Hole Finishing with Reamer

The hole would be bigger then 5mm, you want to leave about .5mm on the diameter for the reamer. Less than that will result in the reamer 'dancing' in the hole and it will cut oversize and most likely out of round. Surface finish would suffer as well.

Just a note, the reamer will follow the drill, it the hole need to to be straight, you should consider using a boring bar rather then a reamer.

Just a bit of correction, the reamin allowance depends on

Material

Size

Tool Supplier recommendation (eg ISCAR normally specifies a bit more allowance)

Genearlly the allowances are

<5 mm : 0.15mm

5-20: 0.25

20-32 - 0.3

33-50 - 0.5

51-70 - 0.8

71-120 - 1.0

(these are our ranges, upto 150 we have the chart where the allowance must be 1.5mm)

THANKS..!

Depends on hardness.

Softer materials reamer will cut more. In Harder materials it will take less.

As others have posted, drill undersize leaving sufficent allowance for reamer to remove the coldworked as drilled layer.

Follow manufacturer guidleins for allowance based on hardness/ material.

This link should help:

skilledtradesmath.com/files/Reaming_Holes.ppt

milo

You should tell your instructor that this is a trick question. Why would anyone ream a hole which is already 5mm with a 5mm ream? April fool.