"Reverse the shipper-rod"... huh?

[showmedata]

From "How to run a lathe", 1935 edition:


I've looked all through the book and can't find "shipper-rod" identified anywhere. Is there a way to reverse the carriage travel without getting out of synch, other than stopping and reversing the motor? Since I converted to a 3-phase motor on a VFD, my lathe doesn't start and stop quickly.

I'm just learning to cut threads, so if anyone has links to a how-to that is applicable for my 1937 model T 11" SBL, I would appreciate a pointer. I've searched the usual forums and haven't found anything yet.

Thanks.

 

[benmychree]

If you have a thread dial, there is no need to reverse the shipper rod, which on a line shaft lathe reverses the spindle rotation by engaging the clutch on the countershaft with the crossed belt as opposed to the other clutch with the open belt. Note that this manual suggests cutting the thread with infeed of the cross slide, not the compound rest; not only did some old lathes not have a thread dial, but some did not have a compound rest, so threading would have to be done with a straight in plunge cut, which does not make for satisfactory threading, due to chips being generated on both sides of the cut and interfering with each other, this is especially true with coarser pitches, At any rate, with archaic lathes, the shipper rod extended down from the countershaft overhead, over the headstock, and was essentially a lever that worked the clutches, it sometimes would have a horizontal extension to the right of the lever to allow shifting directions when the person, if working further to the right of the lever, could reach the extension rather than the lever itself.

 

[showmedata]

Thank you very much, @benmychree, for the great explanation! It is a little odd that the diagram clearly shows a cross slide with compound, but (as you said) says to use the cross-slide for cutting feed.

I'll be practicing with the threading dial, I suppose.

 

[benmychree]

Yes, the threading dial is where its at, all in all it is pretty simple to use; even numbers of threads can be closed on any line on the dial, odd threads can be cut on any NUMBERED line, half threads on opposite numbers and quarter threads on a single number (only). If one has metric transposing gears and wants to cut metric threads, the half nuts must be kept closed and the carriage run back by reversing the spindle. The threading dial takes a bit of finesse to master, especially if running fast, it is easy to miss the mark and close too early or late, you should make sure that the line falls on the reference line closely, it may need a bit of adjustment if it does not.

 

[benmychree]

I use a thread stop on my two lathes, but do not use it for infeeding, but I use it to get back to zero after pulling the tool out at the end of a pass, especially when cutting coarse threads where I may back the cross slide out more than one turn. One important thing is that it makes it much easier to pull out at the end of the thread is to set zero with the cross feed crank at about 10:00, this position makes it easy to get rotation going and you will always know where to find the crank handle while also disengaging the half nuts. If you always infeed with the compound, you never have to worry about zeroing the compound infeed, you just turn it in after every cut. Controversy surrounds the angle to set the compound, I use 30 degrees, some tout 29 1/2 deg. I was taught to use 30 deg. and every journeyman in the shop did the same for 60 degree threads, the backside of the thread was cleaned up by putting a slight amount of drag on the carriage handwheel during the last pass

 

[SLK001]

This info sheet works for a SB with an 8-TPI leadscrew. DOUBLE CHECK to see if it works for your lathe:



I've included a better resolution .pdf of this below.

 

[benmychree]

Same as I said, but it is a good presentation with the diagrams, suitable for posting on the wall behind one's lathe.

 

[SLK001]

Same as I said, but it is a good presentation with the diagrams, suitable for posting on the wall behind one's lathe.

I took a printout down to an office store and had them laminate it.