[Uhrenholt]

Hi,

I’m trying to figure out how to machine some H7 fit holes with a conical clearance from the backside. The H7 holes are rather deep, and I want to make proposal for the customer with this conical hole from the backside, as if possible to drill/ream, will make the part a lot easier to make. It is for the food industry, so I can’t just drill a bigger hole with a drill, as it will be impossible to clean. And I need to make about 500 10H7 holes????

I have been searching the internet for conical pin reamers and drills, but I can’t find anything that is made for machining centers, and can be used to machine stainless steel.

Any help is appreciated☺️

Cheers,

Daniel Uhrenholt

[Jim Dawson]

How about a tapered end mill? They come in many angles.

[Uhrenholt]

How about a tapered end mill? They come in many angles.

Hi Jim,

That might actually work! It is still a bit about cycle time, but with this it might pay off milling it, instead of having a drill/reamer broken and stuck in a part, that is rather complex and have been CNC milled for days! (Been there with another part!) Material cost is also $$ Stainless Steel and Amaloy 210 is not cheap with this size of parts! I will find some cutting data Monday and power up hypermill and take a look at it??

My only concern is about the chips and getting them out of the hole,
I’m thinking about using a 8 millimeter tapered end mill with 1degree angle to get the hole right, and make a circular pocket with a step over around 0.1mm at full depth. Coolant is internal, but I might need a new shrink fit holder to get the coolant where I need it...

If anyone has ideas about this, any input is greatly appreciated. I need a realistic plan for my boss and our customer Thursday morning!

Cheers,

Daniel

[awerby]

I'm sure you can get tapered reamers just the size you need, although if it's an extremely odd size it might need to be custom-made. But if you use a tapered endmill for this, leave some clearance and do a circular trepan, rather than just jamming it into the hole.