Hand reaming with chucking reamer

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Clunker1

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I have a harley engine nose cone bushing that must be line reamed with the right side crankcase. The pinion shaft bushing in the nose cone is in a blind hole. I fabricated a pilot sleeve for the bearing race of the crankcase to line ream. I plan to use a chucking reamer as there is not enough room in the bushing blind hole for a hand reamer to get past the taper.

It would be very difficult to anchor the crankcase/nose cone assembly nose down to my milling machine table. Is it feasible to machine a square end on the chucking reamer and use it as a hand reamer?
 
Clunker1 said:
It would be very difficult to anchor the crankcase/nose cone assembly nose down to my milling machine table. Is it feasible to machine a square end on the chucking reamer and use it as a hand reamer?
Click to expand...
Probably. Unlikely that the shank is very hard. Hit it with a file. That will tell you.
 
Do you have a turret type mill where you could clamp long parallels to the table and attach the housing to the underside of the parallels, swing the head and bore the bushing? Or possibly bore the bushing prior to install as the bore ”should” be in the correct location?
 
I have an old 8d Gorton with fixed head.

I dont know if I could put bars across the crankcase half, (split side up and nose cone down), using long studs from the bars to t nuts in the table to sandwich the assembly down to the table? I'm afraid it would scoot though.

Line reaming is required to line the crankshaft pinion with the nose cone bushing in the bolted on nose cone. Tolerance for the bushing bore to the pinion shaft is .0005- .0012 loose. It is doubtful I could line up the bores with that accuracy. Loose fit on this bushing means low oil pressure to the rod bearings as well as the rest of the engine..
 
Clunker1 said:
Line reaming is required to line the crankshaft pinion with the nose cone bushing in the bolted on nose cone. Tolerance for the bushing bore to the pinion shaft is .0005- .0012 loose. It is doubtful I could line up the bores with that accuracy. Loose fit on this bushing means low oil pressure to the rod bearings as well as the rest of the engine..
Click to expand...
But, do you really need circa 0.0005" accuracy over the full space between the bushings, or just an angular
accuracy that leads to .0005" precision on the relative tilt of one bushing bore to its mate? It would
seem that you could make a fixture to locate the blind bush, and dial in accurately enough to co-locate
the open-end one.

I envision a fixture that engages as a locating pin to the blind hole.
 
Clunker1 said:
I have an old 8d Gorton with fixed head.

I dont know if I could put bars across the crankcase half, (split side up and nose cone down), using long studs from the bars to t nuts in the table to sandwich the assembly down to the table? I'm afraid it would scoot though.

Line reaming is required to line the crankshaft pinion with the nose cone bushing in the bolted on nose cone. Tolerance for the bushing bore to the pinion shaft is .0005- .0012 loose. It is doubtful I could line up the bores with that accuracy. Loose fit on this bushing means low oil pressure to the rod bearings as well as the rest of the engine..
Click to expand...
OOF.


My fear here is that if you take away the lead taper of the reamer, and leave it flat across the ends of the flutes it will want to cut big.

How big is anyone's guess.
 
Might sound crazy, but you could mig weld or braze a square nut on the round end for use with a tap wrench. You can always remove it later, and it's faster than milling a square end onto the reamer. Center the nut by eye and hold it with a vise grip underneath in a vise vertically, 5 seconds later with the mig, and it's done.
 
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?
 
Probably would wobble due to the uneven hand torque on the tap handle. still need pictures
 
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