Glenn5ft19
Registered User
I made this attachment to roll threads on the tail brace wires. The 3 legs are 1”x 8” x 1/8”. For the rollers I single point threaded some drill rod 32 T.P.I .700 dia. x .600 x .250dia. hole. Heat treated with a torch then oil quenched. Measured Rc 50. If I were to do it again I would make the rollers .650dia. as now they just barely do 3/16 x 32 tpi. without interfering with each other. Also I would make the holes 5/16ths for added stiffness. To make the rollers I started off by threading a 3” length of stock. I used a file to taper the first 5 threads then parted it to length. Filed the first 5 threads of the next roller then parted it to length and the same for the third one.
The rollers have about .065” end play on the pins to allow them to follow each other into the thread. The jaw pressure in the lathe was set using a 10-32 screw, then removed it with a screw driver. You have to add a bit more pressure, maybe a 1/16th turn on the chuck key. The end rod I was threading (.169”dia.) was tapered for about 3/8ths” to allow it to start. We either held it in a drill chuck in the tail stock or clamped in the tool post and hand fed it. Once it starts, it is self feeding so only a light hand pressure is required to overcome the drag. I tried using the half nut to feed it at 32tpi. But for some reason the rollers wouldn’t follow each other and it chewed up the thread. You may notice in one picture that I used a hose clamp on the end of the pins. This was to stop the pins from flaring too much. The jaw pressure and hose clamp had to be adjusted and fiddled with a bit to get the thread on size.
I was using a Hercus lathe, which is the same as a small South Bend, set at the slowest speed on belt drive, 356 rpm. The deformation speed of a material is about 3 times it’s cutting speed so it seemed to work much better than when we were going really slow in back gear. After it threaded for about 2 inches, the lathe was reversed and the rod backed out. It worked fine on some old steel tail brace wires but I haven’t tried it on stainless yet. When I do I will run some tensile tests and let you know the results.
Cheers
Glenn
The rollers have about .065” end play on the pins to allow them to follow each other into the thread. The jaw pressure in the lathe was set using a 10-32 screw, then removed it with a screw driver. You have to add a bit more pressure, maybe a 1/16th turn on the chuck key. The end rod I was threading (.169”dia.) was tapered for about 3/8ths” to allow it to start. We either held it in a drill chuck in the tail stock or clamped in the tool post and hand fed it. Once it starts, it is self feeding so only a light hand pressure is required to overcome the drag. I tried using the half nut to feed it at 32tpi. But for some reason the rollers wouldn’t follow each other and it chewed up the thread. You may notice in one picture that I used a hose clamp on the end of the pins. This was to stop the pins from flaring too much. The jaw pressure and hose clamp had to be adjusted and fiddled with a bit to get the thread on size.
I was using a Hercus lathe, which is the same as a small South Bend, set at the slowest speed on belt drive, 356 rpm. The deformation speed of a material is about 3 times it’s cutting speed so it seemed to work much better than when we were going really slow in back gear. After it threaded for about 2 inches, the lathe was reversed and the rod backed out. It worked fine on some old steel tail brace wires but I haven’t tried it on stainless yet. When I do I will run some tensile tests and let you know the results.
Cheers
Glenn
