Hand reaming with chucking reamer

[RaisedByWolves]

The crankshaft passes through the right ctankcase half in a roller bearing. I made a 1.5 inch long bushing fitted into the crankcase bearing race bored to guide the reamer in the center. The end of the crankshaft that extends into the bolted on nose cone fits into a bushing in the nose cone and has to be in- line with the center of the bearing race in the crankcase. The fit on the nose cone bushing which is about 3/4" long is supposed to be 0.0005-0.0012 loose on the reduced diameter end of the crankshaft (0.5615 diameter) . The fit needs to be the length of the bushing since oil pressure is applied in the end of the bushing blind hole bore to feed the oil port in the end of the crankshaft. I'll try to incude a picture of the parts and the reaming set-up. Gotta learn how to do it first.

If the pilot bushing I have in the crankcase to guide the reamer in the centerline, would the chucking reamer wobble if used as a hand reamer? Is it because of the slow turning speed? Would it be better to chuck it into a hand drill?

My initial reply was in regards to squaring the business end of the reamer, now I understand you want to put a square for a tap wrench.

If your bushing was reamed with the reamer you need for the bushing I would think hand reaming would be ok. If it was made otherwise it will likely wobble and be inconsistent in the way it cuts.

 

[Clunker1]

Attached are a couple of photos. One shows the crankcase half (see large race where crankshaft protrudes into nose cone bushing). The nose cone is next to it showing inside and small bushing that supports the reduced diameter end of the crankshaft. The aluminum guide bushing that inserts into the race to guide the reamer is also there.

The next picture shows the assembly to be line reamed with my attempt at a d bit reamer inserted that did not work well.

 

[OTmachine]

Thanks for the pictures! Looks like you need to do some CMM type work on your mill. There must be some alignment / locating dowels on your component faces, (you need 2). Housing surfaces need to be parallel to table surface. Usually it is best to align the dowel pins true to the X or Y axis. Pick up location of the crankcase dowels and record. In the same setup, pick up the bearing bore and record. Place the nose cone housing to be bored in the same orientation as the crankcase housing was. Align the corresponding dowel pins or bores the same as you had aligned the crankcase housing. Move machine head to bearing bore location and bore out bushing.

 

[Clunker1]

The bushing to guide the reamer will need to be bored on the lathe centered in the od of the bushing. The reason for this is that the multi-flute chucking reamer is larger in diameter than the shank. The bore will be as close to the shank diameter and still allow a sliding fit.