Reassembling Atlas lead screw direction changing box

 Ronald Crowell (Atlas And Craftsman lathes) Facebppl

(1) There are several things to pay attention to when assembling it. First, mount the assembled case on the lathe and thread the screw through all the parts including the 9-52A stub screw drive that goes on the left side. The screw aligns all the bores of the parts.
(2) Do the following in the next paragraphs (3-) with only the above assembly (in (1), then install the inner gear guard over the case boss on the left. Look to see if it is flat against the head stock without needing to bend the case as in para (3). Then install the rest of the parts (spacer washer and a gear and the washer, nut) and repeat para (3) below.
(3) With the 9-50A shift collar (dogs) in the middle (with the handle centered) you should be able to turn the screw with your fingers, and while doing so the stub end of the screw (that sticks out the left side) should not wobble at all. If the screw does not turn easily, then the lead screw is probably binding inside the aforementioned stub's bore because the aluminum alloy (or Zamak) case's left side is bent and the stub is not exactly in axial alignment with the screw. The case's left side is easily bent during abuse, and can be bent back (slowly and carefully). (I cannot tell by a photo if yours is deformed; but if it, is then it is probably not bent so much that heating (at 350°F) is needed.)
(4) When shifting from forward to center to reverse, you are engaging the shift collar's square dogs, so you have to wait for the driven miter gear (whichever, either stub's or lead screw's) to turn until it will let the dog drive in. You must wait for it to line up while one is turning, you can not force it.
(5) Another possible culprit in keeping you from shifting is a bad detent under the shift lever. You will have to look at that with a keener eye...we cannot do that for you by photos.
• Basically, pay attention to every detail of its design and assembly. It's much better than internet advise in the long run.
• (edited)

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