Drilling or machining vertical hole/pocket in edge of cylinder?

[4ssss]

A key point is that the plug is as close to the same material as the part as possible. Don't use a steel plug in an aluminum part, for example.

Correct.

 

[chips&more]

Sorry, not enough info. What is total of 2 holes length, diameter of hole(s), any steps in holes, tolerances?...etc. Can’t help with tool procurement without more info…Dave

 

[Ray C]

I think lot's of ways to skin this cat. Hmmm, maybe I would pre-drill starting with a slight undersize (by 1/64") diameter of the small bore in the base. Next, another drill hole slightly undersized of the larger holes. Finally, I'd get a sacrificial drill bit of the desired diameter and grind a shoulder on it.

There's one more thought to cloud things up even more ...

Ray

 

[RandyM]

Interesting comments. I personally don't understand the design. I think a lot could be done to solve all concerns. I mean, if those are mounting holes, why not just use the flanges preventing the need to counterbore the holes.

 

[coherent]

I mean, if those are mounting holes, why not just use the flanges preventing the need to counterbore the holes.

That's a very valid question and may be the easiest option. There is a mounting plate on my Z axis that is pre-drilled and tapped for mounting such a fixture. But, the spacing is much narrower (the width of the hole spacing I've put in the drawing. I could just drill some through holes in the flanges for mounting (obviously what they were made for) and drill and tap new holes in the Z plate to match... however using the flange spacing they would interfere with existing screws/spacing where the plate mounts to the linear bearings unless it's placed higher than I wanted to mount it. One option would be to have a plate sandwiched between the two... drilled to match the existing bolt hole pattern on the z then another set of threaded holes to match the flange's holes. The right thing to do would have been to just machine my own mount in the first place, or spend $100 for a spindle mount from the company the machine is from instead of a cheap ebay mount. I was thinking quick, cheap and easy. As usual one of those expected results seem to always be proven incorrect. I think simply plunging very slowly with a center cut end mill will work for the pockets. It's aluminum and I think if I go very slowly it will be ok. I was just wondering if there was a really easy "duh" way of doing this I was not thinking of. I think I'm over thinking a fairly simple task.