Eccentric Hole in Bearing
Eccentric Hole in Bearing
I want to make a camshaft bearing for a 1924 Citroen. The damaged original (see photo) was of cast iron. I want to turn a new one of bronze. As you can see, the I.D. is off-center. This was necessary because of its position in the crankcase. The 2 bolt holes are critical to the alignment, also. The O.D. is 42mm, the I.D. 24mm. I can understand how to turn this part were the hole centered. Any tips on how to locate the off-center I.D. accurately? I do have a 4-jaw chuck.
Phil
Phil
Eccentric Hole in Bearing
Here is a drawing of the part (though the numbers aren't very clear).
Phil
Phil
-
- Posts: 1754
- Joined: Sat Dec 21, 2002 12:16 am
- Location: Green Bay Wisconsin USA
- Contact:
Re: Eccentric Hole in Bearing
Start off by doing the ID first. That will make it easier to know what the offset is when turning the OD by using
a dowel pin in the bore for measuring offset
Rich
a dowel pin in the bore for measuring offset
Rich
- Bill Shields
- Posts: 10459
- Joined: Fri Dec 21, 2007 4:57 am
- Location: 39.367, -75.765
- Contact:
Re: Eccentric Hole in Bearing
Why bronze? Didn't the original last long enough?
Anyway...I would make all except the finished ID...
Start with a rough ID that is on center but small enough to finish out eccentric.
Make a fixture to hold in a mill where you know the locations of the flange screws relative to the center and the axes of the mill.
Move off center and bore it to size.
This assuming that you have a good boring head and the mill has a power feed on the quill.
Anyway...I would make all except the finished ID...
Start with a rough ID that is on center but small enough to finish out eccentric.
Make a fixture to hold in a mill where you know the locations of the flange screws relative to the center and the axes of the mill.
Move off center and bore it to size.
This assuming that you have a good boring head and the mill has a power feed on the quill.
Too many things going on to bother listing them.
Re: Eccentric Hole in Bearing
First bore the proper size hole in the stock that you are going to use and finish it to the proper length.
Make an arbor to fit the hole. Put the original part on the arbor and chuck it up in the four jaw and adjust the chuck until the OD of the part runs true using a dial indicator.
Remove the original part from the arbor and install the new part/stock.
Turn to the proper OD and add the required features.
Make an arbor to fit the hole. Put the original part on the arbor and chuck it up in the four jaw and adjust the chuck until the OD of the part runs true using a dial indicator.
Remove the original part from the arbor and install the new part/stock.
Turn to the proper OD and add the required features.
Glenn
Operating machines is perfectly safe......until you forget how dangerous it really is!
Operating machines is perfectly safe......until you forget how dangerous it really is!
- Bill Shields
- Posts: 10459
- Joined: Fri Dec 21, 2007 4:57 am
- Location: 39.367, -75.765
- Contact:
Re: Eccentric Hole in Bearing
I thought the original was worn and required replacement ...
Too many things going on to bother listing them.
Re: Eccentric Hole in Bearing
As an alternative to making an off-center arbor (or moving the part in the 4-jaw chuck), do you have a mill in addition to the lathe? If so, turn the OD and flange, then mount it in the mill, find the center, and then offset the desired amount and drill/bore the center hole and screw locations.
Re: Eccentric Hole in Bearing
Thanks for those ideas. I'll post a photo when it's done.
Phil
Phil
Re: Eccentric Hole in Bearing
I think I'd look into boring the bearing and making a 660 bronze bushing to press in assuming there is part of the bore or a chamfer to indicate the offset and clock position accurately.
BC
If there was only one way to do each machining job, the smell of sulphurized cutting oil smoke would have fewer fond memories.
If there was only one way to do each machining job, the smell of sulphurized cutting oil smoke would have fewer fond memories.
Re: Eccentric Hole in Bearing
Easy. Put stock in lathe. Turn OD. Put DI on stock and use chuck jaws to move it over offset dimension. If I am reading your drawing right, that is square root of 8 units.
Drill, bore, ream center hole.
Drill, bore, ream center hole.