2mm NTK cutoff and didn't have much of a hold on it with the subspindle, maybe .050" of grip length. The 2mm tool was putting too much pressure on the part during cutoff and chipping the edge (it wasn't the chamfer op). The part was pulling out of the sub collet.

Switched to a 1mm cutoff and it worked perfectly with no additional changes.