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Part too large for a 5" chuck?
- Thread starter martik777
- Start date
- Joined
- Apr 23, 2013
- Messages
- 1,060
Find center of part . Center punch drill and tap 1/2 -13 hole about 1 inch deep Using hand drill or drill press.
Use a piece of 1/2 -13 allthread thru spindle with a washer to retain part against
face plate or chuck. Turn 3.7 step on end. Remove allthread . Chuck on step and finish.
Jimsehr
Use a piece of 1/2 -13 allthread thru spindle with a washer to retain part against
face plate or chuck. Turn 3.7 step on end. Remove allthread . Chuck on step and finish.
Jimsehr
Sounds fine to me.
I don’t see how the suggestions to drill a hole and put it on an arbor or threaded rod is going to work, you need to machine the tapered counterbore before flipping it and doing the large taper, so there can’t be anything through the bore to do that. One way around that is an expanding mandrel that stops short of the counterbore so that feature can be machined.
If you have a face plate, you can hold it on the perimeter with clamps and do the bore and counterbore, then face it to the step diameter. Once that is done, you can use a through bolt to hold it to do the step on the back side, then you will be able to hold it in your 5” chuck to do the front side taper.
What lathe are you doing this on? Might be an opportunity to get a 6” or larger 4 jaw chuck, then this will be simple, and you will have the 4 jaw for future projects.
If you have a face plate, you can hold it on the perimeter with clamps and do the bore and counterbore, then face it to the step diameter. Once that is done, you can use a through bolt to hold it to do the step on the back side, then you will be able to hold it in your 5” chuck to do the front side taper.
What lathe are you doing this on? Might be an opportunity to get a 6” or larger 4 jaw chuck, then this will be simple, and you will have the 4 jaw for future projects.
- Joined
- Jan 31, 2016
- Messages
- 12,379
If you could make a straight cut on the tapered end which your chuck could grab safely , the job would be a piece of cake .
Order of ops would be
Straight cut tapered side to 4.5" x 1/2" depth and face . Just don't cut too deep , you'll be into the taper .
Flip part and face , complete entire bore , counterbore , OD step and OD .
Flip part again , indicate finished face and .760 bore , compound the taper .
Are you done yet ? ( my boss used to ask me this as soon as he handed me the job . I always told him the dunyet was a river in Africa )
If you feel unsafe doing it this way , just use a pressure pad or put a center in it and hold it in place with the tailstock also . It won't go anywhere .
Order of ops would be
Straight cut tapered side to 4.5" x 1/2" depth and face . Just don't cut too deep , you'll be into the taper .
Flip part and face , complete entire bore , counterbore , OD step and OD .
Flip part again , indicate finished face and .760 bore , compound the taper .
Are you done yet ? ( my boss used to ask me this as soon as he handed me the job . I always told him the dunyet was a river in Africa )
If you feel unsafe doing it this way , just use a pressure pad or put a center in it and hold it in place with the tailstock also . It won't go anywhere .