Back Chamfer help needed

[Fueler]

Using this tool.

https://www.maritool.com/Cutting-Tools-End-Mills-Chamfer-Mills-Back-Chamfer-Tools/c78_79_154_380/p16...

The top chamfer is no problem but I am semi stumped on the second operation of chamfering the bottom of the hole.

Haven't found the combination yet to get it to the bottom of the hole, beyond and back into it.

Can someone advise please?

Thanks

Dave

[LibertyMachine · Accepted solution]

Couple of these; You had your lead-in settings set too high and it was recognizing the collision that was going to occur. You also had your angle set to 30 degrees, for some reason. Personally, when working with circles, I prefer to set my Lead-In/Out angle to 135 degrees, somewhat mimicking a "return to center" type move that you would find in the Circular or Bore milling operations. I also reduced your lead in to prevent collisions.

Now, onto the issue of the Back Chamfer. This is one operation where math gets you close, and then fudging and guessing gets you the rest of the way. Once you get it set perfectly, do yourself a favor and save that as a template so you don't have to go through the whole mess again.

Chamfer mill (regardless of how there are defined) don't yet recognize cutting on the upper side. You have two options if you want to cut a backside chamfer:

1) Math and fudging "Stock to leave" and Bottom height Offsets

2) Dovetail Mill and select the bottom contour of the chamfer. Also using Stock to leave in the Axial and Radial

Take a look at what I did for your part and let me know if you have any questions

[Fueler]

Thank you Seth,

You cleared the forest from the trees.

I now have an new understanding how "stock to leave" can be used beyond it's inferred title.

Was there some math involved or did you just adjust the stock left until the sim lined up?

Dave

[LibertyMachine]

Yes? 

Simple math, really. You need to know the distance from the end of tool to centerline of the 45 degree tips (this is full diameter). Selecting the very bottom chamfer and then giving it an offset (in the Bottom Height offset) of that same amount allows it to go to centerline, rather than off the lower portion of the tool. In the Chamfer section, I also gave it another .01 offset. Because it's the chamfer offset, it has the effect as moving it radially and axially. I could have put it all in the Bottom Height offset, but that would have changed my Stock to Leave.

The Stock to leave....That was adjusting until the Sim lined up. I'm sure there was math one could do to arrive at the value needed, but I'll be honest, the fudging was easier