Precision hole thru thin wall

[Justin Beebe at Folsom Tool]

I have a part with a small tab that sticks up. The tab is .060 thick. I have to drill a hole thru the .060 thick wall that is .1895 +- .0005

The material is 1505 stainless. I am going to drill to .165 diameter, plunge with .177 endmill then ream with a .1895 reamer. My question is should I leave the wall thicker ream the hole then go back and cut the wall to thickness or should I ream the hole when the wall is already .060 thick, or will it work either way. I will try to post a screen shot.

 

Thanks

[Justin Beebe at Folsom Tool]

[/img]

[Justin Beebe at Folsom Tool]

[Guest CNC Apps Guy 1]

I'd favor leaving it as is because of the tight size requirement. When you were to leave it heavy, when you finished it to size, you'd end up with a burr that ultimately could scrap your part whe you remove it. I'd also leave only about .003/side for ream.

 

JM2C

[Justin Beebe at Folsom Tool]

CNCapps

 

The burr was one of my concerns. Also I thought the hole might distort if I went back and milled it. I just wasn't sure how the reamer would react going thru the thin wall. As it stands now I'm leaving .00625 per side for the reamer. That is as long as my endmill doesn't cut oversize. If it gives me any problems I'll try to leave less.

[MotorCityMinion]

Idea: Finish the flange, which by itself is an obstacle, then clamp a sacrificial spacer between those two flanges, then drill, e-mill, ream.

 

.006 per side for ream on a hole that small does seem a bit heavy.

 

Depending on the machine that your using, I might even eliminate the reamer all together and just size with the e-mill. Our Hass would make that hole kinda iffy. Our Makino, no problem.