[WATERJET71]

Hi,

I need to ream a hole .250 dia Plus .000 minus 0.0005 can I get the tol with a reamer? I have a haas mini mill brand new. or can I use an endmill the depth its about .625 the material is aluminum.

Tx

[txcncman]

I always found finish ream size is hit or miss. A new ream might cut oversize. A dull one might cut even more oversize. Run at one RPM and feed and get one result. Change RPM or feed and get a different result. Milling it might get you a tapered hole. Want a guarantee? There is not one. Personally, I would get one 0.249 ream and two 0.2495 reams. Then I would try them and find the right combination of tool, RPM, and feed.

[rockcliff]

everything txcncman said, plus sometimes it can help to slightly chamfer the hole before going in with a reamer, you can also play with the hole size, which will give different results, but overall I would say yes once you get to size, you should be able to hold 0.0005" on quite a few parts, before you start to see some inconsistency's