[thoru]

Hi all,

I've to ream the upper hole (see photo) to 15H7. How do I align the reamer to the hole and get the piece fixated at the right position? I'm planning on using a press drill for the operation. The hole isn't exactly round, so I can't use a countersink drill or something else conical to align.
Attachment 277532.
For some smaller holes with the same problem I "fixed" the work piece by hand. But for this large size I'm a bit afraid that things might go wrong.
Any advice is highly appreciated.

Kind regards,

Remco Poelstra

[gabedrummin]

On a thin piece you had better bore it.On die blocks that I ream the dowel pins . 1.5 thick Center drill , Drill in at least three steps for a 3/8 reamer, then grab an end mill in a collet the size of the reamer cut .250 deep change out the end mill for the reamer ream through .

[thoru]

Hi,

Thanks for your reply.
That seems the proper way to do it if you start from scratch. The problem is now that these parts came in a kit and are manufactured this way. So all I've is a slightly undersized hole and a reamer (or drill). The drawing states 15H7 (mm), so it seems that a drill will not suffice for the accuracy.

Regards,

Remco Poelstra

[AARONT]

Put it on the drill press use a reamer that is approx .003"-.01" smaller than finish size. Don't fasten the part to the table, let it "float". The reamer will align the part. Then finish with the correct size reamer. The hole won't go oversize this way.

[jeffreyab]

You say the hole is not round . I would make it rainforest or you will have more than just centering problem . Try centering the ream by eye you might be surprised how close you get.