Need Help!- Accurate Small Hole Milling in 15-5 PH Steel

[yaji63]

I have an application where i need to mill a 1.6mm diameter hole to a depth of 5mm in a 15-5 PH steel component. The accuracy of the hole is +/- 0.005mm. I have been trying to interpolate using a 1mm endmill which has a flute length of 2mm and the back is relieved. I' am not able to get consistency and each component comes out differently. I use a Deckel Maho machine which is very accurate. Can anyone help me with an alternative process idea or some method where i can get consistency in hole size with my present method ?

Using a Reamer is tough as the positioning accuracy is also very important and a reamer usually takes the drill position so the drill can guide it to wrong position. Just letting you guys know in case somebody thinks of reamer as an option.

Thanks

[Geof]

Drill, interpolate a very small amount undersize to get the position precise, then ream; the reamer will follow the interpolated hole.

[yaji63]

Thanks. i was thinking on the same lines but was wondering whether a reamer of this size will work in 42 HRC PH steel. Any recommendation for reamer ?

[Delw]

Carbide Reamers work good.

one other thing you can do if your having problems is use a precision Boring head, you might have to make a bushing to hold a solid carbide boring bar for the boring head as most have small 1/8 shanks. Micro 100 sells boring bars that would work for your application.

if you have a 5/8 dia hole in your boring head you can use hardinge tooling split bushings to hold the bars they make them in all dia and hold boring bars very rigid

[rapidtraverse]

With boreing heads, I've experienced repeatative success with inserts. Although micro 100 is a total quality product, perhaps inserts are more cost effective.

[beege]

Originally Posted by rapidtraverse With boreing heads, I've experienced repeatative success with inserts. Although micro 100 is a total quality product, perhaps inserts are more cost effective.

Did you see the hole size at 1.6mm? It'd have to be a special insert, yes?
+1 on the drill/bore/ream. Just have to be very careful with reamer runout. Carbide, yes; ±.005mm about uses up the +.005mm tolerance the reamer manufacturer usually makes them to. Measure all your reamer carefully!