Colchester 1965 Roundhead Lathe Restoration Project

Hi Kroll and Techie, I am trying to see an adjustment screw that pushes the wedge down, and to my way of thinking, it should be just to the rear of the large bolt with the lubricator that holds the nut to the cross slide. I can't see one on either picture of the cross slides. Have I got it wrong on how the wedge is adjusted? I am interested because I have two of these nuts to make, and I am thinking of making them to this design.
Phil
 
Guys I have ask the same question over on PM and the results are bout the same.How to adjust it,is the big question as of now still a question without answer.Really wanting to know or if this is the only lathe out there like this.If someone at the factory forgot to finish,guessing that the wedge should stay in the same place.But if there was a screw what would it push against to allow it to move either up/down.Phil here a link to my post on PM http://www.practicalmachinist.com/v...lchester-cross-slide-screw-nut-adjust-314740/
 
Good morning well while watching the news I pull out my manual and look at the diagram again.Now I kinda understand how it should be installed and the openings that should be there to access the adjustments.My slide does not have the small openings and the screw nut does not have an adjustment if its original to the lathe.Though I would post this pic so that others could see if their cross slide has a hole to adjust their cross slide nut.
DSC02892.JPG
 
Guys giving it some though I think that part #8630 the wedge the hole should not be tap but just a spot for the extended point of the setscrew will fit into.I think that the cross slide should have a tap hole that the setscrew will thread into and push down on the wedge #8630 or loosen up to allow the wedge raise up that will allow both halfs of the screw nut to come closer together.Does this make sense???
 
Yes, that makes sense and is what I had envisioned it would do. I suppose it's possible that the slide is from an earlier version of the lathe. I don't recall what the wedge looks like and more photos would be good to see. If the wedge is perpendicular on one side and angled on the side that is in contact with the movable portion, that would confirm your observation. An indent would be a bad idea if the wedge is tapered on both sides since the center of the indent would move off the center of the adjusting screw.

Edit: I just looked at the past photos and it is perpendicular on the fixed face portion.
 
Yes sir it is only taper on one side,I wish I would have taken more photo's of it before installing it.I guess that having the Carter keys or split keys holding it together allowing it to expand and contract when adjusted.I agree,I bet your right that the cross slide has been change out.In all I think the mystery has been solved,Phil help this is helpful to you.Its been very helpful to me thanks to the membership
 
Thanks for that Kroll, it all makes sense now, could not understand why there was no adjustment hole in the top of the cross slide, I think the nut is from a later model, or even a different machine using the same thread. There are various different types of adjustable cross slide nut, and I even sat down and designed an automatic self adjusting one once, only to find someone else had beaten me to it! That design is a new one on me, but Tyrone said he had seen it before, and he is a lot more experienced than I am! He also mentioned the problem with wear in the middle of the thread (my student has some), but I got a new nut made by a local engineer (non adjustable), and it has virtually eliminated the backlash I had, but you can tell it is slightly looser in the middle of the slide travel. I have to make one for a Raglan milling machine table feed, and I think I will use Sir John Stevensons method of boring out the old thread and locktighting in a new one!
Phil
 
I have a theory. The cross slide is the original for the lathe and the nut had worn out. They either replaced it with the wrong one or it was an upgrade from Colchester that wasn't installed correctly to accommodate the adjustable new nut.
 
I had a similar problem with my lead screw half nut when I bought the lathe the lead screw turned but the carriage Didn't advance, when the handle was engaged thinking the halfnut was stuffed I just went about finding a replacement half nut on finding the price I decided to remove it to see if I can make a new one on the Myford. Well the half nut proved to be for another model lathe, the nut itself is in good nick but the drive pin that sits in the scroll is in the wrong position. A job came in it all had to go back together and to solve the problem the lower lever stop was removed the lever now has a large amount of travel but have the feel of it now and don't bring it all the way up when threading
So pull it down and take a look
 
Back
Top