- Joined
- Aug 7, 2018
- Messages
- 668
Hi Luc,
The standard way to cut any thread on a tube, is to use a mandrel ! 5/8" 27 should be easy.
Turn up a piece of bar long enough to hold in the three jaw plus the length of your work.
Turn to suit your tube. Make it a good fit for your tube without it binding.
Drill and thread the free end, any convenient size.
Countersink the threaded end.
Mark the mandrel so that you can put it back into the three jaw in exactly the same place it came from.
I use a pop mark to indicate jaw 1 and a scribed line to indicate the face of that jaw.
Now slit the mandrel at the threaded end, down its length about 2/3 of the length of the workpiece.
Make a cone that will fit on your screw and fit the countersink that you made in the mandrel.
Using a screw with the cone on it, screw it into your mandrel.
Now when you put your tube onto the mandrel, tightening the screw will cause the mandrel to expand gripping your workpiece.
If your tube is very long, make the mandrel longer and use a hex head bolt with a center drilled in the head. Then support it with a live center in the tailstock.
The standard way to cut any thread on a tube, is to use a mandrel ! 5/8" 27 should be easy.
Turn up a piece of bar long enough to hold in the three jaw plus the length of your work.
Turn to suit your tube. Make it a good fit for your tube without it binding.
Drill and thread the free end, any convenient size.
Countersink the threaded end.
Mark the mandrel so that you can put it back into the three jaw in exactly the same place it came from.
I use a pop mark to indicate jaw 1 and a scribed line to indicate the face of that jaw.
Now slit the mandrel at the threaded end, down its length about 2/3 of the length of the workpiece.
Make a cone that will fit on your screw and fit the countersink that you made in the mandrel.
Using a screw with the cone on it, screw it into your mandrel.
Now when you put your tube onto the mandrel, tightening the screw will cause the mandrel to expand gripping your workpiece.
If your tube is very long, make the mandrel longer and use a hex head bolt with a center drilled in the head. Then support it with a live center in the tailstock.